THE MM3 FORCE-FIELD FOR 12-VERTEX BORANES AND CARBORANES

A model and parameters were developed which allow conformational calcu lations to be carried out on the 12-vertex boranes, carboranes and the ir derivatives, within the framework of the MM3 force field. In order to avoid description of all the bond angles, the molecule was represen ted as a superposition of two rings and two cap groups. The valence bo nds between these moieties were described by a Buckingham potential. T he statistical analysis of carborane molecules found in the Cambridge Structural Database has been carried out in order to find the mean val ues of the bond lengths and angles for these molecules. A parameter se t was developed and used for the calculations on substituted carborane s, and the results show good agreement with the experimental data. (C) 1997 Elsevier Science S.A.