PHOTOELECTRON-SPECTRUM AND QUANTUM-CHEMICAL ANALYSIS OF THE STRUCTUREOF BIS(1,3,6-TRIMETHYLURACILYL-5)METHANE

Photoelectron spectra of bis(1,3,6-trimethyluracilyl-5)methane (I) and 1,3,6-trimethyluracil (II) were studied; AM1 optimization of geometri c characteristics was carried out. The total energy minimum and the be st agreement between the values of IPm and -epsilon(m) were obtained f or conformations with nearly orthogonal location of uracilyl fragments . In such conformations the highest occupied orbitals are pseudodegene rate. To interpret the photoelectron spectra, we employed ab initio ca lculations in STO-3G and 4-31G basis sets. For uracil and its derivati ves, all methods give the pi, pi, n(-), n(+), pi sequence of the highe st orbitals.