PUMA publications for /user/b_schwederski/uvhttps://puma.ub.uni-stuttgart.de/user/b_schwederski/uvPUMA RSS feed for /user/b_schwederski/uv2024-03-28T12:43:02+01:00The conjugative bridging of organometallic reaction centers in heterodinuclear complexes (OC)3ClRe(m-L)MCl(C5Me5)+, M = Rh or Ir - Spectroscopic consequences of reductive activationhttps://puma.ub.uni-stuttgart.de/bibtex/2fd5463166a06bf4a5f23cc0750009b79/b_schwederskib_schwederski2019-07-15T13:41:23+02:00ESR IR UV arom bis bridged chelate chelate;redox chelate;rhenium compd complex complex;spectroelectrochem conjugated electrochem half heterobinuclear heterocyclic iridium ligand;rhodium nitrogen potential prepn;pyrazine prepn;redn pyrimidine rhenium rhodium sandwich tetrazole <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/192aa14ea83b3c7ab8303e2b1f266d0c1/author/0"><span itemprop="name">W. Kaim</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Thomas Scheiring" itemprop="url" href="/person/192aa14ea83b3c7ab8303e2b1f266d0c1/author/1"><span itemprop="name">T. Scheiring</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Michael Weber" itemprop="url" href="/person/192aa14ea83b3c7ab8303e2b1f266d0c1/author/2"><span itemprop="name">M. Weber</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Jan. Fiedler" itemprop="url" href="/person/192aa14ea83b3c7ab8303e2b1f266d0c1/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">Zeitschrift fuer Anorganische und Allgemeine Chemie</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">630 </span></span>(<span itemprop="issueNumber">12</span>):
<span itemprop="pagination">1883--1893</span></em> </span>(<em><span>2004<meta content="2004" itemprop="datePublished"/></span></em>)</span>Mon Jul 15 13:41:23 CEST 2019Zeitschrift fuer Anorganische und Allgemeine Chemie121883--1893The conjugative bridging of organometallic reaction centers in heterodinuclear complexes [(OC)3ClRe(\textgreek{m}-L)MCl(C5Me5)]+, M = Rh or Ir - Spectroscopic consequences of reductive activation6302004ESR IR UV arom bis bridged chelate chelate;redox chelate;rhenium compd complex complex;spectroelectrochem conjugated electrochem half heterobinuclear heterocyclic iridium ligand;rhodium nitrogen potential prepn;pyrazine prepn;redn pyrimidine rhenium rhodium sandwich tetrazole Heterobimetallic rhenium-rhodium and rhenium-iridium organometallic complexes bridged by conjugated bis-chelate nitrogen heterocyclic ligands, were prepd.; their electroredn. gives corresponding radical-anions, which were studied by ESR and IR spectroscopy. Complexes (I-III) [as PF6- salts; M = (\textgreek{h}5-C5Me5)RhCl, (\textgreek{h}5-C5Me5)IrCl] were prepd. by complexation of corresponding rhenium complexes Re(CO)3Cl(bpip), Re(CO)3Cl(bptz) and Re(CO)3Cl(bpym) (bpip, bptz, bpym are for 2,5-bis(1-phenyliminoethyl)pyrazine, 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine and 2,2'-bipyrimidine, resp.) with [(\textgreek{h}5-C5Me5)MCl]2. The stepwise reductive activation accompanied by chloride dissocn. was studied by cyclic voltammetry and spectroelectrochem. in the range of CO stretching vibrations (IR), charge transfer absorptions (UV/Vis) and ESR for paramagnetic intermediates of the mono- and heterobinuclear compds. While complexes of bpip and bptz form one-electron reduced radical intermediates [(OC)3ClRe(\textgreek{m}-L)MCl(C5Me5)].bul., the compds. with bpym follow MCl-dissociative two-electron redn. pathway, giving [(OC)3ClRe(\textgreek{m}-L)M(C5Me5)]. [on SciFinder(R)]Molecule-Bridged Mixed-Valent Intermediates Involving the RuI Oxidation Statehttps://puma.ub.uni-stuttgart.de/bibtex/29f99aa99299b5413b3d79ed4b99a3e16/b_schwederskib_schwederski2019-07-15T13:41:23+02:00UV arene areneruthenium azobispyridine bridged charge complex complex;redox complex;ruthenium dimer;EPR dimer;cyclic diruthenium iminomethylpyrazine mixed potential prepn spectra transfer transition valence voltammetry <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/161c9e4c8a6fd65f897db460b152b8ee1/author/0"><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/161c9e4c8a6fd65f897db460b152b8ee1/author/1"><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/161c9e4c8a6fd65f897db460b152b8ee1/author/2"><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/161c9e4c8a6fd65f897db460b152b8ee1/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">Journal of the American Chemical Society</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">126 </span></span>(<span itemprop="issueNumber">45</span>):
<span itemprop="pagination">14706--14707</span></em> </span>(<em><span>2004<meta content="2004" itemprop="datePublished"/></span></em>)</span>Mon Jul 15 13:41:23 CEST 2019Journal of the American Chemical Society4514706--14707Molecule-Bridged Mixed-Valent Intermediates Involving the RuI Oxidation State1262004UV arene areneruthenium azobispyridine bridged charge complex complex;redox complex;ruthenium dimer;EPR dimer;cyclic diruthenium iminomethylpyrazine mixed potential prepn spectra transfer transition valence voltammetry Binuclear diruthenium cymene complexes bridged by azobis(pyridine) and pyrazine-bis-imine ligands are prepd. and studied by cyclic voltammetry. The diruthenium(II) complexes [(\textgreek{m}-L)[RuCl(\textgreek{h}6-MeC6H4iPr-4)]2](PF6)n, (1, L = 2,2'-azobispyridine (abpy), n = 1; 2, L = 2,5-bis(1-phenyliminoethyl)pyrazine (bpip), n = 2) were prepd. and characterized by NMR and EPR spectroscopy. Whereas the complex 1 has the structure of radical-anion-bridged RuIIRuII complex, the three-electron redn. under loss of both chloride ions produces the ions [(\textgreek{m}-L)[Ru(Cym)]2]+, which could be identified as RuI(4d7)-contg. mixed-valent species (Ru0RuI or RuIRuII) by its intervalence charge-transfer bands around 1500 nm in UV-vis-NIR spectroelectrochem. and EPR, which shows rhombic g tensor anisotropy. The weak metal-metal interaction of the d\textgreek{s} electrons from the eg set is responsible for the small electrochem. coupling with comproportionation consts. Kc $\approx$ 102. [on SciFinder(R)]A study of the reduced states of four isomeric bidiazines (diaza-2,2'-bipyridines) by UV-VIS/NIR-spectroelectrochemistryhttps://puma.ub.uni-stuttgart.de/bibtex/29b4fd11b0ed6cea75e9fce6ff49c1d3e/b_schwederskib_schwederski2019-07-15T13:41:23+02:00IR IR;reduced UV bidiazine bipyrazine bipyridazine bipyrimidine isomer reduced <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Michael Krejcik" itemprop="url" href="/person/1809254d9aa5ddb13f9c21edfb5048cbc/author/0"><span itemprop="name">M. Krejcik</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Stanislav Zalis" itemprop="url" href="/person/1809254d9aa5ddb13f9c21edfb5048cbc/author/1"><span itemprop="name">S. Zalis</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Monika Ladwig" itemprop="url" href="/person/1809254d9aa5ddb13f9c21edfb5048cbc/author/2"><span itemprop="name">M. Ladwig</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Walter Matheis" itemprop="url" href="/person/1809254d9aa5ddb13f9c21edfb5048cbc/author/3"><span itemprop="name">W. Matheis</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang. Kaim" itemprop="url" href="/person/1809254d9aa5ddb13f9c21edfb5048cbc/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, Perkin Transactions 2: Physical Organic Chemistry</span>, </em> </span>(<em><span>1992<meta content="1992" itemprop="datePublished"/></span></em>)</span>Mon Jul 15 13:41:23 CEST 2019Journal of the Chemical Society, Perkin Transactions 2: Physical Organic Chemistry112007--2010A study of the reduced states of four isomeric bidiazines (diaza-2,2'-bipyridines) by UV-VIS/NIR-spectroelectrochemistry1992IR IR;reduced UV bidiazine bipyrazine bipyridazine bipyrimidine isomer reduced Singly and doubly reduced forms of the four isomeric bidiazines 2,2'-bipyrazine, 3,3'-bipyridazine, 2,2'- and 4,4'-bipyrimidine have been generated in a spectroelectrochem. cell and studied by UV-visible/near-IR spectroscopy. As derivs. of 2,2'-bipyridine the compds. exhibit several groups of vibrationally structured long-wavelength bands in the paramagnetic anion radical state. The assignments and variations of transition energies depending on the diaza perturbation may be rationalized using CNDO/S CI calcns. [on SciFinder(R)]Ground state electron transfer between TCNE and one or more 16-electron species containing vanadium, osmium, ruthenium or cobalthttps://puma.ub.uni-stuttgart.de/bibtex/24d129055e8c8edfe8de235a00850986c/b_schwederskib_schwederski2019-07-15T13:41:23+02:00TCNE UV cobalt complex;IR complex;electron complex;magnetic complex;osmium electron ground metal property state transfer transfer;electrochem transfer;ruthenium transfer;vanadium <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/17e0c6ce13896ea30f73750d2c41a793a/author/0"><span itemprop="name">F. Baumann</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Martina Heilmann" itemprop="url" href="/person/17e0c6ce13896ea30f73750d2c41a793a/author/1"><span itemprop="name">M. Heilmann</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Walther Matheis" itemprop="url" href="/person/17e0c6ce13896ea30f73750d2c41a793a/author/2"><span itemprop="name">W. Matheis</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Andreas Schulz" itemprop="url" href="/person/17e0c6ce13896ea30f73750d2c41a793a/author/3"><span itemprop="name">A. Schulz</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang Kaim" itemprop="url" href="/person/17e0c6ce13896ea30f73750d2c41a793a/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="Jeanne. Jordanov" itemprop="url" href="/person/17e0c6ce13896ea30f73750d2c41a793a/author/5"><span itemprop="name">J. Jordanov</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">251 </span></span>(<span itemprop="issueNumber">1-2</span>):
<span itemprop="pagination">239--248</span></em> </span>(<em><span>1996<meta content="1996" itemprop="datePublished"/></span></em>)</span>Mon Jul 15 13:41:23 CEST 2019Inorganica Chimica Acta1-2239--248Ground state electron transfer between TCNE and one or more 16-electron species containing vanadium, osmium, ruthenium or cobalt2511996TCNE UV cobalt complex;IR complex;electron complex;magnetic complex;osmium electron ground metal property state transfer transfer;electrochem transfer;ruthenium transfer;vanadium The reactions between tetracyanoethene (TCNE) and organometallic 16 valence electron fragments from the early, middle and late transition series such as V(C5R5)2Br (R = H, Me), M(PiPr3)2(CO)(H)Cl (M = Os, Ru) or Co(C5H5)(CO) (with Co(C5H5)(CO)2 as precursor) yield complexes which exhibit rather different electronic structures as evident from electrochem., IR and UV-visible absorption spectroscopy, and magnetic susceptibility measurements. With V(C5R5)2Br, the resulting compds. are VIV(C5R5)2Br(TCNE-I) and [VIV(C5R5)2Br]2(TCNE-II); for R = Me, the nonconjugated dinuclear complex exhibits magnetically weakly coupled d1 centers and nitrile stretching bands which are very similar to those of the room temp. magnet [V(TCNE)x]·yCH2Cl2 and of structurally characterized [IrI(PPh3)2(CO)]2(TCNE-II). In contrast to this spectroscopic and magnetic evidence for two consecutive metal-to-TCNE electron transfers, the reaction of TCNE with M(PiPr3)2(CO)(H)Cl (M = Ru, Os) involves an electron transfer process only for the 1st metal coordination step. Di- and tetranuclear [Os(PiPr3)2(CO)(H)Cl]2,4(TCNE) show a similar behavior to the recently reported organomanganese and pentaammineruthenium compds. with corresponding d electron configurations. Attempts are made to correlate spectroscopic results with the structurally detd. \textgreek{p} conjugation and the extent of metal-to-ligand electron transfer in the ground state. Three different kinds of electron configurations in dinuclear systems of \textgreek{m},\textgreek{h}1:\textgreek{h}1-TCNEn- are thus described: nonconjugated d1-(TCNE2-)-d1 (V) and d8-(TCNE2-)-d8 (Ir) and conjugated d6-(TCNE·-)-d5 (Os, Mn). In contrast, the 16-electron species Co(C5H5)(CO) probably binds to reduced TCNE only once and in a side-on fashion. [on SciFinder(R)]Electronic Structure of p-Conjugated Redox Systems with Borane/Borataalkene End Groupshttps://puma.ub.uni-stuttgart.de/bibtex/2f080c53f8fcf59bcd951a0838924a422/b_schwederskib_schwederski2019-07-15T13:41:23+02:00IR IR;borane IR;conformation UV anion borane borataalkene;MO conjugated dimesitylphenylborane dimesitylphenylborane;electronic dimesitylphenylborane;spectroelectrochem mesityl mesitylphenylborane mesitylphenylborane;crystal model phenyl radical redox spectroelectrochem structure system;mol <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Jan Fiedler" itemprop="url" href="/person/169ccca4ad216da33e02187bb7f180892/author/0"><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/169ccca4ad216da33e02187bb7f180892/author/1"><span itemprop="name">S. Zalis</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Axel Klein" itemprop="url" href="/person/169ccca4ad216da33e02187bb7f180892/author/2"><span itemprop="name">A. Klein</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Fridmann Hornung" itemprop="url" href="/person/169ccca4ad216da33e02187bb7f180892/author/3"><span itemprop="name">F. Hornung</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang. Kaim" itemprop="url" href="/person/169ccca4ad216da33e02187bb7f180892/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">Inorganic Chemistry</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">35 </span></span>(<span itemprop="issueNumber">10</span>):
<span itemprop="pagination">3039--3043</span></em> </span>(<em><span>1996<meta content="1996" itemprop="datePublished"/></span></em>)</span>Mon Jul 15 13:41:23 CEST 2019Inorganic Chemistry103039--3043Electronic Structure of \textgreek{p}-Conjugated Redox Systems with Borane/Borataalkene End Groups351996IR IR;borane IR;conformation UV anion borane borataalkene;MO conjugated dimesitylphenylborane dimesitylphenylborane;electronic dimesitylphenylborane;spectroelectrochem mesityl mesitylphenylborane mesitylphenylborane;crystal model phenyl radical redox spectroelectrochem structure system;mol The compds. 1,4-bis(dimesitylboryl)benzene (1), 4,4'-bis(dimesitylboryl)biphenyl (2), and dimesitylphenylborane (3) were studied by UV/visible/near-IR spectroelectrochem. In contrast to the colorless precursor compds., all neg. charged species 1.bul.-/2-, 2.bul.-/2-, and 3.bul.- exhibit intense long-wavelength absorption maxima in the visible or near-IR region, e.g., at 1305 nm (\textgreek{e} = 31,200 M-1 cm-1; 2.bul.-) or at 736 nm (\textgreek{e} = 67,700 M-1 cm-1; 22-). The absorption bands of the organoborane anion radicals and their appearance, including their vibrational structuring, resemble those of corresponding amine radical cations such as Wurster's Blue. The conformation of the dimesitylboryl substituent toward a Ph ring was established using the crystal structure results for 3 (C24H27B, monoclinic, space group C2/c, a 13.324(3), b 9.143(2), c 16.303(3) {\AA}, \textgreek{b} 98.93(3)°, Z = 4, R = 0.0493). Ab initio calcns. (6-31G**) on the BH2-substituted analogs of 1-3 and on 3 proper confirmed the concept of an increasingly quinonoid distortion of the organoboron redox systems on redn. and served in assigning the obsd. electronic transitions. A 23-35{\%} participation of the B \textgreek{p} centers at the lowest unoccupied MOs is in agreement with results from EPR/ENDOR measurements of the radical intermediates, indicating sizable contributions from the diboratasemiquinone or -in the extreme- from delocalized BIII/BII mixed-valent formulations in the bifunctional compds. 1.bul.- and 2.bul.-. [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> 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)]Singlet Diradical Complexes of Ruthenium and Osmium: Geometrical and Electronic Structures and their Unexpected Changes on Oxidationhttps://puma.ub.uni-stuttgart.de/bibtex/28950c41ae4f0d549e5eaf027172d5bcf/b_schwederskib_schwederski2019-07-15T13:41:23+02:008 ESR UV crystal diradical electrochem metal osmium oxidn phenylaminophenylazopyridine phenylaminophenylazopyridine;group prepn ruthenium singlet spectroelectrochem;phenylaminophenylazopyridine structure <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Subhas Samanta" itemprop="url" href="/person/11b1d485edea96886ada4586681e9f47f/author/0"><span itemprop="name">S. Samanta</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Priti Singh" itemprop="url" href="/person/11b1d485edea96886ada4586681e9f47f/author/1"><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/11b1d485edea96886ada4586681e9f47f/author/2"><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/11b1d485edea96886ada4586681e9f47f/author/3"><span itemprop="name">S. Zalis</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang Kaim" itemprop="url" href="/person/11b1d485edea96886ada4586681e9f47f/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="Sreebrata. Goswami" itemprop="url" href="/person/11b1d485edea96886ada4586681e9f47f/author/5"><span itemprop="name">S. Goswami</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">47 </span></span>(<span itemprop="issueNumber">5</span>):
<span itemprop="pagination">1625--1633</span></em> </span>(<em><span>2008<meta content="2008" itemprop="datePublished"/></span></em>)</span>Mon Jul 15 13:41:23 CEST 2019Inorganic Chemistry51625--1633Singlet Diradical Complexes of Ruthenium and Osmium: Geometrical and Electronic Structures and their Unexpected Changes on Oxidation4720088 ESR UV crystal diradical electrochem metal osmium oxidn phenylaminophenylazopyridine phenylaminophenylazopyridine;group prepn ruthenium singlet spectroelectrochem;phenylaminophenylazopyridine structure Reaction of HL, HLa (2-[(2-N-phenylamino)phenylazo]pyridine), HLb (2-[{2-N-(4-methylphenyl)amino}phenylazo]pyridine), or HLc (2-[{2-N-(4-chlorophenyl)amino}phenylazo]pyridine), with KRuO4 or OsO4 and PPh3 under exhaustive deoxygenation (PPh3 $\rightarrow$ OPPh3) yields diamagnetic compds. ML2. Crystal structure detn. for M(La)2 indicates the ligand radical dianion state, L.bul.2-, as evident from a typical N-N bond length of $\sim$1.33 {\AA} for a 1-electron reduced azo function. The resulting spin-coupled complexes, MIV(L.bul.2-)2, can be oxidized in two reversible 1-electron steps, as probed by cyclic voltammetry and UV-visible-NIR spectroelectrochem. The paramagnetic intermediates, [M(La)2]+, are distinguished by intense NIR absorption, largely metal-centered spin as revealed by EPR, and, in the case of [Os(La)2]I3, by crystallog. detd. shortening of the N=N bond to $\sim$1.30 {\AA}, corresponding to a coordinated unreduced azo function. Thus, oxidn. of MIV(L.bul.2-)2 involves partial redn. of the metal in [MIII(L-)2]+ because intramol. double electron transfer is offsetting the external charge removal. D.-functional theory calcns. were employed to confirm the structural features and to support the spectroscopic assignments. [on SciFinder(R)]Complexes of a-diimines with pentamethylcyclopentadienylrhodium in different oxidation stateshttps://puma.ub.uni-stuttgart.de/bibtex/27fd87499daf447df52eae24ed953ffa9/b_schwederskib_schwederski2019-07-15T13:41:23+02:00UV complex complex;diazabutadiene cyclic diimine electrochem;rhodium pentamethylcyclopentadienyl pentamethylcyclopentadienylrhodium prepn voltammetry <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Ralf Reinhardt" itemprop="url" href="/person/133abf273b6b5b9501e8e1bb5d49ab5f8/author/0"><span itemprop="name">R. Reinhardt</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang. Kaim" itemprop="url" href="/person/133abf273b6b5b9501e8e1bb5d49ab5f8/author/1"><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">Zeitschrift fuer Anorganische und Allgemeine Chemie</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">619 </span></span>(<span itemprop="issueNumber">12</span>):
<span itemprop="pagination">1998--2005</span></em> </span>(<em><span>1993<meta content="1993" itemprop="datePublished"/></span></em>)</span>Mon Jul 15 13:41:23 CEST 2019Zeitschrift fuer Anorganische und Allgemeine Chemie121998--2005Complexes of \textgreek{a}-diimines with pentamethylcyclopentadienylrhodium in different oxidation states6191993UV complex complex;diazabutadiene cyclic diimine electrochem;rhodium pentamethylcyclopentadienyl pentamethylcyclopentadienylrhodium prepn voltammetry Cationic complexes [Cp*RhCl(\textgreek{a}-diimine)]+ of trivalent rhodium and heterocyclic \textgreek{a}-diimines or 1,4-disubstituted 1,4-diazabutadienes were isolated as hexafluorophosphates and subjected to electrochem. studies. Chem. or electrochem. two electron redn. yields intensely colored and highly reactive neutral complexes Cp*Rh(\textgreek{a}-diimine) which are very easily oxidized and which can be reduced further at neg. potentials. The electronic structure of these compds. was studied using 1H-NMR and UV/Vis spectroscopy. Comparisons of charge transfer (CT) transition energies with redox potentials suggest very variable geometrical changes between ground and CT excited states. [on SciFinder(R)]Probing Mixed Valence in a New tppz-Bridged Diruthenium(III,II) Complex (μ-tppz)Ru(bik)Cl23+ (tppz = 2,3,5,6-Tetrakis(2-pyridyl)pyrazine, bik = 2,2'-Bis(1-methylimidazolyl)ketone): EPR Silence, Intervalence Absorption, and nCO Line Broadeninghttps://puma.ub.uni-stuttgart.de/bibtex/2c41133118aa0b9c23b8cd30ea2ceac86/b_schwederskib_schwederski2019-07-15T13:41:23+02:00ESR IR UV charge electrochem methylimidazolylketone methylimidazolylketone;intervalence methylimidazolylketone;ruthenium mixed oxidn prepn pyridylpyrazine redn ruthenium transfer transition valent <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Moumita Koley" itemprop="url" href="/person/1824c1221f56dc19adb48da1837f4f0bf/author/0"><span itemprop="name">M. Koley</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Biprajit Sarkar" itemprop="url" href="/person/1824c1221f56dc19adb48da1837f4f0bf/author/1"><span itemprop="name">B. Sarkar</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Sandeep Ghumaan" itemprop="url" href="/person/1824c1221f56dc19adb48da1837f4f0bf/author/2"><span itemprop="name">S. Ghumaan</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Ece Bulak" itemprop="url" href="/person/1824c1221f56dc19adb48da1837f4f0bf/author/3"><span itemprop="name">E. Bulak</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Jan Fiedler" itemprop="url" href="/person/1824c1221f56dc19adb48da1837f4f0bf/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/1824c1221f56dc19adb48da1837f4f0bf/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/1824c1221f56dc19adb48da1837f4f0bf/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">46 </span></span>(<span itemprop="issueNumber">9</span>):
<span itemprop="pagination">3736--3742</span></em> </span>(<em><span>2007<meta content="2007" itemprop="datePublished"/></span></em>)</span>Mon Jul 15 13:41:23 CEST 2019Inorganic Chemistry93736--3742Probing Mixed Valence in a New tppz-Bridged Diruthenium(III,II) Complex {(μ-tppz)[Ru(bik)Cl]2}3+ (tppz = 2,3,5,6-Tetrakis(2-pyridyl)pyrazine, bik = 2,2'-Bis(1-methylimidazolyl)ketone): EPR Silence, Intervalence Absorption, and \textgreek{n}CO Line Broadening462007ESR IR UV charge electrochem methylimidazolylketone methylimidazolylketone;intervalence methylimidazolylketone;ruthenium mixed oxidn prepn pyridylpyrazine redn ruthenium transfer transition valent The complex dication of the diruthenium(II) compd. {(μ-tppz)[Ru(bik)Cl]2}(ClO4)2 can be oxidized and reduced in two 1-electron steps each. In MeCN/0.1 M Bu4NPF6, the odd-electron intermediates{(μ-tppz)[Ru(bik)Cl]2}n+, n = 1 and 3, have comproportionation consts. of 7 $\times$ 108 and 1 $\times$ 105, resp. Both exhibit near-IR absorptions, in the case of n = 3 the 1640 nm band (\textgreek{e} = 1200 M-1 cm-1, \textgreek{Dn}1/2 = 1560 cm-1) is attributed to an intervalence charge-transfer transition. While the mixed-valent intermediate (n = 3) is EPR silent even at 4 K, the n = 1 form shows g(‖) 2.005 and g($\bot$) 1.994 at that temp., signifying a diruthenium(II) complex of the tppz.bul.- radical anion. The variation of energy and intensity of \textgreek{n}CO and of the ring vibration band around 1590 cm-1 was monitored not only for {(μ-tppz)[Ru(bik)Cl]2}n+, n = 0-4, but also for the mononuclear {(tppz)Ru(bik)Cl}n+, n = 0-2. In the dinuclear complex the carbonyl stretching bands of the spectator ligand bik are shifted by $\sim$15 cm-1 on each 1-electron-transfer step, increasing with the pos. charge. The mixed-valent {(μ-tppz)[Ru(bik)Cl]2}3+ shows a perceptibly broader \textgreek{n}CO band, suggesting incomplete valence averaging (partial localization). [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/b_schwederskib_schwederski2019-07-15T13:41:23+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>Mon Jul 15 13:41:23 CEST 2019Organometallics176305--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)]