# The curious case of the Coulson conjecture on maximum bond number (Seminar DM)

The curious case of the Coulson conjecture on maximum bond number

Nino Bašić

Torek, 7. oktobra 2014, od 10h do 12h, Plemljev seminar, Jadranska 19

Povzetek: We will revisit a longstanding claim about maximum π bonding in Hückel systems. The maximum sum of Coulson bond orders (i.e., the maximum π bond number) for a carbon centre of an sp2 π system is widely stated to be $\sqrt{3}$. This belief is apparently factually correct, but has not been formally proved. We provide empirical evidence on the behaviour of maximum π bond number as a function of vertex count, n, of chemical graphs and describe the family of graphs that realises local maxima for small n.

This is joint work with Patrick W. Fowler.