Tellurium, xanthate structures

Structural Data for Binary Tellurium Xanthates, Te(S2COR)2... 

The molecular structure of Te(S2COEt)(S2CNEt2) (262) is shown in Fig. 163 and it becomes immediately evident that the coordination geometry is the same as that found for the binary tellurium xanthates described above. The xanthate ligand forms Te—SI and Te—S bond distances of 2.535(2) and 2.911(3) A, respectively, and these are longer than the corresponding distances formed by the dithiocarbamate ligand of 2.489(3) and 2.801(3) A, respectively. This key... 

There are single examples of sulfur and selenium xanthates with the remaining structures to be described in this section featuring tellurium as the central element. There are a significant number of binary xanthates and, in common with these, their organotellurium xanthates feature extensive supra-molecular association, usually, but not exclusively, via Te- S secondary bond interactions. A rare example of mixed-ligand 1,1-dithiolate structure is available where the odd dithiolate ligand is a dithiocarbamate. 

Figure 164. Two views of the molecular structure of the anion in fNEt4][Te(S2COMe)3] (a) showing the orthogonal relationship between the S5, S6 xanthate ligand and the remaining xanthate ligands and (b) highlighting the planar coordination about the tellurium atom.

The third diorganotellurium structure to be described has a chelating tellurium-bound organic group. In the molecular structure of [C6H4(CH2)2]Te(S2-COEt)2 (272), shown in Fig. 170, the two xanthate ligands form asymmetric... 

Among the recent reports on metal xanthate chemistry the following are mentioned, dealing with the structural diversity of nickel(II),213 zinc(II),214 mercury(II), 15 and tellurium(II) bis (xanthate) complexes,216 based upon different coordination patterns and supramolecular self-assembly. 

Selenium(II) and tellurium(II) xanthates, dithiocarbamates, and related molecules have planar trapezoidal structures... 

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