Photosolvolysis of cis-[Ru(alpha-diimine)(2)(4-aminopyridine)(2)](2+) Complexes: Photophysical, Spectroscopic, and Density Functional Theory Analysis

Autor(es)

Camilo, Mariana R. ^[1] ; Cardoso, Carolina R. ^[1] ; Carlos, Rose M. ^[1] ; Lever, A. B. P. ^[2]

Afiliação do(s) autor(es)

^[1] Univ Fed Sao Carlos, Dept Quim, BR-13565905 Sao Carlos, SP - Brazil

^[2] York Univ, Dept Chem, Toronto, ON M3J 1P3 - Canada

• Tipo de documento: Artigo Científico
• Fonte: Inorganic Chemistry; v. 53, n. 7, p. 3694-3708, APR 7 2014.
• Citações Web of Science: 22

Resumo

The photochemical and photophysical properties of the cis-{[}Ru-II(alpha-diimine)(2)(4-APy)(2)](2+) complexes, where alpha-diimine = 1,10-phenanthroline (phen) and 4-APy = 4-aminopyridine I, 4,7-diphenyl-1,10-phenanthroline (Ph(2)phen) II, 2,2'-bipyridine (bpy) III, and 4,4'-dimethyl-2,2'-bipyridine (Me(2)bpy) IV, are reported. The four complexes were characterized using high-performance liquid chromatography, H-1 NMR, UV-visible, emission, and transient absorption spectroscopy. Upon photolysis in acetonitrile solution these complexes undergo 4-APy dissociation to give the monoacetonitrile complex (for II, III, and IV) or the bis(acetonitrile) complex (for I). A fairly wide range of excitation wavelengths (from 420 to 580 nm) were employed to explore the photophysics of these systems. Quantum yields and transient spectra are provided. Density functional theory (DFT) and time-dependent DFT analysis of singlet and triplet excited states facilitated our understanding of the photochemical behavior. A detailed assessment of the geometric and electronic structures of the lowest energy spin triplet charge transfer state ((MLCT)-M-3) and spin triplet metal centered state ((MC)-M-3) (d pi -> sigma{*} transitions) for species I-IV is presented. A second, previously unobserved, and nondissociative, (MC)-M-3 state is identified and is likely involved in the primary step of photodissociation. This new (MC)-M-3 state may indeed play a major role in many other photodissociation processes. (AU)

• Processo FAPESP: 08/52859-7 - Compostos de metais de transicao neuroativos: investigacoes fotoquimicas, fotofisicas, fisico-quimicas e citotoxicidade para drogas neuroativas em fase iii.
• Beneficiário: Mariana Romano Camilo Casale
• Linha de fomento: Bolsas no Brasil - Mestrado
• Processo FAPESP: 06/50322-0 - Complexos de Ru(II) como fonte de 4-amidopiridina em fototerapia
• Beneficiário: Mariana Romano Camilo Casale
• Linha de fomento: Bolsas no Brasil - Iniciação Científica
• Processo FAPESP: 09/08218-0 - Novos complexos do tipo Mn(I)-fotosensibilizador: modelos minéticos para o lado doador do PSII em fotossíntese artificial
• Beneficiário: Rose Maria Carlos
• Linha de fomento: Auxílio à Pesquisa - Regular