Studies on renewable two-electron reductant and oxidant aimed at water oxidation and CO2 reduction

2016 Fiscal Year Final Research Report

• Project/Area Number: 26288024
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Inorganic chemistry
• Research Institution: Kyoto University
• Principal Investigator: TANAKA KOJI. 京都大学, 物質ー細胞統合システム拠点, 研究員 (00029274)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: water oxidation / CO2 reduction / NAD/NADH model / Renewable reductant / oxyl radical complexes / Amino radical complexes

Outline of Final Research Achievements

This study is to construct NADH/NAD redox models as renewable two-electron oxidant and reductant for water oxidation and CO2 reduction. Electrochemical reduction of Ru-NADH model in CO2 saturated aqueous solutions catalytically produced HCOO-. This is the first example of catalytic CO2 reduction mediated with renewable organic hydride donor catalyst.
Ru-dioxolene frameworks exhibit very strong dπ-pπ interaction between Ru t2g and ligand π*. Deprotonation of aqua- and amino-Ru-dioxolene complexes further expands π－electron delocalization, which effectively stabilizes unusual oxyl and amino radicals. Oxidative activation of two oxyl radicals derived from dimeric aqua-Ru-dioxolen complexes resulted in O-O bond formation at the stage prior to O2 evolution in water oxidation. Oxidative activation of the anylinyl radical complex brought about intermolecular N-C bond formation through radical coupling between anilinyl radical and para-position of phenyl ring of aniline.

Free Research Field

Coordination Chemistry