The complexation of tetraphenylborate with organic N-heteroaromatic cations

Complexation studies of eleven N-heteroaromatic cations with tetraphenylborate are reported. Tetraphenylborate forms complexes with ve cations and reacts to form Lewis-base boranes with six cations. The complexes and the displacement reaction products were characterised by H-1 NMR spectroscopy, elemental analysis and crystallographic methods. In the complexes C-H . . . pi or N-H . . . pi hydrogen bonds are the principal intermolecular interactions. The stability constants for the complexes are determined by H-1 NMR titration in acetonitrile-methanol (1: 1) solution. Crystal structures of four of the complexes and three of the Lewis-base triphenylborane products are reported.