Synthesis of Novel Chlorins and Carotenoid-Porphyrin Dyads

Abstract

The first part of this thesis discusses the synthesis of chlorins bearing electron donating groups in the 3-position. A 3-dimethylaminochlorin ZnC-(NMe2)3M10 was synthesized in 49% yield, a 3-methoxychlorin ZnC-OMe3M10 was synthesized in 19% yield, and a 3-methylthiochlorin was synthesized in 95% yield from the corresponding 3-bromochlorin. For ZnC-(NMe2)3M10 and ZnC-SMe3M10, the B band and the Qy band were bathochromically shifted relative to the benchmark chlorin ZnC-M10, and the intensity of the Qy band increased relative to the B band. However, for ZnC-OMe3M10, the B band and the Qy band were hypsochromically shifted relative to the benchmark chlorin ZnC-M10, and the intensity of the Qy band decreased relative to the B band. Therefore, the effects of electron donating groups on the chlorin macrocycle are not as clear as for electron withdrawing groups, which produce a bathochromic shift of the B and Qy bands and an increase in the intensity of the Qy band relative to the B band. The second part of this thesis discusses the synthesis of carotenoid-porphyrin dyads in a facile manner by performing an aldol condensation using microwave irradiation. These carotenoid-porphyrin dyads can be synthesized using the commercially available trans-β-apo-8′-carotenal in yields of 47-48%. In each case, the 1H NMR spectrum indicates that the newly formed double bond is of the (E) configuration. The absorption spectrum for each carotenoid-porphyrin dyad shows characteristic features of the benchmark carotenoid and the corresponding benchmark porphyrin. Additionally, a decrease in fluorescence emission intensity of each carotenoid-porphyrin dyad versus that of the corresponding benchmark porphyrin was observed.