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Internal Dynamics in Halogen‐Bonded Adducts: A Rotational Study of Chlorotrifluoromethane–Formaldehyde
Author(s) -
Gou Qian,
Feng Gang,
Evangelisti Luca,
VallejoLópez Montserrat,
Spada Lorenzo,
Lesarri Alberto,
Cocinero Emilio J.,
Caminati Walther
Publication year - 2015
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201406122
Subject(s) - formaldehyde , halogen , adduct , dynamics (music) , rotational dynamics , chemistry , materials science , computational chemistry , polymer chemistry , photochemistry , organic chemistry , physics , molecule , alkyl , acoustics
The rotational spectra of two isotopologues of the 1:1 complex between chlorotrifluoromethane and formaldehyde have been recorded and analyzed by using Fourier‐transform microwave spectroscopy. Only one rotamer was detected, with the two constituent molecules held together through a Cl⋅⋅⋅O halogen bond ( R Cl⋅⋅⋅O =3.048 Å). The dimer displays two simultaneous large‐amplitude intramolecular motions. The internal rotation of formaldehyde around its symmetry axis ( V 2 =28(5) cm −1 ) splits all the rotational transitions into two component lines with a relative intensity ratio of 1:3. On the other hand, the almost free internal rotation ( V 3 ≈2.5 cm −1 ) of the CF 3 symmetric top increases the “rigid” value of the rotational constant A by almost one order of magnitude. In addition, all the transitions display a hyperfine structure due to the 35 Cl (or 37 Cl) nucleus quadrupole effects.