Methylthiophenyl- and Methylthiobiphenyl-Substituted A 2 B Co III corroles: Modulating Electrocatalyzed Hydrogen Evolution Reactions on Surface-Modified Gold Electrodes.

Four A 2 B-type Co III corroles ( 2a-2d ) with electron-donating/withdrawing substituents at the A 2 meso -aryl substituents and a 4-(methylthio)phenyl ring at the B position have been synthesized and characterized, along with a series of meso -extended Co III corroles ( 4a - 4c ) with 4'-(methylthio)biphenyl moieties. The electronic structures and structure-property relationships of the dyes have been analyzed by comparing their redox and optical properties to trends predicted in density functional theory calculations. Au electrodes surface-modified with 2a - 2d and 4a - 4c are highly efficient catalysts for electrocatalyzed hydrogen evolution reactions, and the electrocatalytic properties can be readily modulated by fine-tuning the electronic structure of the Co III corrole and the distance between the "Au-S" bond and Co III center.