10min:

YOSHIO TATAMITANI, YASUFUMI SUZUKI, TERUHIKO OGATA, Department of Chemistry,
Faculty of Science, Shizuoka University, Shizuoka, Japan 422-8529.

The microwave spectra of van der Waals complexes of dimethy ether(DME) dimer and dimethy ether Ar have been studied. Following these investigations, the complexes of dimethyl ether and 1,2-difluoroethane(DFE)/ trifluoroethene(TFE) (CH₃)₂O CF₂=CH₂ and (CH₃)₂O CF₂=CHF have been observed using a Fourie transform microwave spectrometer from 5 to 19 GHz. The samples of 1% DME/DME-d₆ and DFE/TFE in Ar were used to form the complexes in a super sonic expansion. For normal DME DFE, 37 a-type transitions were assigned and 87 a- and b-type transitions were assigned for normal DME TFE. Rotational and centrifugal distortion constants have been determined for these complexes of normal and -d₆ species, leading to molecular structures. Both complexes were found to be C_s symmetry and bound with triple hydrogen bonds: One is the strong O HC type and two are the weaker CH F type. The structures of both complexes are similar, however, the hydrogen bond lengths and bond angles are different. Ab initio MO calculations of MP2/6-311+G(d,p) lebel have been made for these complexes, the structure obtained supported the experimental results and the bonding energies for these complexes were compared.