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Updated: Oct 9, 2026

Green Synthesis of Quinoline-Based Ionic Liquid
Published on: September 27, 2024
Complex formation in the indolo[2,3-b]quinolines--methylene blue systems in aqueous solutions
N Sadlej-Sosnowska1, L Kaczmarek, K Rotkiewicz
1Drug Institute, Warsaw, Poland. sadlej@il.waw.pl
Abstract:
Changes in the absorption spectra of methylene blue (MB) aqueous solutions containing an indoloquinoline can be described by assuming complex formation between MB and the indolinoquinoline. At the low concentration range of the two reactants a simple 1:1 complex stoichiometry was postulated on the basis of the Benesi-Hildebrand, Scott and Scatchard linearization of spectroscopic data and augmented by the formation of an isosbestic point. The estimated association constants were correlated with the ab initio calculated electronic properties of indolo[2,3-b]quinolines.
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Structural Isomerism
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can be...

