Functionalized Boron Nanoparticles: Characterization of Thiol-Ene Click Chemistry

Carboranes are a family of cluster compounds comprised of boron, carbon, and hydrogen that are being investigated in a number of applications, including self-assembling monolayers (SAMs), cancer treatment, and non-catalytic synthetic agents. Various functionalities have been attached to carboranes to facilitate their utilization. Thiol-ene “click” chemistry between thiol-functionalized m-carborane and a variety of maleimide derivatives provides a facile path to a wide variety of functionalized boron nanoparticles. The reaction rate shows a strong dependence on the solvent as well as on the position of the thiol group on the carborane. Reaction rates as a function of temperature have been measured with the reaction following second order kinetics. Preliminary testing revealed reactivity differences greater than an order of magnitude between m-carborane-1-thiol and m-carborane-9-thiol.