Vinylazulenes chromophores: Synthesis and characterization

• DOI: 10.1016/j.dyepig.2016.02.033
• Publication Date: 2016-02-28T17:16:41Z
• Authors: Liviu Birzan; Mihaela Cristea; Constantin C. Dra...; Victorita Tecuceanu; Maria Maganu; Anamaria Hanganu; Alexandru C. Razus; George Octavian B...; Eleonora Mihaela ...
• Keywords: 01 natural sciences; 0104 chemical sciences

Abstract Several vinylazulenes containing heterocyclic units were prepared using Knoevenagel condensation. The condensation took place between electron rich 1-azulenecarbaldehyde derivatives and their vinylogues with heterocycles. The catalysts were chosen in order to catalyze the reaction without giving side reactions, such as heterocycle decomposition or formylazulene decarbonylation. Several NMR signals were briefly discussed. The optical properties of the colored substances were evidenced as a function of their structure. The pH-dependence of the chromophores was evidenced for two compounds; as well as their active solvatochromism. Their electrochemical properties were evaluated from the redox potentials and correlated to their structure.