Development of Controlled Palladium(0)-Catalyzed Suzuki Cross-Coupling Polymerizations

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With this award, the Macromolecular, Supramolecular and Nanochemistry Program of the Division of Chemistry is supporting Professor Qiao-Sheng Hu of the City University of New York-College of Staten Island to develop new approaches to preparing conjugated polymers that are difficult to synthesize by conventional methods. Conjugated polymers have applications in fields ranging from semiconductors, sensors to opto-electronics. In addition to advancing the fundamental knowledge of polymerization chemistry, this research aims to produce new conjugated polymers with potential application as opto-electronic materials. As a part of the broader impacts of this project, the Hu Group is training students and graduate students with state-of-art instruments and techniques for the preparation and characterization of advanced materials. Professor Hu's research group seeks to exploit Pd(0)-catalyzed Suzuki cross-coupling chemistry for controlled polymerizations in the preparation of conjugated polymers/block copolymers. Controlled Pd(0)-catalyzed cross-coupling polymerizations have recently emerged as new tools for the synthesis of conjugated polymers such as poly(arylene)s and poly(aryleneethynylene)s with controlled degree of polymerization. However, limitations exist for reported controlled Pd(0)-catalyzed cross-coupling polymerizations, which include promising but less than ideal polydispersity indexes (PDIs)(~1.20 in general), limited monomer scope, e.g., mainly donor-based AB-type monomers, and difficulty to control chain end functionality. Such limitations greatly impede their applications as powerful tools for the preparation of many valuable conjugated polymers and block copolymers with controlled length, which have great potential in molecular electronics and nanotechnology as well as in fields ranging from semiconductors, sensors to optoelectronics. In this project, the specific foci are: (a) the preparation of new palladacycle-based initiators; and (b) the development of controlled Pd(0)-catalyzed Suzuki cross-coupling polymerizations of acceptor-based and donor-acceptor monomers for the preparation of AB-type and AA/BB-type polymers and block copolymers. The resulting materials are analyzed by size exclusion chromatography, matrix-assisted laser desorption/ionization-time of flight mass spectrometry, nuclear magnetic resonance spectroscopy and other characterization techniques.