Closo fluorination

FLUORINECOMPOUNDS,ORGANIC - FLUORINATED AROMATIC COMPOUNDS] (Vol 11) Decahydro-2,ll-bis(h5-cyclopentadienyl)-2, ll-dicobalt-l-carba-closo-dodecaborate(l-) ion [59422-34-3]... 

Highly Fluorinated closo-Borane and -Carborane Anions... 

Ivanov, S. V., Lupinetti, A. J., Solntsev, K. A., and Shauss, S. H. 1998a. Fluorination of deltahedral closo-borane and -carborane anions with N-fluoro reagents. J. Fluorine Ghem., 89, 65-72. 

It was already pointed out in the introductory remarks that non-nucleophilic reaction conditions are one prerequisite for the synthesis of silylium ions in the condensed phase. The use of weakly coordinating anions is particularly decisive. Halogenated closo-carborate monoanions and - more recently - closo-borate dianions have found the most widespread use besides fluorinated tetraarylborates. While with bulky substituents these anions form silylium ions salts with well-separated cations and borate anions [10, 20, 22, 42], silylium ions with smaller alkyl substituents tend to coordinate directly to the anion forming zwitterionic compounds [7, 31, 32, 47]. For example, upon reaction of trimethylsUane with trityl-cZoso-carborate 86 in excess trimethylsUane the trimethylsUylium carborate 87 is formed (Scheme 27) [44]. 

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