Structure, Bonding, and Reactivity of the Organometallic 1,3,2,4-Dithiadiazole Complex CpCoS2N2

Ln3I5(S2N2)(S2)(THF)10 - a new type of molecular compounds

Unprecedented complexes of the composition Ln3I5(S2N2)(S2)(THF)10 were obtained in the reactions of neodymium and dysprosium iodide-nitrides with sulfur. The inorganic core of the molecules contains the cyclic fragments Ln(μ-S2)Ln, LnSNSN and LnSN. Ten of the fourteen atoms of the core are coplanar, the remaining four S2 and I2 atoms lie in the other two orthogonal planes. The dysprosium complex upon excitation with UV light exhibits the metal-centered luminescence characteristic of the Dy(3+) ion. Geometric parameters of the molecules, computational data, electron spectroscopy and fluorescence suggest the existence of some conjugation in the mentioned heterocycles.

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.

5,6,7,8-Tetrafluoro-3λ4δ2,1,2,4-benzothiaselenadiazine, 5,6,7,8-Tetrafluoro-1,3λ4δ2,2,4-benzodithiadiazine, and Their Hydrocarbon Analogues: Molecular and Crystal Structures

5,6,7,8-Tetrafluoro-3lambda4delta2,1,2,4-benzothiaselenadiazine (1) is prepared by the intramolecular nucleophilic cyclization of C6F5SeN=S=NSiMe3 (2) mediated by CsF. According to an X-ray diffraction analysis, the heterocycle of 1 is bent along the Se(1)...N4 line by 6.0(2) degrees in the crystal. Despite the obvious similarities between 1 and its 1,3-dithia analogue (7) with respect to molecular composition and shape, the crystal packing of 1 is substantially different from that of 7. An interesting consequence of this is the inclusion of atmospheric N2 in the crystal lattice of the selenium derivative 1. The molecular structure and bonding of 1 have been investigated using quantum-chemical calculations at the DFT/B3LYP/6-311+G level of theory, and the results have been compared to those of 5,6,7,8-tetrafluoro-1,3lambda4delta2,2,4-benzodithiadiazine (7) and their hydrocarbon analogues (5 and 8).

η1and η2complexes of λ3-1,2,4,6-thiatriazinyls with CpCr(CO)x

The title heterocyclic radicals coordinate to either 17e CpCr(CO)3 or 15e CpCr(CO)2 moieties as one-electron or as three-electron donors, respectively; in the former the bonding is via the perpendicular p orbital of the sulfur atom, while in the latter bonding is via p(pi) orbitals on both sulfur and nitrogen.

Multidimensional Description of the Aromaticity in Planar Five-Membered NSNS Ring Systems

The effect of the ring-closing fragment on the aromaticity of planar five-membered rings containing an NSNS fragment is investigated systematically. The influence of changing the group or period number of the ring-closing atom is studied as well as the effect of a substituent on this ring-closing element. Two sets of four five-membered ring systems were investigated. To reach a multidimensional description of the aromaticity, a robust set of geometrical, magnetic and energetic aromaticity criteria were combined. pi-Electron populations based on the stockholder scheme were calculated and lead to a quantity that correlates to the other aromaticity criteria. A third set of molecules was introduced to verify the conclusions.