Effects of a strong pi-accepting ancillary ligand on the water oxidation activity of weakly coupled binuclear ruthenium catalysts

Autor(es)

Matias, Tiago A. ^[1] ; Rein, Francisca N. ^[2] ; Rocha, Reginaldo C. ^[2] ; Barboza Formiga, Andre Luiz ^[3] ; Toma, Henrique E. ^[1] ; Araki, Koiti ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Chem, Dept Chem, Av Lineu Prestes 748, BR-05508000 Sao Paulo, SP - Brazil

^[2] Los Alamos Natl Lab, Los Alamos, NM 87545 - USA

^[3] Univ Estadual Campinas, UNICAMP, Inst Chem, POB 6154, BR-13083970 Campinas, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: DALTON TRANSACTIONS; v. 48, n. 9, p. 3009-3017, MAR 7 2019.
• Citações Web of Science: 0

Resumo

Significant differences were found in the proton-coupled redox chemistry and catalytic behavior of the binuclear {[}[Ru(H2O)(bpz)](2)(tpy(2)ph)](PF6)(4) complex {[}bpz = 2,2-bipyrazine; tpy(2)ph = 1,3-bis(4-2,2:6,2-terpyridin-4-yl)benzene] as compared with the structurally analogous derivative with 2,2-bipyridine (bpy) instead of bpz. The differences were assigned to the stronger -accepting character of bpz relative to bpy as the ancillary ligand. The expectation of a positive shift for the Ru-centered redox potentials was confirmed for the lower oxidation state species, but that trend was reversed in the formation of the high-valence catalytic active species as shown by a negative shift of 0.14 V for the potential of the {[}Ru-IV/V?O] process. Moreover, DFT calculations indicated a significant decrease of about 15% on the spin density and oxyl character of the {[}Ru-V?O](3+) fragment. The significantly lower k(cat)(O-2) for the bpz system was attributed to these combined electronic effects. (AU)

• Processo FAPESP: 14/50906-9 - INCT 2014: em Materiais Complexos Funcionais (INOMAT)
• Beneficiário: Fernando Galembeck
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 18/03576-4 - Estudo do mecanismo de oxidação catalítica da água promovida por complexos de rutênio contendo unidades de imidazol
• Beneficiário: André Luiz Barboza Formiga
• Modalidade de apoio: Bolsas no Exterior - Pesquisa