Hypervalent silicon via intramolecular co-ordination in a four-membered ring system: synthesis and structure of SiCl2X[2-C(SiMe3)2C5H4N](X = H or Me); X-ray structures of the former complex and of SiCl2Me(2-CPh2C5H4N)

Abstract

Reaction of SiCl₃X (X = H or Me) with LiR [R = 2-C(SiMe₃)₂C₅H₄N] yields the novel hpervalent five-co-ordinate compounds SiRCl₂X which show strong Intramolecular Si–N interactions in the four-membered chelate ring [Si–N 2.066(9)Å for X = H (X-ray)] which persists in solution; the related compounds, SiR′Cl₂X (X = H or Me for R′= 2-CPh₂C₅H₄N) have four-co-ordinate silicon (deduced from the ²⁹Si NMR spectra and, for X = Me, an X-ray structure).