UC San Diego
Hydrosilylation of Imines Using a Ni(0) Catalyst
- Author(s): Spence, Daniel Patrick
- Advisor(s): Figueroa, Joshua S
- et al.
The following herein introduces a Ni(0) catalyst that effectively does hydrosilylation of imines to form the corresponding aminosilanes which are of interest in the electronics industry. Preliminary studies of bis-1,5-cyclooctadienyl nickel(0), Ni(COD)2, showed it to be an effective catalyst with relatively good conversion at room temperature and low catalyst loadings (~3%). However, selectively for the aminosilane was limited since there was a significant amount of conversion to the corresponding amine. To circumvent amine production, a combination of using a reengineered Ni(0) catalyst and a new silane was used. Ni(COD)2 was reacted with two equivalents of the sterically encumbering m-terphenyl isocyanide CNArMes2 (ArMes2 = 2,6-(2,4,6-Me3C6H2)2C6H3) to form Ni(COD)(CNArMes2)2. In turn, it was used in the catalyst studies showing
less propensity to dehydrocouple and a better selectively for the desired aminosilane. Using hexylsilane in place of phenylsilane led to further improvement, showing complete selectivity for the aminosilane. A scope of imines was explored and showed rather consistent reaction rates (t = 2hr) at room temperature at low catalyst loading (3-2.5%). Studies were carried out to try and isolate an intermediate in the catalytic cycle where oxidative addition occurs of Ni(COD)(CNArMes2)2 with the silane. Insight is given into the possible mechanism.