Alkyl carborane

The related mono-A/-alkylated carboranes, 7-(NH2R)-7-CB2qH22, can be prepared by treatment of decaborane(14) with alkyl isocyanides (125). 

Dymon et al. (2008) designed ILs with carboranes as anions and alkyUmidazolium and pyri-dinium, respectively, as cations. In addition to the already known [c/oso-CBjjH,2] , they investigated the corresponding C-alkylated carborane [c/( i( -RCB H,] (R = Me, Bn) and m do-carborane [nido-C, xi salts (Figure 29.10). 

FIGURE 29.10 Alkylated imidazolium and pyridinium cations with (C-alkylated) carborane and nido-... 

Two alkyl derivatives of the C2B2QH22 carboranes were developed for propeUant additives -hexyl carborane (nYiCT) [20740-05-0],... 

This effect has also been observed in polyphosphazenes containing alkyl- or phenyl-carborane as pendent groups.12 A typical synthetic route to poly(phenyl-carboranyl-di-trifluoroethoxy-phosphazene) having pendent phenyl-carborane groups is shown in scheme 4. A substantial improvement in the thermal stability of the polymer was observed. This is attributed to a retardation of the ring-chain de-polymerization mechanism due to steric hindrance effects of the carborane units, inhibiting helical coil formation. 

A series of alkyl-substituted macrocycles featuring mercury atoms connected by c/-carborane units has been recently synthesized. Examples of such macrocycles include the hexamethyl derivative 58 and the hexadecamethyl derivative 59 whose alkyl-substituted carborane backbones impart improved solubility in hydrocarbon solvents.7 While 58 was synthesized from doso-9, 12-Mc -1 T-I.i -110I R and Hg(OAc)2, compound 59 was obtained as a... 

In addition to the mixed Cp/carborane complexes, there has been one report on the lanthanacarboranes with the open pentadienyl ligand, R7C5 (R = H or an alkyl derivative). This is an alternate 6-7T electron donor that has led to the syntheses of number of so-called open metallocenes where the pentadienyl group replaces one or more Cp ligands. This lanthanacarborane report covered the syntheses and structural determinations of two open... 

CARBORANE. A cry stalline compound composed of boron, carbon, and hydrogen. It can be synthesized in various ways, chiefly by the reaction of a borane (penta-or deca-) with acetylene, either at high temperature in the gas phase or in the presence of a Lewis base. Alkylated derivatives have been prepared. Carborancs have different structural and chemical characteristics and should not be conTused with hydrocarbon derivatives or boron hydrides. The predominant structures arc the cage type, the nest type, and the web type, these terms being descriptive of the arrangement of atoms in the crystals. Active research on cargorane chemistry has been conducted under sponsorship of the U.S. Office of Naval Research, http //www.onr.navy.mil/... 

Reed s group reported the X-ray structures of trialkyl-silicenium ions R3ST6 complexed to low-nucleophilic hexahalo carborane anions90,91. The authors varied systematically both the alkyl substituents R (R = Me, Et, z -Pr and t-Buj and the halogen substitution of the XgCBnlL (X = Cl, Br, I) counterions. The degree of silicenium ion character in the... 

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