Journal of Polymer Science Part A: Polymer Chemistry, Vol.39, No.18, 3112-3120, 2001
Fast and convenient construction of carbamate/urea-based dendrimers with a diisocyanate building block
A novel, fast, and simple synthetic procedure for polycarbamate/urea dendrimers, based on an AB-CD, coupling strategy, is presented. The reactivity difference of the two isocyanate functionalities of the AB building block allows the construction of these dendrimers without the necessity of activation or deprotection steps. This makes it possible to construct dendrimers within 2-3 days, even the largest dendrimers. The resulting dendrimers could be fully characterized by C-13 NMR, IR spectroscopy, and mass spectrometry. The synthetic strategy necessitates only techniques such as stirring, heating, and accurate dosing, and there is no workup required for the purification of the compounds. On account of a wide variety of polyols, amines, and aminoalcohols, this new procedure is not limited to the synthetic strategy followed but allows the incorporation of a large variety of functional molecules in the core, in the branching units, or at the end groups. The method is even applicable when organometallic species are incorporated into the dendritic structure, thereby showing its versatility.