CIDNP

CIDNP (chemically induced dynamic nuclear polarization), often pronounced like "kidnip", is a nuclear magnetic resonance (NMR) technique that is used to study chemical reactions that involve radicals. It detects the non-Boltzmann (non-thermal) nuclear spin state distribution produced in these reactions as enhanced absorption or emission signals.

CIDNP was discovered in 1967 by Bargon and Fischer, and, independently, by Ward and Lawler.[1][2] Early theories were based on dynamic nuclear polarisation (hence the name) using the Overhauser effect. The subsequent experiments, however, have found that in many cases DNP fails to explain CIDNP polarization phase. In 1969 an alternative explanation which relies on the nuclear spins affecting the probability of a radical pair recombining or separating.

It is related to chemically induced dynamic electron polarization (CIDEP) insofar as the radical-pair mechanism explains both phenomena.[3]

  1. ^ Bargon, J.; Fischer, H.; Johnsen, U. (1967). "Kernresonanz-Emissionslinien während rascher Radikalreaktionen". Zeitschrift für Naturforschung A. 22 (10): 1551. doi:10.1515/zna-1967-1014. S2CID 201828719.
  2. ^ "Nuclear magnetic resonance emission and enhanced absorption in rapid organometallic reactions". Journal of the American Chemical Society. 89: 5517. 1967.
  3. ^ Vyushkova, Maria (April 2011). "Basic principles and applications of spin chemistry" (PDF). nd.edu. University of Notre Dame. Retrieved November 21, 2016.