This project, funded by the NSF Chemical Synthesis Program in the Division of Chemistry, supports the research of Professor Peter T. Wolczanski of Cornell University to explore the design and synthesis of first row transition metal complexes containing ligands that expand the chemistry of the metal, primarily through oxidation and reduction processes. The coordinating ligands feature nitrogen (N)- and carbon (C)-donors with multiredox capability, that is they are "redox non-innocent" (RNI) by virtue of giving or taking electrons from the metal, thereby increasing the metal's reactivity. The Wolczanski group employs many first row transition metals such as iron and chromium, making complexes that are uniquely reactive and more environmentally-friendly and sustainable than current precious metal complexes. Professor Wolczanski and his group are active in the local community, actively planning and participating in multi-week after-school experiments for the Chemistry Club at Caroline Elementary School in Ithaca, New York.
This research project focuses on experimental studies that seek to: expand the scope of first row transition metal complexes that express redox non-innocence, increase the field strengths about first row transition metals via chelation and metal-carbon bonds, prepare new species capable of unique carbon-carbon bond-forming processes, and generate metal-carbon clusters based on dicarbides. Redox non-innocent (RNI) ligands "electronically buffer" transition metal centers and expand their ability to conduct redox events inherent to bond-making and bond-breaking reactions. This research project focuses on the application of N-donor chelates to the chemistry of first row transition metal complexes, with an emphasis on stabilizing metal-nitrogen and -carbon multiple bonds while rendering them reactive. Operational, functionality tolerant, first row olefin metathesis catalysts are a critical target. The preparation of nitrogen and carbon-based chelates possessing the strong fields are necessary to transform first row transition metal complexes into those capable of second or third row reactivity. Studies also focus on C-C bond-making, featuring metal-stabilized carbanions that possess radical character. Radical hydrocarbon bond activations have led to ligand design features for hydrogen-atom abstraction and C-C couplings; these bond-making processes are scrutinized with regard to scope and the potential for catalysis. Graduate and undergraduate researchers are actively involved in both the experimental and theoretical aspects of the project. The students receive training in several characterizational techniques including Electron Paramagnetic Resonance and Mossbauer spectroscopies as well as magnetometry and electronic structure calculations.
