Solid angles III. The role of conformers in solid angle calculations

Abstract

The values of the solid angles Ω for a range of commonly encountered ligands in organometallic chemistry (phosphines, phosphites, amines, arsines and cyclopentadienyl rings) have been determined. The solid angles were derived from a single energy conformer in a geometry constrained in a prototypical metal environment, i.e. with the ligand attached to Cr(CO) 5. This choice permits comparison with recent ligand repulsive energies E R reported by Brown. Correlations between Ω, ER and θ for the range of ligands studied typically gave correlation coefficients greater than 0.8. The values of the weighted average solid angle Ω , using an extension of the methodology by Brown and Mosbo, have also been determined. The minimum conformer solid angle values are correlated with the weighted average solid angle ( r = 0.96), suggesting that the minimum-energy conformation is a good approximate measure of steric size.