Self-aggregation of Synthetic Zinc 3-Hydroxymethyl-purpurin-18 and N-Hexylimide Methyl Esters in an Aqueous Solution as Models of Green Photosynthetic Bacterial Chlorosomes

Zinc 31-hydroxy-131-oxo-chlorins possessing a six-membered exo-ring attached at the 13- and 15-positions were prepared by modifying purpurin-18. These synthetic anhydride and imide self-aggregated in an aqueous THF solution to give large oligomers (J-aggregates) similarly with the corresponding natural and artificial chlorophylls possessing a five-membered E-ring.