Heterogenization of Homogeneous Donor-Acceptor Conjugated Polymers for Efficient Photooxidation: An Approach Toward Sustainable and Recyclable Photocatalysis.

Recovery of homogeneous photocatalysts from reaction mixture is challenging, affecting the cost-effectiveness, and masks their advantages, including 4-8 fold higher catalytic activity than corresponding heterogeneous counterparts. Incorporation of long alkyl chains within the rigid π-conjugated backbone of conjugated polymers can augment their solubility in particular organic solvents; accordingly, they can function as homogeneous photocatalysts. Consequently, these polymers facilitate the recovery of catalysts through the reverse dissolution process, thus creating a well-suited platform to meet certain advantages of both homo- and heterogeneous photocatalysts. This work exemplifies the unprecedented perks of donor-acceptor conjugated polymers from benzodithiophene and substituted dibenzothiophene sulfone moieties for their homogeneous phase photoredox activities along with their heterogeneous recovery and reuse up to five runs. The potential intermediate singlet oxygen (O) and superoxide (O•) as reactive oxygen species generated by these photostable conjugated polymers efficiently catalyze the visible-light-driven oxidation of aryl sulfides (up to 92% yield) and oxidative hydroxylation of phenylboronic acids (up to 93% yield), respectively. Therefore, to actualize the heightened catalytic performance and formulate a design strategy for polymeric photoredox catalyst, our work introduces an alternative approach to the advancement of photocatalysis with diverse catalytic activities.