TY - JOUR
T1 - Microwave spectrum and structural parameters for the formamide-formic acid dimer
AU - Daly, Adam M.
AU - Sargus, Bryan A.
AU - Kukolich, Stephen G.
N1 - Funding Information:
This material is based upon work supported by the National Science Foundation under Grant Nos. CHE-0721505 and CHE-0809053. We are very grateful to the NSF for providing funding for this research. We thank and acknowledge the Research Corporation and the Murdoch Charitable Trust for their generous support through Arizona Partners in Science. We also thank Laszlo Sarkozy for the development and use of his spectral analysis program.
PY - 2010/11/7
Y1 - 2010/11/7
N2 - The rotational spectra for six isotopologues of the complex formed between formamide and formic acid have been measured using a pulsed-beam Fourier transform microwave spectrometer and analyzed to obtain rotational constants and quadrupole coupling parameters. The rotational constants and quadrupole coupling strengths obtained for H C 12OOH- H2 14NCOH are A=5889.465 (2), B=2148.7409 (7), 1575.1234(6), eQq aa =1.014 (5), eQqbb =1.99 (1), and eQqcc =-3.00 (1) MHz. Using the 15 rotational constants obtained for the H 13COOH, HCOOD, DCOOH, and H2 15NCHO isotopologues, key structural parameters were obtained from a least-squares structure fit. Hydrogen bond distances of 1.78 Å for R (O3⋯H) and 1.79 Å for R (H4⋯O1) were obtained. The "best fit" value for the (C-O-H) of formic acid is significantly larger than the monomer value of 106.9° with an optimum value of 121.7(3)°. The complex is nearly planar with inertial defect Δ=-0.158 amu Å2. The formamide proton is moved out of the molecular plane by 15(3)° for the best fit structure. Density functional theory using B3PW91, HCTH407, and TPSS as well as MP2 and CCSD calculations were performed using 6-1++G (d,p) and the results were compared to experimentally determined parameters.
AB - The rotational spectra for six isotopologues of the complex formed between formamide and formic acid have been measured using a pulsed-beam Fourier transform microwave spectrometer and analyzed to obtain rotational constants and quadrupole coupling parameters. The rotational constants and quadrupole coupling strengths obtained for H C 12OOH- H2 14NCOH are A=5889.465 (2), B=2148.7409 (7), 1575.1234(6), eQq aa =1.014 (5), eQqbb =1.99 (1), and eQqcc =-3.00 (1) MHz. Using the 15 rotational constants obtained for the H 13COOH, HCOOD, DCOOH, and H2 15NCHO isotopologues, key structural parameters were obtained from a least-squares structure fit. Hydrogen bond distances of 1.78 Å for R (O3⋯H) and 1.79 Å for R (H4⋯O1) were obtained. The "best fit" value for the (C-O-H) of formic acid is significantly larger than the monomer value of 106.9° with an optimum value of 121.7(3)°. The complex is nearly planar with inertial defect Δ=-0.158 amu Å2. The formamide proton is moved out of the molecular plane by 15(3)° for the best fit structure. Density functional theory using B3PW91, HCTH407, and TPSS as well as MP2 and CCSD calculations were performed using 6-1++G (d,p) and the results were compared to experimentally determined parameters.
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U2 - 10.1063/1.3501356
DO - 10.1063/1.3501356
M3 - Article
C2 - 21054029
AN - SCOPUS:78650664495
SN - 0021-9606
VL - 133
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
IS - 17
M1 - 174304
ER -