Controlled Triazine‐Based Covalent Functionalization of Black Phosphorus for Degradable Hybrid Materials

ABSTRACT Controllable covalent surface functionalization of black phosphorus (BP) remains a central challenge in the development of 2D phosphorus‐based materials. Here, we report a scalable route to synthesize biodegradable BP‐polymer hybrids and establish optimal conditions for BP production, exfoliation, and covalent modification. BP sheets, produced via optimized mechanochemical and exfoliation processes, are covalently functionalized with 2‐azido‐4,6‐dichloro‐1,3,5‐triazine via a nitrene‐mediated [2+1] cycloaddition. The reaction yields a P‐N bond, verified by advanced surface analyses and density functional theory (DFT) calculations. The conjugated triazine groups enable subsequent nucleophilic aromatic substitution reactions, providing a versatile platform for controlled post‐modification of BP surface. This covalent functionalization strategy addresses key limitations in BP surface chemistry and provides a route toward biodegradable phosphorus‐based hybrid materials. As a representative example, functionalization with linear polyglycerol sulfate produces BP‐polymer conjugates that inhibit respiratory syncytial virus (RSV) and herpes simplex virus 1 (HSV‐1) at low‐microgram‐per‐milliliter concentrations.