Synthesis and characterization of tetracarbonylmolybdenum(0) and pentacarbonyltungsten(0) complexes of TADDOL-derived, monodentate P-donor ligands

Abstract

TADDOL-derived P-donor ligands are of interest as ligands in transition metal catalyzed transformations; however, few studies have been conducted on the steric and electronic properties of P-donor ligands derived from TADDOL. To gain more insight into these properties four tetracarbonylmolybdenum(0) and two pentacarbonyltungsten(0) complexes of monodentate P-donor ligands derived from TADDOL have been studied. These studies show that exchanging the chloro substituent on the phosphorus for OMe increases the donor ability of the ligand and that the cis-tetracarbonylmolybdenum(0) complex of the ligand having the OMe substituent spontaneously isomerizes in solution. X-ray crystallographic analyses indicate that the orientations of the 1,3,2-dioxaphosphepane ring and the aryl substituents are not always conserved, even within the same complex.