Impact of dendrimer density on epoxide enantioselectivity over an immobilised chiral salen complex

Abstract PAMAM dendrimers were grown on two silica supports with different surface dendrimer densities and subsequently used to immobilise a chiral salen complex. The low density supported sample resulted in the complex exhibiting the ability to act enantioselectively while this effect was all but lost for sample based on the high density support. The negative effect of the high density material was attributed to undesired interactions between the complex and the support. An understanding of this effect allowed partial recovery of enantioselectivity for the high density support based catalysts through operating at higher temperatures.