ELECTRON DONOR-ACCEPTOR COMPLEX OF ICL WITH DIETHYL-ETHER - HE-I PHOTOELECTRON-SPECTROSCOPY AND AB-INITIO MOLECULAR-ORBITAL STUDY

The He I photoelectron spectrum of the diethyl ether-ICl complex has b een obtained. The oxygen orbitals are shifted to higher binding energi es and that of ICl to lower binding energies owing to complex formatio n. Ab initio molecular orbital (MO) calculations of the complex molecu le showed that the bonding is between the sigma-type lone pair of oxyg en and the I atom and that the complex has C-2v symmetry. The binding energy of the complex is computed to be 8.06 kcal mol(-1) at the MP2/3 -21G level. The orbital energies obtained from the photoelectron spec tra of the complex are compared and assigned with orbital energies obt ained by MO calculations. Natural bond orbital analysis (NBO) shows th at charge transfer is from the sigma-type oxygen lone pair to the iodi ne atom and the magnitude of charge transfer is 0.0744 e.