CONFORMATIONAL-ANALYSIS OF MOLECULAR-COMPLEXES BETWEEN SODIUM AND 1,2-DIMETHOXYETHANE - PHOTOIONIZATION AND AB-INITIO MOLECULAR-ORBITAL STUDIES

The molecular complexes formed between sodium and 1,2-dimethoxyethane (DME), Na(DME) and Na-2(DME), were generated in a flow reactor and stu died with photoionization mass spectroscopy. The photoionization thres hold energies of these complexes, which are dependent on the complex c onformations, were obtained from the analysis of the photoionization e fficiency spectra. Ab initio molecular orbital calculations were perfo rmed on the possible conformers of these complexes and their correspon ding ionic states. With the help of theoretical calculations, the phot oionization threshold for the cyclic conformers of Na(DME) was determi ned to be 3.80 +/- 0.02 eV. For the Na-2(DME) complex, the photoioniza tion threshold of the cyclic conformers was determined to be 4.16 +/- 0.02 eV. The conformation-dependent bond dissociation energies and the photoionization threshold energies could be rationalized and classifi ed in terms of the sodium-Lewis base bonding and the intramolecular 1, 5 CH3/O electrostatic interaction of 1,2-dimethoxyethane.