31-Substituent-dependent Self-aggregation of Bacteriochlorophyll-d Analogs in Aqueous Micelles

Abstract

Zinc bacteriochlorophyll-d analogs possessing 31-ethyl, vinyl, and ethynyl groups instead of the original 31-methyl group were prepared by chemically modifying chlorophyll-a. The 31-substituents affected their 31-diastereomerically controlled self-aggregation in an aqueous Triton X-100 micelle solution, where the (31R)-epimers of the ethylated and vinylated derivatives readily formed chlorosomal self-aggregates with red-shifted absorption bands due to exciton coupling in the supramolecule, but the corresponding ethynylated epimer was monomeric.