"The achievements of Dr. McConnell exemplify the guiding principle of the Welch Foundation and the spirit of the Welch Award: basic research in chemistry that contributes to the betterment of humankind," observed Richard J. V. Johnson, foundation chair and chief executive officer.
He pointed out that McConnell's first scientific breakthrough came when he applied quantum mechanics to chemical problems and developed theoretical methods for relating nuclear magnetic resonance (NMR) data to the structure of molecules. McConnell modified the equations governing NMR to include the effects of chemical reactions and used the results to measure chemical kinetics -- that is, the speed at which reactions take place. He also pioneered research on free radicals -- an extremely reactive type of chemical that occurs in biological settings. This research ultimately led to the development of the McConnell Relation, which describes the distribution of electron spin in free radicals.
When McConnell moved to Stanford in 1964, he began to use the methods of physical chemistry to study biological problems, introducing a method called spin labels, in which electron and NMR spectra are used to study the structure and kinetics of proteins and lipids.
His work showed how to measure the movement of molecules through and within membranes in the laboratory -- a technique that was later shown by many researchers to apply to living cell membranes. His research also demonstrated how a protein present in the body combines with a foreign peptide on the cell membrane to enable the body to recognize a pathogenic invader.
"Some of these discoveries are critical to understanding many properties of membranes," McConnell said, "and a large portion of biology takes place in and on membranes, so understanding them is crucial."