Ligand Substitution Chemistry of the Diphosphine Ligand endo,endo-2,3-Bis(diphenylphosphinomethyl)-5-norbornene (dpmn): Syntheses and X-ray Diffraction Structures of PtCl2(dmn) and PtMe2(dpmn)

Abstract

The reaction of phosphine ligand endo,endo-2,3-bis(diphenylphosphinomethyl)-5-norbornene (dpmn) with PtCl2(cod) and PtMe2(cod) yields PtCl2(dpmn) (2) and PtMe2(dpmn) (4), respectively. Treatment of 2 with excess MeLi or MeMgCl also furnishes 4 in good yield. Both new platinum compounds have been isolated and characterized by NMR spectroscopy (1H and 31P), elemental analyses, and X-ray crystallography. 2 Crystallizes, as the CH2Cl2 solvate, in the orthorhombic space group Pnma, a = 18.062(3) A, b = 16.602(3) A, c = 11.088(2) A, V = 3,324.7(9) A3, Z = 4, D cacl = 1.681 mg/m3; R = 0.0432, R w = 0.0759 for 3,755 observed reflections with I > 2σ(I). 4 Crystallizes, as the CH2Cl2 solvate, in the orthorhombic space group Pnma, a = 17.969(3) A, b = 16.689(3) A, c = 11.237(2) A, V = 3,370(1) A3, Z = 4, D cacl = 1.610 mg/m3; R = 0.0268, R w = 0.0665 for 4,098 observed reflections with I > 2σ(I). The solid-state structures of 2 and 4 confirm the coordination of the platinum(II) center by the seven-membered chelating dpmn ligand; 2 and 4 represent the first structurally characterized examples of organometallic compounds based on the endo,endo-2,3-bis(diphenylphosphinomethyl)-5-norbornene ligand. The new platinum(II) compounds PtCl2(dpmn) (2) and PtMe2(dpmn) (4) have been synthesized, and their structures established by NMR spectroscopy (1H and 31P) and X-ray crystallography. Compounds 2 and 4 are the first structurally characterized examples of organometallic compounds containing the endo,endo-2,3-bis(diphenylphosphinomethyl)-5-norbornene (dpmn) ligand.