TY - JOUR
T1 - The Trimethylamine-Formic Acid Complex
T2 - Microwave Characterization of a Prototype for Potential Precursors to Atmospheric Aerosol
AU - Mackenzie, Rebecca B.
AU - Dewberry, Christopher T.
AU - Leopold, Kenneth R.
N1 - Funding Information:
This work was supported by the National Science Foundation (Grant No. CHE-1266320), the Minnesota Supercomputer Institute, and a University of Minnesota Doctoral Dissertation Fellowship awarded to R.B.M.
PY - 2016/4/28
Y1 - 2016/4/28
N2 - The reactions of amines and carboxylic acids have recently received attention for their possible role in the formation of atmospheric aerosol. Here, we report a microwave study of the trimethylamine-formic acid hydrogen-bonded complex, a simple prototype in which to study amine-carboxylic acid interactions. Spectra of three isotopologues of the system have been observed using a tandem cavity and chirped-pulse Fourier transform microwave spectrometer. The complex has a plane of symmetry, with the acidic proton of the formic acid directed toward the lone pair of the nitrogen. The zero-point-averaged hydrogen bond length is 1.702 Å, and the O-H⋯N angle is 177°. 14N nuclear quadrupole hyperfine structure has been used to assess the degree of proton transfer from the formic acid to the trimethylamine. Experimental results are supplemented with density functional theory calculations. M06-2X/6-311++G(3df,3pd) calculations indicate a binding energy of 16.8 kcal/mol with counterpoise correction (17.4 kcal/mol without counterpoise correction).
AB - The reactions of amines and carboxylic acids have recently received attention for their possible role in the formation of atmospheric aerosol. Here, we report a microwave study of the trimethylamine-formic acid hydrogen-bonded complex, a simple prototype in which to study amine-carboxylic acid interactions. Spectra of three isotopologues of the system have been observed using a tandem cavity and chirped-pulse Fourier transform microwave spectrometer. The complex has a plane of symmetry, with the acidic proton of the formic acid directed toward the lone pair of the nitrogen. The zero-point-averaged hydrogen bond length is 1.702 Å, and the O-H⋯N angle is 177°. 14N nuclear quadrupole hyperfine structure has been used to assess the degree of proton transfer from the formic acid to the trimethylamine. Experimental results are supplemented with density functional theory calculations. M06-2X/6-311++G(3df,3pd) calculations indicate a binding energy of 16.8 kcal/mol with counterpoise correction (17.4 kcal/mol without counterpoise correction).
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U2 - 10.1021/acs.jpca.6b01500
DO - 10.1021/acs.jpca.6b01500
M3 - Article
C2 - 27023479
AN - SCOPUS:84965060790
SN - 1089-5639
VL - 120
SP - 2268
EP - 2273
JO - Journal of Physical Chemistry A
JF - Journal of Physical Chemistry A
IS - 14
ER -