On distribution of 𝜋–electrons in double linear hexagonal chains

Abstract

In double linear hexagonal chains the distribution of π-electrons into rings (as computed by means of the Randi´c–Balaban method) is highly non-uniform: The electron contents monotonically decrease along each polyacene chain. As a somewhat surprising result we show that the sum of π-electron contents of two adjacent rings, belonging to different polyacene chains of the double chain is constant, irrespective of the nature of the terminal fragments. This regularity is a proper generalization of what earlier was observed for single linear hexagonal chains (polyacenes), and is not extendible to triple, quadruple, etc. linear hexagonal chains.