Selective oxidation of sulfides by pyrene-π-anthraquinone conjugated microporous polymer photocatalysis

Abstract

Enabled by tailorability and aromaticity, conjugated microporous polymers (CMPs) have become increasingly important in photocatalysis. Both pyrene and anthraquinone are essential building blocks of burgeoning photocatalytic materials like CMPs. Herein, alkynyl groups are embedded between pyrene and anthraquinone, affording Py-π-AQ-CMP. Theoretical calculation indicates that the insertion of alkynyl groups adjusts steric hindrance and ameliorates the planar π-conjugation. Notably, the extended π-conjugation generates a narrower band gap and more extensive optical response, enabling Py-π-AQ-CMP with superior charge carrier’s mobility. Gratifyingly, Py-π-AQ-CMP photocatalysis could enable the highly selective oxidation of organic sulfides in methanol. Significantly, driven by blue light, Py-π-AQ-CMP delivers almost twice of the efficiency of Py-AQ-CMP, a CMP without the alkynyl π-bridge. The mechanistic investigation suggests both electron and energy transfers participate in the activation of dioxygen for the oxidation of sulfides. This work highlights that inserting a π-bridge could afford high-performance photocatalysts of CMPs.