Carboranes methylated

The disilanickela complex 21 was also found to be a good catalyst for the dehydrogenative double silylation of aldehydes. The nickel-catalyzed reactions of 1,2-bis(dimethylsilyl)carborane 11 with aldehydes such as isobutyraldehyde, trimethylacetaldehyde, hexanal, and benzaldehyde afforded 5,6-carboranylene-2-oxa-l,4-disilacyclohexane.32 34 36 The dehydrogenative 1,4-double silylation of methacrolein and tram-4-phenyl-3-buten-2-one in the presence of a catalytic amount ofNi(PEt3)4 also took place under similar conditions. In contrast, the reaction of 11 with a-methyl-tran.s-cinnamaldehyde and irans-cinnamaldehyde under... 

Methylcarborane [l-methyl-l,2-dicarbaclovododecaborane-(12)] may be prepared by hydrolysis of the Grignard reagent formed from the reaction of (bromomethyl)carborane with magnesium in the presence of diethyl ether.2c B h... 

After the addition of methyl iodide, the solution is heated to the reflux temperature for an additional 3 hours. The reaction mixture is allowed to cool to room temperature and it is slowly added with stirring to about 400 ml. of chilled dilute (IN) hydrochloric acid. The mixture is placed in a separatory funnel, and the carborane is extracted first with 250 ml. of diethyl ether... 

The selective basic degradation of 1,2-dicarbaclovodode-carborane(12) and its C-methyl and C-phenyl derivatives has been recently reported.3 The ethanolic potassium hydroxide degradation of C, C"-dimethyl-l, 2-dicarbaclovododecaborane (12) and the isolation of the trimethylammonium salt of the resulting B9C2Hio(CH3)2 anion are described here as an illustration of this general reaction. The properties of the trimethylam-... 

Fig. 18a. 10. Chemical structures of ion exchangers used in polymeric membranes of ion-selective electrodes with preference toward ions as indicated, (a) Tetraphenyl borates anion exchanger, (b) tridodecyl methyl ammonium chloride cation exchanger and (c) newly introduced carborane cation exchanger.

In solution, the TPFPB salt of the methyl-substituted vinyl cation 19 has only limited stability. Decomposition into unidentified products took place during several days. In contrast, the steric and electronic effects provided by the /-butyl substituent confer indefinite stability to the vinyl cation 20 in the absence of nucleophiles. That is, according to the NMR experiments, a solution of 20 TPFPB in benzene showed no sign of decomposition even after weeks at room temperature. With the carborane anion [CBnH6Br6] suitable crystals for... 

The phenyl modified polymers show a significant decrease In weight loss compared to their all methyl analog (6). In a study of the thermal breakdown of phenyl substituted carborane-slloxane polymers, It has been reported that the presence of phenyl groups In carborane-siloxanes leads to cross-linking and less loss of weight ( ) ... 

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