High-efficiency green catalytic conversion for waste CS2 by non-noble metal cage-based MOFs: an access pathway to high-value thiazolidine-2-thione†

Abstract

Green and effective disposal of carbon disulfide (CS₂) waste into high-valued chemicals under mild conditions is meaningful yet challenging. Herein, a novel 3D cluster-based metal–organic framework (MOF) {(Me₂NH₂)₂[Co₃(μ₃-O)(XN)(BDC)₃]·4DMF·5MeOH}_n (compound 1) (XN = 4′-(4-pyridine)4,2′:2′,4′′-terpyridine, H₂BDC = terephthalic acid) assembled by [Co₁₅] and [Co₁₈] nano-cages was harvested, presenting excellent stability. Catalytic characterization demonstrated that compound 1 can efficiently promote the cycloaddition reaction of CS₂ with aziridines to form sole high-valued thiazolidine-2-thione upon 30 °C and 0.1 MPa for 6 h, which matches well with the atom economy and the sustainable development intention. Noteworthily, compound 1 is the mildest and most efficient catalyst for CS₂ treatment and can be reused at least ten times without significant activity degradation; it also retains excellent catalytic capacity in both gram-scale reaction and simulated CS₂ waste liquid, which lays a solid foundation for its practical application. Additionally, density functional theory (DFT) calculations further confirm the synergistic effect of the nanocage characteristic and the Me₂NH₂⁺ cation, which can significantly reduce the reaction energy barrier in this CS₂/aziridine coupling reaction system.