Preparation and crystal structure of [PHBu3][MoHCl4(PBu3)2]

Abstract

The preparation of the series of anionic, paramagnetic, hydrido complexes [PHR₃][MoHCl₄(PR₃)₂](R = Et, X = Cl or Br; R = Bu, X = Cl; R₃= Me₂Ph, X = Br) from the reactions of anhydrous HX with [MoH₄(PR₃)₄] in tetrahydrofuran is described. The structure of one example, [PHBu₃][MoHCl₄(PBu₃)₂], has been determined by X-ray crystallography. The co-ordination geometry of the anion is best described as a distorted pentagonal bipyramid, with apical chloro-groups [(Mo–Cl_ax)_av 2.423(10)Å]. The hydride was located in the structure [Mo–H 1.83(4)Å] and is displaced 0.31 Å out of the equatorial plane towards one of the axial sites. The remaining ligands in the equatorial positions have bond lengths (Mo–Cl_eq)_av 2.485(1) and (Mo–P)_av 2.511 (5)Å.