New 1,8-naphthyridine-based probes for the selective fluorescence signalling of toxic cadmium: synthesis,photophysical studies and molecular modelling |
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| Authors: | Sabir H. Mashraqui Rupesh Betkar Mukesh Chandiramani Kiran Poonia David Quinonero Antonio Frontera |
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| Affiliation: | 1. Department of Chemistry , University of Mumbai , Vidyanagari, Santacruz-E, Mumbai, 400098, India sh_mashraqui@yahoo.com;3. Department of Chemistry , University of Mumbai , Vidyanagari, Santacruz-E, Mumbai, 400098, India;4. Department of Quimica , Universitat de les Illes Balears , Crta. De Valldemossa km 7.5, 07122, Palma, Baleares, Spain |
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| Abstract: | Newly synthesised 1,8-naphthyridine-based molecular probes, NAP-1 and NAP-2, exhibit highly selective fluorescence responses towards the toxic cadmium over coordinatively competing Zn2+ and several other metal ions examined. On the one hand, NAP-1 (MeOH:H2O, v/v 80:20, pH 7.4) exhibits ca. 1.5 order of magnitude higher stability constant for Cd2+ over Zn2+; on the other hand, NAP-2 in MeOH offers unique selectivity only towards Cd2+, exhibiting both absorbance and emission red shifts as well as fluorescence enhancement. By 1H NMR analysis, the tetra-coordinated binding is indicated at least for the NAP-1+Cd2+ complex and theoretical calculations reveal relatively stronger binding of Cd2+ over Zn2+.  |
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| Keywords: | 1,8-naphthyridine fluorophore photophysical studies fluorescent cadmium sensors NMR analysis molecular modelling |
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