The tetrahedral character of the boron atom newly defined -: a useful tool to evaluate the N→B bond

The tetrahedral character at the boron atom in boron complexes with a coordinative N --> B bond has been evaluated on the basis of 144 solid state and gas phase molecular structures in order to obtain additional information on the van der Waals versus covalent relationship of the boron-nitrogen bond. The tetrahedral character has been calculated by a new formula that includes all six bond angles at the boron atom. Thereby, the N --> B bond length and the tetrahedral character are correlated and permit the description of the reaction path for the formation of the N --> B bond. (C) 1999 Elsevier Science S.A. All rights reserved.