Matrix isolation vibrational spectroscopy as a tool for studying conformational isomerism

The use of matrix isolation vibrational spectroscopy to study conformational isomerism is described. Methods of distinguishing conformational splitting from matrix splitting are discussed. Examples are given of molecules for which the conformational equilibrium existing in the gas phase prior to deposition is trapped out in the matrix, of molecules which exhibit reversible interconversion of conformers at matrix temperatures, and of a molecule for which the conformational distribution trapped out in the matrix is strongly dependent on matrix polarity. Results obtained for molecules which exhibit infrared-induced isomerisation in matrices are discussed.