TY - JOUR

T1 - The halogen bond between ethene and a simple perfluoroiodoalkane

T2 - C 2H 4⋯ICF 3 identified by broadband rotational spectroscopy

AU - Stephens, Susanna L.

AU - Mizukami, Wataru

AU - Tew, David P.

AU - Walker, Nicholas R.

AU - Legon, Anthony C.

N1 - Funding Information:
The authors thank the Engineering and Physical Sciences Research Council (UK) for a postgraduate studentship awarded to S.L.S. and project funding (EP/G026424/1). N.R.W. and D.P.T. each thank the Royal Society for University Research Fellowships. W.M. thanks the Canon Foundation for financial support. A.C.L. thanks the Leverhulme Trust for an Emeritus Fellowship and the University of Bristol for a Senior Research Fellowship.

PY - 2012/10

Y1 - 2012/10

N2 - An isolated complex of C 2H 4 and ICF 3 has been generated in the gas phase and studied by chirped-pulse, Fourier transform microwave (CP-FTMW) spectroscopy. Ab initio calculations at the CCSD(T)(F12)/VTZ level support the experimental work and further establish the dissociation energy, D e, and dipole moment, μ, of the complex. Rotational constants, B 0 and C 0, the centrifugal distortion constant, Δ J, nuclear quadrupole coupling constants, χ aa (I) and (χ bb(I)-χ cc(I)) and the nuclear spin-rotation coupling constant C bb(I) of the complex are determined from the experimental data. The iodine atom interacts with π-electrons on C 2H 4 resulting in the formation of a linear (∠(CI⋯)) halogen bond (where indicates the centre of the CC bond) and a complex of C s symmetry. The measured rotational constants allow the length of the halogen bond to be determined as 3.434(2) Å in the r 0 geometry. The complex is formally an asymmetric top but with a very low barrier to internal rotation of C 2H 4 about the C 3 axis defined by the CF 3I sub-unit. Adopting an approach also used in a recent study of H 2O⋯ICF 3, other transitions are assigned using the Hamiltonian of a symmetric top molecule.

AB - An isolated complex of C 2H 4 and ICF 3 has been generated in the gas phase and studied by chirped-pulse, Fourier transform microwave (CP-FTMW) spectroscopy. Ab initio calculations at the CCSD(T)(F12)/VTZ level support the experimental work and further establish the dissociation energy, D e, and dipole moment, μ, of the complex. Rotational constants, B 0 and C 0, the centrifugal distortion constant, Δ J, nuclear quadrupole coupling constants, χ aa (I) and (χ bb(I)-χ cc(I)) and the nuclear spin-rotation coupling constant C bb(I) of the complex are determined from the experimental data. The iodine atom interacts with π-electrons on C 2H 4 resulting in the formation of a linear (∠(CI⋯)) halogen bond (where indicates the centre of the CC bond) and a complex of C s symmetry. The measured rotational constants allow the length of the halogen bond to be determined as 3.434(2) Å in the r 0 geometry. The complex is formally an asymmetric top but with a very low barrier to internal rotation of C 2H 4 about the C 3 axis defined by the CF 3I sub-unit. Adopting an approach also used in a recent study of H 2O⋯ICF 3, other transitions are assigned using the Hamiltonian of a symmetric top molecule.

UR - http://www.scopus.com/inward/record.url?scp=84867679404&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84867679404&partnerID=8YFLogxK

U2 - 10.1016/j.jms.2012.06.002

DO - 10.1016/j.jms.2012.06.002

M3 - Article

AN - SCOPUS:84867679404

VL - 280

SP - 47

EP - 53

JO - Journal of Molecular Spectroscopy

JF - Journal of Molecular Spectroscopy

SN - 0022-2852

IS - 1

ER -