The focus of this research is a broad spectrum study of the transition metal stabilized phophinidenes, which are believed to be singlets in contrast to the uncomplexed triplet phosphinidenes, R-P. Phospinidene triplet-single energy gaps will be determined by high level ab initio calculations, which will also be used to characterize structural and electronic features of the cycloaddition pathways, product stabilities, isomerizations, and P-epimerizations. Mechanistic studies will determine kinetic (absolute and relative rates), thermodynamic (activation enthalpies and entropies), and stereoselectivity data (anti-/syn-ratios) for olefin cycloadditions. Phosphinidenes will be used to synthesize highly strained ring systems, which include alkylidene-phosphiranes, phospha 3 radialenes, phosphaspiranes, phosphabicyclobutanes, phosphiranes derived from aromatic compounds such as buckministerfullerene, and new heteroycles from heteroolefins. With this award, the Organic Dynamics Program is supporting the research of Dr. Koop Lammertsma of the Department of Chemistry at the University of Alabama at Birmingham. Professor Lammertsma will focus his work on the exploration of the unique-carbene-like properties associated with transition metal stabilized phosphinidenes. The study will involve a blend of sophisiticated calculations, detailed analyses of reaction mechanisms, and a spectrum of synthetic applications.
