Silylation of silicon bonded hydroxyl groups by silazanes and siloxanes containing an acetoxy group. N-trimethylsilylimidazole vs. dimethyldiacetoxysilane

In this paper the silylation of silicon bonded hydroxyl groups by the two silylation agents N-trimethylsilylimidazole and diacetoxydimethylsilane is studied. We have used state of the art density functional theory calculations. To estimate minimum energy reaction paths and transition states, the climbing image nudged elastic band method was applied. For both silyation agents hydrogen bridged prereaction complexes were found. Our calculations have shown that the activation energy of the silylation with diacetoxydimethylsilane is smaller than by silylation with N-trimethylsilylimidazole. But in contrast, the silylation with N-trimethylsilylimidazole shows a larger reaction energy. Therefore, depending on their application, both chemicals are promising silylation agents.