PUMA publications for /tag/eprhttps://puma.ub.uni-stuttgart.de/tag/eprPUMA RSS feed for /tag/epr2024-03-29T15:36:40+01:00Tetranuclear Complexes of Fe(CO)2(C5H5)+ with TCNX Ligands (TCNX = TCNE, TCNQ, TCNB): Intramolecular Electron Transfer Alternatives in Compounds (m4-TCNX)MLn4https://puma.ub.uni-stuttgart.de/bibtex/2c2d9f8d10c4e91bd2ae47cd61dba3dff/huebleriachuebleriac2022-06-15T11:26:56+02:00DFT EPR cyclopentadienyl dicarbonyl electrochem electron geometry iron redox structure tetracyanoethene tetracyanoquinodimethane transfer transfer;Moessbauer transfer;electronic transfer;optimized <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Amarendra N. Maity" itemprop="url" href="/person/10d6d985f3a7d15cf424c24b7e9f26385/author/0"><span itemprop="name">A. Maity</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Brigitte Schwederski" itemprop="url" href="/person/10d6d985f3a7d15cf424c24b7e9f26385/author/1"><span itemprop="name">B. Schwederski</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Biprajit Sarkar" itemprop="url" href="/person/10d6d985f3a7d15cf424c24b7e9f26385/author/2"><span itemprop="name">B. Sarkar</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Stanislav Zalis" itemprop="url" href="/person/10d6d985f3a7d15cf424c24b7e9f26385/author/3"><span itemprop="name">S. Zalis</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Jan Fiedler" itemprop="url" href="/person/10d6d985f3a7d15cf424c24b7e9f26385/author/4"><span itemprop="name">J. Fiedler</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Sanjib Kar" itemprop="url" href="/person/10d6d985f3a7d15cf424c24b7e9f26385/author/5"><span itemprop="name">S. Kar</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Goutam K. Lahiri" itemprop="url" href="/person/10d6d985f3a7d15cf424c24b7e9f26385/author/6"><span itemprop="name">G. Lahiri</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Carole Duboc" itemprop="url" href="/person/10d6d985f3a7d15cf424c24b7e9f26385/author/7"><span itemprop="name">C. Duboc</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Matthias Grunert" itemprop="url" href="/person/10d6d985f3a7d15cf424c24b7e9f26385/author/8"><span itemprop="name">M. Grunert</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Philipp Guetlich" itemprop="url" href="/person/10d6d985f3a7d15cf424c24b7e9f26385/author/9"><span itemprop="name">P. Guetlich</span></a></span></span> and 1 other author(s). </span><span class="additional-entrytype-information"><span itemtype="http://schema.org/PublicationIssue" itemscope="itemscope" itemprop="isPartOf"><em><span itemprop="journal">Inorganic Chemistry</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">46 </span></span>(<span itemprop="issueNumber">18</span>):
<span itemprop="pagination">7312--7320</span></em> </span>(<em><span>2007<meta content="2007" itemprop="datePublished"/></span></em>)</span>Wed Jun 15 11:26:56 CEST 2022Inorganic Chemistry187312--7320Tetranuclear Complexes of [Fe(CO)2(C5H5)]+ with TCNX Ligands (TCNX = TCNE, TCNQ, TCNB): Intramolecular Electron Transfer Alternatives in Compounds (\textgreek{m}4-TCNX)[MLn]4462007DFT EPR cyclopentadienyl dicarbonyl electrochem electron geometry iron redox structure tetracyanoethene tetracyanoquinodimethane transfer transfer;Moessbauer transfer;electronic transfer;optimized {(μ4-TCNX)[Fe(CO)2(C5H5)]4}(BF4)4 were prepd. as light-sensitive materials from [Fe(CO)2(C5H5)(THF)](BF4) and the corresponding TCNX ligands (TCNE = tetracyanoethene, TCNQ = 7,7,8,8-tetracyano-p-quinodimethane, TCNB = 1,2,4,5-tetracyanobenzene). Whereas the TCNE and TCNQ complexes are extremely easily reduced species with redn. potentials {\textgreater}+0.3 V vs. ferrocenium/ferrocene, the tetranuclear complex of TCNB exhibits a significantly more neg. redn. potential at $\sim$-1.0 V. Even for the complexes with strongly \textgreek{p}-accepting TCNE and TCNQ, the very pos. redn. potentials, the unusually high nitrile stretching frequencies {\textgreater}2235 cm-1, and the high-energy charge-transfer transitions indicate negligible metal-to-ligand electron transfer in the ground state, corresponding to a largely unperturbed (TCNX°)(FeII)4 formulation of oxidn. states as caused by orthogonality between the metal-centered HOMO and the \textgreek{p}* LUMO of TCNX. Mossbauer spectroscopy confirms the low-spin Fe(II) state, and DFT calcns. suggest coplanar TCNE and TCNQ bridging ligands in the complex tetracations. One-electron redn. to the 3+ forms of the TCNE and TCNQ complexes produces EPR spectra which confirm the predominant ligand character of the then singly occupied MO through isotropic g values slightly {\textless}2, in addn. to a negligible g anisotropy of frozen solns. at frequencies up to 285 GHz and also through an unusually well-resolved soln. X band EPR spectrum of {(μ4-TCNE)[Fe(CO)2(C5H5)]4}3+ which shows four equiv. [Fe(CO)2(C5H5)]+ moieties through 57Fe and 13C(CO) hyperfine coupling in nonenriched material. DFT calcns. reproduce the exptl. EPR data. A survey of discrete TCNE and TCNQ complexes [(\textgreek{m}4-TCNX)(MLn)4] exhibits a dichotomy between the systems {(μ4-TCNX)[Fe(CO)2(C5H5)]4}4+ and {(μ4-TCNQ)[Re(CO)3(bpy)]4}4+ with their negligible metal-to-ligand electron transfer and several other compds. of TCNE or TCNQ with Mn, Ru, Os, or Cu complex fragments which display evidence for a strong such interaction, i.e., an appreciable value \textgreek{d} in the formulation {(μ4-TCNXδ-)[Mx+δ/4Ln]4}. Irreversibility of the 1st redn. of {(μ4-TCNB)[Fe(CO)2(C5H5)]4}(BF4)4 precluded spectroelectrochem. studies; however, the high-energy CN stretching frequencies and charge transfer absorptions of that TCNB analog also confirm the exceptional position of {(μ4-TCNX)[Fe(CO)2(C5H5)]4}(BF4)4. [on SciFinder(R)]UV-vis-NIR and EPR characterization of the redox series MQ32+,+,0,-,2-, M = Ru or Os, and Q = o-quinone derivativehttps://puma.ub.uni-stuttgart.de/bibtex/2201117e52a340571d8bbf96aa411d50f/huebleriachuebleriac2022-06-15T11:26:56+02:00EPR MQ3 NIR deriv electronic osmium quinone ruthenium <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Atanu Kumar Das" itemprop="url" href="/person/14a1d3e88caef0b588410c99193fe6c14/author/0"><span itemprop="name">A. Das</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Ralph Huebner" itemprop="url" href="/person/14a1d3e88caef0b588410c99193fe6c14/author/1"><span itemprop="name">R. Huebner</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Biprajit Sarkar" itemprop="url" href="/person/14a1d3e88caef0b588410c99193fe6c14/author/2"><span itemprop="name">B. Sarkar</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Jan Fiedler" itemprop="url" href="/person/14a1d3e88caef0b588410c99193fe6c14/author/3"><span itemprop="name">J. Fiedler</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Stanislav Zalis" itemprop="url" href="/person/14a1d3e88caef0b588410c99193fe6c14/author/4"><span itemprop="name">S. Zalis</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Goutam Kumar Lahiri" itemprop="url" href="/person/14a1d3e88caef0b588410c99193fe6c14/author/5"><span itemprop="name">G. Lahiri</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang. Kaim" itemprop="url" href="/person/14a1d3e88caef0b588410c99193fe6c14/author/6"><span itemprop="name">W. Kaim</span></a></span></span>. </span><span class="additional-entrytype-information"><span itemtype="http://schema.org/PublicationIssue" itemscope="itemscope" itemprop="isPartOf"><em><span itemprop="journal">Dalton Transactions</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">41 </span></span>(<span itemprop="issueNumber">29</span>):
<span itemprop="pagination">8913--8921</span></em> </span>(<em><span>2012<meta content="2012" itemprop="datePublished"/></span></em>)</span>Wed Jun 15 11:26:56 CEST 2022Dalton Transactions298913--8921UV-vis-NIR and EPR characterization of the redox series [MQ3]2+,+,0,-,2-, M = Ru or Os, and Q = o-quinone derivative412012EPR MQ3 NIR deriv electronic osmium quinone ruthenium The neutral title compds. with Q = 3,5-di-tert-butyl-o-quinone or 4,6-di-tert-butyl-N-phenyl-o-iminobenzoquinone (Qx) were studied by UV-visible-NIR spectroelectrochem. and by EPR spectroscopy in the case of the odd-electron monocation and monoanion intermediates. Supported by DFT and TD-DFT calcns., the results indicate stepwise electron removal from predominantly ligand-based delocalized MOs on oxidn. whereas the stepwise electron uptake on redn. involves unoccupied MOs with considerably metal-ligand mixed character. In both cases, the strong near-IR absorption of the neutral precursors diminishes. In comparison to the ruthenium series, the osmium analogs exhibit larger transition energies from enhanced MO splitting and a different EPR response due to the higher spin-orbit coupling. The main difference between the quinone (1n, 2n) and corresponding monoiminoquinone systems (3n, 4n) is the shift of $\sim$0.6 V to lower potentials for the monoimino analogs. While the absorption features do not differ markedly, the EPR data reflect a higher degree of covalent bonding for the complexes with monoimino ligands. [on SciFinder(R)]Structure and Spectroelectrochemical Response of Arene-Ruthenium and Arene-Osmium Complexes with Potentially Hemilabile Noninnocent Ligandshttps://puma.ub.uni-stuttgart.de/bibtex/2835cae80db788a0a68cd3c2904b7b42f/huebleriachuebleriac2022-06-15T11:26:56+02:00EPR FMO;mol FMO;ruthenium amidophenolate arene crystal electrochem hemilabile osmium prepn redox ruthenium spectroelectrochem structure <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Martina Bubrin" itemprop="url" href="/person/10537377708466f06dd365f32b7068b74/author/0"><span itemprop="name">M. Bubrin</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="David Schweinfurth" itemprop="url" href="/person/10537377708466f06dd365f32b7068b74/author/1"><span itemprop="name">D. Schweinfurth</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Fabian Ehret" itemprop="url" href="/person/10537377708466f06dd365f32b7068b74/author/2"><span itemprop="name">F. Ehret</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Stanislav Zalis" itemprop="url" href="/person/10537377708466f06dd365f32b7068b74/author/3"><span itemprop="name">S. Zalis</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Hana Kvapilova" itemprop="url" href="/person/10537377708466f06dd365f32b7068b74/author/4"><span itemprop="name">H. Kvapilova</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Jan Fiedler" itemprop="url" href="/person/10537377708466f06dd365f32b7068b74/author/5"><span itemprop="name">J. Fiedler</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Qiang Zeng" itemprop="url" href="/person/10537377708466f06dd365f32b7068b74/author/6"><span itemprop="name">Q. Zeng</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Frantisek Hartl" itemprop="url" href="/person/10537377708466f06dd365f32b7068b74/author/7"><span itemprop="name">F. Hartl</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang. Kaim" itemprop="url" href="/person/10537377708466f06dd365f32b7068b74/author/8"><span itemprop="name">W. Kaim</span></a></span></span>. </span><span class="additional-entrytype-information"><span itemtype="http://schema.org/PublicationIssue" itemscope="itemscope" itemprop="isPartOf"><em><span itemprop="journal">Organometallics</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">33 </span></span>(<span itemprop="issueNumber">18</span>):
<span itemprop="pagination">4973--4985</span></em> </span>(<em><span>2014<meta content="2014" itemprop="datePublished"/></span></em>)</span>Wed Jun 15 11:26:56 CEST 2022Organometallics184973--4985Structure and Spectroelectrochemical Response of Arene-Ruthenium and Arene-Osmium Complexes with Potentially Hemilabile Noninnocent Ligands332014EPR FMO;mol FMO;ruthenium amidophenolate arene crystal electrochem hemilabile osmium prepn redox ruthenium spectroelectrochem structure Nine derivs. of [M(L2-)(p-cymene)] (M = Ru, Os, L2- = 4,6-di-tert-butyl-N-aryl-o-amidophenolate) were prepd. and structurally characterized (Ru complexes) as coordinatively unsatd., formally 16 valence electron species. On L2--ligand based oxidn. to EPR-active iminosemiquinone radical complexes, the compds. seek to bind a donor atom (if available) from the N-aryl substituent, as structurally certified for thioether and selenoether functions, or from the donor solvent. Simulated cyclic voltammograms and spectroelectrochem. at ambient and low temps. in combination with DFT results confirm a square scheme behavior (ECEC mechanism) involving the ligand as the main electron transfer site and the metal with fractional (\textgreek{d}) oxidn. as the center for redox-activated coordination. Attempts to crystallize [Ru(Cym)(QSMe)](PF6) (QSMe = 4,6-di-tert-butyl-2-(2-methylthiophenyl)amidophenolate) produced single crystals of [RuIII(QSMe.bul.-)2](PF6) after apparent dissocn. of the arene ligand. [on SciFinder(R)]Mixed-valent and radical states of complexes (bpy)2M(m-abpy)M'(bpy)2n+, M,M' = Ru or Os, abpy = 2,2'-azobispyridine: Electron transfer vs. hole transfer mechanism in azo ligand-bridged complexeshttps://puma.ub.uni-stuttgart.de/bibtex/25d27c98a16a54e45f3b3435359826a36/huebleriachuebleriac2022-06-15T11:26:56+02:00EPR azobispyridine bridge complex complex;electron complex;hole complex;mixed cyclic electrochem heterobinuclear;osmium homobinuclear osmium prepn redox ruthenium spectroelectrochem;radical transfer valence voltammetry <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Martina Heilmann" itemprop="url" href="/person/10eb51d05c6ae17d96f92572ecf443255/author/0"><span itemprop="name">M. Heilmann</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Stephanie Frantz" itemprop="url" href="/person/10eb51d05c6ae17d96f92572ecf443255/author/1"><span itemprop="name">S. Frantz</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang Kaim" itemprop="url" href="/person/10eb51d05c6ae17d96f92572ecf443255/author/2"><span itemprop="name">W. Kaim</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Jan Fiedler" itemprop="url" href="/person/10eb51d05c6ae17d96f92572ecf443255/author/3"><span itemprop="name">J. Fiedler</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Carole. Duboc" itemprop="url" href="/person/10eb51d05c6ae17d96f92572ecf443255/author/4"><span itemprop="name">C. Duboc</span></a></span></span>. </span><span class="additional-entrytype-information"><span itemtype="http://schema.org/PublicationIssue" itemscope="itemscope" itemprop="isPartOf"><em><span itemprop="journal">Inorganica Chimica Acta</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">359 </span></span>(<span itemprop="issueNumber">3</span>):
<span itemprop="pagination">821--829</span></em> </span>(<em><span>2006<meta content="2006" itemprop="datePublished"/></span></em>)</span>Wed Jun 15 11:26:56 CEST 2022Inorganica Chimica Acta3821--829Mixed-valent and radical states of complexes [(bpy)2M(\textgreek{m}-abpy)M'(bpy)2]n+, M,M' = Ru or Os, abpy = 2,2'-azobispyridine: Electron transfer vs. hole transfer mechanism in azo ligand-bridged complexes3592006EPR azobispyridine bridge complex complex;electron complex;hole complex;mixed cyclic electrochem heterobinuclear;osmium homobinuclear osmium prepn redox ruthenium spectroelectrochem;radical transfer valence voltammetry The title complexes were obtained as MIIM'II species [(bpy)2M(\textgreek{m}-abpy)M'(bpy)2](PF6)4 (M,M' = Ru or Os, abpy = 2,2'-azobispyridine, bpy = 2,2'-bipyridine) using the new mononuclear precursor [(bpy)2Os(abpy)](PF6)2 for the Os-contg. dinuclear complexes. One-electron redn. produces radical complexes [(bpy)2M(\textgreek{m}-abpy)M'(bpy)2].bul.3+ and [(bpy)2M(abpy)].bul.+ with significant contributions from the metals, as evident from the EPR effects on successive replacement of Ru by Os with its much higher spin-orbit coupling const. The diruthenium and diosmium radical complexes were also studied by EPR at high-frequency (285 GHz), the latter shows an unusually large g anisotropy g1 - g3 = 0.25 in frozen soln. Further redn. was monitored by UV/visible spectroelectrochem. Oxidn. produced OsIII EPR signals for [(bpy)2Os(abpy)]3+ and [(bpy)2Os(\textgreek{m}-abpy)Ru(bpy)2]5+, indicating a RuIIOsIII species for the latter. The diosmium(III,II) and diruthenium(III,II) mixed-valent species remained EPR silent at 4 K, however, they exhibit weak inter-valence charge transfer (IVCT) bands at $\sim$1460 nm. Whereas the cyclic voltammetric response towards redn. is only marginally different for the three dinuclear complexes, successive replacement of Ru by Os causes the first oxidn. potential to decrease. The much higher comproportionation const. Kc for the mixed valent diosmium(III,II) state (Kc {\textgreater} 1015) in comparison to the diruthenium(III,II) analog with Kc = 1010 confirms the electron transfer alternative for the valence exchange mechanism, in contrast to the hole transfer established for analogous dinuclear complexes with the formally related diacylhydrazido(2-) bridging ligands. [on SciFinder(R)]Sensitivity of a Strained C-C Single Bond to Charge Transfer: Redox Activity in Mononuclear and Dinuclear Ruthenium Complexes of Bis(arylimino)acenaphthene (BIAN) Ligandshttps://puma.ub.uni-stuttgart.de/bibtex/2407a9f92187861fb201adf6a13b4a935/huebleriachuebleriac2022-06-15T11:26:56+02:00DFT EPR acetylacetonato bisphenyliminoacenaphthene calcn complex complex;ruthenium crystal electrochem prepn ruthenium structure tetrakispyridylpyrazine <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Prasenjit Mondal" itemprop="url" href="/person/1cb3fb851b57939848e82c034871e6472/author/0"><span itemprop="name">P. Mondal</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Hemlata Agarwala" itemprop="url" href="/person/1cb3fb851b57939848e82c034871e6472/author/1"><span itemprop="name">H. Agarwala</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Rahul Dev Jana" itemprop="url" href="/person/1cb3fb851b57939848e82c034871e6472/author/2"><span itemprop="name">R. Jana</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Sebastian Plebst" itemprop="url" href="/person/1cb3fb851b57939848e82c034871e6472/author/3"><span itemprop="name">S. Plebst</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Anita Grupp" itemprop="url" href="/person/1cb3fb851b57939848e82c034871e6472/author/4"><span itemprop="name">A. Grupp</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Fabian Ehret" itemprop="url" href="/person/1cb3fb851b57939848e82c034871e6472/author/5"><span itemprop="name">F. Ehret</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Shaikh M. Mobin" itemprop="url" href="/person/1cb3fb851b57939848e82c034871e6472/author/6"><span itemprop="name">S. Mobin</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang Kaim" itemprop="url" href="/person/1cb3fb851b57939848e82c034871e6472/author/7"><span itemprop="name">W. Kaim</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Goutam Kumar. Lahiri" itemprop="url" href="/person/1cb3fb851b57939848e82c034871e6472/author/8"><span itemprop="name">G. Lahiri</span></a></span></span>. </span><span class="additional-entrytype-information"><span itemtype="http://schema.org/PublicationIssue" itemscope="itemscope" itemprop="isPartOf"><em><span itemprop="journal">Inorganic Chemistry</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">53 </span></span>(<span itemprop="issueNumber">14</span>):
<span itemprop="pagination">7389--7403</span></em> </span>(<em><span>2014<meta content="2014" itemprop="datePublished"/></span></em>)</span>Wed Jun 15 11:26:56 CEST 2022Inorganic Chemistry147389--7403Sensitivity of a Strained C-C Single Bond to Charge Transfer: Redox Activity in Mononuclear and Dinuclear Ruthenium Complexes of Bis(arylimino)acenaphthene (BIAN) Ligands532014DFT EPR acetylacetonato bisphenyliminoacenaphthene calcn complex complex;ruthenium crystal electrochem prepn ruthenium structure tetrakispyridylpyrazine [Ru(acac)2(BIAN)], BIAN = bis(arylimino)acenaphthene (aryl = Ph (1a), 4-MeC6H4 (2a), 4-OMeC6H4 (3a), 4-ClC6H4 (4a), 4-NO2C6H4 (5a)), were synthesized and structurally, electrochem., spectroscopically, and computationally characterized. The \textgreek{a}-diimine sections of the compds. exhibit intrachelate ring bond lengths 1.304 {\AA} {\textless} d(CN) {\textless} 1.334 and 1.425 {\AA} {\textless} d(CC) {\textless} 1.449 {\AA}, which indicate considerable metal-to-ligand charge transfer in the ground state, approaching a RuIII(BIAN.bul.-) oxidn. state formulation. The particular structural sensitivity of the strained peri-connecting C-C bond in the BIAN ligands toward metal-to-ligand charge transfer is discussed. Oxidn. of [Ru(acac)2(BIAN)] produces EPR and UV-visible-NIR (NIR = near IR) spectroelectrochem. detectable RuIII species, while the redn. yields predominantly BIAN-based spin, in agreement with d. functional theory (DFT) spin-d. calcns. Variation of the substituents from CH3 to NO2 has little effect on the spin distribution but affects the absorption spectra. Dinuclear {(μ-tppz)[Ru(Cl)(BIAN)]2}(ClO4)2, tppz = 2,3,5,6-tetrakis(2-pyridyl)pyrazine; aryl (BIAN) = Ph ([1b](ClO4)2), 4-MeC6H4 ([2b](ClO4)2), 4-OMeC6H4 ([3b](ClO4)2), 4-ClC6H4 ([4b](ClO4)2), were also obtained and investigated. The structure detn. of [2b](ClO4)2 and [3b](ClO4)2 reveals trans configuration of the chloride ligands and unreduced BIAN ligands. The DFT and spectroelectrochem. results (UV-visible-NIR, EPR) indicate oxidn. to a weakly coupled RuIIIRuII mixed-valent species but redn. to a tppz-centered radical state. The effect of the \textgreek{p} electron-accepting BIAN ancillary ligands is to diminish the metal-metal interaction due to competition with the acceptor bridge tppz. [on SciFinder(R)]Widely Separated Reduction Processes of abpy-Coupled Areneosmium(II) Reaction Centers (abpy = 2,2'-Azobispyridine): Stabilization of the Radical Intermediate and of the Os0OsII Statehttps://puma.ub.uni-stuttgart.de/bibtex/26ea5ed9e751d121fcf7d05f0f28b635f/huebleriachuebleriac2022-06-15T11:26:56+02:00EPR arene azobispyridine binuclear bipyrimidine bridged cation complex complex;osmium diosmium mixed osmium potential;radical redox spectra valence <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Frank Baumann" itemprop="url" href="/person/1f4a36d58d4abd338c6d3bd6bb589fca0/author/0"><span itemprop="name">F. Baumann</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang Kaim" itemprop="url" href="/person/1f4a36d58d4abd338c6d3bd6bb589fca0/author/1"><span itemprop="name">W. Kaim</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Gert Denninger" itemprop="url" href="/person/1f4a36d58d4abd338c6d3bd6bb589fca0/author/2"><span itemprop="name">G. Denninger</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Hans-Juergen Kuemmerer" itemprop="url" href="/person/1f4a36d58d4abd338c6d3bd6bb589fca0/author/3"><span itemprop="name">H. Kuemmerer</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Jan. Fiedler" itemprop="url" href="/person/1f4a36d58d4abd338c6d3bd6bb589fca0/author/4"><span itemprop="name">J. Fiedler</span></a></span></span>. </span><span class="additional-entrytype-information"><span itemtype="http://schema.org/PublicationIssue" itemscope="itemscope" itemprop="isPartOf"><em><span itemprop="journal">Organometallics</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">24 </span></span>(<span itemprop="issueNumber">8</span>):
<span itemprop="pagination">1966--1973</span></em> </span>(<em><span>2005<meta content="2005" itemprop="datePublished"/></span></em>)</span>Wed Jun 15 11:26:56 CEST 2022Organometallics81966--1973Widely Separated Reduction Processes of abpy-Coupled Areneosmium(II) Reaction Centers (abpy = 2,2'-Azobispyridine): Stabilization of the Radical Intermediate and of the Os0OsII State242005EPR arene azobispyridine binuclear bipyrimidine bridged cation complex complex;osmium diosmium mixed osmium potential;radical redox spectra valence Mono- and binuclear 2,2'-azobispyridine and 2,2'-bipyrimidine-bridged osmium arene complexes were prepd.; their redox reactions afford mixed-valence odd-electron intermediates, which structure was evaluated by EPR spectra. Electrochem. reactivity patterns were established by cyclic voltammetry, EPR, and UV/vis spectroelectrochem. for the transition [(C6Me6)ClOs]+/[(C6Me6)Os] in mononuclear and dinuclear complexes with the 2,2'-azobispyridine (abpy) and 2,2'-bipyrimidine (bpym) bridging ligands. The isolated electron reservoir intermediate {[(μ-abpy)OsCl(C6Me6)]2}.bul.+ could be analyzed by X band and W band EPR with regard to 189Os hyperfine splitting and g anisotropy as an abpy anion radical species with significant contribution from the metal centers. The function of the \textgreek{p}-conjugated acceptor ligand in mediating the interaction between two equiv. electron and atom transfer sites was analyzed through simulation of the cyclic voltammograms. In comparison with the system bridged by 2,2'-bipyrimidine, the dinuclear abpy complex displays a much stronger interaction between the two organometallic reaction centers, as illustrated by the 1.14 V vs. 0.42 V splitting between the redox potentials sepg. the two chloride-dissociative processes, i.e., stabilizing the Os0OsII mixed-valent form [(Me6C6)Os(\textgreek{m}-abpy)OsCl(C6Me6)]+. This result parallels the observations made for (C5Me5)Rh- and (C5Me5)Ir-contg. analogs and for the coupling of pure electron transfer centers through such bridging ligands. [on SciFinder(R)]Sensitive Oxidation State Ambivalence in Unsymmetrical Three-Center (M/Q/M) Systems (acac)2Ru(m-Q)Ru(acac)2n, Q = 1,10-Phenanthroline-5,6-dione or 1,10-Phenanthroline-5,6-diimine (n = +, 0, -, 2-)https://puma.ub.uni-stuttgart.de/bibtex/2c667a58e5aeec47917babf1ccda86a5c/huebleriachuebleriac2022-06-15T11:26:56+02:00EPR complex dinuclear oxidn phenanthrolinediimine phenanthrolinediimine;ruthenium phenanthrolinedione prepn ruthenium spectroelectrochem state unsym <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Sandeep Ghumaan" itemprop="url" href="/person/1b9a51e090dca12569f4cd3d0d0a0c0da/author/0"><span itemprop="name">S. Ghumaan</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Biprajit Sarkar" itemprop="url" href="/person/1b9a51e090dca12569f4cd3d0d0a0c0da/author/1"><span itemprop="name">B. Sarkar</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Srikanta Patra" itemprop="url" href="/person/1b9a51e090dca12569f4cd3d0d0a0c0da/author/2"><span itemprop="name">S. Patra</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Joris van Slageren" itemprop="url" href="/person/1b9a51e090dca12569f4cd3d0d0a0c0da/author/3"><span itemprop="name">J. van Slageren</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Jan Fiedler" itemprop="url" href="/person/1b9a51e090dca12569f4cd3d0d0a0c0da/author/4"><span itemprop="name">J. Fiedler</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang Kaim" itemprop="url" href="/person/1b9a51e090dca12569f4cd3d0d0a0c0da/author/5"><span itemprop="name">W. Kaim</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Goutam Kumar. Lahiri" itemprop="url" href="/person/1b9a51e090dca12569f4cd3d0d0a0c0da/author/6"><span itemprop="name">G. Lahiri</span></a></span></span>. </span><span class="additional-entrytype-information"><span itemtype="http://schema.org/PublicationIssue" itemscope="itemscope" itemprop="isPartOf"><em><span itemprop="journal">Inorganic Chemistry</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">44 </span></span>(<span itemprop="issueNumber">9</span>):
<span itemprop="pagination">3210--3214</span></em> </span>(<em><span>2005<meta content="2005" itemprop="datePublished"/></span></em>)</span>Wed Jun 15 11:26:56 CEST 2022Inorganic Chemistry93210--3214Sensitive Oxidation State Ambivalence in Unsymmetrical Three-Center (M/Q/M) Systems [(acac)2Ru(\textgreek{m}-Q)Ru(acac)2]n, Q = 1,10-Phenanthroline-5,6-dione or 1,10-Phenanthroline-5,6-diimine (n = +, 0, -, 2-)442005EPR complex dinuclear oxidn phenanthrolinediimine phenanthrolinediimine;ruthenium phenanthrolinedione prepn ruthenium spectroelectrochem state unsym The new redox systems [(acac)2Ru(\textgreek{m}-Q1)Ru(acac)2]n (1n) and [(acac)2Ru(\textgreek{m}-Q2)Ru(acac)2]n (2n) with Q1 = 1,10-phenanthroline-5,6-dione and Q2 = 1,10-phenanthroline-5,6-diimine were studied for n = +, 0, -, and 2- using UV-visible-NIR spectroelectrochem. and, in part, EPR and susceptometry. The ligands can bind the first metal (left) through the phenanthroline N atoms and the second metal (right) at the o-quinonoid chelate site. The neutral compds. are already different: Compd. 1 is formulated as a RuII(\textgreek{m}-Q1).bul.-RuIII species with partially coupled semiquinone and Ru(III) centers. In contrast, a RuIII(\textgreek{m}-Q2)2-RuIII structure is assigned to 2, which shows a weak antiferromagnetic spin-spin interaction (J = -1.14 cm-1) and displays an intense half-field signal in the EPR spectrum. The 1-electron reduced forms are also differently formulated as RuII(\textgreek{m}-Q1)2-RuIII for 1- with a RuIII-typical EPR response and as RuII(\textgreek{m}-Q2).bul.-RuII for 2- with a radical-type EPR signal at g = 2.0020. In contrast, both 12- and 22- can only be described as RuII(\textgreek{m}-Q)2-RuII species. The monooxidized forms 1+ and 2+ show very similar spectroscopy, including a RuIII-type EPR signal. Although no unambiguous assignment was possible here for the alternatives RuII(\textgreek{m}-Q)0RuIII, RuIII(\textgreek{m}-Q)2-RuIV or RuIII(\textgreek{m}-Q).bul.-RuIII, the last description is favored. The reasons for identical or different oxidn. state combinations are discussed. [on SciFinder(R)]Structural Reassessment of W(CO)5(TCNE): N (s) Coordination Instead of an Olefin (p) Complexhttps://puma.ub.uni-stuttgart.de/bibtex/203cef2280b0a591f005ea1d23701b3d2/huebleriachuebleriac2022-06-15T11:26:56+02:00EPR IR TCNE UV Vis;DFT bond complex coordination crystal cyano geometry mol nitrogen optimized pentacarbonyltungsten reassessment;TCNE sigma spectroelectrochem structure <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Martina Bubrin" itemprop="url" href="/person/1cf59c020e099b8fb97df6001ecc46248/author/0"><span itemprop="name">M. Bubrin</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Michael J. Krafft" itemprop="url" href="/person/1cf59c020e099b8fb97df6001ecc46248/author/1"><span itemprop="name">M. Krafft</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Lisa Steudle" itemprop="url" href="/person/1cf59c020e099b8fb97df6001ecc46248/author/2"><span itemprop="name">L. Steudle</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Ralph Huebner" itemprop="url" href="/person/1cf59c020e099b8fb97df6001ecc46248/author/3"><span itemprop="name">R. Huebner</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="John S. Field" itemprop="url" href="/person/1cf59c020e099b8fb97df6001ecc46248/author/4"><span itemprop="name">J. Field</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Stanislav Zalis" itemprop="url" href="/person/1cf59c020e099b8fb97df6001ecc46248/author/5"><span itemprop="name">S. Zalis</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang. Kaim" itemprop="url" href="/person/1cf59c020e099b8fb97df6001ecc46248/author/6"><span itemprop="name">W. Kaim</span></a></span></span>. </span><span class="additional-entrytype-information"><span itemtype="http://schema.org/PublicationIssue" itemscope="itemscope" itemprop="isPartOf"><em><span itemprop="journal">Organometallics</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">31 </span></span>(<span itemprop="issueNumber">17</span>):
<span itemprop="pagination">6305--6311</span></em> </span>(<em><span>2012<meta content="2012" itemprop="datePublished"/></span></em>)</span>Wed Jun 15 11:26:56 CEST 2022Organometallics176305--6311Structural Reassessment of [W(CO)5(TCNE)]: N (\textgreek{s}) Coordination Instead of an Olefin (\textgreek{p}) Complex312012EPR IR TCNE UV Vis;DFT bond complex coordination crystal cyano geometry mol nitrogen optimized pentacarbonyltungsten reassessment;TCNE sigma spectroelectrochem structure The blue title compd., long assumed to be an olefin complex on the basis of an apparently single unresolved CN stretching band in the IR spectrum, has been identified by expt. and through DFT anal. as a \textgreek{s} complex with the tungsten atom coordinated to one of the nitrile N centers. The previously reported data are reinterpreted in light of the new structural assignment, and spectroelectrochem. results (UV-vis, IR, EPR) are presented. [on SciFinder(R)]Electron transfer reactions of (C5R5)2(CO)2Ti (R = H or Me) with TCNE or TCNQ spectroelectrochemical assignment of metal and ligand oxidation states in (C5Me5)2(CO)Ti(TCNX)2-/-/o/+https://puma.ub.uni-stuttgart.de/bibtex/27c4368c17e39616b6c89ea8ec04eca5c/huebleriachuebleriac2022-06-15T11:26:56+02:00EPR carbonyl complex cyclopentadienyl electrochem electron redox tetracyanoethene tetracyanoquinodimethane titanium;IR titanium;titanium transfer <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Heiko Hartmann" itemprop="url" href="/person/1efc373401d526957970aabdba2c1de25/author/0"><span itemprop="name">H. Hartmann</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Biprajit Sarkar" itemprop="url" href="/person/1efc373401d526957970aabdba2c1de25/author/1"><span itemprop="name">B. Sarkar</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang Kaim" itemprop="url" href="/person/1efc373401d526957970aabdba2c1de25/author/2"><span itemprop="name">W. Kaim</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Jan. Fiedler" itemprop="url" href="/person/1efc373401d526957970aabdba2c1de25/author/3"><span itemprop="name">J. Fiedler</span></a></span></span>. </span><span class="additional-entrytype-information"><span itemtype="http://schema.org/PublicationIssue" itemscope="itemscope" itemprop="isPartOf"><em><span itemprop="journal">Journal of Organometallic Chemistry</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">687 </span></span>(<span itemprop="issueNumber">1</span>):
<span itemprop="pagination">100--107</span></em> </span>(<em><span>2003<meta content="2003" itemprop="datePublished"/></span></em>)</span>Wed Jun 15 11:26:56 CEST 2022Journal of Organometallic Chemistry1100--107Electron transfer reactions of (C5R5)2(CO)2Ti (R = H or Me) with TCNE or TCNQ spectroelectrochemical assignment of metal and ligand oxidation states in [(C5Me5)2(CO)Ti(TCNX)]2-/-/o/+6872003EPR carbonyl complex cyclopentadienyl electrochem electron redox tetracyanoethene tetracyanoquinodimethane titanium;IR titanium;titanium transfer The TCNX ligands TCNE (tetracyanoethene) and TCNQ (7,7,8,8-tetracyano-p-quinodimethane) react instantaneously with (C5R5)2(CO)2Ti, R = H or Me, to yield highly air-sensitive mononuclear complexes (C5R5)2(CO)Ti(TCNX) of which the sol. species (R = Me) were characterized also in the oxidized and reduced forms through cyclic voltammetry, EPR, IR and UV-visible spectroelectrochem. While oxidn. at rather low potentials yields labile carbonyltitanium(IV) species of the TCNX.bul.- ligands, the redn. occurs stepwise at unusually neg. potentials, first on the ligand (to yield coordinated TCNX2-) and then on the metal (to form TiII). For the neutral complexes (C5R5)2(CO)Ti2+q(TCNX-q) the results support a rather large amt. of charge transfer 1 {\textless} q {\textless} 2 from the metal to the acceptors TCNX. Evidence for the previously formulated {(μ-TCNE2-)[(C5H5)2TiIV(CO)]2}(TCNE2-) could not be found. (C5R5)2(CO)Ti(TCNE) are compared with related compds. (C5R5)2BrV(TCNE), (C6R6)(CO)2Cr(TCNE) and (C5R5)(CO)2Mn(TCNE). [on SciFinder(R)]Metal-Induced Thiophene Ring Opening and C-C Bond Formation To Produce Unique Hexa-1,3,5-trienediyl-Coupled Non-Innocent Ligand Chelateshttps://puma.ub.uni-stuttgart.de/bibtex/2f2bf57e917d809bbeb82b933ff28a7d0/huebleriachuebleriac2022-06-15T11:26:56+02:00DFT EPR acetylacetonate acetylacetonate;ruthenium complex crystal electrochem hexatrieneazothiocarbonyl magnetism prepn ruthenium structure <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Fabian Ehret" itemprop="url" href="/person/108d3e67f5d08e1f83fb6a9e95a54b44a/author/0"><span itemprop="name">F. Ehret</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Martina Bubrin" itemprop="url" href="/person/108d3e67f5d08e1f83fb6a9e95a54b44a/author/1"><span itemprop="name">M. Bubrin</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Stanislav Zalis" itemprop="url" href="/person/108d3e67f5d08e1f83fb6a9e95a54b44a/author/2"><span itemprop="name">S. Zalis</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Jose Luis Priego" itemprop="url" href="/person/108d3e67f5d08e1f83fb6a9e95a54b44a/author/3"><span itemprop="name">J. Priego</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Reyes Jimenez-Aparicio" itemprop="url" href="/person/108d3e67f5d08e1f83fb6a9e95a54b44a/author/4"><span itemprop="name">R. Jimenez-Aparicio</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang. Kaim" itemprop="url" href="/person/108d3e67f5d08e1f83fb6a9e95a54b44a/author/5"><span itemprop="name">W. Kaim</span></a></span></span>. </span><span class="additional-entrytype-information"><span itemtype="http://schema.org/PublicationIssue" itemscope="itemscope" itemprop="isPartOf"><em><span itemprop="journal">Chemistry - A European Journal</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">21 </span></span>(<span itemprop="issueNumber">43</span>):
<span itemprop="pagination">15163--15166</span></em> </span>(<em><span>2015<meta content="2015" itemprop="datePublished"/></span></em>)</span>Wed Jun 15 11:26:56 CEST 2022Chemistry - A European Journal4315163--15166Metal-Induced Thiophene Ring Opening and C-C Bond Formation To Produce Unique Hexa-1,3,5-trienediyl-Coupled Non-Innocent Ligand Chelates212015DFT EPR acetylacetonate acetylacetonate;ruthenium complex crystal electrochem hexatrieneazothiocarbonyl magnetism prepn ruthenium structure Ring opening of thiophenes contg. an azo function in 2-position and subsequent dimerization through C-C coupling were obsd. on reaction with [Ru(acac)2(CH3CN)2] (acac=acetylacetonate) to produce two 1,3,5-hexatriene-linked redox-active azothiocarbonyl chelate systems. Interaction of the non-innocent chelate ligands and of the metals at a nanoscale distance of 1.45 nm via the conjugated hexatriene bridge was studied by magnetic and electron spectroscopic measurements in conjunction with DFT calcns., revealing four-center magnetic interactions of this unique setting and weak intervalence coupling after redn. [on SciFinder(R)]Changeover in a multimodal copper(II) catenate as monitored by EPR spectroscopyhttps://puma.ub.uni-stuttgart.de/bibtex/28892d25c93ffafc4334ba087fd8a02b8/huebleriachuebleriac2022-06-15T11:26:56+02:00EPR catenate coordinate copper electrochem reaction rearrangement spectroscopy;electrooxidn spectroscopy;five <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Frank Baumann" itemprop="url" href="/person/14ad2c60df6ea7b5467d33159aa71c7b5/author/0"><span itemprop="name">F. Baumann</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Aude Livoreil" itemprop="url" href="/person/14ad2c60df6ea7b5467d33159aa71c7b5/author/1"><span itemprop="name">A. Livoreil</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang Kaim" itemprop="url" href="/person/14ad2c60df6ea7b5467d33159aa71c7b5/author/2"><span itemprop="name">W. Kaim</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Jean-Pierre. Sauvage" itemprop="url" href="/person/14ad2c60df6ea7b5467d33159aa71c7b5/author/3"><span itemprop="name">J. Sauvage</span></a></span></span>. </span><span class="additional-entrytype-information"><span itemtype="http://schema.org/PublicationIssue" itemscope="itemscope" itemprop="isPartOf"><em><span itemprop="journal">Chemical Communications (Cambridge, United Kingdom)</span>, </em> </span>(<em><span>1997<meta content="1997" itemprop="datePublished"/></span></em>)</span>Wed Jun 15 11:26:56 CEST 2022Chemical Communications (Cambridge, United Kingdom)135--36Changeover in a multimodal copper(II) catenate as monitored by EPR spectroscopy1997EPR catenate coordinate copper electrochem reaction rearrangement spectroscopy;electrooxidn spectroscopy;five The electrochem. triggered rearrangement of a copper catenate was monitored by EPR spectroscopy; the initially generated tetrahedral copper(II) complex (with higher g-factor components and lower metal hyperfine splitting) is converted to a stable five-coordinate copper(II) species, within a few minutes at room temp., in anhyd. MeCN. [on SciFinder(R)]Electrochemical, spectroscopic and EPR study of transition metal complexes of dipyrido3,2-a:2',3'-cphenazinehttps://puma.ub.uni-stuttgart.de/bibtex/2c6299e2e28d5b4a790bdedcfc7812afe/huebleriachuebleriac2022-06-15T11:26:56+02:00EPR absorption complex complex;cyclic complex;electrochem complex;electroredn dipyridophenazine metal spectra spectroscopic study transition voltammetry <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Jorg Fees" itemprop="url" href="/person/1f7ac3b1d9b527f8d409e0d88e502cd13/author/0"><span itemprop="name">J. Fees</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Michael Ketterle" itemprop="url" href="/person/1f7ac3b1d9b527f8d409e0d88e502cd13/author/1"><span itemprop="name">M. Ketterle</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Axel Klein" itemprop="url" href="/person/1f7ac3b1d9b527f8d409e0d88e502cd13/author/2"><span itemprop="name">A. Klein</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Jan Fiedler" itemprop="url" href="/person/1f7ac3b1d9b527f8d409e0d88e502cd13/author/3"><span itemprop="name">J. Fiedler</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang. Kaim" itemprop="url" href="/person/1f7ac3b1d9b527f8d409e0d88e502cd13/author/4"><span itemprop="name">W. Kaim</span></a></span></span>. </span><span class="additional-entrytype-information"><span itemtype="http://schema.org/PublicationIssue" itemscope="itemscope" itemprop="isPartOf"><em><span itemprop="journal">Journal of the Chemical Society, Dalton Transactions: Inorganic Chemistry</span>, </em> </span>(<em><span>1999<meta content="1999" itemprop="datePublished"/></span></em>)</span>Wed Jun 15 11:26:56 CEST 2022Journal of the Chemical Society, Dalton Transactions: Inorganic Chemistry152595--2600Electrochemical, spectroscopic and EPR study of transition metal complexes of dipyrido[3,2-a:2',3'-c]phenazine1999EPR absorption complex complex;cyclic complex;electrochem complex;electroredn dipyridophenazine metal spectra spectroscopic study transition voltammetry The electronic structures of [Ru(dppz)3]2+ and (dppz)MLn, MLn = [Ru(bpy)2]2+, [Os(phen)2]2+, [Cu(PPh3)2]+, Re(CO)3Cl, Mo(CO)4, PtPh2 or Pt(Mes)2 (Mes = 2,4,6-trimethylphenyl), were compared, based on cyclic voltammetry and spectroscopic studies (UV/visible, EPR of paramagnetic states). According to all exptl. evidence, the lowest lying \textgreek{p}* orbital of dppz which is singly occupied in complexes of the dppz radical anion is localized almost exclusively in the phenazine part of the ligand. Among the consequences of this situation are a very weak coupling of the 1st three redn. processes of [Ru(dppz)3]n, very little difference in the redn. potentials and in the EPR spectra of the radical complexes (dppz.bul.-)MLn, absorption spectra with the intense MLCT transitions to higher lying \textgreek{a}-diimine orbitals. [on SciFinder(R)]High-frequency EPR study of reduced diruthenium and dirhenium polypyridine complexes based on the 1,2,4,5-tetrazine radical bridgehttps://puma.ub.uni-stuttgart.de/bibtex/2f936397ced1169ef45dda5f08e02ff8b/huebleriachuebleriac2022-06-15T11:26:56+02:00EPR EPR;ruthenium bridge polypyridine prepn radical rhenium tetrazine <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Biprajit Sarkar" itemprop="url" href="/person/1da90e6d381dd753bfb5e6a4b06a6f80d/author/0"><span itemprop="name">B. Sarkar</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Stephanie Frantz" itemprop="url" href="/person/1da90e6d381dd753bfb5e6a4b06a6f80d/author/1"><span itemprop="name">S. Frantz</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang Kaim" itemprop="url" href="/person/1da90e6d381dd753bfb5e6a4b06a6f80d/author/2"><span itemprop="name">W. Kaim</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Carole. Duboc" itemprop="url" href="/person/1da90e6d381dd753bfb5e6a4b06a6f80d/author/3"><span itemprop="name">C. Duboc</span></a></span></span>. </span><span class="additional-entrytype-information"><span itemtype="http://schema.org/PublicationIssue" itemscope="itemscope" itemprop="isPartOf"><em><span itemprop="journal">Dalton Transactions</span>, </em> </span>(<em><span>2004<meta content="2004" itemprop="datePublished"/></span></em>)</span>Wed Jun 15 11:26:56 CEST 2022Dalton Transactions213727--3731High-frequency EPR study of reduced diruthenium and dirhenium polypyridine complexes based on the 1,2,4,5-tetrazine radical bridge2004EPR EPR;ruthenium bridge polypyridine prepn radical rhenium tetrazine The radical complexes {(μ-L)[Ru(bpy)2]2}.bul.3+, {(μ-bmtz)[Ru(cym)Cl]2}.bul.+ and {(μ-L)[Re(CO)3Cl]2}.bul.-, where L are 3,6-disubstituted 1,2,4,5-tetrazines such as 3,6-bis(2-pyrimidyl)-1,2,4,5-tetrazine (bmtz) and p-cymene (cym), were studied by X-band EPR in fluid soln. and by 285 GHz EPR in glassy frozen soln. A comparison with other transition metal complexes (Cu, Rh, Os, Ir, Pt) involving tetrazine radical ligands reveals that the g anisotropy reflects (i) the \textgreek{p} acceptor effect of the tetrazine substituents, (ii) the competition from ancillary \textgreek{p} acceptor ligands for back donation from the metal, and (iii) the spin-orbit coupling contributions from the transition metal. [on SciFinder(R)]Spectroelectrochemistry and DFT Analysis of a New RuNOn Redox System with Multifrequency EPR Suggesting Conformational Isomerism in the RuNO7 Statehttps://puma.ub.uni-stuttgart.de/bibtex/2c2619af4498d85461f5495f0fc5cc840/huebleriachuebleriac2022-06-15T11:26:56+02:00DFT EPR bipyrimidine complex electrochem isomerism multifrequency nitro nitrosyl prepn redn;conformational redox ruthenium system system;spectroelectrochem terpyridine <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Priti Singh" itemprop="url" href="/person/1d4ec00b684d1b5d33ff248e3b2f94627/author/0"><span itemprop="name">P. Singh</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Jan Fiedler" itemprop="url" href="/person/1d4ec00b684d1b5d33ff248e3b2f94627/author/1"><span itemprop="name">J. Fiedler</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Stanislav Zalis" itemprop="url" href="/person/1d4ec00b684d1b5d33ff248e3b2f94627/author/2"><span itemprop="name">S. Zalis</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Carole Duboc" itemprop="url" href="/person/1d4ec00b684d1b5d33ff248e3b2f94627/author/3"><span itemprop="name">C. Duboc</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Mark Niemeyer" itemprop="url" href="/person/1d4ec00b684d1b5d33ff248e3b2f94627/author/4"><span itemprop="name">M. Niemeyer</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Falk Lissner" itemprop="url" href="/person/1d4ec00b684d1b5d33ff248e3b2f94627/author/5"><span itemprop="name">F. Lissner</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Thomas Schleid" itemprop="url" href="/person/1d4ec00b684d1b5d33ff248e3b2f94627/author/6"><span itemprop="name">T. Schleid</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang. Kaim" itemprop="url" href="/person/1d4ec00b684d1b5d33ff248e3b2f94627/author/7"><span itemprop="name">W. Kaim</span></a></span></span>. </span><span class="additional-entrytype-information"><span itemtype="http://schema.org/PublicationIssue" itemscope="itemscope" itemprop="isPartOf"><em><span itemprop="journal">Inorganic Chemistry</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">46 </span></span>(<span itemprop="issueNumber">22</span>):
<span itemprop="pagination">9254--9261</span></em> </span>(<em><span>2007<meta content="2007" itemprop="datePublished"/></span></em>)</span>Wed Jun 15 11:26:56 CEST 2022Inorganic Chemistry229254--9261Spectroelectrochemistry and DFT Analysis of a New {RuNO}n Redox System with Multifrequency EPR Suggesting Conformational Isomerism in the {RuNO}7 State462007DFT EPR bipyrimidine complex electrochem isomerism multifrequency nitro nitrosyl prepn redn;conformational redox ruthenium system system;spectroelectrochem terpyridine [Ru(NO)(bpym)(terpy)](PF6)3, bpym = 2,2'-bipyrimidine and terpy = 2,2':6',2''-terpyridine, with a {RuNO}6 configuration (angle Ru-N-O 175.2(4)°) was obtained from the structurally characterized precursor [Ru(NO2)(bpym)(terpy)](PF6), which shows bpym-centered redn. and metal-centered oxidn., as evident from EPR spectroscopy. The relatively labile [Ru(NO)(bpym)(terpy)]3+, which forms a structurally characterized MeCN substitution product [Ru(MeCN)(bpym)(terpy)](PF6)2 upon treatment with MeOH/MeCN, is electrochem. reduced in 3 1-electron steps of which the 3rd, leading to neutral [Ru(NO)(bpym)(terpy)], involves electrode adsorption. The 1st-two redn. processes cause shifts of \textgreek{n}(NO) from 1957 via 1665 to 1388 cm-1, implying a predominantly NO-centered electron addn. UV-visible-NIR Spectroscopy shows long-wavelength ligand-to-ligand charge transfer absorptions for [RuII(NO-1)(bpym)(terpy)]+ in the visible region, whereas the paramagnetic intermediate [Ru(NO)(bpym)(terpy)]2+ exhibits no distinct absorption max. {\textgreater}309 nm. EPR spectroscopy of the latter at 9.5, 95, and 190 GHz shows the typical invariant pattern of the {RuNO}7 configuration; however, the high-frequency measurements at 4 and 10 K reveal a splitting of the g1 and g2 components, which is tentatively attributed to conformers resulting from the bending of RuNO. DFT calcns. support the assignments of oxidn. states and the general interpretation of the electronic structure. [on SciFinder(R)]Separation of Metal Binding and Electron Transfer Sites as a Strategy To Stabilize the Ligand-Reduced and Metal-Oxidized Form of Mo(CO)4Lhttps://puma.ub.uni-stuttgart.de/bibtex/2030d67625868b50a92b41fd418856d77/huebleriachuebleriac2022-06-15T11:26:56+02:00DFT;seven EPR chelate complex;mol complex;optimized crystal electrochem geometry membered metallacycle methylimidazolylquinoxaline molybdenum prepn seven structure <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Ece Bulak" itemprop="url" href="/person/1ca79435a37427c130fc4c0305964a467/author/0"><span itemprop="name">E. Bulak</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Tereza Varnali" itemprop="url" href="/person/1ca79435a37427c130fc4c0305964a467/author/1"><span itemprop="name">T. Varnali</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Brigitte Schwederski" itemprop="url" href="/person/1ca79435a37427c130fc4c0305964a467/author/2"><span itemprop="name">B. Schwederski</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Denis Bubrin" itemprop="url" href="/person/1ca79435a37427c130fc4c0305964a467/author/3"><span itemprop="name">D. Bubrin</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Jan Fiedler" itemprop="url" href="/person/1ca79435a37427c130fc4c0305964a467/author/4"><span itemprop="name">J. Fiedler</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang. Kaim" itemprop="url" href="/person/1ca79435a37427c130fc4c0305964a467/author/5"><span itemprop="name">W. Kaim</span></a></span></span>. </span><span class="additional-entrytype-information"><span itemtype="http://schema.org/PublicationIssue" itemscope="itemscope" itemprop="isPartOf"><em><span itemprop="journal">Organometallics</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">30 </span></span>(<span itemprop="issueNumber">23</span>):
<span itemprop="pagination">6441--6445</span></em> </span>(<em><span>2011<meta content="2011" itemprop="datePublished"/></span></em>)</span>Wed Jun 15 11:26:56 CEST 2022Organometallics236441--6445Separation of Metal Binding and Electron Transfer Sites as a Strategy To Stabilize the Ligand-Reduced and Metal-Oxidized Form of [Mo(CO)4L]302011DFT;seven EPR chelate complex;mol complex;optimized crystal electrochem geometry membered metallacycle methylimidazolylquinoxaline molybdenum prepn seven structure The zerovalent metal in [Mo(CO)4(bmiq)] binds the two imidazole-N-imine donors of 2,3-bis(1-methylimidazol-2-yl)quinoxaline (bmiq), resulting in a seven-membered chelate ring coordinated in cis configuration. DFT calcns. confirm the preference for a seven-membered vs. five-membered ring chelation alternative as well as the exptl. structural parameters. The complex is reversibly reduced in CH2Cl2 at -2.08 V and reversibly oxidized at -0.14 V vs. ferrocenium/ferrrocene. The facilitated oxidn. to a stable cation is attributed to the donor effect from the imidazole rings. In agreement with the DFT-calcd. characteristics of the HOMO and LUMO, the in situ EPR studies at a Pt electrode reveal a Mo(I) signature for the cation (g1 = 1.967, g2 = 1.944, g3 = 1.906; Aiso(95,97Mo) = 50 G) and a quinoxaline radical-type EPR spectrum with dominant 14N coupling (2 N) of 6.0 G for the anion. IR spectroelectrochem. confirms these assignments, showing small (\textgreek{Dn} $\leq$ 20 cm-1) low-energy shifts of carbonyl stretching bands on redn. but significantly larger high-energy shifts (\textgreek{Dn} = 77-142 cm-1) after oxidn. The neutral compd. with a weak, broad MLCT absorption band at 500 nm is photolabile in soln. The unusual stability of both the anion and the cation is attributed to the spatial and electronic sepn. of the sites for electron loss (at the metal) and for electron uptake (at the uncoordinated quinoxaline ring). [on SciFinder(R)]EPR study of paramagnetic rhenium(I) complexes (bpy.-)Re(CO)3X relevant to the mechanism of electrocatalytic CO2 reductionhttps://puma.ub.uni-stuttgart.de/bibtex/21e663b79f334ef8355cdcaa117b38da7/huebleriachuebleriac2022-06-15T11:26:56+02:00EPR bipyridyl carbon carbonyl complex dioxide electrocatalytic redn;paramagnetic rhenium <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Thomas Scheiring" itemprop="url" href="/person/1f7f3e4a4c81a0076070ccae0cb8e0884/author/0"><span itemprop="name">T. Scheiring</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Axel Klein" itemprop="url" href="/person/1f7f3e4a4c81a0076070ccae0cb8e0884/author/1"><span itemprop="name">A. Klein</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang. Kaim" itemprop="url" href="/person/1f7f3e4a4c81a0076070ccae0cb8e0884/author/2"><span itemprop="name">W. Kaim</span></a></span></span>. </span><span class="additional-entrytype-information"><span itemtype="http://schema.org/PublicationIssue" itemscope="itemscope" itemprop="isPartOf"><em><span itemprop="journal">Journal of the Chemical Society, Perkin Transactions 2: Physical Organic Chemistry</span>, </em> </span>(<em><span>1997<meta content="1997" itemprop="datePublished"/></span></em>)</span>Wed Jun 15 11:26:56 CEST 2022Journal of the Chemical Society, Perkin Transactions 2: Physical Organic Chemistry122569--2571EPR study of paramagnetic rhenium(I) complexes (bpy.-)Re(CO)3X relevant to the mechanism of electrocatalytic CO2 reduction1997EPR bipyridyl carbon carbonyl complex dioxide electrocatalytic redn;paramagnetic rhenium In situ redn. of fac-(bpy)Re(CO)3Cl, bpy = 2,2'-bipyridine, at a platinum cathode under CO2 atmosphere in acetonitrile or acetone has produced a series of distinct EPR spectra which are attributed to (bpy.-) contg. species and which invariably reveal the interaction of the unpaired electron with the metal nuclei (185,187Re, I=5/2). The EPR investigation of various model complexes (bpy.-)Re(CO)3X, generated by electrochem. redn. under argon of diamagnetic precursors (bpy)Re(CO)3X, X = Cl-, CF3SO3-, CH3O-, H-, THF, CH3CN, CO, HCO2-, HCO3- and CH3C(O)- has been used to interpret the results from the reactions under CO2 atmosphere. [on SciFinder(R)]EPR evidence for related electronic structures of a-diimine complexes with bis(bipyridine)ruthenium(2+) (Ru(bpy)22+) and rhenium carbonyl(Re(CO)3)(halide) fragmentshttps://puma.ub.uni-stuttgart.de/bibtex/29bf064a519c0edaeaeedcb83efb1deb4/huebleriachuebleriac2022-06-15T11:26:56+02:00EPR ESR;electronic ESR;rhenium azobipyridine carbonyl diimine;photocatalyst diimine;pyridine halo rhenium structure <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="W. Kaim" itemprop="url" href="/person/13c7f8ff30e6c2078df14fdfd51898b7e/author/0"><span itemprop="name">W. Kaim</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="S. Kohlmann" itemprop="url" href="/person/13c7f8ff30e6c2078df14fdfd51898b7e/author/1"><span itemprop="name">S. Kohlmann</span></a></span></span>. </span><span class="additional-entrytype-information"><span itemtype="http://schema.org/PublicationIssue" itemscope="itemscope" itemprop="isPartOf"><em><span itemprop="journal">Chemical Physics Letters</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">139 </span></span>(<span itemprop="issueNumber">3-4</span>):
<span itemprop="pagination">365--369</span></em> </span>(<em><span>1987<meta content="1987" itemprop="datePublished"/></span></em>)</span>Wed Jun 15 11:26:56 CEST 2022Chemical Physics Letters3-4365--369EPR evidence for related electronic structures of \textgreek{a}-diimine complexes with bis(bipyridine)ruthenium(2+) ([Ru(bpy)2]2+) and rhenium carbonyl(Re(CO)3)(halide) fragments1391987EPR ESR;electronic ESR;rhenium azobipyridine carbonyl diimine;photocatalyst diimine;pyridine halo rhenium structure Low-lying unoccupied orbitals of the fragments Re(CO)3X, X = Cl and Br, were inferred from EPR spectroscopy of mono- and dinuclear complexes with the singly reduced \textgreek{a}-diimine ligands 2,2'-dipyridine and azo-2,2'-bipyridine. The magnitudes of 185,187Re and unresolved halide hyperfine splitting could be established in spite of the poor spectra resoln. The spectroscopic similarities between \textgreek{a}-diimine complexes of Re(CO)3X and [Ru(bpy)2]2+ fragments are discussed with respect to their related electronic structures and photocatalytic reactivities. [on SciFinder(R)]EPR and absorption spectra of singly reduced mono- and dinuclear diorganoplatinum complexes of heterocyclic a-diimineshttps://puma.ub.uni-stuttgart.de/bibtex/2c140679ef9adc3759719635769185354/huebleriachuebleriac2022-06-15T11:26:56+02:00EPR complex diimine heterocyclic platinum reduced <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Paul S. Braterman" itemprop="url" href="/person/189016c9a443b16ac56f9679d23eb44c4/author/0"><span itemprop="name">P. Braterman</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Jae Inh Song" itemprop="url" href="/person/189016c9a443b16ac56f9679d23eb44c4/author/1"><span itemprop="name">J. Song</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Conny Vogler" itemprop="url" href="/person/189016c9a443b16ac56f9679d23eb44c4/author/2"><span itemprop="name">C. Vogler</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang. Kaim" itemprop="url" href="/person/189016c9a443b16ac56f9679d23eb44c4/author/3"><span itemprop="name">W. Kaim</span></a></span></span>. </span><span class="additional-entrytype-information"><span itemtype="http://schema.org/PublicationIssue" itemscope="itemscope" itemprop="isPartOf"><em><span itemprop="journal">Inorganic Chemistry</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">31 </span></span>(<span itemprop="issueNumber">2</span>):
<span itemprop="pagination">222--224</span></em> </span>(<em><span>1992<meta content="1992" itemprop="datePublished"/></span></em>)</span>Wed Jun 15 11:26:56 CEST 2022Inorganic Chemistry2222--224EPR and absorption spectra of singly reduced mono- and dinuclear diorganoplatinum complexes of heterocyclic \textgreek{a}-diimines311992EPR complex diimine heterocyclic platinum reduced The diorganoplatinum(II) complexes [(bpy)Pt(Ph)2], [(bpym)Pt(Ph)2], [(\textgreek{m}-bpym)(Pt(p-tol)2)2], and [(\textgreek{m}-bpym)(PtAd2)2], (bpy = 2,2'-bipyridine; bpym = 2,2'=bipyrimidine; Ph = phenyl; p-tol = p-tolyl; Ad = (1-adamantylmethyl) were subjected to two successive one-electron redns., and the one-electron redn. products were studied in situ by UV-vis-near-IR and EPR spectroscopy. The first redn. is at the heterocyclic ligand, in contrast to the metal-centered redns. in such closely similar species as [Pt(bpy)(py)2]2+. We attribute this difference to the greater ligand field strength of carbanionic as opposed to neutral N-bound ligands. While the EPR signals of the paramagnetic species show sizable g anisotropy (1.92-2.02) in frozen soln. due to the large spin-orbit coupling const. of the metal, the rhombic g pattern, the low isotropic values (giso {\textless} 2), and the isotropic hyperfine coupling as obsd. and reproduced in the case of [(bpym)Pt(Ph)2].bul.- all suggest a predominant localization of the unpaired electron at the \textgreek{a}-diimine ligand. [on SciFinder(R)]EPR insensitivity of the metal-nitrosyl spin-bearing moiety in complexes LnRuII-NO.bul.khttps://puma.ub.uni-stuttgart.de/bibtex/2e4f9ffd6c988d34ff8c1162d9c438968/huebleriachuebleriac2022-06-15T11:26:56+02:00EPR bipyrazine bipyridine nitrosyl prepn pyridine radical ruthenium terpyridine <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Stephanie Frantz" itemprop="url" href="/person/1173a0951abcf65f96200c98d0d123330/author/0"><span itemprop="name">S. Frantz</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Biprajit Sarkar" itemprop="url" href="/person/1173a0951abcf65f96200c98d0d123330/author/1"><span itemprop="name">B. Sarkar</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Monika Sieger" itemprop="url" href="/person/1173a0951abcf65f96200c98d0d123330/author/2"><span itemprop="name">M. Sieger</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang Kaim" itemprop="url" href="/person/1173a0951abcf65f96200c98d0d123330/author/3"><span itemprop="name">W. Kaim</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Federico Roncaroli" itemprop="url" href="/person/1173a0951abcf65f96200c98d0d123330/author/4"><span itemprop="name">F. Roncaroli</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Jose A. Olabe" itemprop="url" href="/person/1173a0951abcf65f96200c98d0d123330/author/5"><span itemprop="name">J. Olabe</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Stanislav. Zalis" itemprop="url" href="/person/1173a0951abcf65f96200c98d0d123330/author/6"><span itemprop="name">S. Zalis</span></a></span></span>. </span><span class="additional-entrytype-information"><span itemtype="http://schema.org/PublicationIssue" itemscope="itemscope" itemprop="isPartOf"><em><span itemprop="journal">European Journal of Inorganic Chemistry</span>, </em> </span>(<em><span>2004<meta content="2004" itemprop="datePublished"/></span></em>)</span>Wed Jun 15 11:26:56 CEST 2022European Journal of Inorganic Chemistry142902--2907EPR insensitivity of the metal-nitrosyl spin-bearing moiety in complexes [LnRuII-NO.bul.]k2004EPR bipyrazine bipyridine nitrosyl prepn pyridine radical ruthenium terpyridine A survey of 18 paramagnetic [LnRu(NO)]k, including seven new examples studied by in situ electrolysis, reveals a surprisingly narrow range of EPR parameters despite a wide variety of ligands such as pyridine, polypyridines, imines, amines, nitriles, phosphines, carbonyl, cyclopentadienides, halides, hydride, hydroxide, thiocyanate or cyanide: g1 = 2.015 $\pm$ 0.02, g2 = 1.990 $\pm$ 0.015, g3 = 1.892 $\pm$ 0.03, gav = 1.968 $\pm$ 0.02, \textgreek{D}g = g1 - g3 = 0.122 $\pm$ 0.037, A2(14N) = 3.3 $\pm$ 0.5 mT. This rather small variability, smaller still if the organometallic compds. are excluded, differs from the wider range of EPR data reported for nitrosyliron species with S = 1/2; apparently, the {RuNO}7 configuration involves a rather invariant and relatively covalent metal-NO interaction. DFT calcns. were employed for [(NC)5Ru(NO)]3- to reproduce the EPR data, to evaluate the spin distribution (58{\%} spin d. on NO), and to reveal structural changes on redn. such as the Ru-N-O bending and Ru-NO bond lengthening. The possibility of staggered and eclipsed conformations is discussed. [on SciFinder(R)]The p* Molecular Orbital Crossing a2(q)/b1(y) in 1,10-Phenanthroline Derivatives. Ab Initio Calculations and EPR/ENDOR Studies of the 4,7-Diaza-1,10-phenanthroline Radical Anion and Its M(CO)4 Complexes (M = Cr, Mo, W)https://puma.ub.uni-stuttgart.de/bibtex/20c7885dd81bf307061c8a0f5e6ca1db4/huebleriachuebleriac2022-06-15T11:26:56+02:00EPR MO ab carbonyl chromium complex crossing deriv deriv;MO diazaphenanthroline initio initio;ENDOR initio;diazaphenanthroline initio;molybdenum initio;tungsten metal phenanthroline <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Sylvia Ernst" itemprop="url" href="/person/1554c893c1331bbf0702878fe51b680a4/author/0"><span itemprop="name">S. Ernst</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Conny Vogler" itemprop="url" href="/person/1554c893c1331bbf0702878fe51b680a4/author/1"><span itemprop="name">C. Vogler</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Axel Klein" itemprop="url" href="/person/1554c893c1331bbf0702878fe51b680a4/author/2"><span itemprop="name">A. Klein</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang Kaim" itemprop="url" href="/person/1554c893c1331bbf0702878fe51b680a4/author/3"><span itemprop="name">W. Kaim</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Stanislav. Zalis" itemprop="url" href="/person/1554c893c1331bbf0702878fe51b680a4/author/4"><span itemprop="name">S. Zalis</span></a></span></span>. </span><span class="additional-entrytype-information"><span itemtype="http://schema.org/PublicationIssue" itemscope="itemscope" itemprop="isPartOf"><em><span itemprop="journal">Inorganic Chemistry</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">35 </span></span>(<span itemprop="issueNumber">5</span>):
<span itemprop="pagination">1295--1300</span></em> </span>(<em><span>1996<meta content="1996" itemprop="datePublished"/></span></em>)</span>Wed Jun 15 11:26:56 CEST 2022Inorganic Chemistry51295--1300The \textgreek{p}* Molecular Orbital Crossing a2(\textgreek{q})/b1(\textgreek{y}) in 1,10-Phenanthroline Derivatives. Ab Initio Calculations and EPR/ENDOR Studies of the 4,7-Diaza-1,10-phenanthroline Radical Anion and Its M(CO)4 Complexes (M = Cr, Mo, W)351996EPR MO ab carbonyl chromium complex crossing deriv deriv;MO diazaphenanthroline initio initio;ENDOR initio;diazaphenanthroline initio;molybdenum initio;tungsten metal phenanthroline Ab initio, semiempirical, and HMO perturbation calcns. were employed to assess the relative positioning of the closely situated low-lying unoccupied \textgreek{p}* MOs a2(\textgreek{q}) and b1(\textgreek{y}) in 1,10-phenanthroline (phen) and its 3,4,7,8-tetra-Me (tmphen) and four sym. diaza derivs. (n,m-dap). Compared to a2(\textgreek{q}), the b1(\textgreek{y}) \textgreek{p} MO is distinguished by markedly higher MO coeffs. at the chelating nitrogen \textgreek{p} centers in 1,10-positions; eventually, a higher Coulomb integral value at those positions will thus always favor the lowering of b1 beyond a2. Using the Coulomb integral parameter at the chelating 1,10-nitrogen \textgreek{p} centers as the HMO perturbation variable, the crossing of both energy levels in terms of decreasing preference for the a2(\textgreek{q}) over the b1(\textgreek{y}) orbital as the LUMO follows the sequence 5,6-dap {\textgreater} 2,9-dap {\textgreater} 4,7-dap {\textgreater} phen {\textgreater} 3,8-dap. The calcns. reveal a2(\textgreek{q}) as the LUMO in 5,6-dap for all reasonable perturbation parameters, in agreement with previous observations for ruthenium(II) complexes which reveal a discrepancy between the lowest-lying {\dq}redox \textgreek{p}* orbital{\dq} (a2) and the {\dq}optical \textgreek{p}* MO{\dq} (b1) to which the most intense low-energy MLCT transition occurs. According to the HMO calcns., the situation is more ambiguous for the 4,7-dap analog, yet EPR/ENDOR studies clearly show that the one-electron-reduced ligand and its tetracarbonylmetal(0) complexes (Cr, Mo, W) have the b1(\textgreek{y}) orbital singly occupied. Only ab initio calcns. with double-\textgreek{z} basis and inclusion of d polarization functions reproduced correctly the exptl. obsd. orbital ordering for tmphen (a2 {\textgreater} b1) and for phen and 4,7-dap (b1 {\textgreater} a2). [on SciFinder(R)]