Electron Paramagnetic Resonance

Electron paramagnetic resonance (EPR) spectroscopy is the method of choice for the study of paramagnetic systems with unpaired electron spins. It is in particular successful in case of magnetically diluted solids where EPR methods allow a detailed exploration of structural and electronic properties of the paramagnetic centers. We present an introduction in the basic principles of continuous-wave EPR spectroscopy of porous materials and introduce briefly more recently established pulsed EPR experiments in the first part. Selected application examples of EPR methods for the investigation of paramagnetic species in metal–organic framework materials are discussed and reviewed in the second part. They involve the spectroscopic characterization of paramagnetic framework transition metal ions, paramagnetic adsorption complexes, and radical species.