Site-isolated porphyrin catalysts in imprinted polymers.
A meso-tetraaryl ruthenium porphyrin complex having four polymerizable vinylbenzoxy groups (2) has been synthesized by reaction of pyrrole with 4-(vinylbenzoxy)benzaldehyde and subsequent metalation with [Ru3(CO)12]. The porphyrin complex was immobilized by copolymerization with ethylene glycol dimethacrylate. The resulting polymer P2 was found to catalyze the oxidation of alcohols and alkanes with 2,6-dichloropyridine N-oxide without activation by mineral acids. Under similar conditions, the homogeneous catalyst 2 was completely inefficient. By using diphenylaminomethane and 1-aminoadamantane as coordinatively bound templates during the polymerization procedure, the molecularly imprinted polymers P3 and P4 have been synthesized. Compared with the polymer P2, the imprinted catalysts displayed a significantly increased activity with rate enhancements of up to a factor of 16.
Institut de Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland.
Estelle
E
Burri
Margarita
M
Ohm
Corinne
C
Daguenet
Kay
K
Severin