PUMA publications for /user/b_schwederski/vib%20electrochemhttps://puma.ub.uni-stuttgart.de/user/b_schwederski/vib%20electrochemPUMA RSS feed for /user/b_schwederski/vib%20electrochem2024-03-29T07:31:13+01:00Four bridging bis chelate ligands with very low lying p* orbitals. MO perturbation calculations, electrochemistry, and spectroscopy of mononuclear and binuclear group 6 metal tetracarbonyl complexeshttps://puma.ub.uni-stuttgart.de/bibtex/232ee25b910134ec22e13a1b299291934/b_schwederskib_schwederski2019-07-15T13:41:23+02:00Group MO VIB azobipyridine bipyrimidine bischelant carbonyl;Group carbonyl;MO carbonyl;electronic carbonyl;energy electrochem electrochem;bipyrimidine electrochem;electrochem electrochem;pyridyltetrazine level pyridylpyrazine pyridyltetrazine;pyridylpyrazine transition <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/16939cad18951d07991ceb8002a8240c6/author/0"><span itemprop="name">W. Kaim</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Stephan. Kohlmann" itemprop="url" href="/person/16939cad18951d07991ceb8002a8240c6/author/1"><span itemprop="name">S. Kohlmann</span></a></span></span>. </span><span class="additional-entrytype-information"><span itemtype="http://schema.org/PublicationIssue" itemscope="itemscope" itemprop="isPartOf"><em><span itemprop="journal">Inorganic Chemistry</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">26 </span></span>(<span itemprop="issueNumber">1</span>):
<span itemprop="pagination">68--77</span></em> </span>(<em><span>1987<meta content="1987" itemprop="datePublished"/></span></em>)</span>Mon Jul 15 13:41:23 CEST 2019Inorganic Chemistry168--77Four bridging bis chelate ligands with very low lying \textgreek{p}* orbitals. MO perturbation calculations, electrochemistry, and spectroscopy of mononuclear and binuclear group 6 metal tetracarbonyl complexes261987Group MO VIB azobipyridine bipyrimidine bischelant carbonyl;Group carbonyl;MO carbonyl;electronic carbonyl;energy electrochem electrochem;bipyrimidine electrochem;electrochem electrochem;pyridyltetrazine level pyridylpyrazine pyridyltetrazine;pyridylpyrazine transition Coordination characteristics of the 4 bridging, \textgreek{p}-delocalized bis chelate ligands 2,2'-bipyrimidine (bpym), 2,5-bis(2-pyridyl)pyrazine (bppz), 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine (bptz), and azo-2,2'-bipyridine (abpy) were evaluated with use of \textgreek{p} MO perturbation calcns. and were studied exptl. by example of mononuclear and binuclear complexes with the fragments M(CO)4 (M = Cr, Mo, W). The substantial stabilization of the \textgreek{p}* (LUMO) levels in the order bpym, bppz, bptz, abpy strongly facilitates redn. of the complexes and causes shifts of the intense metal-to-ligand charge-transfer (LMCT) absorption bands out into the near-IR region. Despite a notable activation barrier for the formation of binuclear abpy complexes with 6-coordinate metals, (abpy)[Mo(CO)4]2 was prepd. and it exhibits most remarkable spectral properties such as an intense yet rather narrow and solvent-insensitive MLCT absorption band at 11,000 cm-1, another detectable absorption max. {\textgreater}30,000 cm-1, a redn. potential close to that of the ref. electrode, SCE, and closely spaced yet well-resolved CO stretching frequencies in the IR spectrum. All these spectral results can be correlated to \textgreek{p} MO calcn. data, which strongly suggest the use of bptz and abpy for studies concerned with ligand-mediated electronic interactions between metal centers. A particular asset of binuclear abpy complexes is the unusually short metal-metal distance caused by their coordination-induced S-frame conformation. [on SciFinder(R)]Chemical and electrochemical reduction of pentacarbonyl(4-cyanopyridine) complexes of chromium(0), molybdenum(0) and tungsten(0)https://puma.ub.uni-stuttgart.de/bibtex/25056e1fad6ccf8772eaa446088a4cf10/b_schwederskib_schwederski2019-07-15T13:41:23+02:00Group VIB carbonyl chem chromium complex;ESR complex;tungsten cyanopyridine cyanopyridine;molybdenum electrochem electroredn electroredn;cyanopyridine electroredn;redn pentacarbonyl redn redn;electroredn <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/1d86f453cd52b5ebeb4eac3a93ee78896/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">Inorganic Chemistry</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">23 </span></span>(<span itemprop="issueNumber">4</span>):
<span itemprop="pagination">504--506</span></em> </span>(<em><span>1984<meta content="1984" itemprop="datePublished"/></span></em>)</span>Mon Jul 15 13:41:23 CEST 2019Inorganic Chemistry4504--506Chemical and electrochemical reduction of pentacarbonyl(4-cyanopyridine) complexes of chromium(0), molybdenum(0) and tungsten(0)231984Group VIB carbonyl chem chromium complex;ESR complex;tungsten cyanopyridine cyanopyridine;molybdenum electrochem electroredn electroredn;cyanopyridine electroredn;redn pentacarbonyl redn redn;electroredn The complexes [LM(CO)5] (L = 4-cyanopyridine and M = Cr, Mo, W) were reduced by K in THF and at a glassy C electrode in DMF. The resulting radical anion complexes [LM(CO)5]-. were also obtained from replacement reactions of the metal hexacarbonyls with the ligand radical anion L-. or via electron transfer from decacarbonyldimetalates to the free ligand L. The radical complexes were characterized by high resoln. ESR. The unpaired electron resides predominately in the heterocyclic ligand; only minor perturbations of spin distribution occur via the metal fragments. The results are related to the MLCT features in the electronic spectra of these complexes. [on SciFinder(R)]Ambidentate ligand with high p-acceptor capacity: D6-metal complexes of 4,4'-bipyrimidinehttps://puma.ub.uni-stuttgart.de/bibtex/2dd46420ded7276f8b1fe5f6a1f5c2fbe/b_schwederskib_schwederski2019-07-15T13:41:23+02:00Group VIB bipyridine bipyrimidine bipyrimidine;bipyrimidine bipyrimidine;chromium bipyrimidine;tungsten carbonyl carbonyl;molybdenum carbonyl;redox electrochem metal ruthenium ruthenium;carbonyl transition <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/1a7fdf3b06bd5b5af5d5653c78b31ab31/author/0"><span itemprop="name">S. Ernst</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang. Kaim" itemprop="url" href="/person/1a7fdf3b06bd5b5af5d5653c78b31ab31/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">Angewandte Chemie</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">97 </span></span>(<span itemprop="issueNumber">5</span>):
<span itemprop="pagination">431--433</span></em> </span>(<em><span>1985<meta content="1985" itemprop="datePublished"/></span></em>)</span>Mon Jul 15 13:41:23 CEST 2019Angewandte Chemie5431--433Ambidentate ligand with high \textgreek{p}-acceptor capacity: D6-metal complexes of 4,4'-bipyrimidine971985Group VIB bipyridine bipyrimidine bipyrimidine;bipyrimidine bipyrimidine;chromium bipyrimidine;tungsten carbonyl carbonyl;molybdenum carbonyl;redox electrochem metal ruthenium ruthenium;carbonyl transition M(CO)5(THF) (M = Cr, Mo, W), Ru(bpy)2Cl2 (bpy = 2,2'-bipyridine), and RuCl2(DMSO)4 reacted with 4,4'-bipyrimidine (L) to give M(CO)4L, [Ru(bpy)2L](PF6)2, and [RuL3](PF6)2, resp. [W(CO)5]2L, that was prepd. from W(CO)5(THF) and L (2:1 ratio), under reflux was converted to W(CO)4L. The redox potentials are obtained for M(CO)4L, [Ru(bpy)2L](PF6)2, and [W(CO)5]2L. For [RuL3](PF6)2 the elec. potentials were obtained for the Ru3+/Ru2+, Ru2+/Ru+, Ru+/Ru0, and Ru0/Ru- couples. The complexes were characterized by IR, electronic, NMR, and ESR spectra. [on SciFinder(R)]