Synthesis, characterization and solvent dependent reversible binding of carbon monoxide to Ru(III) Schiff base complexes

Abstract

Ruthenium(III) Schiff base complexes of the composition [RuLXY] where L=Schiff base, viz. bis(salicylaldehyde)-o-phenylenediimine (saloph), bis(salicylaldehyde)ethylenediimine (salen), bis(salicylaldehyde)diethylenetriimine (saldien) bis(picolinaldehyde)-o-phenylenediimine (picoph), bis(picolinaldehyde)ethylenediimine (picen), bis(picolinaldehyde)diethylenetriimine (picdien); X=chloro(Cl⁻); Y=chloro(Cl⁻), imidazole (Im) or 2-methylimidazole (2-MeIm) were synthesized and characterized by various physicochemical methods. The reversible binding of carbon monoxide to the Ru(III) Schiff base complexes was carried out in DMF, CH₃CN, CH₃OH and CH₃COCH₃ at 10, 25 and 40°C. The polarity of the solvents as well as the electron donating subituents on Schiff base complexes increase the affinity of the complexes for CO. The thermodynamic parameters δH°, δG° and δS° for the carbonylation of Schiff base complexes were evaluated.