Tunable Hydrazination of sp 2 and sp 3 C–H Bonds of Polystyrenes with Fe( III )

Comprehensive Summary Post‐functionalization of polystyrene (PS) holds a crucial role in creating novel materials from commercially available plastics as it enables the introduction of diverse chemical groups to enhance the material's properties for advanced applications. Despite the ability to introduce various functional groups onto PS, forming C–N bonds on either aromatic ring or aliphatic chain remains a significant challenge. Herein, we present a versatile strategy for site‐selective C–H hydrazination of PS plastics, enabling precise functionalization of both aromatic (sp 2 ) and aliphatic (sp 3 ) bonds under tunable catalytic conditions. Using FeCl 3 / N ‐chlorosuccinimide (NCS) for electrophilic aromatic hydrazination and photoinduced TBAFeCl 4 for radical‐mediated aliphatic C–H cleavage, we achieve the controlled introduction of hydrazine motifs into PS derivatives with high efficiencies. A range of styrene‐based polymers, including PS, SAN, SIS, SEBS, and PMS, can be used to synthesize diverse aminated plastic materials. This method can be also applicable for selective hydrazination of PS from mixed plastic. While the functionalized materials exhibit good ability in being a compatibilizer, the subsequent functional group transformations show great potential for creating (multi)functional materials. And comparative degradation studies reveal that the aliphatic C–H hydrazination might enhance the oxidative degradation of PS materials.