Synthesis and characterization of transition metal complexes of a new bidentate ligand {2-(diphenylphosphino)ethyl}benzylamine

Abstract

A new bidentate ligand {2-(diphenylphosphino)ethyl}benzylamine(DPEBA) was synthesized and characterized based on the IR, mass and 1H, 13C and 31P NMR spectra. Various complexes of platinum group metal ions and Ni(II) and Co(II) ions with the ligand were synthesized. Reaction of RuCl 2(PPh 3) 3 or RuCl 2(Me 2SO) 4 with the ligand DPEBA, resulted in formation of a penta-coordinate, Ru(II) species of the composition [RuCl(DPEBA) 2]Cl. Carbonylation of [RuCl(DPEBA) 2]Cl gave an octahedral carbonyl complex of the type [RuCl(CO)(DPEBA) 2]Cl. The reaction of RuCl 3·3H 2O or RuCl 3(AsPh 3) 2MeOH with a twofold excess of the ligand gave an octahedral Ru(III) cationic species [Ru(DPEBA) 2Cl 2]Cl. Carbonylation of the Ru(III) complex gave rise to a carbonyl complex [RuCl(CO)(DPEBA) 2]Cl 2. The ligand DPEBA reacts with cobalt(II) chloride in methanol to give the 1 : 1 complex [Co(DPEBA)Cl 2]. A series of Rh(I) complexes [Rh(DPEBA) 2Cl], [ RhCl(CO)(DPEBA)] and [Rh(DPEBA) 2]Cl were synthesized by the reaction of DPEBA with RhCl(PPh 3) 3, RhCl(CO)(PPh 3) 2 and [Rh(COD)Cl] 2, respectively. Reaction of [Ir(COD)Cl] 2 and IrCl(CO)(PPh 3) 2 with the ligand DPEBA, gave the square-planar complexes [Ir(DPBA) 2]Cl and [Ir(DPEBA)(CO)Cl], respectively. Octahedral cationic complexes of the type [M(DPEBA) 2Cl 2]Cl (M = Rh(III), Ir(III)) were synthesized by the reaction of the ligand DPEBA and rhodium and iridium trichlorides. Reaction of NiCl 2·6H 2O with DPEBA in 1 : 2 molar equivalents, in boiling butanol gave an octahedral neutral complex [Ni(DPEBA) 2Cl 2] which readily rearranges to the square-planar complex [Ni(DPEBA) 2]Cl 2 in methanol. Reaction of Pd(II) and Pt(II) chlorides with DPEBA gave square-planar, cationic complexes of the type [M(DPEBA) 2Cl]Cl (M = Pd, Pt). All the complexes were characterized on the basis of their analytical and spectral data.