Evidence for Bidirectional Noninnocent Behavior of a Formazanate Ligand in Ruthenium Complexes

0446716 - ÚFCH JH 2016 RIV US eng J - Journal Article
Mandal, A. B. - Schwederski, B. - Fiedler, Jan - Kaim, W. - Lahiri, G. K.
Evidence for Bidirectional Noninnocent Behavior of a Formazanate Ligand in Ruthenium Complexes.
Inorganic Chemistry. Roč. 54, č. 16 (2015), s. 8126-8135. ISSN 0020-1669. E-ISSN 1520-510X
R&D Projects: GA ČR(CZ) GA14-05180S
Institutional support: RVO:61388955
Keywords : ELECTRON-PARAMAGNETIC-RESONANCE * DENSITY-FUNCTIONAL THEORY * BORON DIFLUORIDE COMPLEXES
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 4.820, year: 2015

Redox series of the complexes [Ru(L)(L′)2]n, L = 1,5-diphenyl-3-(4-tolyl)-formazanate and L′ = 2,4-pentanedionate (acac-), 2,2′-bipyridine (bpy), or 2-phenylazopyridine (pap), were studied by cyclic and differential pulse voltammetry and by TD-DFT-supported spectroelectrochemistry (UV-vis-NIR, EPR). The precursors [RuIII(L-)(acac-)2], [RuII(L-)(bpy)2]ClO4, and [RuII(L-)(pap)2]ClO4 were identified in their indicated oxidation states by X-ray crystal structure determination. The six-membered formazanato-ruthenium chelate rings have an envelope conformation with puckering of the metal. DFT calculations indicate a pronounced sensitivity of the N-N bond lengths toward the ligand oxidation state. Several electrochemically accessible charge states were analyzed, and the derived oxidation numbers RuII, RuIII, or RuIV, L′ or (L′)•-, and L-, L•2-, or the new formazanyl ligand L• for the two-way noninnocent formazanate reflect the increasing acceptor effect of the ancillary ligands L′ in the series acac- < bpy < pap. (Figure Presented).
Permanent Link: http://hdl.handle.net/11104/0248700