The Influence of the Intramolecular 2D Interactions on the Physicochemical Properties of Hexasubstituted Benzene Derivatives

This paper contains a comprehensive study regarding the synthesis and physicochemical properties of new hexasubstitued benzene derivatives. In this work, three compounds of this type (including two electropolymerisable monomers) were synthesized in a one-step reaction with good yields ranging from 34% to 56%. A thermal investigation shows that this type of compound is stable up to 360 °C (10% weight loss temperature). The influence of the substituents in the first and second position of the central benzene on the stability, luminescence, and (spectro)electrochemical behavior was thoroughly studied with the aid of theoretical calculations. In each case, strong blue shifting of the π-π* transition (according to 1,4-disubstitued analogs) was observed, proving this moieties’ orthogonal orientation. In the case of derivatives with a Bt-core-Bt formula (where Bt = 2,2′-bithiophene-5-yl), an electrochemical oxidation process transformed them into conducting polymers. The polymer presents extraordinary stability during multiple p-doping; thus, spectroelectrochemical measurements of polymeric films were also performed.