Issue 38, 2015

The accessibility of nitrogen sites makes a difference in selective CO2 adsorption of a family of isostructural metal–organic frameworks

Abstract

By using three rigid diisophthalate organic linkers incorporating different numbers and orientations of Lewis basic nitrogen atoms into the spacers between two terminal isophthalate moieties, namely, 5,5′-(quinoline-5,8-diyl)-diisophthalate, 5,5′-(isoquinoline-5,8-diyl)-diisophthalate, and 5,5′-(quinoxaline-5,8-diyl)-diisophthalate, a family of isostructural copper-based metal–organic frameworks, ZJNU-43, ZJNU-44 and ZJNU-45, were successfully solvothermally synthesized and structurally characterized by single-crystal X-ray diffraction. The three MOFs, after activation, exhibited almost the same porosities but distinctly different CO2 adsorption properties. At room temperature and 1 atm, the adsorption capacities for CO2 reached 103, 116 and 107 cm3 (STP) g−1 for ZJNU-43a, ZJNU-44a and ZJNU-45a, respectively. Furthermore, Ideal Adsorbed Solution Theory (IAST) and simulated breakthrough analyses indicated that ZJNU-44a bearing much more easily accessible nitrogen sites is the best among the three MOFs for the separation of the following two binary gas mixtures at 296 K, i.e., 50/50 CO2/CH4 and 15/85 CO2/N2 gas mixtures, indicating that the accessibility of nitrogen sites plays a much more crucial role, which is further confirmed by comprehensive quantum chemical calculations. The work demonstrates that the CO2 adsorption properties of MOFs depend not only on the number of Lewis basic nitrogen sites but also more importantly on their accessibility.

Graphical abstract: The accessibility of nitrogen sites makes a difference in selective CO2 adsorption of a family of isostructural metal–organic frameworks

Supplementary files

Article information

Article type
Paper
Submitted
18 Jul 2015
Accepted
10 Aug 2015
First published
10 Aug 2015

J. Mater. Chem. A, 2015,3, 19417-19426

Author version available

The accessibility of nitrogen sites makes a difference in selective CO2 adsorption of a family of isostructural metal–organic frameworks

C. Song, J. Hu, Y. Ling, Y. Feng, R. Krishna, D. Chen and Y. He, J. Mater. Chem. A, 2015, 3, 19417 DOI: 10.1039/C5TA05481H

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements