Jump to main content
Jump to site search

Issue 45, 2020
Previous Article Next Article

Ab initio metadynamics calculations of dimethylamine for probing pKb variations in bulk vs. surface environments

Author affiliations

Abstract

The basicity constant, or pKb, is an intrinsic physical property of bases that gives a measure of its proton affinity in macroscopic environments. While the pKb is typically defined in reference to the bulk aqueous phase, several studies have suggested that this value can differ significantly at the air–water interface (which can have significant ramifications for particle surface chemistry and aerosol growth modeling). To provide mechanistic insight into surface proton affinity, we carried out ab initio metadynamics calculations to (1) explore the free-energy profile of dimethylamine and (2) provide reasonable estimates of the pKb value in different solvent environments. We find that the free-energy profiles obtained with our metadynamics calculations show a dramatic variation, with interfacial aqueous dimethylamine pKb values being significantly lower than in the bulk aqueous environment. Furthermore, our metadynamics calculations indicate that these variations are due to reduced hydrogen bonding at the air–water surface. Taken together, our quantum mechanical metadynamics calculations show that the reactivity of dimethylamine is surprisingly complex, leading to pKb variations that critically depend on the different atomic interactions occurring at the microscopic molecular level.

Graphical abstract: Ab initio metadynamics calculations of dimethylamine for probing pKb variations in bulk vs. surface environments

Back to tab navigation

Supplementary files

Article information


Submitted
19 Jul 2020
Accepted
03 Nov 2020
First published
04 Nov 2020

Phys. Chem. Chem. Phys., 2020,22, 26265-26277
Article type
Paper

Ab initio metadynamics calculations of dimethylamine for probing pKb variations in bulk vs. surface environments

S. Biswas, H. Kwon, K. C. Barsanti, N. Myllys, J. N. Smith and B. M. Wong, Phys. Chem. Chem. Phys., 2020, 22, 26265
DOI: 10.1039/D0CP03832F

Social activity

Search articles by author

Spotlight

Advertisements