Fluorine exchange between four-, five-, and six-coordinate silicon compounds

Abstract

Intermolecular fluorine exchange in the systems SiF4–SiF5−, MeSiF3–MeSiF4−, PhSiF3–PhSiF4−, SiF5−–SiF62−, SiF4–SiF62−, and MeSiF3–SiF62− has been studied by fluorine and proton nmr spectroscopy. Exchange is postulated to involve fluorine-bridged intermediates; alternative pathways of exchange, such as fluoride dissociation or impurity (HF and H2O) catalyzed exchange, have been eliminated. Addition of NH3 to SiF5−–SiF62− slows down exchange whereas addition of Et2NH to MeSiF3 promotes exchange.