Abstract
AbstractNaHCOO(aq) and NaDCOO(aq) solutions were measured using Raman spectroscopy from dilute to concentrated solutions at 23 °C in water and heavy water from 50 to 4300 cm−1. A concentrated NaHCOO solution in heavy water was also measured. The Raman band parameters of HCOO−(aq) and DCOO−(aq) such as peak position, full width at half maximum (fwhm), integrated intensities, and depolarization values were determined. From the Raman spectroscopic data, it was concluded that the HCOO−(aq) and DCOO−(aq) symmetry is lower than C2v and probably as low as C1. In contrast to the solution state, $$\tt \normalsize \tt \normalsize {\text{HCO}}_{2}^{ - }$$
HCO
2
-
($$\tt \normalsize\tt\normalsize {\text{DCO}}_{2}^{ - }$$
DCO
2
-
) possess C2v symmetry in the gas phase and the DFT frequencies are given. DFT frequencies on a cluster of HCOO−/DCOO− with five implicit water molecules in the first sphere and placed in a polarizable continuum deviate not more than 1–2% from the measured ones. In the Raman spectrum in NaHCOO(aq), a band doublet at 2730 cm−1 and 2820 cm−1 occurs instead of a single band. The band doublet is due to Fermi resonance and results from the interaction of the overtone of the bending C–H mode, 2ν6 at 1382 cm−1 and ν1. The undisturbed C–H stretching mode, ν1 amounts to 2785 cm−1. In DCOO−(aq), a Fermi doublet was also observed at 2030.5 and 2116.5 cm−1, and the undisturbed wavenumber position amounts to 2101 cm−1. Furthermore, a solution of HCOO− in D2O showed slightly changed frequencies compared with the ones in water caused by the solvent isotope effect. Ion pairing between Na+ and HCOO− characterizes the Raman spectrum at high solute concentrations which are melt-like enabling direct contact between the ions. A NaHCOO solution with high amounts of LiCl added showed large perturbations of the HCOO− bands especially νsCOO− and δ COO− of HCOO−and revealed a stronger affinity of Li+ toward HCOO−. The ion pairs formed are most likely contact ion pairs between Li+ and HCOO− which have different stoichiometry of Li+: HCOO− such as 1:1 and 2:1.
Graphical Abstract
Funder
Technische Universität Dresden
Publisher
Springer Science and Business Media LLC
Subject
Physical and Theoretical Chemistry,Molecular Biology,Biochemistry,Biophysics
Reference33 articles.
1. Hietala, J., Vuori, A., Johnsson, P., Pollari, I., Reutemann, W., Kieczka, H.: Formic acid. In: Ullmann’s Encyclopedia of Industrial Chemistry, pp. 1–22. Wiley, Weinheim (2000)
2. Leung, K., Rempe, S.B.: Ab initio molecular dynamics study of formate ion hydration. J. Am. Chem. Soc. 126(1), 344–351 (2004). https://doi.org/10.1021/ja036267q
3. Chen, Q., Liu, Z., Wong, C.H.: An ab initio molecular dynamics study on the solvation of formate ion and formic acid in water. J. Theor. Comput. Chem. 11(05), 1019–1032 (2012). https://doi.org/10.1142/s021963361250068x
4. Moreno, M.A., Gálvez, O., Maté, B., Herrero, V.J., Escribano, R.: Formate ion: structure and spectroscopic properties. J. Phys. Chem. A 115(1), 70–75 (2011). https://doi.org/10.1021/jp108326x
5. Yasuo, K., Takahiro, M., Takashi, N., Takeshi, U., Osamu, U.: Structure of concentrated aqueous sodium formate solutions. Bull. Chem. Soc. Jpn. 69(6), 1495–1504 (1996). https://doi.org/10.1246/bcsj.69.1495
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