A new Zn-based metal–organic framework with 8-connected hex topology constructed from bipyridine and carboxylate ligands, namely [Zn(cpna)3(tmbpy)]n·4DMF (1) (H2cpna = 6-(4-carboxyphenyl)nicotinic acid; tmbpy = 3,3′-dimethyl-4,4′-bipyridine), has been synthesized under solvothermal conditions. The Zn-MOF was structurally characterized and retained a good crystal structure after activation (1a), an indication of permanent porosity. 1a exhibits a BET surface of 770 m2 g−1 and the maximum aperture of 8.60 Å. Single component adsorption isotherm measurements of C2H2, CO2, CH4, CO and N2 on 1a were performed both at 273 K and 298 K, and the selectivities for C2H2/CH4, C2H2/CO2, CO2/CO, CO2/CH4 and CO2/N2 were estimated on the basis of the ideal adsorbed solution theory (IAST). 1a shows the uptake of C2H2 (3.89 mmol g−1) and CO2 (3.52 mmol g−1) at 273 K and 100 kPa, respectively. Due to the Lewis basic pyridyl sites inside the channel of the framework, 1a showed good adsorption selectivities for C2H2/CH4(50 : 50) and C2H2/CO2(50 : 50) at 298 K (100 kPa).
Peng Yan,Jucai Yang,Deyun Ma,Siyun Zhang,Shigong Zeng,Liting Feng,Sihui Zhan,Qiaquan Lin
A water-stable porous cobalt(II)–organic framework functionalized by ethoxyl groups with a chemical formula, {[Co 6 (5-EIA) 5 (tmbpy)(OH) 2 (H 2 O) 2 ]∙4(H 2 O)} n ( 1 ) (5-H 2 EIA = 5-ethoxy-isophthalic acid; tmbpy = 3,3′-dimethyl-4,4′-bipyridine) has been constructed and studied in terms of structure and performance. 1 shows a 3D framework, and has a 1D channel of 8.1 × 6.0 Å 2 along the a axis. The framework 1 exhibits high humid and thermal stability according to PXRD and TGA results. The C 2 H 2 and CO 2 uptakes of the activated 1 ( 1a ) were up to 2.07 mmol g −1 and 1.89 mmol g −1 at 273 K (100 kPa), respectively. More importantly, 1a shows excellent C 2 H 2 /CH 4 (1:1) and CO 2 /CH 4 (1:1) separations with IAST selectivity of 23.7 and 11.4 at 298 K (100 kPa), respectively. Furthermore, 1a showed good reuse performance, suggesting that 1a could be applied to the separation of C 2 H 2 /CH 4 or CO 2 /CH 4 .