Karla Tersago

Roesky’s ketone: a spectroscopic study

We present a joint experimental-theoretical spectroscopic study of 5-oxo-1,3,2,4-dithiadiazole, also known as Roesky’s ketone. The theoretical results of a vibrational analysis, calculated at the DFT/B3LYP/6-311+G* level of theory, of the title compound have been compared with experimental data, consisting of Raman and IR frequencies in different phases, and the bands have been assigned to the normal vibrations of the molecule. Additionally, an analysis of the origin of the high intensity of the band assigned to the CO stretching mode was performed based on calculated stockholder charges and atomic dipoles. The results of theoretical calculations of the 13C and 14N NMR chemical shifts are compared to experimentally obtained shifts.

Structure, bonding, aromaticity and reactivity of Roesky's sulfoxide

The molecular and crystal structure of 1-oxo-1,2,4,3,5-trithiadiazole () has been studied experimentally by the determination of the crystal structure and theoretically at the DFT/B1B95/aug-cc-pVTZ level of theory. The combination of the geometrical data with a number of properties of the title compound, consisting of orbital topologies, Hirshfeld charges and bond orders, aromaticity parameters and Fukui functions, led to a description of its structure, aromaticity and reactivity. In addition, the nature of the long sulfur-sulfur bond has been investigated. The bands in newly recorded infrared and Raman spectra have been assigned to the normal vibrations of the molecule, based on calculated vibrational data. The results of theoretical calculations of the 14N NMR chemical shifts have been compared to the experimentally obtained shifts.

A computational study of the molecular structure of 1,3\lambda^{4}\delta^{2},2,4 -benzodithiadiazine

Abstract The molecular structure of 1,3 λ 4 δ 2 ,2,4-benzodithiadiazine ( 1 ) has been studied theoretically by a large number of computational methods. The results of calculations using different DFT functionals are compared with those obtained from HF, MP2, MP4(SDQ), QCISD and CCSD calculations. In addition, the influence of a number of basis sets on the calculated geometry was investigated. The results of the post-HF methods show that convergence of the geometrical parameters is already obtained for the relatively small 6-311+G∗ basis set. Taking the MP4(SDQ)/cc-pVTZ geometry as a reference the DFT/B1B95 functional appears to provide the most satisfactory description of all the examined functionals.