J-Coupling: a rigorous definition of the emergent chemical bond
Jonathan Yates (Principal Investigator)
Chemists use many concepts in order to understand the structure and properties of materials. Descriptions of atomic level structure use the concept of bonding; pairs of atoms might be said to be bonded and that bonding further classified as strong or weak, covalent or ionic. However, these classifications do not correspond to some directly measured observable. The project was an investigation of how calculations based on quantum mechanics can make a link between concepts of bonding and parameters that can be directly observed in experiment. This focuses on Solid-state NMR, a uniquely sensitive probe of atomic scale structure, which uses the interaction between the magnetic moment of an atomic nucleus and radio-frequency radiation to provide information on the local environment of an atom. In particular, Jonathan Yates and Tim Green have shown that the coupling measured between atoms (known as J-coupling) is a sensitive probe of interactions between molecules in a solid. This is the first time J-couplings have been observed in a material between molecules that do not possess a formal bond. The work has significant implications for the study of structures via NMR (NMR Crystallography) with impacts on materials ranging from pharmaceuticals to catalysis.
In addition to the publications below, the project produced code that was taught at the 2015 CASTEP workshop held in Oxford to 85 participants.
(2016) Tim Green and Jonathan Yates (with others): 'Investigating Unusual Homonuclear Intermolecular “Through-Space” J Couplings in Organochalcogen Systems' Inorganic Chemistry
(2015) Tim Green and Jonathan Yates (with others): 'Unusual Intermolecular “Through-Space” J Couplings in P–Se Heterocycles' Journal of the American Chemical Society
(All presentations were in 2015)
• University of Orleans, France
• University of Southampton
• Weizmann Institute, Israel
• CMR Meeting, St Andres
• AIX University, Marseilles
• CCPN meeting Buxton
• Alpine NMR Conference
• Psik Meeting – San Sebastian