PUMA publications for /user/b_schwederski/complex;substituent%20configurationhttps://puma.ub.uni-stuttgart.de/user/b_schwederski/complex;substituent%20configurationPUMA RSS feed for /user/b_schwederski/complex;substituent%20configuration2024-03-28T23:16:40+01:00When Is an Odd-Electron Dinuclear Complex a Mixed-Valent Species? Tuning of Ligand-to-Metal Spin Shifts in Diruthenium(III,II) Complexes of Noninnocent Bridging Ligands OC(R)NNC(R)Ohttps://puma.ub.uni-stuttgart.de/bibtex/285037b5699fc4d95fb243b6f4e00bb97/b_schwederskib_schwederski2019-07-15T13:41:23+02:00azodicarbonyl complex complex;electron complex;mixed complex;substituent configuration dinuclear effect electrochem ruthenium valence <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Volker Kasack" itemprop="url" href="/person/125714849b0526cc5cc087918a8ef7ff4/author/0"><span itemprop="name">V. Kasack</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Wolfgang Kaim" itemprop="url" href="/person/125714849b0526cc5cc087918a8ef7ff4/author/1"><span itemprop="name">W. Kaim</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Herbert Binder" itemprop="url" href="/person/125714849b0526cc5cc087918a8ef7ff4/author/2"><span itemprop="name">H. Binder</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Jeanne Jordanov" itemprop="url" href="/person/125714849b0526cc5cc087918a8ef7ff4/author/3"><span itemprop="name">J. Jordanov</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Eberhard. Roth" itemprop="url" href="/person/125714849b0526cc5cc087918a8ef7ff4/author/4"><span itemprop="name">E. Roth</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">34 </span></span>(<span itemprop="issueNumber">7</span>):
<span itemprop="pagination">1924--1933</span></em> </span>(<em><span>1995<meta content="1995" itemprop="datePublished"/></span></em>)</span>Mon Jul 15 13:41:23 CEST 2019Inorganic Chemistry71924--1933When Is an Odd-Electron Dinuclear Complex a Mixed-Valent Species? Tuning of Ligand-to-Metal Spin Shifts in Diruthenium(III,II) Complexes of Noninnocent Bridging Ligands OC(R)NNC(R)O341995azodicarbonyl complex complex;electron complex;mixed complex;substituent configuration dinuclear effect electrochem ruthenium valence {(Adc-R)[Ru(bpy)2]2}n with bpy = 2,2'-bipyridine and adc-R = azodicarbonyl ligands O:C(R)N:NC(R):O, R = NR'2 (piperidyl), OEt, OCH2Ph, Me, Ph, 4-C6H4COOH, and 4-C6H4COOMe, can exist in several oxidn. states (n = 2-, 0, 2+, 3+, 4+) of which the stable (comproportionation const. Kc {\textgreater} 5 $\times$ 107) and isolable paramagnetic intermediates (n = 3+) exhibit a considerable and remarkably tunable degree of metal/ligand/metal orbital mixing. The occurrence of intense (\textgreek{e} {\textgreater} 7000 M-1 cm-1) and small solvatochromic absorption bands at $\sim$1500 nm, the temp.-dependent magnetic moment (\textgreek{m}eff = 1.6-2.1 \textgreek{m}B) detd. for one deriv., and the IR vibrational spectra did not allow one to make a conclusive detn. of metal oxidn. states; however, the EPR spectra observable only {\textless}50 K reveal a strongly substituent- (R-) dependent degree of metal contribution to the singly occupied MO. XPS measurements of two 3+ ions which show Ru(II) and Ru(III) signals also exhibit a marked substituent effect on the electronic structure. Whereas the 4+ ions formed at rather pos. potentials also seem to possess strongly mixed frontier orbitals, the stable 2+ ions clearly contain two Ru(II) centers and fully reduced, i.e. 1,2-dicarbonylhydrazido(2-), bridging ligands, [O:C(R)-N-N-C(R):O]2-. The results are interpreted within a hole vs. electron transfer scheme, based on a three-site MO model for the metal/metal communication in ligand-bridged mixed-valent dimers according to which the intermediates {(adc-R)[Ru(bpy)2]2}3+ are best described as delocalized systems with varying contributions from RuII/(adc-R).bul.-/RuII and RuII/(adc-R)2-/RuIII resonance forms. [on SciFinder(R)]