Fun with photons, reactive intermediates, and friends. Skating on the edge of the paradigms of physical organic chemistry, organic supramolecular photochemistry, and spin chemistry.

This Perspective presents a review and survey of the science and philosophy of my research career over the past five decades at Columbia as a physical organic chemist and photochemist. I explore the role of paradigms, structure, and geometric thinking in my own cognitive and intellectual development. The Perspective describes my investigations of high energy content molecules in electronically excited states and the development of electronic spin and supramolecular photochemistry chemistry. Current research dealing with the nuclear spin chemistry of H(2) incarcerated in buckyballs is illustrated. In the second part of this Perspective, I recount a personal role of the philosophy and history of science and the scientific communities' use of paradigms in their every day research and intellectual activities. Examples are given of the crucial role of geometry and structure in the rapid development of organic chemistry and physical organic chemistry over the past century.