PUMA publications for /user/b_schwederski/osmium%20complex;osmium%20valencehttps://puma.ub.uni-stuttgart.de/user/b_schwederski/osmium%20complex;osmium%20valencePUMA RSS feed for /user/b_schwederski/osmium%20complex;osmium%20valence2024-03-28T22:08:13+01:00Widely Separated Reduction Processes of abpy-Coupled Areneosmium(II) Reaction Centers (abpy = 2,2'-Azobispyridine): Stabilization of the Radical Intermediate and of the Os0OsII Statehttps://puma.ub.uni-stuttgart.de/bibtex/26ea5ed9e751d121fcf7d05f0f28b635f/b_schwederskib_schwederski2019-07-15T13:41:23+02:00arene osmium EPR complex diosmium mixed cation redox valence bipyrimidine spectra azobispyridine potential;radical complex;osmium binuclear bridged <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Frank Baumann" itemprop="url" href="/person/1f4a36d58d4abd338c6d3bd6bb589fca0/author/0"><span itemprop="name">F. Baumann</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang Kaim" itemprop="url" href="/person/1f4a36d58d4abd338c6d3bd6bb589fca0/author/1"><span itemprop="name">W. Kaim</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Gert Denninger" itemprop="url" href="/person/1f4a36d58d4abd338c6d3bd6bb589fca0/author/2"><span itemprop="name">G. Denninger</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Hans-Juergen Kuemmerer" itemprop="url" href="/person/1f4a36d58d4abd338c6d3bd6bb589fca0/author/3"><span itemprop="name">H. Kuemmerer</span></a></span>, </span> und <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Jan. Fiedler" itemprop="url" href="/person/1f4a36d58d4abd338c6d3bd6bb589fca0/author/4"><span itemprop="name">J. Fiedler</span></a></span></span>. </span><span class="additional-entrytype-information"><span itemtype="http://schema.org/PublicationIssue" itemscope="itemscope" itemprop="isPartOf"><em><span itemprop="journal">Organometallics</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">24 </span></span>(<span itemprop="issueNumber">8</span>):
<span itemprop="pagination">1966--1973</span></em> </span>(<em><span>2005<meta content="2005" itemprop="datePublished"/></span></em>)</span>Mon Jul 15 13:41:23 CEST 2019Organometallics81966--1973Widely Separated Reduction Processes of abpy-Coupled Areneosmium(II) Reaction Centers (abpy = 2,2'-Azobispyridine): Stabilization of the Radical Intermediate and of the Os0OsII State242005arene osmium EPR complex diosmium mixed cation redox valence bipyrimidine spectra azobispyridine potential;radical complex;osmium binuclear bridged Mono- and binuclear 2,2'-azobispyridine and 2,2'-bipyrimidine-bridged osmium arene complexes were prepd.; their redox reactions afford mixed-valence odd-electron intermediates, which structure was evaluated by EPR spectra. Electrochem. reactivity patterns were established by cyclic voltammetry, EPR, and UV/vis spectroelectrochem. for the transition [(C6Me6)ClOs]+/[(C6Me6)Os] in mononuclear and dinuclear complexes with the 2,2'-azobispyridine (abpy) and 2,2'-bipyrimidine (bpym) bridging ligands. The isolated electron reservoir intermediate {[(μ-abpy)OsCl(C6Me6)]2}.bul.+ could be analyzed by X band and W band EPR with regard to 189Os hyperfine splitting and g anisotropy as an abpy anion radical species with significant contribution from the metal centers. The function of the \textgreek{p}-conjugated acceptor ligand in mediating the interaction between two equiv. electron and atom transfer sites was analyzed through simulation of the cyclic voltammograms. In comparison with the system bridged by 2,2'-bipyrimidine, the dinuclear abpy complex displays a much stronger interaction between the two organometallic reaction centers, as illustrated by the 1.14 V vs. 0.42 V splitting between the redox potentials sepg. the two chloride-dissociative processes, i.e., stabilizing the Os0OsII mixed-valent form [(Me6C6)Os(\textgreek{m}-abpy)OsCl(C6Me6)]+. This result parallels the observations made for (C5Me5)Rh- and (C5Me5)Ir-contg. analogs and for the coupling of pure electron transfer centers through such bridging ligands. [on SciFinder(R)]Valence Delocalization despite Weak Metal-Metal Coupling in a Bis(organoosmium(III,II)) Complex with a Pyrazine Bridgehttps://puma.ub.uni-stuttgart.de/bibtex/20d01fac4d94e4cf3b665bacaa9a7d77a/b_schwederskib_schwederski2019-07-15T13:41:23+02:00dinuclear complex;osmium pyrazine delocalization;spectroelectrochem osmium complex electrochem complex;mixed bridged valence oxidn prepn <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Markus Gloeckle" itemprop="url" href="/person/19be7c5bab07080bb3df97b131144d3f5/author/0"><span itemprop="name">M. Gloeckle</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang Kaim" itemprop="url" href="/person/19be7c5bab07080bb3df97b131144d3f5/author/1"><span itemprop="name">W. Kaim</span></a></span>, </span> und <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Jan. Fiedler" itemprop="url" href="/person/19be7c5bab07080bb3df97b131144d3f5/author/2"><span itemprop="name">J. Fiedler</span></a></span></span>. </span><span class="additional-entrytype-information"><span itemtype="http://schema.org/PublicationIssue" itemscope="itemscope" itemprop="isPartOf"><em><span itemprop="journal">Organometallics</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">17 </span></span>(<span itemprop="issueNumber">23</span>):
<span itemprop="pagination">4923--4925</span></em> </span>(<em><span>1998<meta content="1998" itemprop="datePublished"/></span></em>)</span>Mon Jul 15 13:41:23 CEST 2019Organometallics234923--4925Valence Delocalization despite Weak Metal-Metal Coupling in a Bis(organoosmium(III,II)) Complex with a Pyrazine Bridge171998dinuclear complex;osmium pyrazine delocalization;spectroelectrochem osmium complex electrochem complex;mixed bridged valence oxidn prepn Carbonyl vibrational spectroelectrochem. of {(μ-pz)[Os(PiPr3)2(CO)(H)Cl]2}0/+ in dichloromethane reveals valence delocalization of the mixed-valent state despite relatively weak metal-metal coupling, as evident from the comproportionation const. Kc = 104.3 and the intervalence charge-transfer band at 1705 nm (\textgreek{e} = 1250 M-1 cm-1, \textgreek{Dn}1/2 = 3700 cm-1). The rather low charge and nonpolar medium, i.e., the absence of valence trapping by counterions or solvent mols., favor this particular situation. [on SciFinder(R)]