Metal dicarbollides

Even the addition of 4 equiv. of dimethylzinc to a bis(dicarbollide)tantalum dichloride, Scheme 23, produced only the monomethyl complex 26 in an isolated yield of 75%.63 In these reactions, the oxidation state of the transition metal and the steric bulk of its ligands obviously play a role in the degree of alkylation. 

As a second illustrative aspect of the boron/carbon connection, we consider the dicarbollide ion, C2B9H112-, which can be pictured as derived from Bi2Hi22- by removing one BH(t) vertex and replacing two adjacent borons of the exposed pentagonal face by carbon atoms, as shown in Fig. 3.116. This ion exhibits remarkable electronic mimicry of the cyclopentadienyl ion (C5H5-, Section 3.3.2), forming similar coordination and sandwich complexes with many metallic species.162... 

In the early 1960s it was recognized (6,187) that there were bonding similarities between the pentagonal face of the isomeric [nirio-(y HjJ2- ions and the well-known cyclopentadienide ion (Cp ) [CydJ- (Fig. 16). The isomeric nido-C2B9H1 J2- ions, which are commonly known as dicarbollide ions, and many other carborane anions, form stable complexes with most of the metallic elements. Indeed nearly all metals can be combined with polyborane hydride clusters to produce an apparently limitless variety of cluster compounds. 

Like many late transition metals, nickel has featured, albeit briefly, in the pursuit of poly(pyrazolyl)borate-metal-carbollide complexes. Thus, [c/oso-3-(r 2-Ph2Bp)-3,l,2-NiC2B9H11] (90 ) has been obtained as the tet-ramethylammonium salt,39 via the reaction of [Me4N][Ph2Bp] with the neutral bisphosphine nickel dicarbollide [doso-3,3-(PhEt2P)2-3,l,2-... 

Rais, J., Griiner, B. 2004. Extraction with metal bis(dicarbollide) anions Metal bis(dicarbollide) extractants and their applications in separation chemistry. In Ion Exchange and Solvent Extraction, A Series of Advances Vol. 17. Marcus, Y., SenGupta, A.K., Marinsky, J.A. Eds. Marcel Dekker, New York, pp. 243-334. 

EXTRACTION WITH METAL BIS(DICARBOLLIDE) ANIONS METAL BIS(DICARBOLLIDE) EXTRACTANTS AND THEIR APPLICATIONS IN SEPARATION CHEMISTRY ]iH Rais and Bohumir Griiner... 

High yields of bis(dicarbollyl)cobalt(II I) derivatives in which the 1,2-dicarbollide ion is unsubstituted, 1,2-dimethyl or 1-phenyl have been obtained by the anhydrous route using cobalt(II) chloride (12, 18). An internal redox process occurs in this reaction and cobalt metal is formed. 

Addition of palladium acetylacetonate in glyme to a cold glyme solution of excess dicarbollide ion produced the air-sensitive (l,2-B9C2Hn)2Pd2 ion (42). Solutions of this ion deposited palladium metal on standing. The Pd(II) compound was oxidized with iodine to produce the neutral species, (l,2-B9C2Hn)2Pd. 

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