Origin of Free Energy Barriers of Decarboxylation and the Reverse Process of CO2Capture in Dimethylformamide and in Water

Shaoyuan Zhou, Bach T. Nguyen, John P. Richard, Ronald Kluger, Jiali Gao

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

In aqueous solution, biological decarboxylation reactions proceed irreversibly to completion, whereas the reverse carboxylation processes are typically powered by the hydrolysis of ATP. The exchange of the carboxylate of ring-substituted arylacetates with isotope-labeled CO2 in polar aprotic solvents reported recently suggests a dramatic change in the partition of reaction pathways. Yet, there is little experimental data pertinent to the kinetic barriers for protonation and thermodynamic data on CO2 capture by the carbanions of decarboxylation reactions. Employing a combined quantum mechanical and molecular mechanical simulation approach, we investigated the decarboxylation reactions of a series of organic carboxylate compounds in aqueous and in dimethylformamide solutions, revealing that the reverse carboxylation barriers in solution are fully induced by solvent effects. A linear Bell-Evans-Polanyi relationship was found between the rates of decarboxylation and the Gibbs energies of reaction, indicating diminishing recombination barriers in DMF. In contrast, protonation of the carbanions by the DMF solvent has large free energy barriers, rendering the competing exchange of isotope-labeled CO2 reversible in DMF. The finding of an intricate interplay of carbanion stability and solute-solvent interaction in decarboxylation and carboxylation could be useful to designing novel materials for CO2 capture.

Original languageEnglish (US)
Pages (from-to)137-141
Number of pages5
JournalJournal of the American Chemical Society
Volume143
Issue number1
DOIs
StatePublished - Jan 13 2021

Bibliographical note

Funding Information:
This work was partially supported by Shenzhen Municipal Science and Technology Innovation Commission (KQTD2017-0330155106581), and part of the study was completed at Minnesota, which is supported by the National Institutes of Health (GM046736). The work at Buffalo has been supported by the NIH (GM134881). The computations were performed at the Supercomputing Center of Shenzhen Bay Laboratory and completed at the Minnesota Supercomputing Institute.

Publisher Copyright:
©

PubMed: MeSH publication types

  • Journal Article
  • Research Support, Non-U.S. Gov't
  • Research Support, N.I.H., Extramural

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