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Description:

Five merocyanine derivatives with a 5,10-diphenyl-dihydrophenazine donor and various indanone and indandione based acceptors with one or two dicyanovinylene groups were prepared by Knoevenagel condensation for tuning absorption and fluorescence in near infrared region. Molecular conformation, bond length alternation and molecular packing in the solid-state were studied by X-ray diffraction of single crystals in combination with density functional theory calculations. By enhancing electron accepting ability, considerable decrease of LUMO energy by 1.01 eV and retained HOMO energy within 0.13 eV were estimated by cyclic and rotating disc electrode voltammetry, relating semi-quantitatively to DFT prediction. Optical properties in solutions with various polarity, neat amorphous films, and crystalline powder states were studied. The absorption maxima of the neat films evolved from 545 nm to 931 nm. Ultranarrow optical band gap of DPPZ-IDD (1.09 eV) was found from the onset of thin film absorption and well agreed with electrochemical gap of 0.93 eV. Detectable fluorescence in the NIR region was observed in the film and polycrystalline powder states.

Rights:

• Creative Commons BY-NC-ND Attribution-NonCommercial-NoDerivs 4.0 International
  

Keyword: chromophore, dihydrophenazines, merocyanine, narrow bandgap, NIR emission

Date published: 2025-07-25

Publisher: Wiley

Journal:

• CHEMISTRY-A EUROPEAN JOURNAL (ISSN: 15213765) vol. 31 issue. 42

Funding:

• National Institute for Materials Science
• Grantová Agentura České Republiky 24–10479S
• Grantová Agentura České Republiky 24–10479S
• Grantová Agentura České Republiky 24‐10479S
• Grantová Agentura České Republiky e‐INFRA CZLM2018140
• Ministerstvo Školství, Mládeže a Tělovýchovy
• Grantová Agentura České Republiky 24–10479S
• Grantová Agentura České Republiky 24–10479S
• Grantová Agentura České Republiky 24‐10479S

Manuscript type: Publisher's version (Version of record)

MDR DOI:

First published URL: https://doi.org/10.1002/chem.202501864

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Updated at: 2025-07-29 12:30:33 +0900

Published on MDR: 2025-07-29 12:21:26 +0900