Synthesis of zinc bacteriochlorophyll-d analogs bearing an alkoxyimino group at the 131-position and their self-aggregation in an aqueous micelle solution

Abstract

Zinc complexes of methyl 3-hydroxymethyl-131-deoxo-131-alkoxyimino-pyropheophorbides-a were prepared through the condensation of the 13-keto carbonyl group with several alkoxyamines. The E/Z-stereoisomers of the synthetic alkoximes were successfully separated by silica gel column chromatography. The zinc bacteriochlorophyll-d analogs formed J-type self-aggregates in an aqueous micelle solution to give red-shifted electronic absorption bands, which were similar to those of the original bacteriochlorophyll-d bearing the 131-oxo group. The self-aggregation was largely dependent on the size of the alkoxyimino groups and their E/Z-stereochemistry.