INTERMOLECULAR AND INTRAMOLECULAR COORDINATION INTERACTIONS IN SOLUTIONS OF N-(DIMETHYLCHLOROSILYLMETHYL) ACETAMIDES

The coordinate structure of N-methyl- and N-phenyl-N-(dimethylchlorosilylmethyl) acetamide in solutions is investigated by multinuclear H-1,C-13,O-17, and Si-29 NMR spectroscopy. At low temperatures (up to - 90 degrees C), two pentacoordinated silicon species are detected for the first time as an example of compounds including the coordinative OSiC3Cl unit. At higher temperatures their fast (on the NMR time scale) interconversions are observed. On the basis of concentration, solvent and temperature dependence we assume that one species contains the intramolecular coordination O --> Si bond, while the other includes the intermolecular coordination O --> Si bond.