Reactions Affecting the Tellurium Atom

The 4-alkylidene-4/f-tellurins combine with an equimolar amount of chlorine, bromine, or iodine in dichloromethane or carbon tetrachloride to produce 7e,7h-dihalides. 

When 4-(2,6-diphenyl-tellurinium-4-ylmethylidene)-2,6-diphenyl-47/-tellurin was reacted with one equivalent of chlorine, bromine, or iodine, only one tellurium atom was attacked with formation of 7c,re-dihalides. When the halogens were added in excess, insoluble polyhalogenated materials were obtained.  

The 7e,7e-diiodide was isolated as the 1 1 mixture of the tetrafluoroborate and the triiodide salt. The electronic absorption spectra of the diiodide in various solvents are identical to the spectrum of the iodine-free compound.  

The compounds consisting of a chalcogeninium group joined to the 4/f-tellurin by three methine groups reacted with one equivalent of bromine with conversion of the tellurin-tellurium atom to the 7e,7e-dibromide.  

4-(Dicyanomethylidene)-2,6-di-/er/.-butyl (or phenyl)-4/f-tellurin was oxidized by per-oxyacetic acid and converted to the re,re-diacetate by acetic acid in dichloromethane.  

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