TY - JOUR
T1 - Acetonitrile/sulfuric acid/water clusters
T2 - A matrix isolation infrared and computational study
AU - Rozenberg, Mark
AU - Loewenschuss, Aharon
AU - Nielsen, Claus J.
N1 - Publisher Copyright:
© 2019
PY - 2020/1/5
Y1 - 2020/1/5
N2 - In continuation of our studies of sulfuric acid H-bonded complexes of atmospheric relevance we report the infrared spectra of the matrix isolated complexes formed between acetonitrile (CD3CN) and sulfuric acid. Due to the “free” electron pair on its nitrogen, acetonitrile is of basic nature and a formation of the relatively strong intermolecular O–H⋯N hydrogen bond with sulfuric acid may be expected. However, the matrix isolation spectra of this system are complicated by the inevitable presence of water in the vapor and in the matrix. We identify the spectral signatures of the binary 1:1 CD3CN*H2SO4 and triple 1:1:1 CD3CN*H2O*H2SO4 H-bonded complexes. The infrared matrix isolation spectra are accompanied by quantum mechanical studies of relevant model H-complexes. By its red shift from the position of the “free” v(OH) band of sulfuric acid and by the calculated H-bond length of the R(O–H⋯N) hydrogen bond it is concluded that the acetonitrile/sulfuric acid interaction energy is considerably higher than that of acetonitrile/water on the one hand and significantly lower than the sulfuric acid/water interaction, on the other.
AB - In continuation of our studies of sulfuric acid H-bonded complexes of atmospheric relevance we report the infrared spectra of the matrix isolated complexes formed between acetonitrile (CD3CN) and sulfuric acid. Due to the “free” electron pair on its nitrogen, acetonitrile is of basic nature and a formation of the relatively strong intermolecular O–H⋯N hydrogen bond with sulfuric acid may be expected. However, the matrix isolation spectra of this system are complicated by the inevitable presence of water in the vapor and in the matrix. We identify the spectral signatures of the binary 1:1 CD3CN*H2SO4 and triple 1:1:1 CD3CN*H2O*H2SO4 H-bonded complexes. The infrared matrix isolation spectra are accompanied by quantum mechanical studies of relevant model H-complexes. By its red shift from the position of the “free” v(OH) band of sulfuric acid and by the calculated H-bond length of the R(O–H⋯N) hydrogen bond it is concluded that the acetonitrile/sulfuric acid interaction energy is considerably higher than that of acetonitrile/water on the one hand and significantly lower than the sulfuric acid/water interaction, on the other.
KW - FTIR spectroscopy
KW - H-bonding
KW - Sulfuric acid H-Bonded complexes
UR - http://www.scopus.com/inward/record.url?scp=85071072709&partnerID=8YFLogxK
U2 - 10.1016/j.molstruc.2019.126948
DO - 10.1016/j.molstruc.2019.126948
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AN - SCOPUS:85071072709
SN - 0022-2860
VL - 1199
JO - Journal of Molecular Structure
JF - Journal of Molecular Structure
M1 - 126948
ER -