Solvent-Directed Construction of a Nanoporous Metal-Organic Framework with Potential in Selective Adsorption and Separation of Gas Mixtures Studied by Grand Canonical Monte Carlo Simulations.

In this report, a microporous metal-organic framework of [Ca(TDC)(DMA)] (1) and a two-dimensional coordination polymer of [Ca(TDC)(DMF) ] (2), (TDC =Thiophene-2,5-dicarboxylate, DMA=N, N'-dimethylacetamide and DMF=N, N'-dimethylformamide) based on Ca(II) were designed by the effect of solvent, and X-ray analysis was performed for the single crystals of 1 and 2. Then, compound 1 was synthesized in three different methods and identified with a set of analyses. Compared to other adsorbents, MOFs are widely used in the field of adsorption and separation of various gases due to a series of distinctive features such as diverse and adjustable structures pores with different dimensions, high porosity and surface area with regular distribution of active sites. Therefore, the ability of 1 to uptake single gases (CH , CO , C H , H and N ) and separation of several binary mixtures of gases (CO /CH , CO /N , CO /H and CO /C H ), were investigated using Grand Canonical Monte Carlo simulations. Volumetric and gravimetric adsorption isotherms in various operating conditions, the isosteric heat of adsorption (q ), the chemical potential for each thermodynamic state, and snapshots during the simulation process were reported in all cases. The results obtained from the adsorption simulation indicate that compound 1 has a high capacity for uptake of H (16 mmol g ) and N (12.5 mmol g ), CO (6.6 mmol g ), C H (5 mmol g ) and CH (1.5 mmol g ) gases at 1 bar. It also performs well in separating CO in binary mixtures, which can be attributed to the presence of open metal sites in nodes of 1 and their electrostatic tendency to interact with CO containing the higher quadrupole dipole moment compared to other components of the mixture.