Influence of ortho group in rhodamine B hydrazide based Schiff base for selective recognition of Cu2+ and Fe3+ ions: A mechanistic approach by DFT and colorimetric studies.

[Display omitted] • Can select the sensor molecules for the selective recognition of Cu2+ and Fe3+ ions before their synthesis. • The use of chemicals will be controlled in this approach. • The effect of ortho -substituents or heteroatom must play a vital role in selective recognition process. • The mechanism of metal ion recognition was established via theoretically and spectroscopic methods. Herein we have implemented a computational approach in designing sensor molecules for the selective recognition of Cu2+ and Fe3+ ions. Seven rhodamine B hydrazide-based Schiff base derivatives were designed and analysed their chemosensing properties against Cu2+ and Fe3+ ions in ethanol solution theoretically. The theoretical calculations revealed that the selective recognition of Cu2+ and Fe3+ ions takes place via spirolactam ring-opening and there is a pivotal role of ortho substituents and N -heteroatoms. The two best chemosensors were synthesised and used for the detection of Cu2+ and Fe3+ ions by colorimetric methods. [ABSTRACT FROM AUTHOR]