THE MICROWAVE SPECTRA AND CONFORMATION OF 3,6 DIHYDRO-2H PYRAN AND 2,3 DIHYDRO-p-DIOXIN (DIOXENE)

This research was supported by the petroleum Research Fund, American Chemical Society and by the Biological and Physical Science Research Institute, Mississippi State University.Author Institution: Department of Physics, Mississippi State University, Mississippi State, Mississippi, 39762.The microwave spectra of 3,6 Dihydro-2H pyran (I) and 2,3 Dihydro-p-dioxin (II) have been studied from 26.5 to 40.0 GHz with a Hewlett packard 8400 Microwave Spectrometer. [FIGURE] The spectra have been assigned for each molecule in the ground state and several vibrationally excited states. The ground state rotational constants are (in MHz) (I) A = 5086.20, B = 4848.41, C = 2712.50, and (II) A = 5697.70, B = 4968.41, C = 2865.17. The data are consistent with twisted ring structures with the twist angle being approximately $30^{\circ}$ in both cases. Studies of the Stark effect are in progress