Tailored Band Gaps in Sulfur- and Nitrogen-Containing Porous Donor-Acceptor Polymers

This is the pre-peer reviewed version of the following article: Schwarz, D.; Kochergin, Y. S.; Acharja, A.; Ichangi, A.; Opanasenko, M. V.; Čejka, J.; Lappan, U.; Arki, P.; He, J.; Schmidt, J.; Nachtigall, P.; Thomas, A.; Bojdys,* M. J. Chem. – Eur. J. 2017, DOI: 10.1002/chem.201703332.

Donor-acceptor dyads hold the key to tuning of electrochemical properties and enhanced mobility of charge carriers, yet their incorporation into a heterogeneous polymer network proves difficulty due to the fundamentally different chemistry of the donor- and acceptor-subunits. We present a family of sulphur and nitrogen containing porous polymers (SNPs) that are obtained via Sonogashira-Hagihara cross-coupling and that combine electron-withdrawing triazine (C₃N₃) and electron donating, sulphur-containing linkers. Choice of building blocks and synthetic conditions determines the optical band gap (from 1.67 to 2.58 eV) and nanoscale ordering of these microporous materials with BET surface areas of up to 545 m² g^-1 and CO₂ capacities up to 1.56 mmol g^-1. Our results highlight the advantages of the modular design of SNPs, and we report one of the highest photocatalytic hydrogen evolution rates for a cross-linked polymer without Pt co-catalyst (194 µmol h^-1 g^-1).