a, SIFSIX-2-Cu; pore size 13.05 Å, BET apparent surface area (N2 adsorption) 3,140 m2 g−1. b, SIFSIX-2-Cu-i; pore size 5.15 Å, BET apparent surface area (N2 adsorption) 735 m2 g−1. c, SIFSIX-3-Zn; pore size 3.84 Å, apparent surface area (determined from CO2 adsorption isotherm) 250 m2 g−1. Colour code: C (grey), N (blue), Si (yellow), F (light blue), H (white). All guest molecules are omitted for clarity. Note that the green net represents the interpenetrated net in SIFSIX-2-Cu-i. The nitrogen-containing linker present in SIFSIX-2-Cu and SIFSIX-2-Cu-i is 4,4′-dipyridylacetylene (dpa) whereas that in SIFSIX-3-Zn is pyrazine (pyr).

Effective separation and purification technologies, capable of removing unwanted impurities from raw materials and industrial byproducts, are of paramount importance for the economy and the environment.  Especially, separation and capture of CO2 in a cost effective way is of great interest.  Porous crystalline materials that can exploit both equilibrium and kinetic selectivity, can perform this function, the challenge is to keep the energy footprint of the process low.  In a letter published in Nature a group a researchers from the University of South Florida and from the King Abdullah University of Science and Technology, Saudi Arabia, presents results obtained applying crystal engineering to metal-organic materials (MOMs).  The engineered MOMs offer an unprecedented CO2 sorption selectivity and are therefore relevant to CO2 separation in the context of post-combustion, pre-combustion and natural gas upgrading.  The crystalline structure of these MOMs was studied at the ChemMatCARS 15-IDB Crystallography station, at the APS.


Patrick Nugent, Youssef Belmabkhout, Stephen D. Burd, Amy J. Cairns, Ryan Luebke, Katherine Forrest, Tony Pham, Shengqian Ma, Brian Space, Lukasz Wojtas, Mohamed Eddaoudi & Michael J. Zaworotko
Porous materials with optimal adsorption thermodynamics and kinetics for CO2separation
Nature 495, 80–84 (2013).  Author affiliations:  1University of South Florida, USA. 2King Abdullah University of Science and Technology (KAUST), Saudi Arabia.