Studying the activity of the MacMillan catalyst embedded within hydrophobic cross-linked polymeric nanostructures

The immobilization of the MacMillan catalyst within a unique hydrophobic environment created by a lightly cross-linked nanogel structure and its resulting catalytic activity is reported. The catalytic activity and selectivity of the catalyst were evaluated using the Diels–Alder (DA) reaction between cyclopentadiene and cinnamaldehyde. The relatively easy synthetic route applied allowed for the synthesis of a collection of nanogels with catalyst incorporations ranging from 0.5 to 25 wt%. In addition, core–shell type nanogels were synthesized to evaluate potential recovery and reuse of the catalytic system. The influence of the concentrator effect and possible partition coefficient on the catalyst activity was investigated. The results indicate catalyst loading/concentration can be more significantly reduced when the catalyst is embedded within the polymeric nanostructures compared to the small molecule equivalent.