Angular geometry, binding strength and charge transfer for the complex H 2S⋯ICl determined by rotational spectroscopy

Abstract

Ground-state rotational spectra of the isotopomers H 2 S⋯ I 35 Cl , H 2 S⋯ I 37 Cl , HDS⋯ I 35 Cl and D 2 S⋯ I 35 Cl of a complex of hydrogen sulphide and iodine monochloride were measured. Rotational constants, centrifugal distortion constants, halogen nuclear quadrupole coupling constants, and I spin–rotation coupling constants were determined. Interpretation of various spectroscopic constants showed that the complex has a geometry in which the S⋯I–Cl nuclei are collinear, with r(S⋯I)=3.154(3) Å and the ICl subunit almost perpendicular to the plane of the H 2S nuclei [ φ=91.9(12)°]. Observed I and Cl nuclear quadrupole coupling constants are used with a simple model to deduce that intramolecular charge transfer from S to I is ∼0.05 e −. The intermolecular stretching force constant k σ =16.6(3) N m −1.