Journal Article

Chemically Mediated Artificial Electron Transport Chain

Henkelman, Graeme, Yang, Yu-Dong, Chau, Calvin V., Yang, Jian, Bucher, Christophe, Gong, Han-Yuan, Zhang, Qian, Khrouz, Lhoussain, Sessler, Jonathan L., Wang, Yuying

2024

Overview

Electron transport chains (ETCs) are ubiquitous in nearly all living systems. Replicating the complexity and control inherent in these multicomponent systems using ensembles of small molecules opens up promising avenues for molecular therapeutics, catalyst design, and the development of innovative energy conversion and storage systems. Here, we present a noncovalent, multistep artificial electron transport chains comprising cyclo[8]­pyrrole (1), a meso-aryl hexaphyrin(1.0.1.0.1.0) (naphthorosarin 2), and the small molecules I2 and trifluoroacetic acid (TFA). Specifically, we show that 1) electron transfer occurs from 1 to give I3 – upon the addition of I2, 2) proton-coupled electron transfer (PCET) from 1 to give H 3 2 •2+ and H 3 2 + upon the addition of TFA to a dichloromethane mixture of 1 and 2, and 3) that further, stepwise treatment of 1 and 2 with I2 and TFA promotes electron transport from 1 to give first I3 – and then H 3 2 •2+ and H 3 2 + . The present findings are substantiated through UV-vis-NIR, 1H NMR, electron paramagnetic resonance (EPR) spectroscopic analyses, cyclic voltammetry studies, and DFT calculations. Single-crystal structure analyses were used to characterize compounds in varying redox states.

• Publisher: American Chemical Society,ACS Publications
• Subject: Catalysts / Chemical Sciences / Crystal structure / Dichloromethane / Electron paramagnetic resonance / Electron spin resonance / Electron transfer / Electron transport / Electron transport chain / Energy conversion / Energy storage / Iodine / Medical innovations / NMR / Nuclear magnetic resonance / Oxidation / Single crystals / Storage systems / Trifluoroacetic acid