INFRARED MATRIX ISOLATION INVESTIGATION OF THE MOLECULAR COMPLEXES OF SILICON AND GERMANIUM TETRAFLUORIDES WITH WEAK LEWIS BASES
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Date
1985
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Ohio State University
Abstract
The matrix isolation technique has been applied for the study of the intermediate, 1:1 complexes of the Lewis acids $SiF_{4}$ and $GeF_{4}$ with weak Lewis bases, including $CH_{3}CN$ and $HCN$, as well as the stronger base pyridine. All three are characterized by distinct, shifted vibrational modes of both the acid and base subunits; these shifts suggest that the complexes are bound through the nitrogen atom of the base to the silicon or germanium center. The pyridine complexes showed by far the greatest shifts, as well as the highest product yield. The HCN complexes were unusual, in that the HCN act as a Lewis base in this system, contrary to its usual chemical behavior. All of the vibrational modes of the coordinated HCN subunit were observed in the $GeF_{4}$ complex; the C-H stretch shifted $15 cm^{-1}$ to lower energy, the C-N stretch $40 cm^{-1}$ to higher energy, and the bending mode roughly $30 cm^{-1}$ to higher energy. This latter mode did not split upon coordination, suggesting a linear arrangement for the H-C-N-Ge linkage. Additional complexes with weak bases are under investigation, and will be discussed.
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Author Institution: Department of Chemistry, University of Cincinnati