On the bonding, structure and thermodynamics of phosphorus halide boron halide complexes X3P center dot BY3 (X, Y=Cl, Br, I)

Donor-acceptor complexes X3P . BY3 (X, Y = Cl, Br, I) and their fragments h ave been studied using density functional (B3LYP) and ab initio methods (MP 2, CCSD(T)) with effective core potentials. The bonding, charge transfer an d structure of all X3P . BY3 is discussed on the basis of natural bond orbi tal (NBO) analysis. The estimated free molecular enthalpies of dissociation indicate: that all X3P . BY3 represent thermodynamically labile species wh ich are stabilized by the lattice energies in the solid state. The total di stortion energy increases in accordance with the decreasing complex dissoci ation enthalpy. With regard to halogen exchange between the PX3 and BY3 moi ety in X3P . BY3 (g) adducts, only the complexes where Y = X and where X re presents a heavier halogen than Y are thermodynamically stable. (C) 2001 El sevier Science B.V. All rights reserved.