Reductive Arylation of PVC by Dual-Metal Catalyzed Cross-Electrophile Coupling

Poly(vinyl chloride) (PVC) is one of the world's most widely produced thermoplastics. Its wide range of properties depend upon high loadings of noncovalent additives that are susceptible to migration and leaching. Recent efforts have sought to address this material flaw by covalently attaching additives directly onto the backbone of PVC. However, known grafting reactions of PVC are limited to alkylation or nucleophilic substitution reactions and are not applicable to arylation. This synthetic limitation precludes the covalent grafting of aromatic additives like colorants, antioxidants, and flame retardants onto PVC. This work details a mild and controllable methodology for electroreductive arylation of PVC with a range of aryl bromides. The reaction is catalyzed by a combination of Co and Ni complexes to enable on-bond arylation of PVC with functional aromatic architectures that are common additives in formulations of commercial PVC plastics. The simple transformation can be applied directly to postconsumer PVC on multigram scale without chain scission. The arylated PVCs exhibit excellent chemical resistance without leaching of the aromatic additives.