ABSTRACT
The release of carbon disulfide can have adverse effects on our environment and human health. The stability of carbon disulfide and the slow kinetics of hydrolysis can make it challenging to achieve efficient and practical cleavage of the CS bonds. Herein, a calix[4]arene-based porous organic polymer (CPOP-1) is innovatively synthesized through an optimized polycondensation reaction using C-Methylcalix[4]resorcinarene and hexafluoro-hexaazatriphenylene as monomers. Subsequently, palladium-induced calix[4]arene-based porous organic polymer was also synthesized via strong Pd-N coordination bonds to construct the metal-induced porous catalyst (CPOP-2). The polymeric catalyst active center [Pd2+(N^N)(NO3-)2] demonstrated outstanding catalytic hydrolysis performance (11.14 µmol g-1 h-1) in 10.5 h which is significantly enhanced by ca.13.2 times as compared to reported mononuclear Bpy-Pd(NO3)2, and 7.07 times than model trinuclear complex catalyst HATN-Pd-1, respectively. The control experiments revealed that POP catalysts showcased robust stability, prolonged effectiveness, and feasible recyclability during the hydrolytic cleavage of carbon disulfide at room temperature in aqueous solutions. Furthermore, the coordination environment of [Pd2+(N^N)] was validated through XPS, EXAFS, and isotope labeling measurements, and the hydrolysis cleavage products were confirmed e. g. CO2, sulfide, and protons. More importantly, a reaction mechanism was formulated coupled with theoretical calculations, and simulations. The proposed mechanism involves sequential OH- nucleophilic attacks on the carbon atoms of insert-coordinated CS2 and COS, leading to the cleavage of double CS bonds and the formation of CO bonds. The concurrent dissociation of the C-S bond and liberation of CO2 result in an intermediate structure characterized by [(N^N)Pd2+](SH-)2. This intermediate motif serves as the source of the thermodynamic driving force for the reaction.
ABSTRACT
The self-assembly of mechanoluminochromic polynuclear gold(I) complexes has attracted more and more attention in the field of supramolecular gold(I) chemistry. In this work, we adopted a stepwise self-assembly strategy to precisely synthesize two polynuclear gold(I) supramolecular clusters. Through cooperative AuI···AuI and Au-N interactions, the gold(I) clusters 1+â¢BF4- and 24+â¢4BF4- with Au4 and Au16 cores, respectively, were successfully constructed. In these supramolecular clusters, (dppm)Au2Cl2 coordination motifs and trithiocyanuric linkers were stepwise assembled via sequential thiolate-chloride/phosphine coordination substitution and Au-S/Au-N coordination bond rearrangement. Two well-defined gold(I) supramolecular clusters displayed intense emission both in the solid state and in solution. Furthermore, the ladder-shaped cluster 24+â¢4BF4- exhibited reversible mechanochromic luminescence behavior in the solid state as well as aggregation-caused redshifted emission in solution. Upon mechanical grinding, the emission of the cluster 24+â¢4BF4- changed from yellow at 582 nm to red at 612 nm. The initial emission could be fully recovered by treatment with acetonitrile.
