Fine-tuning pore size by shifting coordination sites of ligands and surface polarization of metal-organic frameworks to sharply enhance the selectivity for CO2

Liting Du; Zhiyong Lu; Kaiyuan Zheng; Junyi Wang; Xin Zheng; Yi Pan; Xiaozeng You; Junfeng Bai

doi:10.1021/ja309992a

Fine-tuning pore size by shifting coordination sites of ligands and surface polarization of metal-organic frameworks to sharply enhance the selectivity for CO2

J Am Chem Soc. 2013 Jan 16;135(2):562-5. doi: 10.1021/ja309992a. Epub 2012 Dec 31.

Authors

Liting Du¹, Zhiyong Lu, Kaiyuan Zheng, Junyi Wang, Xin Zheng, Yi Pan, Xiaozeng You, Junfeng Bai

Affiliation

¹ State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China.

PMID: 23268731
DOI: 10.1021/ja309992a

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.