An extended pi-system and enhanced electronic delocalization on symmetric [Ru3O(CH3COO)(6)(L)(3)](n) complexes combined with azanaphthalene ligands

Autor(es)

Possato, Bruna ; Deflon, Victor M. ; Naal, Zeki ; Formiga, Andre L. B. ; Nikolaou, Sofia

• Tipo de documento: Artigo Científico
• Fonte: DALTON TRANSACTIONS; v. 46, n. 24, p. 7926-7938, JUN 28 2017.
• Citações Web of Science: 4

Resumo

We report on the investigation of a new series of symmetric trinuclear ruthenium complexes combined with azanaphthalene ligands: {[}Ru3O(CH3COO)(6)(L)(3)]PF6 where L = (1) quinazoline (qui), (2) 5-nitroisoquinoline (5-nitroiq), (3) 5-bromoisoquinoline (5-briq), (4) isoquinoline (iq), (5) 5-aminoisoquinoline (5-amiq), and (6) 5,6,7,8-tetrahydroisoquinoline (thiq). The crystal structure of complex 1, {[}Ru3O (CH3COO)(6)(qui)(3)]PF6, was determined by X-ray diffraction analysis, showing a high degree of co-planarity between the {[}Ru3O] plane and the azanaphthalene ligands. Spectroscopic (UV-visible, NMR and infra-red) and electrochemical (cyclic voltammetry and spectroelectrochemistry) data showed correlation with the pKa values of the azanaphthalene ligands and this dependence was rationalized in terms of the molecular orbital of the {[}Ru3O] unit and the structure of the ligands. By analysing the spectroscopic and electrochemical correlations, the ability of the azanaphthalene ligands to extend the electronic p-system of the {[}Ru3O] unit to the periphery of the compounds was demonstrated. This electronic effect accounts for the planarity of the structure of complex 1. It was also shown through molecular modeling results that, to explain the spectroscopic and electrochemical behaviour of these species, it is not possible to neglect the electronic mixing between the metallic and the acetate orbitals. Finally, this work revealed that electronic coupling is more pronounced in the azanaphthalene series of complexes than in pyridinic analogues and it is this coupling that determines the spectroscopic and electrochemical behaviour of the new species. (AU)

• Processo FAPESP: 13/22127-2 - Desenvolvimento de novos materiais estratégicos para dispositivos analíticos integrados
• Beneficiário: Lauro Tatsuo Kubota
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 15/20302-7 - Uso de anti-inflamatórios não esteroidais, azanaftalenos e fenazinas como ligantes na obtenção de carboxilatos bi- e trinucleares de rutênio com potencial atividade antialérgica, tumoricida e tripanocida
• Beneficiário: Sofia Nikolaou
• Modalidade de apoio: Auxílio à Pesquisa - Regular