Title: Thionitrosyl cyanide (NCNS)
Authors: Nguyen, Minh Tho ×
Allaf, AW
Flammang, R
Van Haverbeke, Y #
Issue Date: 1997
Series Title: Journal of molecular structure. Theochem vol:418 issue:2-3 pages:209-220
Conference: date:Katholieke Univ Leuven, Dept Chem, B-3001 Louvain, Belgium; Atom Energy Commiss, Dept Chem, Damascus, Syria; Univ Mons, Organ Chem Lab, B-7000 Mons, Belgium
Abstract: Thionitrosyl cyanide and its radical-cation have been generated for the first time by dissociative ionization of 1,2,5-thiadiazolo [3,4-c](1,2,5)-thiadiazole and characterized by collisional activation (CA) and neutralization-reionization (NR) mass spectrometry. Both neutral and ionized forms are stable species and do not undergo unimolecular rearrangement under the experiment conditions. The NCNS molecule is further characterized by ab initio molecular orbital calculations using various levels of theory up to QCISD(T)/6-311++G(3df,2p) based on MP2/6-311++G(d,p) geometries. The stability ordering of the four possible [C, N-2, S] isomers is (kcal mol(-1)): NCNS 1 (0) > NCSN 2 (14) > CNSN 4 (25) > CNNS 3 (34) > CN + NS (73). The classical energy barrier for the 1,2-migration of the cyano and thionitrosyl groups connecting 1 with 2 and 1 with 3 amount to 80 and 83 kcal mol(-1), respectively, values being larger than the dissociation energy. The geometry and rotational constants of NCNS were predicted using calculations and empirical corrections based on available data on similar molecules; A=51.986 +/- 0.7 GHz, B=3.521 +/- 0.1 GHz, C=3.298 +/- 0.1 GHz. Vibrational wavenumbers of both NCNS and NCSN isomers were computed using QCISD/6-311G(d) wavefunctions. The protonation of thionitrosyl cyanide occurs preferentially at the cyano-nitrogen with a proton affinity PA (NCNS) = 178 +/- 3 kcal mol(-1). Several molecular properties of NCNS have also been computed. Mass spectrometric experiments confirm that the product of the reaction NSCl + AgCN --> AgCl + [C, N-2, S] is the isomeric thiazyl cyanide(NCSN). (C) 1997 Elsevier Science B.V.
ISSN: 0166-1280
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Quantum Chemistry and Physical Chemistry Section
× corresponding author
# (joint) last author

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