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RESEARCH PRODUCT

Nonbonded Indirect Nuclear Spin–Spin Couplings (J Couplings “Through-Space”) for Structural Determination in Small Organic and Organometallic Species

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Abstract Spin–spin coupling constant J provides decisive data for organic compound characterization. This electron-mediated coupling is usually taught as transmitted between covalently bonded magnetic atoms. However, this physical interaction between nuclear spins is much more complex than that with regard to chemical bonding concept. Independent experimental and theoretical studies related to small organic and organometallic species (molecular mass below 2000 g mol − 1 ) have highlighted the existence of J couplings operating via clearly nonbonded interactions and known as “through-space” couplings. Interactions of this type are frequently reported and couplings involving 19  F, 13 C, 77 Se, 15  N, 31 P, or 1 H in hydrogen bonding are now clearly identifiable. This chapter aims to clarify this phenomenon often poorly known by routine users of NMR. Thus, nonbonded spin couplings can provide critical data for studying and determining molecular structures both in solution and in the solid state. This is illustrated herein through selected examples picked in different families of small organic and organometallic compounds.