Microwave spectrum, structure, and dipole moment of cis-thionylimide

Abstract

The microwave spectrum of thionylimide, HNSO, has been observed and assigned to the planar cis form. The structural parameters are <fNH = 1.029 ± 0.01 Á, dNS = 1.512 ± 0.005 Á, dso -1.451 ± 0.005 Á, ZHNS = 115.8 ± 1°, and ZNSO = 120.4 ± 0.5°, where the uncertainties are estimated to account for the effects of zero-point vibrations. The dipole moment and its components along the principal axes in the HN15SO isotopic species are µ = 0.893 ± 0.003 D, µb = 0.181 ± 0.005 D, and µ -0.911 ± 0,003 D, where the uncertainties are the standard deviations of the reported values, from the least-squares analysis. Since no attempts were made to make a complete assignment of the impure sample, no comments can be made about the possible existence of f/ww-HNSO.

High-resolution FTIR spectroscopy of HNSO—Analysis of the highly perturbed ν4, ν6 and 2ν5 bands

“…Ultraviolet absorption spectroscopy of HNSO indicated electronic excitation centered at the S atom [8]. A planar, cis conformation for the HNSO molecule, in agreement with theory, was established from analysis of its microwave spectrum at room temperature [9] and quartic centrifugal distortion constants [10] and the hyperfine constants [11] were determined later. The frequencies of the six fundamental vibrations and a harmonic force field were first derived from low-resolution studies of the IR spectra of HNSO and DNSO in the gas phase [12,13] and in matrices [14].…”

“…As first reported from the microwave study [9] HNSO has a cis planar near-prolate structure of C s symmetry.…”

14N Nuclear Quadrupole Hyperfine Structure in the Rotational Spectrum of Thionyl Aniline

“…The same conformation has been found in case of methyl thionyl amine CH3NSO [2]. In this case, no quadru pole coupling constants have ever been reported, whereas for HNSO and DNSO these constants have been determined [1]. The microwave spectrum of thionyl aniline has been assigned by Caminati et al [3], The conformation of this molecule has also been confirmed to be ris-planar, see Figure 1.…”

“…The simplest member of this class, H -N = S = 0 , has been studied in some detail by Kirchhoff [1], According to this study, the molecule exists in the gas phase as a planar cis-conformer, i.e., the proton and the oxygen atom are located in a ex position with respect to the N = S double bond. The same conformation has been found in case of methyl thionyl amine CH3NSO [2].…”

The Infrared Spectrum and Force Field of Matrix Isolated cis-Thionylimide (HNSO)

“…Firstly, the molecular parameters assumed in these calculations differ significantly from those determined more recently by microwave spectroscopy (3). Secondly, and more important, Eysel (2) employed a computational technique devised by Becher and Mattes (4) which must be regarded with suspicion.…”