Thianthrene complexes structure

Peroxide complexes of molybdenum(VI) are intermediates in industrially important epoxidation reactions. The so-called Mimoun-type complexes [Mo 0(02)2LaxLeq]° " (12) generally exhibit pentagonal-bipyramidal structures, with an axial 0x0 group trans to Lax and Leq, and two peroxo groups in the equatorial plane. These complexes are effective reagents for the selective oxidation of alcohols to aldehydes, amines to nitroso compounds, sulfldes to sulfoxides and then to sulfones, phenols to o-quinones, and in the sulfoxidation of thianthrene-5-oxide. 

DIPOLE MOMENTS AND MOLECULAR STRUCTURE In a number of cases the magnitude of the dipole moment may be used to determine the geometrical configuration of the atoms in a molecule. Thus the first proof of the triangular structure of water arose from dipole moment measurements. Calculation may also be made of the valency angles from dipole moment data, but the values obtained are not as accurate as the more direct methods employing spectra, x-ray and electron diffraction measurements. However, for complex molecules when the application of more exact methods is not possible, the analysis of the dipole moment data may give valuable information. Thus the moment of thianthrene is 1-57, D,... 

Compound 37a and its derivatives adopt a boat conformation in the solid state as revealed by X-ray crystallographic structure studies [98-100]. However, the 1,4-dithiin ring in 38 is planar in its complex with acridine [101]. This facilitates 7T-7T stacking of 38 and acridine although their interaction is weak. Furthermore, calculations suggest that there is little energy difference between planar and boat conformers [102]. Thus conformational analysis of 1,4-dithiin is similar to that of thianthrene. 

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