Vinyl ruthenium-modified biphenyl and 2,2'-bipyridines

We report here on ruthenium alkenyl complexes 2 and 3 derived from 2,2'-bipyridine and their Re(CO)3X adducts 4a,b and 5. Detailed electrochemical studies on these complexes and spectroscopic characterization of their oxidized forms by IR, UV/vis/NIR, and electron paramagnetic resonance spectro...

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Bibliographic Details
Published in:	Inorganic chemistry Vol. 54; no. 7; p. 3387
Main Authors:	Scheerer, Stefan, Rotthowe, Nils, Abdel-Rahman, Obadah S, He, Xiaoyan, Rigaut, Stéphane, Kvapilová, Hana, Záliš, Stanislav, Winter, Rainer F
Format:	Journal Article
Language:	English
Published:	United States 06.04.2015
ISSN:	1520-510X, 1520-510X
Online Access:	Get more information
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Summary:	We report here on ruthenium alkenyl complexes 2 and 3 derived from 2,2'-bipyridine and their Re(CO)3X adducts 4a,b and 5. Detailed electrochemical studies on these complexes and spectroscopic characterization of their oxidized forms by IR, UV/vis/NIR, and electron paramagnetic resonance spectroscopies as well as quantum chemical studies reveal sizable (bridging) ligand contributions to the redox orbitals. Engagement of the free bipy functions of complexes 2 and 3 in binding to the electron-withdrawing fac-Re(CO)3X (X = Br, Cl) moiety enhances the metal-to-ligand charge-transfer character of the optical excitations, causes sizable anodic shifts of the redox potentials, and decreases the number of observable anodic redox waves by one when compared to complexes 2 and 3. Despite the decreasing electron density at the terminal or bridging alkenyl bipyridine ligand, the anodic redox processes still maintain appreciable ligand character as is seen by the shifts of the Ru(CO) and Re(CO)3 stretching frequencies on oxidation. Binding of the fac-Re(CO)3X moiety also attenuates the degree of ground-state delocalization in the mixed-valent states.
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	1520-510X 1520-510X
DOI:	10.1021/ic503075e