Methyl carboranes complexes

Methyl abstraction of Cp2ZrMe2 with a trityl salt of a highly methylated carborane anion, [GPh [closo-HCBuMen], shown in Equation (47), leads to formation of the cationic complex 727 in which the methyl zirconocene cation is closely associated with the methylated carborane anion through the Zr(/x-CH3)B motif.562 The Zr- H3G interaction is maintained in solution, as shown by a change in chemical shift for the methyl group... 

Polymerization of methyl methacrylate (MMA) and styrene in bulk via ruthenacarboranes and carbon tetrachloride was investigated first, ft was found that proposed ruthenium complexes were able to efficiently catalyze polymerization of MMA in conjunction with carbon tetrachloride as an initiator. Moreover, as follows from the data obtained (Table I), high conversion of the monomer is achieved in a number of cases. The structure of ruthenium carborane complexes closo or exo-nido) has a substantial effect on the kinetic parameters of MMA and styrene polymerization, as well as on the molecular-weight characteristics of synthesized polymers. 

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... 

The bispyridine-substituted carbyne complexes 182 react with several anionic bidentate donor ligands to afford the anionic / -ketenyl complexes 183 [Eq. (149)] (149,167). The bis(pyrrole carboxaldiminato) complexes were further transformed into alkoxyacetylene complexes by methylation at the ketenyl oxygen atom. Addition of trimethylphosphine to the anionic carborane-substituted carbyne complex 184 at — 30°C gives the ketenyl complex 185 [Eq. (150)] (135). The hydroxy and methoxyacetylene complexes were obtained by further addition of HBF4 and methyl triflate. 

Capillary and packed (GC) columns are of value in the analysis of complex mixtures of lipids. The best capillary column length will depend on the complexity of the material injected, however, 30-m columns are often employed. In packed columns, many types of stationary phases are available for lipid separation, and these include silicone and alkylated or cyanogenated derivatives, polyesters, polyglycol, and carboranes. It is also common to derivatize the fatty-acid side chains to the corresponding methyl esters by reaction in BF3/ methanol prior to chromatographic analysis to achieve more distinct and uniform separations. 

Carborane or B(C6F5)3 abstracts a methyl ligand from a dimethylplatinum complex with PPP3 ligands to form the cationic phosphaplatinacyclobutane containing THE ligand 547 (Scheme 75)." " The T-shaped methylplatinum(ii)... 

Depending on the stoichiometric quantity of Br2 and the reaction temperature, electrophilic bro-mination of 1 with Brj in the presence of catalytic amounts of AICI3 gave 9-bromo-o-carborane (31, 95% yield), 9,12-dibromo-o-carborane (32), and 8,9,12-tribromo-o-carborane (33), as shown in Scheme 6.5 (Smith et al., 1965). Under similar reaction conditions, 1,2-dimethyl-o-carborane (28) was found to be tetrabrominated (34), presumably due to the electron donating effect of the methyl groups. 3-Bromo-o-carborane (35, 65% yield) was obtained by the reaction of 14 with a boron tribromide-methylsulflde complex [BBr3-S(CH3)3] (Li and Jones, 1990). 

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