Synthesis and photophysical study of novel coumarin based styryl dyes

• Novel coumarin based highly fluorescent styryl compounds were prepared.
• Stereochemistry of double bond depends upon the type of substitution.
• These dyes show brilliant color in daylight.
• Synthesized compounds studied for UV–Vis absorption and show solvatochromism.

New organic dyes comprising phenothiazine, carbazole, indole, diphenylamine moieties, as the electron donors, and coumarin ring as the electron acceptor through ethylenic π bridge were synthesized and characterized. The reaction of different coumarin-4-acetic acids with phenothiazine-3-carbaldehyde in the presence of piperidine in methanol gives highly fluorescent styryl derivatives having cis configuration of ethylenic double bond. Under similar conditions 7-methylcoumarin-4-acetic acid was condensed with indole-3-carbaldehyde, carbazole-3-carbaldehyde, and diphenyl amine aldehyde to give different styryl derivatives with trans configuration of ethylenic double bond. Synthesized compounds were also studied for photophysical properties and show solvatochromism.

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