Structural studies of tris(dialkylamino) sulfonium (TAS) fluorosilicates

✍ Scribed by David A. Dixon; William B. Farnham; W. Heilemann; R. Mews; M. Noltemeyer

• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: English
• Weight: 706 KB
• Volume: 4
• Category: Article
• ISSN: 1042-7163
• DOI: 10.1002/hc.520040225

✦ Synopsis

The crystal structures of two pentavalent silicon anions are discussed. The structure of [SiMe,F,]-1 shows a trigonal bipyramidal structure with the fluorines in apical positions. The Si-F bond distances are the longest known of this type. The crystal structure of fluorosilicate

) is distorted toward a rectangular structure along the Berry pseudorotation coordinate. The lone Si-F bond distance in 2 is much shorter than that in 1. The ab initio calculations on a variety of pentavalent fluorinated silicon anions are reported, and good agreement with the experimental data are found. Fluoride affinities for the fluorosilanes are reported and are in reasonable agreement with the experimental values where known. The fluoride affinity of the tetra-coordinated species is related to the length of the Si-F bond in the pentavalent anion. Dedicated to Prof. James Cullen Martin on the occasion of his *To whom correspondence should be addressed. sixty-fifth birthday.