TY - JOUR
T1 - Intramolecular Dispersion Attraction in Tetraalkylammonium Cations Revealed by Cryogenic Ion Mobility Mass Spectrometry
AU - Ohshimo, Keijiro
AU - Sato, Ryosuke
AU - Misaizu, Fuminori
N1 - Funding Information:
The authors thank Dr. Hiroshi Ueno for providing the sample of [Li@C]TFSI salt. This work was supported by JSPS KAKENHI grant no. JP16K05641, the Institute for Quantum Chemical Exploration, Steel Foundation for Environmental Protection Technology, and The Salt Science Research Foundation (grant no. 1916). Computations were partly performed using the Research Center for Computational Science, Okazaki, Japan. + 60 –
Publisher Copyright:
© 2020 American Chemical Society.
PY - 2020/10/1
Y1 - 2020/10/1
N2 - We performed cryogenic ion mobility mass spectrometry and quantum chemical calculations of tetraalkylammonium (TAA) cations, (CnH2n+1)4N+ (n = 4-8), to study geometrical structures of TAA cations. We measured collision cross sections (CCSs) of TAA cations with He buffer gas atoms at 86 K. In addition, CCSs were calculated for optimized structures of TAA ions to compare with experimental CCSs. For n = 4 and 5, calculated CCSs of nearly planar conformers with all-trans four alkyl chains agree well with experimental CCSs. On the other hand, for n = 8, calculated CCSs of a conformer with two gauche alkyl chains reproduce experimental CCSs. The structural transition from all-trans to gauche conformers occurs around n = 6-8. The dispersion attraction between alkyl chains is a major interaction to stabilize the gauche conformer of n = 8.
AB - We performed cryogenic ion mobility mass spectrometry and quantum chemical calculations of tetraalkylammonium (TAA) cations, (CnH2n+1)4N+ (n = 4-8), to study geometrical structures of TAA cations. We measured collision cross sections (CCSs) of TAA cations with He buffer gas atoms at 86 K. In addition, CCSs were calculated for optimized structures of TAA ions to compare with experimental CCSs. For n = 4 and 5, calculated CCSs of nearly planar conformers with all-trans four alkyl chains agree well with experimental CCSs. On the other hand, for n = 8, calculated CCSs of a conformer with two gauche alkyl chains reproduce experimental CCSs. The structural transition from all-trans to gauche conformers occurs around n = 6-8. The dispersion attraction between alkyl chains is a major interaction to stabilize the gauche conformer of n = 8.
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U2 - 10.1021/acs.jpca.0c04817
DO - 10.1021/acs.jpca.0c04817
M3 - Article
C2 - 32876452
AN - SCOPUS:85092681588
SN - 1089-5639
VL - 124
SP - 7999
EP - 8004
JO - Journal of Physical Chemistry A
JF - Journal of Physical Chemistry A
IS - 39
ER -