1,4-Dihydrophosphinolines and their complexes with group 10 metals

Abstract

Syntheses and characterizations of novel phosphaheterocycles, 1-phenyl-4,4-dimethyl-1,4-dihydrophosphinoline (2a) and 1-phenyl-2-bromo-4,4-dimethyl-1,4-dihydrophosphinoline (2b), and their complexes with Pd(II) and Pt(II) are described. Reduction of 1-phenyl-4,4-dimethyl-1,4-dihydrophosphinoline 1-oxide (1a) and 1-phenyl-2-bromo-4,4-dimethyl-1,4-dihydrophosphinoline 1-oxide (1b) using trichlorosilane in refluxing benzene gave the target phosphines in a yield of 83–87%. Reactions of phosphines with acetonitrile complexes of Pd(II) (3) and Pt(II) (4) yielded bis(phosphine) species [MCl₂L₂] (5–8). Complexes 5–8 were characterized by ¹H, ¹³C, ³¹P, ¹⁹⁵Pt NMR and HRMS. The structures of all these new complexes were determined with single crystal X-ray diffraction. The configuration of the complexes in a CDCl₃ solution was investigated via comparing of ³¹P NMR data in solution and solid state.