Synthesis and properties of Group 5B ligand analogues of o-phenylenebis(dimethylarsine), o-C6H4(EMe2)(E′Me2) where E, E′= P, N, As, or Sb

Abstract

Lithium dimethylphosphide prepared from lithium and PMe₂Ph in tetrahydrofuran reacts with o-dichlorobenzene to produce o-phenylenebis(dimethylphosphine). Similar reactions using the appropriate o-bromophenyl derivatives o-C₆H₄Br(Y)(Y = NMe₂, AsMe₂, or SbMe₂) yield o-C₆H₄(PMe₂)Y. o-Phenylenebis(dimethylstibine) is best prepared from (o-bromophenyl)dimethylstibine and Na[SbMe₂]. Preparations for the other members of the series, o-C₆H₄(AsMe₂)(SbMe₂), o-C₆H₄(AsMe₂)(NMe₂), and o-C₆H₄(SbMe₂)(NMe₂), and for (o-methoxyphenyl)- and (o-methylthiophenyl)-dimethylphosphine o-C₆H₄(PMe₂)Z (Z = OMe or SMe) are reported. The ¹H and ³¹P n.m.r. and mass spectra of the ligands, intermediates, and quaternary derivatives are reported and discussed.