Chemical Shifts and Solid-State Molecular-Level Structure

This article discusses the relationship between chemical shifts and different structural and bonding characteristics that affect molecular structure. The article starts with a discussion of the effect of changes in the bonding environment and tautomeric form on measured chemical shifts, followed by examples of how chemical shifts vary as a function of bond lengths, bond angles, dihedrals angles, and steric influences. The use of quantum chemical calculations of the magnetic shielding tensor to aid in the determination of these effects is highlighted throughout. In addition, the three-dimensional nature of the effects on structure, as revealed by the tensorial nature of the chemical shifts, is discussed. © 2009 John Wiley & Sons, Ltd.