Carborane cages

Hawthorne and co-workers have reported the selective uptake of homogeneous flourescein-labeled nzYfo-carboranyl oligomeric phosphate diesters nido-OPDs) by cell nuclei within 2h after microinjection. The location in the cell of nido-OPDs uptake was found to depend on the location of the carboranyl moiety in the nido-OPDs. When the carborane cage was located on a side chain attached to the oligomeric... 

UB and UB H solution-state NMR spectra (see Fig. la) clearly show the different boron environments within the m-carborane unit. The eight peaks in the -10 to 0 ppm range are indicative of the different boron environments in the w-carborane cage, including B—B, B—C, and B—H bonds. The spectrum also contains... 

Figure 3 3D computerized tomography (CT) image of a foamed polysiloxane incorporating a small admixture of carborane cages. 

Figure 15 Structure of [166-(N03)2(H20)]2. Carborane cages have been omitted for clarity.

Scheme 16 Synthesis of an oxide ion encapsulating tetralanthanide tetrahedron, surrounded by carbons apart carborane cages. Reproduced by permission of the American Chemical Society from Organometallics 2004, 23, 4621.

The extreme hydrophobicity, or in other words, the low water solubility, of the carborane cage is a major disadvantage in terms of biodistribution. However, 0-C2B10 can be readily converted into a water-soluble degradation product. 0-C2B10 reacts with strong nucleophiles such as alkoxides, aliphatic amines and fluoride anion to... 

Nitrene cycloaddition was also used by Yinghuai and co-workers to append C2B10 carborane cages to SWCNTs [31]. One of the derivatives showed very interesting potential in medicinal applications as it was found that boron atoms had higher concentrations in tumor cells than in blood or other organs when administered to mice. This finding could inspire further research on the use of these systems as nanovehicles for... 

However, separation of the carborane cage from The phos-phazene ring or chain by a methylene spacer group allows metals to be Inserted into the open face of the carborane. These syntheses were accomplished by the reaction routes shown in Schemes 3 and A. High polymeric analogues of these transformations have also been accomplished following polymerization of XXX. The rhodium-bound cyclophosphazenes and polyphosphazenes are catalysts for the hydrogenation of 1-hexene. In this, they show a similar behavior to metallocarboranes linked to polystyrene... 

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