Synthesis and characterization of mono and dinuclear Ru(II) complexes with hexadentate ligands having N₂P₄ and N₂As₄ donor atoms

Abstract

The reactions of RuCl₂(DMSO)₄ (1) and RuCl₂(PPh₃)₃ (2) with the ligands α, α'-bis(bis(2-(diphenylphosphino)ethyl)amino)ethane (BDPE), α, α'-bis(bis(2-(diphenylarsino)ethyl)amino)ethane (BDAE) and α, α'-bis(bis(2-(diphenylphosphino)-m-xylene (BDPX) were carried out with 2:1 or 1:1 metal ligand molar ratios in different conditions. In the reaction of 1 with L (L=BDPE, BDPX) with a 2:1 molar ratio a mixture of two dinuclear octahedral complexes of the compositions [Ru₂L(DMSO)₄Cl₂]Cl₂ and [Ru₂L(DMSO)₂Cl₄] were obtained. These complexes were separated by column chromatography and characterized. With a 1:1 molar ratio of 1 and L, mononuclear complexes as the major product along with some quantities of dinuclear complexes were formed. These complexes were separated and characterized. The reaction of 2 with the ligands L (L=BDPE, BDAE, BDPX) with a 2:1 molar ratio in dichloromethane resulted in the formation of dinuclear complexes of composition [Ru₂L(PPh₃)₂Cl₄]. The reaction of 2 with BDPE and BDPX in ethanol with longer refluxing time resulted in the displacement of all the three PPh₃ groups of 2 with the formation of complexes of the composition [Ru₂LCl₄]. Electrochemical studies of these complexes were also carried out.