Studies on rhodamine and pyrazoline based aluminum ion selective fluorescent chemosensor

Abstract

The aim of the thesis is concerned with development and synthesis of five different rhodamine and pyrazoline based receptors (R1-R5) for selective detection of Al3+ ion over other metal ions through naked eye as well as fluorometric method. These receptors display an excellent selective and sensitive response towards Al3+ ion over other metal ions. Among them, receptors R1 and R2 are rhodamine based chemosensors, the colorimetric response of Al3+ ion demonstrates from colorless to pink with strong fluorescence, it can be conveniently detected even by naked eye and both can serve as Turn- Onand#8223; sensor for Al3+ ion. The receptor R3 is pyrene appended pyrazoline based chemosensor, upon binding with Al3+ ion; exhibits color change from colorless to green with strong green emission, R3 can be used as selective Turn-Onand#8223; sensor for Al3+ ion. The receptors R4 and R5 are thiophene and furan appended pyrazoline based receptors, upon addition of Al3+ ion the fluorescence nature of receptor gradually decreased. Receptors R4 and R5 can be used as selective Turn-Offand#8223; sensor for Al3+ ion. The synthesized materials were subjected to standard characterization techniques such as FT-IR, 1H-NMR, 13C-NMR, and ESI-MS. The optical properties of the materials were examined by UV-visible and fluorescence spectrophotometers. newline