Visible light-induced reduction properties of diphenylviologen with water-soluble porphyrin

Abstract

Molecular conversion reaction system containing a dye and a biocatalyst catalyzing a reaction of a carbon–carbon bond formation from CO2 as a feedstock were constructed. For example, NADP-malic enzyme (ME, EC1.1.1.40) catalyzes the reaction of introducing CO2 as a carboxy group to pyruvate (C3 compound) to form malate (C4 compound) via oxaloacetate in the presence of natural co-enzyme NADPH. In a recent study, visible light-induced oxaloacetate production from pyruvate and CO2 with the system consisting an electron donor, a photosensitizer, diphenylviologen (PV2+) derivative as an electron mediator and ME was reported. However, the visible light-induced reduction properties of PV2+ with water-soluble Zn porphyrin have not been clarified. In this study, chemical and photo-redox properties of PV2+ were studied. In addition, to produce malate, CO2 saturated reaction solution containing triethanolamine, tetraphenylporphine tetrasulfonate (H2TPPS), pyruvate, PV2+ and ME in the presence of Mg2+, co-factor for ME was irradiated with visible-light, the oxaloacetate and malate were produced.