Anion complexation and migration in 8-Silyl-l-naphthylboranes, participation of hypervalent silicon.

Compounds 1-3, of general structure 8-RMe(2)Si-1-Me(2)B-naphthalene, were prepared, and their complexes with F(-) were examined. The structure of 1(.)F(-) (R=Me) was determined by multinuclear NMR and X-ray crystallography, revealing an interaction between F(-) and pentacoordinate Si. Syntheses of 2 (R=OEt) from dimethyl (8-iodo-1 naphthyl)silane and 3 (R=F) from 2 proceeded via intramolecular anion migrations and hypervalent Si intermediates. Compound 2 is the only reported example of a silyl ether coordinated to a borane. The complex 3(.)F(-) was more stable than 1(.)F (-) because of increased participation of FMe(2)Si in F(-) bonding compared to Me(3)Si. This work represents the first consideration of Si as a participant in bidentate anion complexation and the first exploration of bidentate Lewis acids in which the two active functional groups are different.