According to a company history, the Varian brothers “intentionally settled near Stanford in order to enjoy the benefits of interchange with the various scientific programs in progress at the University.” In 1948 two brothers, Russell and Sigurd Varian, armed with $22,000, founded Varian Associates to manufacture scientific instruments. What had started out as a tool for physicists quickly moved into the chemical laboratory. In 1955 William Dauben at the University of California at Berkeley and Elias Corey at Illinois were the first chemists to use NMR to assign previously unknown molecular structures.Ĭhemists quickly realized that NMR had great utility it allowed them to recognize the detailed structure of a molecule as they synthesized it. Other advances in analyzing structure came with the discovery by Herbert Gutowsky, David McCall, and Charles Slichter at the University of Illinois of spin-spin coupling, a measure of atomic interactions within a molecule. The ability to measure the chemical shift was a boon to chemists it meant they could perform non-destructive chemical analyses of samples to determine molecular identity and structure much faster and more simply than before. Other researchers soon discovered the chemical shift, a small variation in NMR frequency as a result of a variation in molecular electron distribution. Purcell and Bloch shared the 1952 Nobel Prize in Physics.
The Harvard group led by Edward Purcell discovered the phenomenon in solid paraffin the Stanford group, under the wing of Felix Bloch, found it in liquid water. In 1945 two groups of physicists, one at Stanford, the other at Harvard, first reported the detection of NMR signals in condensed matter. Medical practitioners employ magnetic resonance imaging (MRI), a multidimensional NMR imaging technique, for diagnostic purposes. Chemists use it to determine molecular identity and structure. NMR spectroscopy is the use of NMR phenomena to study the physical, chemical, and biological properties of matter. NMR is a phenomenon that occurs when the nuclei of some, but not all, atoms in a static magnetic field and are subjected to a second oscillating electromagnetic field in the form of radio frequency radiation, which causes the nucleus to resonate. A nuclear magnetic resonance (NMR) spectrometer is the tool of choice for researchers probing chemical structures. Hardly a chemistry laboratory is without one. Development of Nuclear Magnetic Resonance (NMR)
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