The incorporation of the metal nanoparticles in polymers has attracted much attention and research interest over the last few years. Such composites show various properties directly relevant and of benefit to dielectrics, energy storage and catalytic activity. We have employed a coupled redox synthesis system with molecular precursors for the synthesis of nanometal-polymers, employing gold, copper or palladium compounds with various anilines and substituted anilines as starting materials. The resulting nanometal-polyaniline structures can be controlled at the nanoscale by manipulation of the synthesis variables.
Exposure of the nanometal within the polymer matrix can be controlled to some extent by synthesis conditions and subsequent thermal conditioning and can be monitored by employing a catalytic test reaction. In addition, specific manipulations can be used to control catalytic properties for specific applications.
The present work describes the synthesis and characterization of a metal-polymer hybrid material formed by the combination of palladium nanoparticles and poly-(o-phenylenediamine) by an in-situ, one pot chemical synthesis route using palladium acetate and o-phenylenediamine as precursors [1]. Palladium nanoparticles (~2 nm) are uniformly dispersed within the polymer matrix. IR and Raman spectra indicate that both the benzenoid and the quinoid rings are present in the polymer structure. This hybrid material is used for the Heck reaction [2] of aryl halides with different olefins and Suzuki coupling reaction [3] of aryl halides with phenyl boronic acid. All the reactions were performed in a very mild and ligand free condition using triethyl amine as base and afforded the coupling product with excellent yields.
References:
[1] K. Mallick, M. J. Witcomb, M. S Scurrell, Journal of Macromolecular Science: Pure and Applied Chemistry 43 (2006) 1469.
[2] R. F. Heck, J. P. Nolley, Journal of Organic Chemistry 37 (1972) 2320.
[3] N. Miyaura, A. Suzuki, Chemical Communication (1979) 866.