PUMA publications for /user/b_schwederski/density%20complexhttps://puma.ub.uni-stuttgart.de/user/b_schwederski/density%20complexPUMA RSS feed for /user/b_schwederski/density%20complex2024-03-29T00:41:08+01:00Multifrequency EPR Study and Density Functional g-Tensor Calculations of Persistent Organorhenium Radical Complexeshttps://puma.ub.uni-stuttgart.de/bibtex/24d706dcb4a19a406cc9383fec48be027/b_schwederskib_schwederski2019-07-15T13:41:23+02:00EPR complex complex;UV complex;spin density g multifrequency organo persistent radical rhenium spectra tensor visible <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/1171b2796c8cc6986ef821d23de1ae9a2/author/0"><span itemprop="name">S. Frantz</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Heiko Hartmann" itemprop="url" href="/person/1171b2796c8cc6986ef821d23de1ae9a2/author/1"><span itemprop="name">H. Hartmann</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Natasa Doslik" itemprop="url" href="/person/1171b2796c8cc6986ef821d23de1ae9a2/author/2"><span itemprop="name">N. Doslik</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Matthias Wanner" itemprop="url" href="/person/1171b2796c8cc6986ef821d23de1ae9a2/author/3"><span itemprop="name">M. Wanner</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang Kaim" itemprop="url" href="/person/1171b2796c8cc6986ef821d23de1ae9a2/author/4"><span itemprop="name">W. Kaim</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Hans-Juergen Kuemmerer" itemprop="url" href="/person/1171b2796c8cc6986ef821d23de1ae9a2/author/5"><span itemprop="name">H. Kuemmerer</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Gert Denninger" itemprop="url" href="/person/1171b2796c8cc6986ef821d23de1ae9a2/author/6"><span itemprop="name">G. Denninger</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Anne-Laure Barra" itemprop="url" href="/person/1171b2796c8cc6986ef821d23de1ae9a2/author/7"><span itemprop="name">A. Barra</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Carole Duboc-Toia" itemprop="url" href="/person/1171b2796c8cc6986ef821d23de1ae9a2/author/8"><span itemprop="name">C. Duboc-Toia</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Jan Fiedler" itemprop="url" href="/person/1171b2796c8cc6986ef821d23de1ae9a2/author/9"><span itemprop="name">J. Fiedler</span></a></span></span> und 3 andere Autor(en). </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">124 </span></span>(<span itemprop="issueNumber">35</span>):
<span itemprop="pagination">10563--10571</span></em> </span>(<em><span>2002<meta content="2002" itemprop="datePublished"/></span></em>)</span>Mon Jul 15 13:41:23 CEST 2019Journal of the American Chemical Society3510563--10571Multifrequency EPR Study and Density Functional g-Tensor Calculations of Persistent Organorhenium Radical Complexes1242002EPR complex complex;UV complex;spin density g multifrequency organo persistent radical rhenium spectra tensor visible The dinuclear radical anion complexes {(μ-L)[Re(CO)3Cl]2}.bul.-, L = 2,2'-azobispyridine (abpy) and 2,2'-azobis(5-chloropyrimidine) (abcp), were studied by EPR at 9.5, 94, 230, and 285 GHz (abpy complex) and at 9.5 and 285 GHz (abcp complex). Whereas the X-band measurements yielded only the isotropic metal hyperfine coupling of the 185,187Re isotopes, the high-frequency EPR expts. in glassy frozen CH2Cl2/toluene soln. revealed the g components. Both the a(185,187Re) value and the g anisotropy, g1 - g3, are larger for the abcp complex, which contains the better \textgreek{p}-accepting bridging ligand. Confirmation for this comes also from IR and UV/visible spectroscopy of the new {(μ-abcp)[Re(CO)3Cl]2}o/.bul.-/2- redox system. The g values are reproduced reasonably well by d. functional calcns. which confirm higher metal participation at the singly occupied MO and therefore larger contributions from the metal atoms to the g anisotropy in abcp systems compared to abpy complexes. Addnl. calcns. for systems {(μ-abcp)[M(CO)3X]2}.bul.- (M = Tc or Re and X = Cl, and X = F, Cl, or Br with M = Re) provided further insight into the relation between spin d. distribution and g anisotropy. [on SciFinder(R)]Varying 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> und <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> und <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)]What determines the comproportionation constant in molecule-bridged mixed-valence complexes? Evidence for the crucial role of the ligand LUMO in four ruthenium(II)ruthenium(III) dimershttps://puma.ub.uni-stuttgart.de/bibtex/299b300f3415ae63df8e73244441279dd/b_schwederskib_schwederski2019-07-15T13:41:23+02:00azobipyridine bipyridine complex complex;LUMO complex;electron complex;pyridylpyrazine comproportionation;comproportionation comproportionation;pyridyltetrazine comproportionation;sym comproportionation;voltammetry density dinuclear heterocycle mixed nitrogen ruthenium valent voltammetry <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/11c9f5bb409e2cf5c26cf63b9bab8aab6/author/0"><span itemprop="name">S. Ernst</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Volker Kasack" itemprop="url" href="/person/11c9f5bb409e2cf5c26cf63b9bab8aab6/author/1"><span itemprop="name">V. Kasack</span></a></span>, </span> und <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang. Kaim" itemprop="url" href="/person/11c9f5bb409e2cf5c26cf63b9bab8aab6/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">Inorganic Chemistry</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">27 </span></span>(<span itemprop="issueNumber">7</span>):
<span itemprop="pagination">1146--1148</span></em> </span>(<em><span>1988<meta content="1988" itemprop="datePublished"/></span></em>)</span>Mon Jul 15 13:41:23 CEST 2019Inorganic Chemistry71146--1148What determines the comproportionation constant in molecule-bridged mixed-valence complexes? Evidence for the crucial role of the ligand LUMO in four ruthenium(II)ruthenium(III) dimers271988azobipyridine bipyridine complex complex;LUMO complex;electron complex;pyridylpyrazine comproportionation;comproportionation comproportionation;pyridyltetrazine comproportionation;sym comproportionation;voltammetry density dinuclear heterocycle mixed nitrogen ruthenium valent voltammetry Electrochem. data of 4 bis chelate bridged complexes {[Ru(bpy)2]2(μ, η4-L)}n+ (bpy = 2,2'-bipyridine, L = sym. N heterocycle such as 3,6-di-2-pyridyl-1,2,4,5-tetrazine, 2,5-di-2-pyridylpyrazine, 2,2'-bipyrimidine or azo-2,2'-bipyridine) show conclusively that the electron d. at the coordination centers in the LUMO of the bridging \textgreek{p} ligand dets. the comproportionation const. of the RuIIRuIII mixed-valence state (n = 5). Neither the no. of mediating \textgreek{p} centers nor the distance or the orientation of the 2 metal centers plays a significant role. The presence of 2 equiv chiral metal centers in these complexes leads to formation of meso and DL diastereomers, as shown for one example by 1H NMR. [on SciFinder(R)]