Electron Paramagnetic Resonance Spectroscopy

Abstract

Electron paramagnetic resonance spectroscopy, also known as electron spin resonance spectroscopy, provides detailed information about the electronic structure of metal centers with unpaired electrons and interactions with neighboring nuclear or electron spins. Samples may be in fluid solution or solid state. Examples are provided for copper, nickel, iron, manganese and molybdenum centers in proteins, chromium toxicity, Gd–Gd interactions as probes of distances in biomolecules, and the search for vanadium complexes with long coherence times as potential qubits. Specific systems are selected to illustrate the use of a range of EPR techniques and characteristics of various paramagnetic metal centers. Advances in molecular orbital calculations, primarily using density functional theory, have dramatically enhanced the interpretation of experimental data.