Tantalum, tris structure

Tantalum. tris(diethyldithiocarbamato)thio-stereochemistry, 1, 82 Tantalum, tris(phenylenedithio)-structure, 1, 63 Tantalum chloride Ta4Cl2o structure, 1,28 Ta6Qi5... 

Xenon difluoride reacts also with some halosubstituted alkanes18,19 at room temperature in chloroform, carbon tetrachloride, dichloromethane or bromoform, and depending on the nature of the solvent used chloro or bromo derivatives are isolated with imidazo-(l,2-fr)-pyridazine18. Carbon tetrachloride reacts with xenon difluoride at 180°C, while room-temperature transformations are achieved when various catalysts [antimony trifluoride, tantalum(V) fluoride or silica dioxide] are used, whose structure also influences the product distribution20. Tris(fluorosulfonyl)methane gives a fluoro-substi-tuted product in its reaction with xenon difluoride in difluorodichloromethane21. 

Schrock discovered that the r-butylalkylidene complex of tantalum (and in lower yield, niobium) was a structural analog to the phosphorus ylide. The complex proved to be a reagent for r-butylalkene formation. Of the Wittig-type reactions tried, most notable was the ability of the complex to react with esters and amides to form the corresponding r-butylalkenes in good yields. 

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