Paramagnetic Shifts and Paramagnetic Relaxation Enhancements

Paramagnetic centers originate from unpaired electrons that are intrinsic features of organic radicals and of many transition metal ions. In this lecture, we will illustrate how unpaired electrons affect the NMR spectrum of the surrounding nuclear spins, namely by altering their chemical shifts and by increasing their relaxation rates. The effects arising from paramagnetism depend in a well-defined manner on th e electronic configuration of the metal and on the structure and dynamics of the molecule, providing information on the electronic states of the paramagnetic center, as well as a number of structural restraints with wide ranging implications for molecular and biological sciences.