Topological Approach to the Chemistry of Conjugated Molecules

"The second step is to determine constitution, Le. which atoms are bonded to which and by what types of bond. The result is ex­ pressed by a planar graph (or the corresponding connectivity mat­ rix) •••• In constitutional formulae, the atoms are represented by letters and the bonds by lines. They describe the topology of the molecule." VLADIMIR PRELOG, Nobel Lecture, December l2;h 1975. In the pre...