J. Spanget-Larsen

The electronic structure of dibenzotetrathiafulvalene

Abstract The electronic polarization spectrum in stretched polyethylene film and the photoelectron spectrum of dibenzotetrathiafulvalene are reported. The spectra are compared with those of tetrathiafulvalene, and discussed in terms of semi-empirical calculations.

The electronic structure of cyclazines

The electronic structure of cyclopenta[h]cycl[4.2.2]azine (1) has been investigated by means of photoelectron spectroscopy and by polarized electronic absorption spectroscopy in stretched polyethylene sheets at 77 K. The measured transitions have been assigned to transitions calculated by a number of semi-empirical methods. The analysis of the results implies that the essential features of the electronic structure of 1 are well described in terms of those of a planar [14]annulene, perturbed by single-bond cross-links.

Electronic states of the [2 n ]cyclophanes

Low energy singlet and triplet states for a series of [2n]cyclophanes are discussed in terms of the results of a simple model calculation. Experimental trends can be explained under the assumption of significant σ-π interaction involving the saturated bridges. This interaction destabilizes low energy “excimer” states, in contrast to the usual red shift observed for alkylbenzenes. The observed near-constancy of the onset of the absorption spectra can be explained by near-cancelation of through-bond and through-space contributions.