Ab initio molecular orbital study of structure and NMR 11B chemical shifts of Lewis base adducts of CO, NH 3, PF 3, and PH 3 with small nido-boranes, B 3H 7 and B 4H 8

Abstract

The geometries, formation energies, and NMR 11B chemical shifts of B 3H 7CO, B 3H 7N 3, B 4H 8CO, B 4H 8PH 3, and B 4H 8PF 3, Lewis base adducts of the B 3H 7 and B 4H 8 nido-boranes have been investigated by the ab initio molecular orbital method. MP2/6-31G* optimized geometries and calculated NMR chemical shifts are in good agreement with experiment. Lewis bases cause pronounced elongation of BB distances and a strong upfield chemical shift for the attacked boron atoms.