Stereodynamic Coordination Complexes

点击翻译按钮获取中文摘要

Over the last several years, the Canary laboratory has discovered bistable molecules that can be electrically switched between two distinct states. These substances are complexes of copper with three-armed organic ligands that exhibit a molecular propeller-like twist, the pitch of which can be modulated or inverted. Mechanistic investigations revealed that oxidation/reduction of the central copper ion led to exchange of the atoms bound to the metal which in turn resulted in dramatic changes in the conformation and shape of the organic portion of the complex. In this grant cycle, electron-induced changes in conformation of the organic ligand will be applied to three problems. First, the reorientation of two of the arms in the three-arm complexes will be used to study take-up and release of neurotransmitter-like guest molecules and electrically controlled catalysis of organic reactions. Such technology could enable electronic control of chemical signaling, catalysis, or open new strategies for redox-mediated drug delivery. Second, ligand reorganization will be used to construct a molecule that can be extended or retracted with an electrical trigger, affording a nanometer-scale electromechanical transducer whose properties will be probed by atomic force microscopy (AFM). Such materials could be of interest for valves and constrictors in nanodevices. Third, the principles used to develop the three-arm copper complexes will be applied to the design of peptides that reversibly convert between alpha-helical and beta-sheet secondary structures upon electronic stimulation. Besides potential materials applications, such peptide transitions may be relevant to processes associated with redox stress in biological systems or neurodegenerative disease. This research project will be undertaken by undergraduate and graduate students and postdoctoral fellows, including individuals from underrepresented groups, who will learn valuable synthetic and physical skills that will enable them to become productive contributors to our nation?s research enterprise. Summers will include participation by faculty from predominantly undergraduate institutions as well as New York City high school students. The members of the research team will participate in annual outreaches at public museums and other K-12 activities. The project leader will serve the scientific community by organizing and facilitating interdisciplinary conferences and discussion groups.