SYNTHESIS AND X-RAY STRUCTURE OF INTRAMOLECULARLY COORDINATED SILYL CATIONS

Bis[2-((dimethylamino)methyl)phenyl]silyl triflate and [2-((dimethylam ino)methyl)phenyl]-phenylsilyl triflate were prepared by treatment of the corresponding dihydrosilanes with trimethylsilyl triflate in excel lent yield. X-ray crystallography shows [Ar2SiH](+)[OSO2CF3](-) (Ar = 2-(Me(2)NCH(2))C6H4; triclinic, P ($) over bar 1, a = 8.421(2) Angstro m, b = 9.892(3) Angstrom, c = 13.183(4) Angstrom, alpha = 82.78(2)degr ees, beta = 74.00(1)degrees, gamma = 75.84(2)degrees, Z = 2) to exist in the solid state as a separated ion pair with a pentacoordinated cat ionic silicon center, whereas [Ar(Ph)SiH](+)[OSO2CF3](-)(monoclinic, P 2(1)/n, a = 8.923(2) Angstrom, b = 9.957(2) Angstrom, c = 20.132(3) An gstrom, beta = 98.74(1)degrees, Z = 4) forms a tight ion pair, in whic h the triflate anion occupies one axial position of the trigonal bipyr amid around silicon.