Chalcogen ligands

The amido and imido derivates of phosphorus-chalcogen ligands have been of much interest to coordination chemists due to the fact that they possess both hard (nitrogen) as well as soft (chalcogen) donor sites and are therefore able to act as heteroleptic ligand systems.56... 

Also, Yam and Cheung [62] have carried out the synthesis of a series of novel polynuclear mercury(II) diimine complexes with bridging chalcogenate ligands and studied their luminescence and electrochemical properties. 

Figure 1.74 Gold (I)—Cold (III) complexes with bridging chalcogen ligands.

Scheme 5-36. Tin(iv) compounds with ferrocenyl chalcogenate ligands [217].

The oxidation can be carried out in two steps, thus affording mixed chalcogen ligands. The first phosphorus atom is oxidized by adding oxygen or sulfur, and in the second step an identical or a different chalcogen is added to the other phosphorus site 33,34... 

Detailed variable temperature NMR studies established the existence of pyramidal inversion about the coordinated selenium ligand atom and an intramolecular 1,2-metal shift between adjacent chalcogen ligand atoms (85JCS(D)1569>. 

The copper atoms in the vast majority of the clusters can be assigned a formal charge of +1, while the chalcogen ligands are formally viewed as E or RE groups. Some of the selenium-bridged species, however - and nearly all copper telluride clusters - form nonstoichiometric compounds that display mixed valence metal centers in the formal oxidation states 0 and +I or +I and +11. These observations correlate with those made for the binary phases CU2S, Cu2 xSe, and Cu2- Te [38-40]. 

Rudd, M.D., Lindeman, S.V and Husebye, S., Three-centre, four-electron bonding and structural characteristics of two-coordinate iodine(I) complexes with halogen and chalcogen ligands. Synthesis, spectroscopic characterization and x-ray structural studies of (triiodo) [tris(dimethylamino)phosphaneselenide]iodine and bis (triiodo) [tri(iV-morpholyl)phosphaneselenide]iodine(I) /diiodine molecular complex, Acta Chem. Scand. 51 (6-7), 689-708 (1997). 

Carbenes coordinated with a chalcogen ligand are transformed to electronically saturated compounds with a C=E group such as X2C=E (E = O, S, Se, Te). In this series the hitherto unknown substance is X2C=Te. 

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