Fine-Tuning Pore Size by Shifting Coordination Sites of Ligands and Surface Polarization of Metal–Organic Frameworks To Sharply Enhance the Selectivity for CO₂

Abstract

Based upon the (3,6)-connected metal-organic framework {Cu(L1)·2H(2)O·1.5DMF}(∞) (L1 = 5-(pyridin-4-yl)isophthalic acid) (SYSU, for Sun Yat-Sen University), iso-reticular {Cu(L2)·DMF}(∞) (L2 = 5-(pyridin-3-yl)isophthalic acid) (NJU-Bai7; NJU-Bai for Nanjing University Bai group) and {Cu(L3)·DMF·H(2)O}(∞) (L3 = 5-(pyrimidin-5-yl)isophthalic acid) (NJU-Bai8) were designed by shifting the coordination sites of ligands to fine-tune pore size and polarizing the inner surface with uncoordinated nitrogen atoms, respectively, with almost no changes in surface area or porosity. Compared with those of the prototype SYSU, both the adsorption enthalpy and selectivity of CO(2) for NJU-Bai7 and NJU-Bai8 have been greatly enhanced, which makes NJU-Bai7 and NJU-Bai8 good candidates for postcombustion CO(2) capture. Notably, the CO(2) adsorption enthalpy of NJU-Bai7 is the highest reported so far among the MOFs without any polarizing functional groups or open metal sites. Meanwhile, NJU-Bai8 exhibits high uptake of CO(2) and good CO(2)/CH(4) selectivity at high pressure, which are quite valuable characteristics in the purification of natural gases.

A stable metal–organic framework with suitable pore sizes and rich uncoordinated nitrogen atoms on the internal surface of micropores for highly efficient CO2 capture

“…36 Its selectivity is evidently superior to most MOFs and this ranks NENU-520 among the highest selectivity values (Table S5 †) with the absence of unsaturated metal centres, charged units and amine groups. 46,[48][49][50][51][52][53][54][55][56][57] Thus, NENU-520 is one of the best materials to facilitate effective CO 2 capture and separation from the perspective of comprehensive properties.…”

Versatile coordination behaviour of a multi-dentate Schiff base with manganese(II), copper(II) and zinc(II) ions and their corrosion inhibition study

“…In the past two decades, immense interest has been paid to design and synthesis of coordination polymers (CPs) and metal-organic frameworks (MOFs) not only for the aesthetically pleasing structures but also for their potential applications in gas adsorption and separation [1], magnetism [2], sensing of target molecules [3], catalysis [4], luminescence [5], etc. The main reason for scientists to be interested in building coordination polymers is the creation of new tunable functional materials with unique physical and chemical properties [6,7].…”

Crystal structure of diaquabis(benzoato-κO)(1,10-phenanthroline- κ2N,N')- manganese(II) 1.5 hydrate, C26H25MnN2O7.5

“…The study of coordination polymers has gained great recognition as an importantinterface betweensynthetic chemistryand materialss cience andp rovidesas olid foundationf or understanding howm olecules can be organized and how functions can be achieved.I nt he recent years, the supramolecular chemistry of transition metal-organic polymers based on coordination bonds and/or weaker intermolecular forces (such as hydrogen bonding and p-p stacking interaction) has been widely investigated due to their variety of intriguing architectures and topologies [1][2][3][4] and their potential applications in magnetism,electric conductivity, molecular adsorption, heterogeneous catalysis, and fluorescent materials [5][6][7][8][9]. Ag reat research effort was made to obtain designed andp redictable frameworks and properties by using an versatileo rganic ligand and functional metal ionsi nsitu solvothermal synthesis.…”