Synthesis and Catalytic Activity of Water-Soluble Ruthenium(II) Complexes Bearing a Naphthyridine–Carboxylate Ligand

Abstract

The synthesis of water-soluble (η 6 -arene)ruthenium(II) complexes based on pyrazolyl–naphthyridine ligands modified with a carboxylate group is reported. The complexes are easily accessible in good yields via complexation of [(arene)RuCl 2 ] 2 with 7-pyrazolyl-1,8-naphthyridine-2-carboxylic acid ( 1 ). All complexes have been characterized by spectroscopic and elemental analyses. The complexes {[Ru(η 6 -arene)( N,N ′- 1 )Cl]Cl} (arene = benzene ( 5 ), p -cymene ( 6 )) were further confirmed by X-ray diffraction studies. These complexes are soluble in water (ca. 10 mg/mL) and are catalytically active in hydrogen-transfer reduction of carbonyl compounds in aqueous medium with the use of HCOOH/HCOONa as the hydrogen source.