INFRARED SPECTROSCOPIC CHARACTERIZATION OF 1-1 MOLECULAR-COMPLEXES OF SO2 WITH BENZENE AND RELATED CONJUGATED PI-ELECTRON DONORS IN ARGON MATRICES

1:1 Molecular complexes of sulfur dioxide with electron donors containing conjugated π electrons have been isolated and characterized in argon matrices. The SO2 subunit was perturbed in each of the complexes, with a shift to lower energy of the symmetric and antisymmetric SO2 stretching modes. At the same time, the bending mode was not perturbed, within the bandwidth of the parent absorption. Certain modes of the base subunit were shifted as well, in a direction which agreed with earlier studies of the HF complexes of these bases. The spectra obtained here are consistent with the recently determined structure of the SO2·C6H6 complex in a supersonic expansion. © 1990.