Polymer Brushes Synthesis Characterization Applications
To facilitate the asymmetric catalysis process, we designed novel polymeric chiral catalysts. Since quaternary ammonium salts of cinchona alkaloid derivatives show efficient catalytic activity in various asymmetric transformations, we have synthesized novel chiral polymer catalysts containing cinchonidinium moieties in the main chain of the polymer. Repetitive Mizoroki–Heck coupling reactions between the cinchona alkaloid-derived dimer and diiodide afforded the chiral polymer catalysts, which were subsequently used as catalysts in asymmetric benzylation reactions to yield the corresponding phenylalanine derivatives in higher yields and levels of enantioselectivity than can be obtained with a monomeric catalyst. Because of the insolubility of the polymeric catalysts, they were easily recovered from the reaction mixture and reused several times.
polymer brushes synthesis characterization applications ..
In this Account, we review our recent progress on the synthesis, properties, and novel applications of dopant cross-linked CPGs. We first describe the synthetic strategies, in which molecules with multiple functional groups are adopted as cross-linkers to cross-link conductive polymer chains into a 3D molecular network. These cross-linking molecules also act as dopants to improve the electrical conductivity of the gel network. The microstructure and physical/chemical properties of CPGs can be tuned by controlling the synthetic conditions such as species of monomers and cross-linkers, reaction temperature, and solvents. By incorporating other functional polymers or particles into the CPG matrix, hybrid gels have been synthesized with tailored structures. These hybrid gel materials retain the functionalities from each component, as well as enable synergic effects to improve mechanical and electrical properties of CPGs. We then introduce the unique structure-derived properties of the CPGs. The network facilitates both electronic and ionic transport owing to the continuous pathways for electrons and hierarchical pores for ion diffusion. CPGs also provide high surface area and solvent compatibility, similar to natural gels. With these improved properties, CPGs have been explored to enable novel conceptual devices in diverse applications from smart electronics and ultrasensitive biosensors, to energy storage and conversion devices. CPGs have also been adopted for developing hybrid materials with multifunctionalities, such as stimuli responsiveness, self-healing properties, and super-repellency to liquid.
Shigeru Yamago received his B.S. and Ph.D in chemistry from Tokyo Institute of Technology in 1986 and 1991, respectively, under the supervision of Professor Eiichi Nakamura. During that time, he joined Professor Peter Vollhardt’s group at U.C. Berkeley as a summer student (1988). He became an assistant professor at Tokyo Institute of Technology in 1991 in the group of Professor Eiichi Nakamura and then moved to Kyoto University in 1995 in the group of Professor Jun-ichi Yoshida. He was a Visiting Scientist in Dr. Chryssostomos Chatgilialoglu’s group at Consiglio Nazionale delle Ricerche in Bologna (2000). In 2003, he was appointed Professor of Osaka City University. He had been a Research Fellow of PRESTO program in the Japan Science and Technology Agency from 2002 to 2006. In 2006, he joined Institute for Chemical Research at Kyoto University where he holds Professorship. He received the Incentive Award in Synthetic Organic Chemistry from the Society of Synthetic Organic Chemistry, Japan, in 2001. His research interests include synthetic organic and polymer chemistry, radical chemistry, and element chemistry.