title: Porphyrins as Photoredox Catalysts: Experimental and Theoretical Studies.
abstract: Metalloporphyrins not only are vital in biological systems but also are valuable catalysts in organic synthesis. On the other hand, catalytic properties of free base porphyrins have been less explored. They are mostly known as efficient photosensitizers for the generation of singlet oxygen via photoinduced energy transfer processes, but under light irradiation, they can also participate in electron transfer processes. Indeed, we have found that free base tetraphenylporphyrin (H2TPP) is an efficient photoredox catalyst for the reaction of aldehydes with diazo compounds leading to α-alkylated derivatives. The performance of a porphyrin catalyst can be optimized by tailoring various substituents at the periphery of the macrocycle at both the β and meso positions. This allows for the fine tuning of their optical and electrochemical properties and hence their catalytic activity.
authors.affiliation: Institute of Organic Chemistry, Polish Academy of Sciences , Kasprzaka 44/52, 01-224 Warsaw, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Rybicka-Jasińska
authors.affiliation: University of Houston , Department of Chemistry, Houston, Texas 77204-5003, United States.
authors.forename: Wenqian
authors.initials: W
authors.lastname: Shan
authors.affiliation: Medical University of Warsaw , Faculty of Pharmacy with the Laboratory Medicine Division, Department of Physical Chemistry, Banacha 1, 02-097 Warsaw, Poland.
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Zawada
authors.affiliation: University of Houston , Department of Chemistry, Houston, Texas 77204-5003, United States.
authors.forename: Karl M
authors.initials: KM
authors.lastname: Kadish
authors.affiliation: Institute of Organic Chemistry, Polish Academy of Sciences , Kasprzaka 44/52, 01-224 Warsaw, Poland.
authors.forename: Dorota
authors.initials: D
authors.lastname: Gryko