Chalcogen bonding

Sulfur and selenium analogues of 91 are also susceptible of this type of rearrangement. Its rate is defined by the strength of the C-chalcogen bonds in 91 and analogues and was found to increase in the order of S < Se < Te (94MI1). 

It has, however, also been reported that the reaction of aryl ditellurides with Ni°, Pd°, and Pt° may result in the cleavage of the carbon-chalcogen bond. The oxidative addition of... 

Figure 27 Oxidative addition of the organochalcogen compounds to low-valent transition metal centers most often resulting in the cleavage of the chalcogen-chalcogen bond and the formation of mono- or dinuclear complexes with anionic bridging or terminal RE- (E = Se, Te) ligands.

There were a considerable number of reports over the period 1990-2004 on polyhedral boron hydride species with exo-chalcogen bonds and the following section is structured in terms of increasing polyhedral size. There were also a few reports on polyhedral carborane species, which are at the end of this section, but there were no reports on other heteroborane species with exo-chalcogen bonds. 

Preparation, Characterisation and Properties of Compounds Containing Phosphorus-Chalcogen Bonds... 

Studies on the solid-state structures, vibrational frequencies and dipole moments of tertiary phosphine chalcogenides have shown the phosphorus to be in an approximately tetrahedral environment with phosphorus-chalcogen bond lengths in-between those expected for single and double bonds.21 There has been much debate on the nature of the phosphorus-chalcogen bond in these... 

What is the region of bond distances for hypervalent bonds of chalcogens Bond orders of hypervalent 3c-4e are typically around 0.5. A bond distance with a bond order of 0.5 is predicted to be 0.18 A longer than that with a bond order of 1.0.16... 

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