THERMOLYSIS OF ETHOXY-5,5-DIMETHYL-TRIANGLE(3)-1,3,4-OXADIAZOLINE STUDIED WITH PHOTOELECTRON-SPECTROSCOPY - HE(I) PHOTOELECTRON-SPECTRUM OFDIMETHOXYCARBENE

Gas phase thermolysis of dimethoxy-5,5-dimethyl-Delta(3)-1,3,4-oxadiaz oline (1) in an ultraviolet photoelectron spectrometer by means of a C W CO, laser as directed heat source at 26 W gave a complex PE spectrum that included ionization bands belonging to acetone, tetramethoxyethy lene (3), and dimethyl oxalate (4). Subtraction of the spectra of acet one, 3, and 4 from the pyrolysis spectrum of 1 left a simple PE spectr um that is attributed to dimethoxycarbene (2) along with some ethane. Becke3LYP/6-31+G calculations gave first adiabatic and vertical ioniz ation potentials of 2 as well as orbital energies that are in perfect agreement with experimental values. From the available experimental an d calculational data, 2 is assumed to adopt a w conformation.