A novel Lewis acid–base bifunctional Zn­(II)-based MOF-Zn-1 [Zn2L2MA·2DMF] (MA = melamine, H2L = 2,5-thiophenedicarboxylic acid), with abundant micropores and free -NH2 groups was facilely assembled by incorporating zinc­(II) ion with nitrogen-rich melamine and 2,5-thiophenedicarboxylic acid ligands. The constructed MOF-Zn-1 presented an excellent affinity toward CO2 molecules due to the Lewis-base property together with abundant micropores. The Zn active sites could be used for epoxide activation. The acid–base synergistic effects facilitated CO2 conversion into cyclic carbonates under ambient temperature using the porous MOF-Zn-1 as a heterogeneous catalyst. Moreover, the MOF-Zn-1 exhibited satisfied stability and versatility, and it was easy to recycle with no obvious decrease of catalytic activity. Then the feasible synergistic mechanism of MOF-Zn-1/Bu4NBr catalysts for CO2 conversion was proposed.

A new tetratopic bridging ligand 1,1′-(propane-1,3diyl)bis(1H-pyrazole-3,5-dicarboxylic acid) (PDC) with functional pyrazole groups was designed and used for reacting with environmentally friendly zinc centers in mixed solvents; the resulting framework [Zn 3.5 (PDC) 2 (H 2 O) 10 ] (abbreviated as MOF Zn-2PDC) contained numerous organic−inorganic crablike blocks and had high density of zinc sites and coordinated water molecules. Abundant open metal sites (OMSs) were generated after the removal of coordinated water molecules by vacuum drying, which produced exceptionally catalytic performance for CO 2 cycloaddition to bulky styrene oxide, and the produced styrene carbonate yield and selectivity reached up to 86 and 97% under mild conditions of 55 °C, 12 h, and 1 MPa. Moreover, MOF Zn-2PDC also showed general applicability to other bulky epoxides. Meanwhile, the MOF Zn-2PDC catalyst remained with good catalytic performance after six cycles.

Novel metal-free tri-s-triazine terminal-linked ionic liquids have been developed from various precursors of urea derivative-based ionic liquid/urea by co-condensation method. These were successfully used for the chemical fixation of CO 2 to epoxides producing cyclic carbonates under mild and green conditions in which no co-catalyst and solvent were needed. The tri-s-triazine terminal-linked ionic liquids so prepared possess multi-functionalities of hydrogen bond donor (HBD) ability, nucleophilicity, and Lewis base property, which are vital to the ring-opening of epoxide and the activation of CO 2. Reaction parameters (temperature, CO 2 pressure, catalyst loading, time, water content) on cycloaddition of CO 2 with propylene oxide (PO) to propylene carbonate (PC) over tri-s-triazine terminal-linked ionic liquids were optimized. It has been shown that, under the optimal conditions, the catalyst is also

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An efficient Zn(Bmic)(AT) MOF with available Lewis acid− base blocks was prepared by a solvothermal method combining the mixed ligands 5-aminotetrazole (HAT) and 1-benzimidazole-5-carboxylic acid (H 2 Bmic). The prepared Zn(Bmic)(AT) catalyst is rich in amino groups, uncoordinated oxygen atoms, and multiple open metal sites (OMSs), which contribute to CO 2 adsorption of 79 cm 3 /g at 273 K and 52 cm 3 /g at 298 K, with high adsorption enthalpy (28 kJ mol −1 ). Furthermore, its multiple functional sites facilitate CO 2 cycloaddition to various small-molecule epoxides to give five-ring cyclic carbonates with the assistance of a Bu 4 NBr cocatalyst, achieving a high TON of 170 for propylene carbonates (PC) under solventfree, mild conditions (80 °C, 5 bar). In addition, the Zn(Bmic)(AT) catalyst exhibits good recyclability for six consecutive cycles. Moreover, a feasible synergistic mechanism of Zn(Bmic)(AT)/Bu 4 NBr catalysts for CO 2 conversion into cyclic carbonate is proposed.

Multi-functional and hierarchical Zn-MOF was rapidly synthesized by room-temperature stirring using an organic amine as a protonation agent and exhibited remarkable improvement for CO2 cycloaddition to bulky epoxides.

A novel, simple, economic and efficient method utilizing polar solvents to prepare graphene oxide sheets of homogeneous size has been developed.

Amino acid ionic liquids (AAILs) are widely considered as biocompatible and biodegradable green absorbents, solvents and catalysts that have been utilized in sustainable chemistry. Several AAILs containing the ether functionalized...