Copper complexes with non-innocent ligands: probing CuII/catecholato-CuI/o-semiquinonato redox isomer equilibria with EPR spectroscopy

Autor:	Matthias Wanner, Axel Knödler, Wolfgang Kaim, Stanislav Záliš
Rok vydání:	2002
Předmět:	Ligand chemistry.chemical_element Disproportionation Photochemistry Copper Redox Non-innocent ligand law.invention Inorganic Chemistry Electron transfer Crystallography chemistry law Intramolecular force Materials Chemistry Physical and Theoretical Chemistry Electron paramagnetic resonance
Zdroj:	Inorganica Chimica Acta. 337:163-172
ISSN:	0020-1693
Popis:	The temperature-dependent intramolecular metal/ligand electron transfer equilibrium (L)Cu II (Q 2− )⇌(L)Cu I (Q − ) has been quantitatively analyzed by EPR as a function of the non-innocent o -quinonoid ligand Q and of the co-ligand L. Suitable co-ligands were 1-methyl-(2-methylthiomethyl)-1 H -benzimidazole and 1-diphenylphosphino-2-dimethylaminoethane (dde) which can tolerate both copper oxidation states. EPR hyperfine data were extracted for a variety of alkyl- and methoxy-substituted o -semiquinones and their copper(I) complexes in solution. A close match of Q and Cu redox orbitals is essential for observing the redox isomer equilibrium which has been similarly reported for aminoxidase enzymes. Efforts to isolate the mixed-ligand compounds from solution failed due to coordination disproportionation. The new [Cu(dde) 2 ](ClO 4 ) was structurally characterized with comparable CuN and CuP distances of 2.24–2.27 A and a PCuP angle of 142.41(5) o , the ‘2+2’ coordination pattern could be reproduced by DFT calculations.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::e0ddbc8c4116c01c3ae406586d2dcff4 https://doi.org/10.1016/s0020-1693(02)01081-2 Zobrazit plný text záznamu Full Text from ScienceDirect