Synergy of Dual Functional Sites for Conversion of CO₂ in a Cycloaddition Reaction under Solvent-Free Conditions by a Zn(II)-Based Coordination Network with a Ladder Motif

Abstract

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.

An Amino-Decorated Self-Catenated Metal–Organic Framework for Efficient Capture and Conversion of CO2

“…As we know, due to the pore size restriction, only a few MOFs exhibit high catalysis for converting 2-epoxydecane and styrene oxide with large group hindrance. However, because of the highly connective SBU in 1 that promotes the rigidity of framework, the excellent catalytic performance of 1 is comparable to that of some reported MOFs-based catalysts (Table S3), such as UiO-67-IL , Py-UiO-66 , ADES-3 , and JLU-MOF58 …”

Bifunctional {Pb10K2}–Organic Framework for High Catalytic Activity in Cycloaddition of CO2 with Epoxides and Knoevenagel Condensation

“…According to the above-mentioned discussion and our recent research results, the high-porosity distribution PbOFs are targeted to develop with the bifunctional N-containing heterocyclic ligand 2,4,6-tri­(2,4-dicarboxyphenyl)­pyridine (H 6 TDP), which possesses the following unique merits: (i) spatial self-regulation: its triaxial angle-adjustable planar skeleton endows three branched carboxylphenyl groups rotating freely around the central pyridine to support the more dynamic architectures and (ii) metal cluster orientation: two α-carboxyl groups adjacent to pyridine possess a strong chelating coordination tendency, which leads to the overall structure orientation. − Herein, the solvothermal self-assembly of Pb 2+ and K + in the presence of the multifunctional H 6 TDP ligand generated a highly robust microporous framework of {(Me 2 NH 2 ) 2 [Pb 5 K­(TDP) 2 (μ 2 -OH)]·4DMF·6H 2 O} n ( NUC-45 ) with the scarcely reported S-shaped [Pb 10 K 2 (μ 2 -OH) 2 (COO) 24 ] cluster as secondary building units (SBUs). Due to the structural advantages of large surface area, stable physicochemical properties, Lewis acid sites including Pb 2+ and K + , Lewis base sites including the μ 2 -OH group and N pyridine atom, and multimodal channels, the activated NUC-45a framework not only demonstrated efficient catalytic performance in the cycloaddition reactions of CO 2 with epoxy compounds under mild conditions but also synchronously displayed excellent catalytic activity in the Knoevenagel condensation reactions of malononitrile and aldehydes.…”

A zinc porphyrin polymer as efficient bifunctional catalyst for conversion of CO2 to cyclic carbonates

“…At present, controlling CO 2 emissions, effectively converting excess CO 2 , and establishing a healthy carbon cycle are common problems faced by mankind. One of the valuable conversions of CO 2 into chemicals and materials is its cycloaddition to produce cyclic carbonates [5][6][7][8][9][10][11]. Ema group reported highly active bifunctional metalloporphyrins homogeneous catalysts for the reaction of CO 2 with epoxides to form cyclic carbonates, and the synergy effect between Lewis acid and nucleophilic reagents is a critical factor for the reaction [12,13].…”

“…Many heterogeneous catalysts have been developed in the field of the CO 2 cycloaddition reaction, such as metal-organic frameworks (MOFs) [7][8][9][10][11], covalent organic frameworks (COFs) [17,18], and porous organic polymers (POPs) [6,19]. Most reported heterogeneous catalysts mainly possess Lewis acid sites and nucleophilic reagents always needed as cocatalyst during the catalytic process [19][20][21][22][23][24][25][26][27][28].…”