Nuclear Magnetic Resonance
Nuclear Magnetic Resonance (NMR) spectroscopy is one of the principal techniques used to obtain physical, chemical, electronic and structural information of molecules. It is based on the physical phenomenon in which nuclei in a magnetic field absorb and re-emit electromagnetic radiation. This energy is at a specific resonance frequency which depends on the strength of the magnetic field and the magnetic properties of the isotope of the atoms. The detection of NMR signals is achieved by polarizing the magnetic nuclear spins with a constant magnetic field H 0 and by perturbing these nuclear spins with radio frequency (RF) pulses. The required perturbing frequency depends on the static magnetic field (H 0) and the nuclei of observation (e.g. 1H, 13C, 19F, 31P). Detailed information on the topology, dynamics and three-dimensional structure of molecules in solution and the solid state can be obtained with NMR. The versatility of the technique allows its application in many different research areas both in academia and industry. In the pharmaceutical industry NMR is widely used in many phases of the discovery process of novel drugs.