The Natural Bite Angle of Chelating Diphosphines

Abstract

Abstract The natural bite angles of chelating diphosphine ligands have been determined by molecular mechanics calculations using the MACROMODEL program with a modified AMBER force field. The natural bite angle (β n ) is defined as the preferred chelation angle determined only by ligand backbone constraints and not by metal valence angles. Potential energy diagrams for diphosphine chelates were constructed to estimate chelate flexibility. Molecular mechanics calculations have been used to select diphosphine ligands with natural bite angles of 120° for diequatorial chelation in trigonal bipyramidal metal complexes.