Publications > Vasilev et al
Assembly of New Merocyanine Chromophores with a 1,8-Naphthalimide Core by a New Method for the Synthesis of the Methine Function.
1. Department of Pharmaceutical and Applied Organic Chemistry, Faculty of Chemistry and Pharmacy, University of Sofia, James Bourchier 1, 1164 Sofia, Bulgaria. 2. Max Planck Institute for Polymer Research, PO Box 3148 - D-55021 Mainz, Germany. 3. Departamento de Química Analítica, Química Física e Ingeniería Química, Universidad de Alcalá, 28871 Alcalá de Henares, Madrid, Spain. 4. Departamento de Química Orgánica, Universidad de Alcalá, 28871 Alcalá de Henares, Madrid, Spain.
Abstract
A new method for the synthesis of the monomethine group using nitro as a leaving group in an SN-Ar reaction is described. A series of novel merocyanine dyes has been synthesised and their photophysical properties have been elucidated. The longest wavelength absorption occurs in the range 519–619 nm and the molar absorptivities vary with the substituents and are in the range 1000–47700 L mol–1 cm–1. The dyes show high chemical and photostability. One example from the series has the ability to distinguish methanol from ethanol. The introduction of a quinoid fragment into the structure leads to a pronounced intramolecular charge transfer and hence a noticeable positive solvatochromism. The structures and electronic properties of the compounds have been studied by density functional theory (DFT) and time-dependent DFT.