STRUCTURES AND STRUCTURAL DISTORTIONS OF METALATED PHOSPHORANES

Abstract

Abstract The 15 published crystal structures of metalated phosphoranes are reviewed. For 12 such structures, the distortion from a trigonal bipyramid towards a rectangular bipyramid and a 30° turnstile geometry is calculated using the method of dihedral angles. When compared to non-metalated phosphoranes, these metalated compounds exhibit a marked preference for the trigonal bipyramidal geometry. It is suggested here that this may be due to the π-donating abilities of the metal substituents. In a few cases, the metalated phosphorane structures also exhibit distortion along the turnstile coordinate as opposed to the Berry pseudorotation mechanism followed by non-metalated phosphoranes. This appears to be due to the considerable steric demands of the metal substituents in the equatorial plane of the phosphorane in these cases.