Lower rim 1,3-di-amide-derivative of calix[4]arene possessing bis-{N-(2,2′-dipyridylamide)} pendants: a dual fluorescence sensor for Zn2+ and Ni2+

✍ Scribed by Roymon Joseph; Balaji Ramanujam; Haridas Pal; Chebrolu P. Rao

• Book ID: 104095748
• Publisher: Elsevier Science
• Year: 2008
• Tongue: French
• Weight: 458 KB
• Volume: 49
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/j.tetlet.2008.08.049

✦ Synopsis

switch-on by Zn 2+ Fluorescence switch-off by Ni 2+ Lower rim 1,3-di-amide-derivative of calix [4]arene .

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Single crystal XRD structure of the lower rim 1,3-di-amide-derivative of calix[4]arene possessing bis-{N-(2,2 0 -dipyridylamide)} pendants (L) exhibit two distinct binding cores, viz., N 4 and O 6 . L was found to be selective for Zn 2+ by switch-on and for Ni 2+ by switch-off fluorescence by forming 1:1 complexes. The binding and the composition of the complex formed have been addressed based on steady state and time-resolved fluorescence spectroscopy in addition to the absorption and ESI MS. As L can detect Zn 2+ and Ni 2+ to a concentration as low as 142 and 203 ppb, respectively, L can be a very sensitive molecular probe for these ions. The coordination details of the metal ion-bound complexes have been addressed based on ab initio calculations showing that the stabilization energies are commensurate with the coordination formed.