Synthesis of complexes containing classically noncoordinating anions as ligands

X-ray crystallography has played an important role in the developing chemistry of classically noncoordinating anions and, in general, structural studies reveal little perturbation in the geometric parameters associated with the anion upon coordination. This has been interpreted O in terms of a large ionic contribution to the metal-anion bonding. 

Beck and Siinkei, in their review artide, discuss the relative donor abilities of anions. Based upon IR and NMR spectroscopic data for [MX(CO 3Cp] (M = Mo, W), the following order of donor abilities for X was 

FPFs FBFa OSO2F, OSO2CF3- 0C103 OTeFs 0Re03 CV 

The relative donor strength of anions has been the subject of a number of 

Several synthetic methods have been developed for the preparation of complexes containing weakly bonded anions derived from strong protic acids. However, ion exchange in a poorly coordinating solvent has proved to be the most productive method and examples are cited in the following paragraphs. 

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