6533b830fe1ef96bd1297b20

RESEARCH PRODUCT

A versatile methodology for the controlled synthesis of photoluminescent high-boron-content dendrimers.

subject

description

Fluorescent star-shaped mol- ecules and dendrimers with a 1,3,5-tri- phenylbenzene moiety as the core and 3 or 9 carborane derivatives at the pe- riphery, have been prepared in very good yields by following different ap- proaches. One procedure relies on the nucleophilic substitution of Br groups in 1,3,5-tris(4-(3-bromopropoxy)phe- nyl)benzene with the monolithium salts of methyl and phenyl-o-carborane. The second method is the hydrosilylation reactions on the peripheral allyl ether functions of 1,3,5-tris(4-allyloxy-phe- nyl)benzene and 1,3,5-tris(4-(3,4,5-tris- AAA with suitable carboranyl-silanes to produce different generations of dendrimers decorated with carboranyl fragments. This approach is very versatile and allows one to introduce long spacers between the fluorescent cores and the boron clusters, as well as to obtain a high loading of boron clusters. The re- moval of one boron atom from each cluster leads to high-boron-content water-soluble macromolecules. Ther- mogravimetric analyses show a higher thermal stability for the three-function- alized compounds than for those con- taining 9 clusters. All compounds ex- hibit photoluminescent properties at room temperature under ultraviolet ir- radiation with high quantum yields; these depend on the nature of the clus- ter and the substituent on the Ccluster. Cyclic voltammetry indicates that there is no electronic communication be- tween the core and the peripheral car- boranyl fragments. Due to the high boron content of these molecules, we currently focus our research on their biocompatibility, biodistribution in cells cultures, and potential applications for boron neutron capture therapy (BNCT).