Coordination polymers (CPs)/metal–organic frameworks (MOFs) are promising catalytic materials for selective carbon capture and utilization (CCU) as a C1 feedstock for the synthesis of value-added chemicals to mitigate the growing CO2 concentration in the atmosphere. Herein, we report the synthesis of a Zn­(II)-based coordination network with a ladder motif (ADES-3) constructed on an acylamide functionalized bipyridyl-based Schiff base (E)-N′-(pyridin-4-ylmethylene)­isonicotinohydrazide (L) and 5-nitroisophthalic acid (5NO 2 -IP) ligands and its utilization as an efficient binary heterogeneous catalyst for CO2 fixation. ADES-3 material has been characterized by various analytical techniques including single-crystal X-ray diffraction, which revealed a ladder motif with highly distorted trigonal bipyramidal geometry with unsaturated Lewis acid metal sites. ADES-3 with bulk phase purity was synthesized via room temperature stirring and exploited as a multifunctional heterogeneous catalyst for a CO2 cycloaddition reaction with aliphatic and aromatic epoxides to produce cyclic carbonates in a moderate reaction condition. Systematic experiments to explore the effect of various reaction parameters toward the optimization of cycloaddition reaction were performed, and ADES-3 offered good conversion ability for almost all tested epoxides under the optimum condition. Moreover, based on structural indication, a plausible mechanism for the cycloaddition reaction is proposed. ADES-3 exhibits a decent chemical and thermal stability during the reaction and can be reused up to four catalytic cycles with retention in catalytic activity suggesting good prospects for the application as a heterogeneous catalyst for CO2 fixation.

Two mixed ligand MOFs {[Zn2(5NO2-IP)2(L)2](H2O)}n (ADES-1) and {[Cd2(5NO2-IP)2(L)2(H2O)4](L)(H2O)(CH3OH)6}n (ADES-2), (where 5NO2-IP = 5-Nitroisophthalate and L = (E)-N'-(pyridin-3-ylmethylene)nicotinohydrazide) has been synthesized and characterized by various analytical methods including SXRD analysis. SXRD...

Functional neutral metal–organic frameworks (MOFs) {[M­(5OH-IP)­(L)]} n [M = Zn­(II) for ADES-4; Cd­(II) for ADES-5; 5OH-IP = 5-hydroxyisophthalate; L = (E)-N′-(pyridin-3-ylmethylene)­nicotinohydrazide) have been synthesized by a diffusion/conventional reflux/mechanochemical method and characterized by various analytical techniques. Crystals were harvested by a diffusion method, and single-crystal X-ray diffraction (SXRD) analysis revealed that an adjacent [M2(COO)2] n ladder chain generates isostructural two-dimensional network motifs by doubly pillaring via L. The bulk-phase purity of ADES-4 and ADES-5 synthesized by a versatile synthetic approach has been recognized by the decent match of powder X-ray diffraction patterns with the simulated one. Both ADES-4 and ADES-5 showed selective adsorption of cationic dyes methylene blue (MB), methyl violet (MV), and rhodamine B (RhB) over anionic dye methyl orange (MO) from water with good uptake and rapid adsorption. Utilization of ADES-4 as a chromatographic column filler for adsorptive removal of individual cationic dyes as well as a mixture of dyes has been demonstrated from the aqueous phase. Interestingly, ADES-4 is reusable with good stability, and it showed a dye desorption phenomenon in methanol. The probable mechanism of cationic dye removal based on insight from structural information and plausible supramolecular interactions has also been explored. Both MOFs also showed efficient catalytic transformation of fructose and glucose into the high-value chemical intermediate 5-hydroxymethylfurfural of industrial significance.