Synthesis and antiproliferatory activity of ruthenium complexes containing N-heterocyclic carboxylates

Abstract

Solvates of the complexes Ru2Cl(pic)4(EtOH) (2), Ru(Im-CO2)3 (3), and Ru(Im-CO2)(Im-CO2H)Cl2 (4), were synthesized from reaction of RuCl3·3H2O or K3[RuCl6] with the N-heterocyclic carboxylic acids pyridine-2-carboxylic acid (picolinic acid, Hpic), and imidazole-4-carboxylic acid (Im-CO2H). Crystals of 2–4 could not be grown and hence characterization was done by elemental analysis, NMR, IR, and conductivity data; 2 and 4 were tested for antiproliferatory activity in vitro against a human breast cancer cell line, but were less active than, for example, Ru complexes containing bis-imidazole or 4,4′-biimidazole that we studied previously [see Can. J. Chem. 89 (2011) 948]. Preliminary work with a third potential ligand, 3-nitro-1,2,4-triazole-5-carboxylic acid (abbreviated HCANT), and other nitro heterocyclic compounds is also presented.