Formaldoxime dimers: Infrared matrix isolation and theoretical study

The infrared spectra of the formaldoxime dimers, trapped in argon matrices at ca. 17 K have been obtained and compared with the theoretical spectra provided by the MP2/6-311++G(2d,2p) calculations. The calculations indicated stability of three hydrogen bonded dimers. The most stable, centrosymmetric C2h dimer involves two OH⋯N bonds, the other one is stabilized by one OH⋯N bond and the less stable dimer involves one OH⋯O bond. The comparison of the theoretical spectra with the experimental ones evidences that in the matrix is formed mainly the centrosymmetric dimer; however there is some evidence that the dimer with one OH⋯N bond is also trapped in the matrix at very low concentration.