Air-Stable Copper(I) Borohydride for Carbon Disulfide Mitigation through Sustainable Hydride Transfer

We report the synthesis and characterization of an air-stable copper(I) borohydride, [Cu(PNN)(μ-BH4)], stabilized by a koneramine-derived PNN ligand featuring mixed phosphorus and nitrogen donors. The ligand framework imparts high oxidation resistance, enabling the isolation of a mononuclear Cu(I)–borohydride. The complex displays efficient hydride transfer reactivity with environmentally harmful small molecules, including CS2, CH3I, and SO2, cleanly affording copper(I) xanthate, halide, and bisulfate derivatives under mild conditions. Complementary density functional theory (DFT) analysis provides mechanistic insights into the hydride transfer process and pollutant activation. Overall, this work establishes [Cu(PNN)(μ-BH4)] as a well-defined, air-stable Cu(I)–borohydride that enables sustainable pollutant remediation and selective C–S/C–X bond formation. By combining structural robustness, selective reactivity, and the use of an earth-abundant metal, this study highlights a sustainable organometallic strategy for pollutant remediation without reliance on precious metals.