Theoretical Study of the Effect of Halogen Substitution in Molecular Porous Materials for CO₂ and C₂H₂ Sorption

Authors

Douglas M. Franz, University of South FloridaFollow
Mak Djulbegovic, University of South FloridaFollow
Tony Pham, University of South FloridaFollow

Document Type

Article

Publication Date

3-2018

Keywords

metal–organic framework, simulation, gas sorption, carbon dioxide, acetylene, gas separation

Digital Object Identifier (DOI)

https://doi.org/10.3934/matersci.2018.2.226

Abstract

Grand canonical Monte Carlo (GCMC) simulations of carbon dioxide (CO₂) and acetylene (C₂H₂) sorption were performed in MPM-1-Cl and MPM-1-Br, two robust molecular porous materials (MPMs) that were synthesized by the addition of adenine to CuX₂ (X = Cl or Br) by solvent diffusion. Previous experimental studies revealed that both MPMs are selective for C₂H₂ over CO₂ [Xie DY, et al. (2017) CIESC J 68: 154–162]. Simulations in MPM-1-Cl and MPM-1-Br were carried out using polarizable and nonpolarizable potentials of the respective sorbates; this was done to investigate the role of explicit induction on the gas sorption mechanism in these materials. The calculated sorption isotherms and isosteric heat of adsorption (Q_st) values for both sorbates are in reasonable agreement with the corresponding experimental measurements, with simulations using the polarizable models producing the closest overall agreement. The modeled CO₂ binding site in both MPMs was discovered as sorption between the halide ions of two adjacent [Cu₂(adenine)₄X₂]2+ (X = Cl, Br) units. In the case of C₂H₂, it was found that the sorbate molecule prefers to align along the X–Cu–Cu–X axis of the copper paddlewheels such that each H atom of the C₂H₂ molecule can interact favorably with the coordinated X− ions. The simulations revealed that both MPMs exhibit stronger interactions with C₂H₂ than CO₂, which is consistent with experimental findings. The effect of halogen substitution toward CO₂ and C₂H₂ sorption in two isostructural MPMs was also elucidated in our theoretical studies.

Rights Information

This work is licensed under a Creative Commons Attribution 4.0 License.

Was this content written or created while at USF?

Yes

Citation / Publisher Attribution

AIMS Materials Science, v. 5, issue 2, p. 226-245

Scholar Commons Citation

Franz, Douglas M.; Djulbegovic, Mak; and Pham, Tony, "Theoretical Study of the Effect of Halogen Substitution in Molecular Porous Materials for CO₂ and C₂H₂ Sorption" (2018). Chemistry Faculty Publications. 54.
https://digitalcommons.usf.edu/chm_facpub/54