1. A chalcogen-bonded complex H 3 NS=C=S formed by ammonia and carbon disulfide characterised by chirped-pulse, broadband microwave spectroscopy
- Author
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European Commission, Gougoula, E., Medcraft, C, Alkorta, Ibon, Walker, N. R., Legon, A. C., European Commission, Gougoula, E., Medcraft, C, Alkorta, Ibon, Walker, N. R., and Legon, A. C.
- Abstract
Ground-state rotational spectra were observed for ten symmetric-top isotopologues H 3 NS=C=S, H 3 N 34 S=C=S, H 3 NS=C= 34 S, H 3 NS= 13 C=S, H 3 15 NS=C=S, H 3 15 N 34 S=C=S, H 3 15 NS=C= 34 S, H 3 15 NS= 13 C=S, H 3 15 N 33 S=C=S, and H 3 15 NS=C= 33 S, the first five in their natural abundance in a mixture of ammonia and carbon disulphide in argon and the second group with enriched 15 NH 3 . The four asymmetric-rotor isotopomers H 2 DNS=C=S, H 2 DN 34 S=C=S, H 2 DNS=C= 34 S, and HD 2 NS=C=S were investigated by using a sample composed of ND 3 mixed with CS 2 . Rotational constants, centrifugal distortion constants, and 33 S nuclear quadrupole coupling constants were determined from spectral analyses and were interpreted with the aid of models of the complex to determine its symmetry, geometry, one measure of the strength of the intermolecular binding, and information about the subunit dynamics. The complex has C 3v symmetry, with nuclei in the order H 3 NS=C=S, thereby establishing that the non-covalent interaction is a chalcogen bond involving the non-bonding electron pair of ammonia as the nucleophile and the axial region near one of the S atoms as the electrophile. The small intermolecular stretching force constant k ¿ = 3.95(5) N m -1 indicates a weak interaction and suggests the assumption of unperturbed component geometries on complex formation. A simple model used to account for the contribution of the subunit angular oscillations to the zero-point motion leads to the intermolecular bond length r(NS) = 3.338(10) Å. © 2019 Author(s).
- Published
- 2019