PUMA publications for /user/b_schwederski/spinhttps://puma.ub.uni-stuttgart.de/user/b_schwederski/spinPUMA RSS feed for /user/b_schwederski/spin2024-03-19T05:45:57+01:00Varying Electronic Structures of Diosmium Complexes from Noninnocently Behaving Anthraquinone-Derived Bis-chelate Ligandshttps://puma.ub.uni-stuttgart.de/bibtex/22326ea65b54fc46d7a9c0ed5822f2cbc/b_schwederskib_schwederski2019-07-15T13:41:23+02:00UV bipyridine complex complex;IR complex;electron complex;osmium crystal density diaminoanthraquinone dihydroxyanthraquinone osmium phenylazopyridine potential prepn redox spectroelectrochem spin structure <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Abhishek Mandal" itemprop="url" href="/person/1981026ca1585cfcaa7070789e4ab8765/author/0"><span itemprop="name">A. Mandal</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Anita Grupp" itemprop="url" href="/person/1981026ca1585cfcaa7070789e4ab8765/author/1"><span itemprop="name">A. Grupp</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Brigitte Schwederski" itemprop="url" href="/person/1981026ca1585cfcaa7070789e4ab8765/author/2"><span itemprop="name">B. Schwederski</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang Kaim" itemprop="url" href="/person/1981026ca1585cfcaa7070789e4ab8765/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="Goutam Kumar. Lahiri" itemprop="url" href="/person/1981026ca1585cfcaa7070789e4ab8765/author/4"><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">54 </span></span>(<span itemprop="issueNumber">16</span>):
<span itemprop="pagination">7936--7944</span></em> </span>(<em><span>2015<meta content="2015" itemprop="datePublished"/></span></em>)</span>Mon Jul 15 13:41:23 CEST 2019Inorganic Chemistry167936--7944Varying Electronic Structures of Diosmium Complexes from Noninnocently Behaving Anthraquinone-Derived Bis-chelate Ligands542015UV bipyridine complex complex;IR complex;electron complex;osmium crystal density diaminoanthraquinone dihydroxyanthraquinone osmium phenylazopyridine potential prepn redox spectroelectrochem spin structure [(Bpy)2OsII(\textgreek{m}-L21-)OsII(bpy)2](ClO4)2 ([1](ClO4)2) and [(pap)2OsII(\textgreek{m}-L21-)OsII(pap)2](ClO4)2 ([2](ClO4)2) (H2L1 = 1,4-dihydroxy-9,10-anthraquinone, bpy = 2,2'-bipyridine, and pap = 2-phenylazopyridine) and [(bpy)2OsII(\textgreek{m}-L2.bul.-)OsII(bpy)2](ClO4)3 ([3](ClO4)3) and [(pap)2OsII(\textgreek{m}-L22-)OsII(pap)2](ClO4)2 ([4](ClO4)2) (H2L2 = 1,4-diamino-9,10-anthraquinone) were anal. identified as the meso and rac diastereoisomers, resp. The paramagnetic [3](ClO4)3 was also characterized by crystal structure detn. In CD3CN soln., [3](ClO4)3 displays rather narrow but widely split (13 {\textgreater} \textgreek{d} {\textgreater} -8 ppm) resonances in the 1H NMR spectrum, yet no EPR signal was obsd. down to 120 K. Cyclic voltammetry and differential pulse voltammetry reveal several accessible redox states on oxidn. and redn., showing that the replacement of 1,4-oxido by imido donors causes cathodic shifts and that the substitution of bpy by the stronger \textgreek{p}-accepting pap ligands leads to a strong increase of redox potentials. Accordingly, system 3n with the lowest (2+/3+) potential was synthetically obtained in the mono-oxidized (3+) form. The (3+) intermediates display small comproportionation consts. Kc of $\sim$103 and long-wavelength near-IR absorptions; an EPR signal with appreciable g splitting (1.84, 1.96, and 2.03) was only obsd. for 43+, which exhibits the smallest spin d. on the osmium centers. An oxidn. state formulation [OsIII(\textgreek{m}-L.bul.3-)OsIII]3+ with some [OsII(\textgreek{m}-L2-)OsIII]3+ contribution was found to best describe the electronic structures. UV-visible-NIR absorption spectra were recorded for all accessible states by OTTLE spectroelectrochem. and assigned from TD-DFT calcns. These results and addnl. EPR measurements suggest rather variegated oxidn. state situations, e.g., the pap ligands competing with the bridge L for electrons, while the oxidn. produces mixed spin systems with variable metal/ligand contributions. [on SciFinder(R)]A structurally characterised redox pair involving an indigo radical: Indigo based redox activity in complexes with one or two Ru(bpy)2 fragmentshttps://puma.ub.uni-stuttgart.de/bibtex/2c3de132b16a417d57d3dd16f5c2a9b32/b_schwederskib_schwederski2019-07-15T13:41:23+02:00DFT bipyridine complex crystal density dinuclear dinuclear;electrochem dinuclear;electron dinuclear;ruthenium electronic indigo mononuclear prepn redox ruthenium spin structure;spectroelectrochem transition <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Madhumita Chatterjee" itemprop="url" href="/person/1aadad110d6b4a72d9dd6b0fbd0c9bc12/author/0"><span itemprop="name">M. Chatterjee</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Prasenjit Mondal" itemprop="url" href="/person/1aadad110d6b4a72d9dd6b0fbd0c9bc12/author/1"><span itemprop="name">P. Mondal</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Katharina Beyer" itemprop="url" href="/person/1aadad110d6b4a72d9dd6b0fbd0c9bc12/author/2"><span itemprop="name">K. Beyer</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Alexa Paretzki" itemprop="url" href="/person/1aadad110d6b4a72d9dd6b0fbd0c9bc12/author/3"><span itemprop="name">A. Paretzki</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang Kaim" itemprop="url" href="/person/1aadad110d6b4a72d9dd6b0fbd0c9bc12/author/4"><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/1aadad110d6b4a72d9dd6b0fbd0c9bc12/author/5"><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">Dalton Transactions</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">46 </span></span>(<span itemprop="issueNumber">15</span>):
<span itemprop="pagination">5091--5102</span></em> </span>(<em><span>2017<meta content="2017" itemprop="datePublished"/></span></em>)</span>Mon Jul 15 13:41:23 CEST 2019Dalton Transactions155091--5102A structurally characterised redox pair involving an indigo radical: Indigo based redox activity in complexes with one or two [Ru(bpy)2] fragments462017DFT bipyridine complex crystal density dinuclear dinuclear;electrochem dinuclear;electron dinuclear;ruthenium electronic indigo mononuclear prepn redox ruthenium spin structure;spectroelectrochem transition The reaction between indigo, H2Ind, and {Ru(bpy)2(EtOH)2}2+ in EtOH/NaOH produced [Ru(bpy)2(HInd)]ClO4 [1]ClO4, rac-{[Ru(bpy)2]2(μ-Ind)}(ClO4)2 [2](ClO4)2, and meso-{[Ru(bpy)2]2(μ-Ind)}(ClO4)3 [2](ClO4)3, which were structurally characterized, the latter as the first stable, isolable radical complex of indigo. The redox pair 22+/23+ showed little structural difference, as confirmed using DFT calcns. The redox series 1n and 2n were studied using voltammetry and spectroelectrochem. (EPR, UV-visible-NIR). Remarkably, the EPR results for 1, 12+, 2+ and 23+ revealed mostly ligand-based spin in Ru(II) complexes of the indigo-derived radical ligands HInd.bul.2-, HInd.bul., Ind.bul.3- and Ind.bul.-, in agreement with the DFT calcd. spin densities. The dominance of the frontier orbitals by the metal-stabilized indigo chromophore was also confirmed via the TD-DFT based assignment of near-IR absorptions as intra-indigo or ligand-to-ligand charge transfer transitions. [on SciFinder(R)]Intramolecular Valence and Spin Interaction in meso and rac Diastereomers of a p-Quinonoid-Bridged Diruthenium Complexhttps://puma.ub.uni-stuttgart.de/bibtex/289b19fd7a76a922fdd0bc07279361251/b_schwederskib_schwederski2019-07-15T13:41:23+02:00bridged crystal diastereoisomer diastereoisomer;electrochem diastereoisomer;magnetic diastereoisomer;quinonoid diruthenium interaction intramol prepn property quinonoid redox spin structure valence <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Doyel Kumbhakar" itemprop="url" href="/person/115998996ed2c6b29c422c00feac95214/author/0"><span itemprop="name">D. Kumbhakar</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Biprajit Sarkar" itemprop="url" href="/person/115998996ed2c6b29c422c00feac95214/author/1"><span itemprop="name">B. Sarkar</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Somnath Maji" itemprop="url" href="/person/115998996ed2c6b29c422c00feac95214/author/2"><span itemprop="name">S. Maji</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Shaikh M. Mobin" itemprop="url" href="/person/115998996ed2c6b29c422c00feac95214/author/3"><span itemprop="name">S. Mobin</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Jan Fiedler" itemprop="url" href="/person/115998996ed2c6b29c422c00feac95214/author/4"><span itemprop="name">J. Fiedler</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Francisco A. Urbanos" itemprop="url" href="/person/115998996ed2c6b29c422c00feac95214/author/5"><span itemprop="name">F. Urbanos</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Reyes Jimenez-Aparicio" itemprop="url" href="/person/115998996ed2c6b29c422c00feac95214/author/6"><span itemprop="name">R. Jimenez-Aparicio</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang Kaim" itemprop="url" href="/person/115998996ed2c6b29c422c00feac95214/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/115998996ed2c6b29c422c00feac95214/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">Journal of the American Chemical Society</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">130 </span></span>(<span itemprop="issueNumber">51</span>):
<span itemprop="pagination">17575--17583</span></em> </span>(<em><span>2008<meta content="2008" itemprop="datePublished"/></span></em>)</span>Mon Jul 15 13:41:23 CEST 2019Journal of the American Chemical Society5117575--17583Intramolecular Valence and Spin Interaction in meso and rac Diastereomers of a p-Quinonoid-Bridged Diruthenium Complex1302008bridged crystal diastereoisomer diastereoisomer;electrochem diastereoisomer;magnetic diastereoisomer;quinonoid diruthenium interaction intramol prepn property quinonoid redox spin structure valence The complexes meso- and rac-[(acac)2Ru(\textgreek{m}-L)Ru(acac)2]n, 1 and 2, where L2- = 1,4-dioxido-2,3-bis(3,5-dimethylpyrazol-1-yl)benzene and acac- = 2,4-pentanedionato, were characterized structurally, magnetically, electrochem., and spectroscopically as well as spectroelectrochem. (UV-visible-NIR, EPR) in the accessible redox states (n = 0, +, -, 2-). Due to steric interference, the neutral compds. contain a severely twisted L2- bridging ligand with 43-48° dihedral angles between the planes of the hydroquinone dianion and those of the ortho positioned pyrazolyl substituents. The difference between meso and rac isomers is rather pronounced in terms of the redox potentials (easier oxidn. and redn. of the rac form 2) and with respect to the absorption spectra of the oxidized states. Susceptibility and EPR measurements confirm the {RuIII(μ-L2-)RuIII} configuration of the neutral species, showing J values of -37 and -21 cm-1 for the spin-spin interaction between the $\sim$7.75 {\AA} sepd. metal centers in 1 and 2, resp. Two-step redn. involves the metals and produces RuIIIRuII mixed-valent monoanions with comproportionation consts. of $\sim$104, with RuIII-type EPR signals, and with broad intervalence charge transfer bands at $\sim$1200-1500 nm absorption max., suggesting localized valence (class II). Oxidn. produces intense near-IR absorption at 892 (1+) or 1027 nm (2+) and narrow isotropic EPR spectra at g $\approx$ 2.005, signifying unprecedented spin localization at the p-semiquinone bridge. These results are not compatible with an (L2-)-bridged {RuIVRuIII} situation nor with an {RuIII(μ-L·-)RuIII} three-spin arrangement with up-down-up spin configuration in the ground state, which would result in metal-centered spin through antiferromagnetic coupling between the adjacent individual spins. Only the {RuIII(μ-L·-)RuIII} situation, with up-up-down spin configuration, leads to ligand-centered resulting spin through the strong antiferromagnetic coupling between the remote metal spins, an unusual situation which is favored here because of weakened metal-radical coupling resulting from the pyrazolyl/p-semiquinone twist. [on SciFinder(R)]High-spin cyclopentadienyl complexes. 1. Synthesis and characterization of the stable dicarbonyl(cyclopentadienyl)iron radical (C5R5)Fe(CO)2 (R = CHMe2)https://puma.ub.uni-stuttgart.de/bibtex/2ddb715d2b76e74fdface7e66628e8c35/b_schwederskib_schwederski2019-07-15T13:41:23+02:002 bromo carbonyl carbonyl;regiospecific complex;iron crystal cyclopentadienyl dimer;high dimer;redn elimination iron isopropylcyclopentadienyl prepn;mol propene radical redn spin structure <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Helmut Sitzmann" itemprop="url" href="/person/1a2fd26c7d1e6f77dcd50256b4190e4e4/author/0"><span itemprop="name">H. Sitzmann</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Thomas Dezember" itemprop="url" href="/person/1a2fd26c7d1e6f77dcd50256b4190e4e4/author/1"><span itemprop="name">T. Dezember</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang Kaim" itemprop="url" href="/person/1a2fd26c7d1e6f77dcd50256b4190e4e4/author/2"><span itemprop="name">W. Kaim</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Frank Baumann" itemprop="url" href="/person/1a2fd26c7d1e6f77dcd50256b4190e4e4/author/3"><span itemprop="name">F. Baumann</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Dietmar Stalke" itemprop="url" href="/person/1a2fd26c7d1e6f77dcd50256b4190e4e4/author/4"><span itemprop="name">D. Stalke</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Joerg Kaercher" itemprop="url" href="/person/1a2fd26c7d1e6f77dcd50256b4190e4e4/author/5"><span itemprop="name">J. Kaercher</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Elmar Dormann" itemprop="url" href="/person/1a2fd26c7d1e6f77dcd50256b4190e4e4/author/6"><span itemprop="name">E. Dormann</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Hubert Winter" itemprop="url" href="/person/1a2fd26c7d1e6f77dcd50256b4190e4e4/author/7"><span itemprop="name">H. Winter</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Christoph wachter" itemprop="url" href="/person/1a2fd26c7d1e6f77dcd50256b4190e4e4/author/8"><span itemprop="name">C. wachter</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Marc. Kelemen" itemprop="url" href="/person/1a2fd26c7d1e6f77dcd50256b4190e4e4/author/9"><span itemprop="name">M. Kelemen</span></a></span></span>. </span><span class="additional-entrytype-information"><span itemtype="http://schema.org/PublicationIssue" itemscope="itemscope" itemprop="isPartOf"><em><span itemprop="journal">Angewandte Chemie, International Edition in English</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">35 </span></span>(<span itemprop="issueNumber">23/24</span>):
<span itemprop="pagination">2872--2875</span></em> </span>(<em><span>1997<meta content="1997" itemprop="datePublished"/></span></em>)</span>Mon Jul 15 13:41:23 CEST 2019Angewandte Chemie, International Edition in English23/242872--2875High-spin cyclopentadienyl complexes. 1. Synthesis and characterization of the stable dicarbonyl(cyclopentadienyl)iron radical [(C5R5)Fe(CO)2] (R = CHMe2)3519972 bromo carbonyl carbonyl;regiospecific complex;iron crystal cyclopentadienyl dimer;high dimer;redn elimination iron isopropylcyclopentadienyl prepn;mol propene radical redn spin structure (C5R4R')Fe(\textgreek{m}-Br)2Fe(C5R4R') (R = iPr; R' = H, iPr) were prepd. and reacted with CO to give (C5R4R')Fe(CO)2Br, which were reduced by Na amalgam or K to give various products, among which was the radical (C5R4R')Fe(CO)2 (R' = iPr). High-spin Fe2+ was found in (C5R4R')Fe(\textgreek{m}-Br)2Fe(C5R4R') with 4 unpaired electrons and parallel spin coupling of the 2 d6-Fe2+ centers within one dimer. Redn. of (C5R4R')Fe(CO)2Br (R = H) by Na amalgam gave (C5R4H)Fe(\textgreek{m}-Br)2Fe(C5R3H2) by regiospecific propene elimination. The radical (C5R4R')Fe(CO)2 (R' = iPr) is monomeric in soln. but dimeric in the solid state as detd. by x-ray crystallog. [on SciFinder(R)]Chemistry of C-Trimethylsilyl-Substituted Heterocarboranes. 21. Syntheses, Structures, EPR Spectra, and Reactivities of Bent-Sandwich and Half-Sandwich Titanacarboranes. Full Analysis of Spin-Spin Coupling in Two Structurally Characterized Titanium(III)-Carborane Dimershttps://puma.ub.uni-stuttgart.de/bibtex/28d64a18b58c53a7c04f578955d998c62/b_schwederskib_schwederski2019-07-15T13:41:23+02:00carborane coupling crystal dimer;EPR dimer;cyclic dimer;electrochem dimer;magnetic dimer;mol dimer;substituent dimer;titanacarborane effect prepn sandwich spin structure susceptibility titanium voltammetry <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Narayan S. Hosmane" itemprop="url" href="/person/17787750adbf04164c214ad99fefc0153/author/0"><span itemprop="name">N. Hosmane</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Ying Wang" itemprop="url" href="/person/17787750adbf04164c214ad99fefc0153/author/1"><span itemprop="name">Y. Wang</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Hongming Zhang" itemprop="url" href="/person/17787750adbf04164c214ad99fefc0153/author/2"><span itemprop="name">H. Zhang</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Kai-Juan Lu" itemprop="url" href="/person/17787750adbf04164c214ad99fefc0153/author/3"><span itemprop="name">K. Lu</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="John A. Maguire" itemprop="url" href="/person/17787750adbf04164c214ad99fefc0153/author/4"><span itemprop="name">J. Maguire</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Thomas G. Gray" itemprop="url" href="/person/17787750adbf04164c214ad99fefc0153/author/5"><span itemprop="name">T. Gray</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Karen A. Brooks" itemprop="url" href="/person/17787750adbf04164c214ad99fefc0153/author/6"><span itemprop="name">K. Brooks</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Eberhard Waldhoer" itemprop="url" href="/person/17787750adbf04164c214ad99fefc0153/author/7"><span itemprop="name">E. Waldhoer</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang Kaim" itemprop="url" href="/person/17787750adbf04164c214ad99fefc0153/author/8"><span itemprop="name">W. Kaim</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Reinhard K. Kremer" itemprop="url" href="/person/17787750adbf04164c214ad99fefc0153/author/9"><span itemprop="name">R. Kremer</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">16 </span></span>(<span itemprop="issueNumber">7</span>):
<span itemprop="pagination">1365--1377</span></em> </span>(<em><span>1997<meta content="1997" itemprop="datePublished"/></span></em>)</span>Mon Jul 15 13:41:23 CEST 2019Organometallics71365--1377Chemistry of C-Trimethylsilyl-Substituted Heterocarboranes. 21. Syntheses, Structures, EPR Spectra, and Reactivities of Bent-Sandwich and Half-Sandwich Titanacarboranes. Full Analysis of Spin-Spin Coupling in Two Structurally Characterized Titanium(III)-Carborane Dimers161997carborane coupling crystal dimer;EPR dimer;cyclic dimer;electrochem dimer;magnetic dimer;mol dimer;substituent dimer;titanacarborane effect prepn sandwich spin structure susceptibility titanium voltammetry The reaction of Cp2TiCl2 with the unsolvated dilithium compds. closo-exo-Li-1-Li-2-(R)-3-(SiMe3)-2,3-C2B4H4 (R = SiMe3, Me, H) produced dimeric mixed-sandwich titanacarboranes [commo-1-Cp-1-Ti(III)-2-(R)-3-(SiMe3)-2,3-C2B4H4]2 (R = SiMe3 (1), Me (2), H (3)) in yields of 60{\%}, 54{\%}, and 60{\%}, resp. The chem. oxidn. of these titanacarboranes in the presence of TiCl4 in THF resulted in the formation of the corresponding diamagnetic Ti(IV) species 1-(Cp)-1-(Cl)-1-(THF)-1-Ti-2-(R)-3-(SiMe3)-2,3-C2B4H4 (R = SiMe3 (7), Me (8), H (9)) in 86{\%}, 58{\%}, and 45{\%} yields, resp. When the bis(trimethylsilyl)-substituted dilithiacarborane precursor was reacted with TiCl3, only the monomeric full-sandwich chlorotitanacarborane [Li(TMEDA)]2[1-Cl-1,1'-Ti-(2,3-(SiMe3)2-2,3-C2B4H4)2] (4) was produced, while replacement of a SiMe3 group with a less sterically demanding Me group afforded the dimeric titanacarborane [Li(TMEDA)]2[1,1'-Ti-(2-Me-3-SiMe3-2,3-C2B4H4)2]2 (5A). On the other hand, when the TMEDA-solvated closo-exo-4,5-[(\textgreek{m}-H)2Li(TMEDA)]-1-Li[(TMEDA)-2,4-(SiMe3)2-2,4-C2B4H4] was the precursor, reaction with TiCl3 yielded only the corresponding monomeric half-sandwich chlorotitanacarborane 1-(TMEDA)-1-Cl-1-Ti(III)-2,4-(SiMe3)2-2,4-C2B4H4 (6). In addn. to the X-ray analyses of 1, 5, 6, and 7, the Ti(III) compds. and an electrochem. generated Ti(IV)/Ti(III) mixed-valence complex (5B) were characterized by EPR spectroscopy. The dimers 1 and 5A exhibit unusually well-resolved triplet EPR features, which were fully analyzed and correlated with the structural results. Magnetic susceptibility measurements reveal a rather small d1-d1 exchange coupling const. of -45.8 cm-1 (antiferromagnetic interaction) for 1. The one-electron oxidn. of 5A produced an anion (S = 1/2) with rhombic EPR features, which was tentatively identified as a delocalized [Ti(+3.5)]2 mixed-valence species (5B). [on SciFinder(R)]High-frequency EPR and structural data as complementary information on stable radical complexes containing the semi-reduced azo functionhttps://puma.ub.uni-stuttgart.de/bibtex/25f09aef9d44dafabe485994be63966f5/b_schwederskib_schwederski2019-07-15T13:41:23+02:00ESR azo coupling electronic function orbit radical spin structure <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/1cb9ab9bc982a14e9a96caa81c04b771b/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/1cb9ab9bc982a14e9a96caa81c04b771b/author/1"><span itemprop="name">S. Frantz</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Sayak Roy" itemprop="url" href="/person/1cb9ab9bc982a14e9a96caa81c04b771b/author/2"><span itemprop="name">S. Roy</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Monika Sieger" itemprop="url" href="/person/1cb9ab9bc982a14e9a96caa81c04b771b/author/3"><span itemprop="name">M. Sieger</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Carole Duboc" itemprop="url" href="/person/1cb9ab9bc982a14e9a96caa81c04b771b/author/4"><span itemprop="name">C. Duboc</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Gert Denninger" itemprop="url" href="/person/1cb9ab9bc982a14e9a96caa81c04b771b/author/5"><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/1cb9ab9bc982a14e9a96caa81c04b771b/author/6"><span itemprop="name">H. Kuemmerer</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang. Kaim" itemprop="url" href="/person/1cb9ab9bc982a14e9a96caa81c04b771b/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">Journal of Molecular Structure</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">890 </span></span>(<span itemprop="issueNumber">1-3</span>):
<span itemprop="pagination">133--138</span></em> </span>(<em><span>2008<meta content="2008" itemprop="datePublished"/></span></em>)</span>Mon Jul 15 13:41:23 CEST 2019Journal of Molecular Structure1-3133--138High-frequency EPR and structural data as complementary information on stable radical complexes containing the semi-reduced azo function8902008ESR azo coupling electronic function orbit radical spin structure Dinuclear metal compds. [(LnM)(\textgreek{m}-BL·-)(MLn)]k involving radical anions of bridging ligands BL such as 2,2'-azobispyridine or 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine and coordinated inorg. or organometallic complex fragments MLn contg. copper(I), rhenium(I), ruthenium(II), osmium(II), rhodium(III) or iridium(III) were studied in frozen solns. using high field EPR spectroscopy at W band (95 GHz) or higher frequencies. The generally small but still rather variable anisotropy of the g factor shows typical patterns reflecting the specific metal/ligand interactions, the competition between bridging and ancillary ligands for spin d., and the spin-orbit coupling consts. of the metals. The EPR data thus specify the structural data as obtained from x-ray crystallog. for a std. series of diphosphinocopper(I) complexes involving the radical ligands indicated. The (RNNR)·- group can be placed next to the related superoxide (OO)·- as a paramagnetic ligand with specific geometrical and electronic structure. [on SciFinder(R)]Spectroelectrochemical Evidence for the Nitrosyl Redox Siblings NO+, NO., and NO- Coordinated to a Strongly Electron-Accepting FeII Porphyrin: DFT Calculations Suggest the Presence of High-Spin States after Reduction of the FeII-NO- Complexhttps://puma.ub.uni-stuttgart.de/bibtex/23c752202409e7e5e56d0f89b0d435677/b_schwederskib_schwederski2019-07-15T13:41:23+02:00DFT accepting complex;spectroelectrochem electron iron nitrogen nitrosyl oxide porphyrin redn redox sibling spin state <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Juan Pellegrino" itemprop="url" href="/person/1c7dea2fc23ec5b33caf39cd817b22ac1/author/0"><span itemprop="name">J. Pellegrino</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Ralph Huebner" itemprop="url" href="/person/1c7dea2fc23ec5b33caf39cd817b22ac1/author/1"><span itemprop="name">R. Huebner</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Fabio Doctorovich" itemprop="url" href="/person/1c7dea2fc23ec5b33caf39cd817b22ac1/author/2"><span itemprop="name">F. Doctorovich</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang. Kaim" itemprop="url" href="/person/1c7dea2fc23ec5b33caf39cd817b22ac1/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">Chemistry - A European Journal</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">17 </span></span>(<span itemprop="issueNumber">28</span>):
<span itemprop="pagination">7868-7874, S7868/1-S7868/9</span></em> </span>(<em><span>2011<meta content="2011" itemprop="datePublished"/></span></em>)</span>Mon Jul 15 13:41:23 CEST 2019Chemistry - A European Journal287868-7874, S7868/1-S7868/9Spectroelectrochemical Evidence for the Nitrosyl Redox Siblings NO+, NO., and NO- Coordinated to a Strongly Electron-Accepting FeII Porphyrin: DFT Calculations Suggest the Presence of High-Spin States after Reduction of the FeII-NO- Complex172011DFT accepting complex;spectroelectrochem electron iron nitrogen nitrosyl oxide porphyrin redn redox sibling spin state Exptl. and computational results for the electron-deficient porphyrin complex [Fe(NO)(TFPPBr8)] (1; TFPPBr8 = 2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetrakis(pentafluorophenyl)porphyrin) are reported with respect to its electron-transfer behavior. Complex 1 undergoes three 1-electron processes: two reversible redns. and one irreversible oxidn. Spectroelectrochem. measurements (IR and UV/visible/NIR spectroscopy) of 14NO- and 15NO-contg. material indicate that the 1st redn. to 1- occurs largely on the NO ligand to produce nitroxyl anion (NO-) character, as evident from the considerable change in \textgreek{n}NO from 1715 to around 1550 cm-1. The 2nd redn. to 12- does not result in a further shift of \textgreek{n}NO to lower frequencies, but to a surprising high-energy shift to 1590 cm-1. This and the notable changes of the characteristic porphyrin vibrations as well as significant changes of the UV/visible absorptions indicate a porphyrin-centered process; DFT calcns. predict the shift of \textgreek{n}NO to higher frequencies for the intermediate- and high-spin states of 12-. The oxidn. of 1 is irreversible on the voltammetry timescale, but chem. reversible in spectroelectrochem. expts., suggesting that the cationic form dissocs. to the corresponding ferric porphyrin and NO. DFT calcns. support the interpretation of the exptl. results. [on SciFinder(R)]Metal compounds of the TCNX redox systems - from electron transfer to spin distribution and magnetismhttps://puma.ub.uni-stuttgart.de/bibtex/21b6a63538a242cf77020a3b3a89d6863/b_schwederskib_schwederski2019-07-15T13:41:23+02:00TCNX compd electron magnetism metal redox spin system transfer <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang. Kaim" itemprop="url" href="/person/18ecf610655c1f553444165260ac2f392/author/0"><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 Chilean Chemical Society</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">53 </span></span>(<span itemprop="issueNumber">1</span>):
<span itemprop="pagination">1353--1355</span></em> </span>(<em><span>2008<meta content="2008" itemprop="datePublished"/></span></em>)</span>Mon Jul 15 13:41:23 CEST 2019Journal of the Chilean Chemical Society11353--1355Metal compounds of the TCNX redox systems - from electron transfer to spin distribution and magnetism532008TCNX compd electron magnetism metal redox spin system transfer The TCNX ligands, TCNE (tetracyanoethene), TCNQ (7,7,8,8-tetracyano-p-quinodimethane), and TCNB (1,2,4,5-tetracyanobenzene), are capable of bridging up to four metal centers in discrete mol. complexes or coordination polymers. In addn., the highly non-innocent TCNX ligands may exist in neutral \textgreek{p} acceptor form, as stable monoanionic radicals, or as dianions, which has generated a unique coordination chem. Several such compds., particular those involving the TCNX bridges, have found interest for mol. magnetism studies, org. conductor research, and in concepts of mol. computing. This contribution focuses on the chem. potential for new materials and on their phys. characterization, esp. with respect to the TCNX/metal electron transfer and to the spin distribution in paramagnetic states. [on SciFinder(R)]Boron Atoms as Spin Carriers in Two- and Three-Dimensional Systemshttps://puma.ub.uni-stuttgart.de/bibtex/2f1bba647c5e162e8a33072f57569a262/b_schwederskib_schwederski2019-07-15T13:41:23+02:00boron carrier review spin <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang Kaim" itemprop="url" href="/person/1ded50dd1587940ef34e9606d8d714423/author/0"><span itemprop="name">W. Kaim</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Narayan S. Hosmane" itemprop="url" href="/person/1ded50dd1587940ef34e9606d8d714423/author/1"><span itemprop="name">N. Hosmane</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Stanislav Zalis" itemprop="url" href="/person/1ded50dd1587940ef34e9606d8d714423/author/2"><span itemprop="name">S. Zalis</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="John A. Maguire" itemprop="url" href="/person/1ded50dd1587940ef34e9606d8d714423/author/3"><span itemprop="name">J. Maguire</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="William N. Lipscomb" itemprop="url" href="/person/1ded50dd1587940ef34e9606d8d714423/author/4"><span itemprop="name">W. Lipscomb</span></a></span></span>. </span><span class="additional-entrytype-information"><span itemtype="http://schema.org/PublicationIssue" itemscope="itemscope" itemprop="isPartOf"><em><span itemprop="journal">Angewandte Chemie, International Edition</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">48 </span></span>(<span itemprop="issueNumber">28</span>):
<span itemprop="pagination">5082--5091</span></em> </span>(<em><span>2009<meta content="2009" itemprop="datePublished"/></span></em>)</span>Mon Jul 15 13:41:23 CEST 2019Angewandte Chemie, International Edition285082--5091Boron Atoms as Spin Carriers in Two- and Three-Dimensional Systems482009boron carrier review spin A review. The unusual bonding of boron in organoboranes or oligoboron clusters is not only apparent in diamagnetic mols. but also in paramagnetic systems, including mixed-valent species and oligoborane/carborane cluster radicals. The singly occupied MO of the radical ion [C4B8R4H8].-, detd. by DFT calcns. Paramagnetic compds. with at least partially boron-centered electron spin can be constructed using either the prototypically electron-accepting boron atoms bridged by planar \textgreek{p}-conjugated org. systems, or by taking advantage of the three-dimensional delocalized bonding in oligonuclear borane, haloborane, or carborane clusters. The concept of mixed valency can thus be transferred from org. and transition-metal chem. to main-group-element mols., and d. functional theory is capable of reproducing the variable spin distribution. [on SciFinder(R)]