A tetranuclear ruthenium complex with bridging pyridine-2,4-dicarboxylato ligands forming a square metallamacrocycle

Abstract

Abstract Treatment of [RuCl2(PPh3)3] with equimolar amounts of 2,4-pyridinedicarboxylic acid (2,4-dipicH2) in the presence of Et3N afforded a tetranuclear complex [Ru(μ-2,4-dipic)(PPh3)2]4 (1) as red crystals. The crystal and molecular structure of [Ru(μ-2,4-dipic)(PPh3)2]4·CHCl3·8H2O (1·CHCl3·8H2O) was determined by single-crystal X-ray diffraction. Each ruthenium center in 1 is six-coordinated with two phosphorus atoms from triphenylphosphine ligands, one nitrogen atom from a pyridyl moiety and three oxygen atoms from two 2,4-dipic2– ligands. 2,4-Pyridinedicarboxylate dianions (2,4-dipic2–) act as bridging ligands to form the stable tetranuclear metallamacrocyclic compound. The electrochemical properties of 1 were also investigated.