Bistriazine-based streptocyanines. Preparation, structural determination and optoelectronic properties

•The preparation of streptocyanine based bistriazines is described.•The structure of bistriazines has been studied by NMR, UV–vis and fluorescence.•Computational calculations were employed to account for the reactivity patterns and UV absorption.•These compounds are blue-emitters with large Stokes shifts.

A series of bistriazine-based streptocyanines has been selectively prepared. A variety of substituents has been introduced into the triazine ring with p-phenylenediamine as a conjugated spacer between the triazine and the streptocyanine moieties. Fukui indices have been used to explain the different sequential reactivity of the chlorine atoms in the triazine ring. 1D- and 2D-DNMR spectroscopy and computational calculations have been carried out to explain the dynamic behavior of these complex systems, which can be explained by the presence of a Cl … H bond. This method was used to build conjugated systems and to show the interaction between the triazine part, the spacer, and the streptocyanine moiety. A study of the optoelectronic properties has been performed by UV–vis and fluorescence spectroscopy. Streptocyanine-based bistriazines are violet-blue emitters and large Stokes shifts of more than 6000 cm−1 were observed. The title compounds showed interesting properties which have potential for use in optoelectronic devices.

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