Teflate anion

The titanium teflate anion [Ti(OTeF5)6]2 is non-basic and weakly coordinating, allowing the isolation of chlorocarbon complexes such as [Ag(Cl2CH2)2]2-[Ti(OTeF5)6].3 ... 

The teflate anion has also been utilized in the preparation of a variety of species containing transition metals, as exemplified by [Fe(OTeF5)3], [Nb(OTeF5)6]-, and [[ (/]2-tol)Ag 2(/n-OTeF5)2]. ... 

Direct fluorination of B(OTeF5)3 at 115° gives a 95% yield of the hypofluorite, FsTeOF, as a colourless gas which condenses to a colourless liquid below 0° and finally to a glass at about —80° the extrapolated bp is 0.6°. The chlorine derivative, ClOTeFs, the so-called teflic acid, HOTeFs, and the teflate anion, FsTeO (as caesium or tetraalkylammonium salts) are also useful synthons for a variety of metal derivatives, e.g. [Fe(OTeF5)3], " [Nb(OTeF5)6] ... 

As discussed above, a major disadvantage of fluoroanions such as BF4, PF6, etc. is the potential for fluoride ion abstraction by electrophiles. This is not a problem for the teflate anion, however. There is no evidence for fluoride ion or fluorine atom loss from free or bound OTeF5 at temperatures below 200°C. 

The teflate ion, (OTeFs)", plays an important role in synthetic main group chemistry. Its effective electronegativity is similar to that of fluoride. A group of anions with a general formula of [M(OTeF5H)6] (M = As, Sb, Bi, Ti, etc.) have recently been prepared. They are only weakly coordinating and serve to stabilize otherwise unstable cations. 

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