New photoactive D-π-A-π-D benzothiadiazole derivative: Synthesis, thermal and photophysical properties

• New π-conjugate compound of type D-π-A-π-D was synthesized with a good yield.
• New π-conjugate compound exhibited absorption maxima at approximately 420 nm.
• Changes in the solvent polarity did not cause a significant solvatochromic effect.
• Compound π-conjugate showed emissions in the blue-green regions.
• The compound type D-π-A-π-D in solution has intense fluorescence emission (ΦF ∼ 0.65).

A new fluorophore containing a 2,1,3-benzothiadiazole unit containing alkylated tetrazoles terminal groups as electron donors connected through a π-conjugated system of type D-π-A-π-D was synthesized and electronically and electrochemically characterized. The compound in solution has an absorption maximum in the visible region (∼417 nm) due to electronic transitions of type 1ππ* (ε ∼ 104 M−1 cm−1) and intense fluorescence emission (ΦF ∼ 0.65) located in the blue-green region depending on the solvent used with a Stokes' shift of ca. 75 nm. Evidences of intramolecular charge transfer character in the excited state was observed from the Lippert–Mataga correlation. The AFM images of the spin-coating depositions of compound 9 using chloroform as solvent on silicon substrate showed the formation of films with clusters. AFM images of the deposition of the acrylic thermoplastic resin doped with 0.05% of 9 showed the formation of a uniform, low-roughness film. Fluorescence emission was shown to be dependent on the method used for the formation of the films.

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