ELECTRONIC-STRUCTURE STUDY OF PLANAR CONJUGATED 8-MEMBERED RING COMPOUNDS

The structure and electronic properties of sym-dibenzo-1,3,5-cycloocta trien-7-yne, its dianion and two more related structures are studied f rom a theoretical point of view. The geometries obtained by theoretica l routes are in good agreement with those reported from X-ray studies, and there is a better agreement when the calculation is carried out a t the HF/3-21G level than when MP2/3-21G is applied. The HOMO-LUMO com binations are shown and a brief discussion of the aromaticity of all t he compounds is presented.