Highly Sensitive and Selective Colorimetric and Off-On Fluorescent Reversible Chemosensors for Al3+ Based on the Rhodamine Fluorophore

• Main Authors: Naveen Mergu, Ashok Kumar Singh, Vinod Kumar Gupta
• Format: Article
• Language: English
• Published: MDPI AG 2015-04-01
• Series: Sensors
• Subjects: chemosensor; rhodamine; colorimetric; fluorescence; naked-eye detection
• Online Access: http://www.mdpi.com/1424-8220/15/4/9097

A series of rhodamine derivatives L1–L3 have been prepared and characterized by IR, 1H-NMR, 13C-NMR and ESI-MS. These compounds exhibited selective and sensitive “turn-on” fluorescent and colorimetric responses to Al3+ in methanol. Upon the addition of Al(III), the spiro ring was opened and a metal-probe complex was formed in a 1:1 stoichiometry, as was further confirmed by ESI-MS spectroscopy. The chemo-dosimeters L1–L3 exhibited good binding constants and low detection limits towards Al(III). We also successfully demonstrate the reversibility of the metal to ligand complexation (opened ring to spirolactam ring).