title: Structural Design Principle of Small-Molecule Organic Semiconductors for Metal-Free, Visible-Light-Promoted Photocatalysis.
abstract: Herein, we report on the structural design principle of small-molecule organic semiconductors as metal-free, pure organic and visible light-active photocatalysts. Two series of electron-donor and acceptor-type organic semiconductor molecules were synthesized to meet crucial requirements, such as 1) absorption range in the visible region, 2) sufficient photoredox potential, and 3) long lifetime of photogenerated excitons. The photocatalytic activity was demonstrated in the intermolecular C-H functionalization of electron-rich heteroaromates with malonate derivatives. A mechanistic study of the light-induced electron transport between the organic photocatalyst, substrate, and the sacrificial agent are described. With their tunable absorption range and defined energy-band structure, the small-molecule organic semiconductors could offer a new class of metal-free and visible light-active photocatalysts for chemical reactions.
authors.affiliation: Max Planck Institute for Polymer Research, 55128, Mainz, Germany.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.affiliation: Max Planck Institute for Polymer Research, 55128, Mainz, Germany.
authors.forename: Wei
authors.initials: W
authors.lastname: Huang
authors.affiliation: Max Planck Institute for Polymer Research, 55128, Mainz, Germany.
authors.forename: Run
authors.initials: R
authors.lastname: Li
authors.affiliation: Max Planck Institute for Polymer Research, 55128, Mainz, Germany.
authors.forename: Dominik
authors.initials: D
authors.lastname: Gehrig
authors.affiliation: Max Planck Institute for Polymer Research, 55128, Mainz, Germany.
authors.forename: Paul W M
authors.initials: PW
authors.lastname: Blom
authors.affiliation: Max Planck Institute for Polymer Research, 55128, Mainz, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Landfester
authors.affiliation: Max Planck Institute for Polymer Research, 55128, Mainz, Germany. kai.zhang@mpip-mainz.mpg.de.
authors.forename: Kai A I
authors.identifier: 0000-0003-0816-5718
authors.initials: KA
authors.lastname: Zhang
keywords: C−H functionalization; metal-free catalysts; photocatalysis; small-molecule organic semiconductor; visible light