The rotational spectra of four isotopologues of the 1:1 complex between chloromethane and water revealed the presence of only one rotamer in a pulsed jet expansion. The two subunits are linked through two weak hydrogen bonds, O-H⋅⋅⋅Cl (R(H⋅⋅⋅Cl) =2.638(2) Å) and C-H⋅⋅⋅O (R(H⋅⋅⋅O) =2.501(2) Å), forming a five-membered ring. All transitions display the hyperfine structure due to the (35)Cl (or (37)Cl) nuclear quadrupole effects. Dynamical features in the spectrum are caused by two large-amplitude motions. Each component line appears as an asymmetric doublet with a relative intensity ratio of 1:3. The splittings led to the determination of barrier to internal rotation of water around its symmetry axis, V(2) =320(10) cm(-1). Finally, an unexpected small value of the inertial defect (-0.96 uÅ(2) rather than -3.22 uÅ(2)) allowed the estimation of the barrier to the internal rotation of the CH(3) group, V(3) ≈8 cm(-1).

Gou, Q., Spada, L., Lopez, J., Grabow, J., Caminati, W. (2015). Chloromethane-Water Adduct: Rotational Spectrum, Weak Hydrogen Bonds, and Internal Dynamics. CHEMISTRY - AN ASIAN JOURNAL, 10(5), 1198-1203 [10.1002/asia.201500013].

Chloromethane-Water Adduct: Rotational Spectrum, Weak Hydrogen Bonds, and Internal Dynamics

GOU, QIAN;SPADA, LORENZO;LOPEZ, JUAN CARLOS;CAMINATI, WALTHER
2015

Abstract

The rotational spectra of four isotopologues of the 1:1 complex between chloromethane and water revealed the presence of only one rotamer in a pulsed jet expansion. The two subunits are linked through two weak hydrogen bonds, O-H⋅⋅⋅Cl (R(H⋅⋅⋅Cl) =2.638(2) Å) and C-H⋅⋅⋅O (R(H⋅⋅⋅O) =2.501(2) Å), forming a five-membered ring. All transitions display the hyperfine structure due to the (35)Cl (or (37)Cl) nuclear quadrupole effects. Dynamical features in the spectrum are caused by two large-amplitude motions. Each component line appears as an asymmetric doublet with a relative intensity ratio of 1:3. The splittings led to the determination of barrier to internal rotation of water around its symmetry axis, V(2) =320(10) cm(-1). Finally, an unexpected small value of the inertial defect (-0.96 uÅ(2) rather than -3.22 uÅ(2)) allowed the estimation of the barrier to the internal rotation of the CH(3) group, V(3) ≈8 cm(-1).
2015
Gou, Q., Spada, L., Lopez, J., Grabow, J., Caminati, W. (2015). Chloromethane-Water Adduct: Rotational Spectrum, Weak Hydrogen Bonds, and Internal Dynamics. CHEMISTRY - AN ASIAN JOURNAL, 10(5), 1198-1203 [10.1002/asia.201500013].
Gou, Q.; Spada, L.; Lopez, J.C.; Grabow, J.-U.; Caminati, W.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/518775
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