Control of aggregation and tuning of the location of porphyrins in synthetic membranes as mimics for cytochrome P450

The aggregation and location of two series of tetraarylporphyrins in positively and negatively charged bilayers have been examined. Aggregation of the porphyrins can be reduced by introducing pyridinium groups on the porphyrin ring. In the positively charged bilayers, the degree of aggregation of the porphyrins increases with the number of charges on it. The opposite behavior is found in the case of negatively charged bilayers. All the charged porphyrins form face to face type aggregates whereas the uncharged ones form edge to edge type aggregates. Reduction of aggregation can also be achieved by using ''picket-fence'' type porphyrins which form head to tail aggregates. The location of the porphyrins in the bilayer is also investigated. The charged porphyrins are located near the aqueous interface and the uncharged ones in the hydrophobic part of the bilayer. Picket-fence porphyrin 7 was found to be the most promising candidate for being studied as a catalyst in cytochrome P450 mimics.