Discovery and Its Applications

Mature Research Projects

Mature Download .PDF

These research projects have been completed under the guidance of Institute Director Prof. M.F. Hawthorne. They serve as the basis for many of the projects currently underway at the Institute.

 

Biomedical Polyhedral Borane Chemistry pdf

Notable biomedical applications of this emerging chemistry impinge upon such representative topics as positron emission tomography (PET), enzyme-impervious agents for radioimaging and radiotherapy, new drug delivery agents for targeting the cell nucleus, use of the cytotoxic boron-10 neutron capture reaction for cancer (BNCT) and arthritis (BNCS) therapies, new drug and diagnostic agent delivery vehicles based upon multivalent cell-targeted unimolecular nanoparticles (closomers and liposomes) and the design and synthesis of catabolism-proof structural modules for incorporation in new pharmaceuticals. These and other related topics are presently under investigation in the Hawthorne Laboratory.

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Camouflaged Polyhedral Species pdf

The three isomers of the icosahedral C2B10H12 (1,2- or ortho-; 1,7- or meta-; and 1,12- orpara-) carboranes and the isoelectronic polyhedral borane dianion B12H122- are uniquely suited to play the role of building-blocks in the construction of molecular scaffolding and stereochemically rigid platforms.

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Carboracylces and Mercuracarborands pdf

Carboracycles were originally prepared for use as precursors to cyclic metallacarboranes and in molecular recognition studies involving localized hydrophobic bonding. A novel application under investigation is the interaction of water-soluble carboracycles with hydrophobic organic guests in aqueous media. Thus water-soluble carboracycles with hydrophobic cavities may support the solubilization of hydrophobic carborods (rotaxane formation), fullerenes, hydrocarbons, and other species through localized hydrophobic bonding.

The template reaction of dilithiated ortho-carborane with mercury salts results in the self-assembly of cyclic arrays (mercuracarborands) composed of alternating carborane icosahedra and mercury atoms linked by C-Hg-C moieties. The carbon vertices of the carborane icosahedra are strongly electron-withdrawing and enhance the Lewis acidity of the mercury centers. This electronic feature enables the mercuracarborands to function as cyclic hosts for anionic and other electron-rich guest species.

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Carborods pdf

Icosahedral carborane modules can be linked with each other by direct C-C bond formation, through a linking moiety such as alkylene, alkenylene, alkynylene and arylene groups, or a metal center such as Hg. The intermodular linkage can be made at a carbon vertex or at a boron vertex of the carborane cage. The functionalization of the C-H vertices of carborane is easily accomplished via metallation. Electrophilic substitution reactions at the B-H vertices of the aromatic carborane modules are comparable to those observed with aryl groups. If the modular components are linked in a cyclic array the macromolecular construct is identified as a carboracycle, but if they are linked in a rigid linear assembly the resulting oligomer is called a carborod.

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Liposomes pdf

The goal of the liposome project is to develop drug delivery modalities consisting of liposomes (or other carriers such as micelles) which contain, or are constructed from, boron-containing compounds. This is accomplished through a) the identification and synthesis of appropriate hydrophilic and lipophilic boron agents; b) the incorporation of the candidate compounds within small unilamellar vesicles (SUVs) or similar delivery vehicles; and c) the evaluation of these preparations in boron biodistribution experiments using animal models.

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Oligomeric Phosphate Diesters pdf

Boron-rich oligomeric phosphate diesters (OPDs) are attractive boron delivery vehicles for use in BNCT. They are readily obtained from selected carborane-containing dihydroxy precursors and assembled using well-established phosphoramidite coupling chemistry. In addition, boron-rich OPDs are inherently hydrophilic or amphiphilic by virtue of their anionic phosphate backbone.

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