Formation of hypervalent complexes of PhCCSiF3 with pyridine through intermolecular silicon...nitrogen interaction.

We report here the synthesis of trifluoro-phenylethynyl-silane (1) that forms with pyridine (Py), through intermolecular Si...N interaction, the pentacoordinate 1.Py complex and at low temperatures also the hexacoordinate 1.Py2 complex. 1H, 19F, 29Si, and 15N NMR spectra, as well as the first report for an intermolecular 29Si...15N one-bond spin-spin coupling, are presented for the two complexes. Quantum mechanical ab initio calculations (MP2/6-31G*) suggest a distorted trigonal bipyramid structure for the 1.Py complex and a nearly ideal octahedral structure for the 1.Py2 complex. The hypervalent complexes of 1 with Py described here imply a possible application of such Si...N intermolecular interactions in supramolecular chemistry.