New (μ-oxo)bis(μ-carboxylato)diruthenium(III) complexes containing 1,4,7-trimethyl-1,4,7-triazacyclononane ligands

Abstract

Treatment of [(Me3tacn)RuCl3·H2O] (Me3tacn = 1,4,7-trimethyl-1,4,7-tri-azacyclononane) with substituted benzoic acid or phenylacetic acid, in water in the presence of potassium hexafluorophosphate gave a series of cationic dinuclear Ru(III)–Ru(III) (μ-oxo)bis(μ-carboxylato) complexes [(Me3tacn)2Ru2(μ-O)(μ-OOCR)2](PF6)2 (R = Ph, 1; -py, 2; -C6H4-2-Cl, 3; -C6H3-2,4-Cl2, 4; -CH2C6H4-2-CH3, 5; -CH2C6H4-4-CH3, 6; -CH2C6H4-4-OCH3, 7; -CH2C6H4-4-Cl, 8). All complexes are well characterized by infrared, UV/Vis and mass spectroscopies, and their electrochemical properties were also investigated. The molecular structures of 1, 2·2C3H6O, 5·2C3H6O, 7 and 8 have been also established by single-crystal X-ray diffraction. The photocatalytic properties for H2 evolution by water splitting of complexes 1, 2, 3, 5, and 7 were also investigated in the paper.