Torsional frequency, barrier to internal rotation, and dipole moment of N-sulphinylaniline from microwave rotational spectra

From Inert to Explosive, The Hydrolytic Reactivity of R−NSO Compounds Understood: A Computational Study

“…The order of saddle points was determined through vibrational frequency calculations. Despite the possibility of configurational isomers for N-sulfinyl compounds, only the most energetically favorable syn configuration − ,,,,,,,,− is considered here. The intrinsic reaction coordinate (IRC) procedure , was applied to selected transition states to verify the nature of the potential energy surface for a proposed reaction path.…”

“…The history of discovery of N-sulfinylamines (R−NSO), sometimes referred to as N-thionyl-, , N-sulphinyl-, − -imines, , -imides, or iminooxosulfuranes can be traced back to the 1890s, when they were synthesized and first investigated by Michaelis and co-workers. , Since then, N-sulfinylamines have found wide application in cycloaddition reactions, which with a few exceptions occur across the NS bond. [2 + 2], [2 + 4], and 1,3-dipolar cycloadditions are the most common reactions of N-sulfinylamines, which in Diels−Alder additions can play the role of either diene or dienophile…”

“…Even though more than 600 N-sulfinyl compounds are known, only a few aromatic N-sulfinylamines, ,,− -hydrazines, , and N-sulfinyl mono- (R−S−NSO) and di- (R−S−S−NSO) sulfides − were structurally characterized and their reactivity analyzed to some extent. While it appears that steric hindrance leads to kinetic stabilization, attempts to determine electronic effects of aromatic substitution were not always conclusive due to the presence of multiple substituents. − Quantitatively, the introduction of a methyl group in para -position of N-sulfinylaniline caused a decrease in the rate constant of its hydrolysis, with the induction period increasing from 4 to 10 h, suggesting that electron-donating substituents stabilize N-sulfinylamines toward water.…”

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

“…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. However, again no quadrupole coupling constants have been determined so far.…”

“…We chose the following twostep procedure: starting with the rotational constants of Caminati et al [3], we first calculated angular momentum expectation values <Pg2), g = a,b, c. These were then used for the hyperfine structure analysis, centre frequencies being treated as fit parameters. The optimized line centre frequencies were then subjected to a fit of the rotational and centrifugal distortion constants.…”