title: Revisiting oxo-centered carbonyl-triruthenium clusters: investigating CO photorelease and some spectroscopic and electrochemical correlations.
abstract: We synthesized and characterized a series of oxo-centered carbonyl-triruthenium complexes with the general formula [Ru3O(CH3COO)6(L)2(CO)], where L = 2,6-dimethylpyrazine (dmpz) (1), isonicotinamide (adpy) (2), 4-acetylpyridine (acpy) (3), 3-methylpyridine (3-pic) (4), 4-methylpyridine (4-pic) (5), 4-tert-butylpyridine (4-tbpy) (6), 4-(dimethyl)aminopyridine (dmap) (7), or 4-aminopyridine (ampy) (8); we also investigated the photoreactivity of these complexes. Single-crystal X-ray diffraction helped to elucidate the structures of 1·H2O, 7·C2H4Cl2, and 8. The unit cell of 8 is composed of four cluster units; the hydrogen bonds between the amino groups of the terminal ligand of a neighboring molecule and the oxygen atoms of CO or acetate bridging ligands hold these cluster units together. The spectroscopic (NMR, UV-visible, and IR) and the electrochemical properties (cyclic voltammetry) of these complexes correlated with the ancillary ligands in terms of their σ-donating and π-accepting characteristics. The molecular orbital and the electronic localized description of the [Ru3O]-CO unit helped to rationalize the correlations. The photoreactivity of compounds 1-8 was investigated by laser excitation at 377 nm. Given the CO photorelease quantum yields, σ-donor ligands and aqueous medium (more polar) stabilized the charge-transfer excited state that culminated in CO photosubstitution, leading to higher Φ values.
authors: Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes 3900, 14040-901, Ribeirão Preto-SP, Brazil. sofia@ffclrp.usp.br.
authors: Mariete B
authors: MB
authors: Moreira
authors: Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes 3900, 14040-901, Ribeirão Preto-SP, Brazil. sofia@ffclrp.usp.br.
authors: Camila F N
authors: CF
authors: Da Silva
authors: Instituto de Química de São Carlos, Departamento de Química e Física Molecular - Universidade de São Paulo, Av. do Trabalhador São Carlense 400, 13566-970, São Carlos-SP, Brazil.
authors: Rafaela B P
authors: RB
authors: Pesci
authors: Instituto de Química de São Carlos, Departamento de Química e Física Molecular - Universidade de São Paulo, Av. do Trabalhador São Carlense 400, 13566-970, São Carlos-SP, Brazil.
authors: Victor M
authors: VM
authors: Deflon
authors: Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes 3900, 14040-901, Ribeirão Preto-SP, Brazil. sofia@ffclrp.usp.br.
authors: Sofia
authors: http://orcid.org/0000-0003-2444-6069
authors: S
authors: Nikolaou