| Polymer immobilized titanium Lewis acid catalysts were synthesized and an application was developed for a Lewis acid catalyzed Diels-Alder reaction. A titanium(IV) complex containing polymerizable aryloxide ligands was copolymerized with styrene/divinylbenzene under conditions suitable for giving a highly crosslinked, yet porous polymer matrix. Upon treatment with an external reagant, the polymer immobilized titanium complex was converted to an active Lewis acid catalyst which was shown to be comparable to the solution analogues. A cationic rhodium complex containing polymerizable phosphine ligands was incorporated into a porous, highly crosslinked poly-ethylene glycol dimethacrylate matrix and was shown to be an active hydrogenation catalyst for a variety of alkenes. To determine the effect of common solvents on the surface area of the macroporous polymer supports, two classes of resins were studied: divinylbenzene/styrene and ethylene glycol dimethacrylate/methyl methacrylate, each with variable crosslink densities. |
