Abstract
Two novel chromogenic 1,3-alternate calix[4]azacrown (1) and calix[4]-bis-azacrown (2) in which an indoaniline chromophore was attached on the nitrogen atom of the azacrown unit with one methylene spacer were synthesized. The 1H NMR spectrum of the ligand 1 and Ca2+ proved that the metal ion is entrapped by the calix[4]azacrown unit and by the conjugated indoaniline system. From the UV/vis band shifts upon metal ion complexation, Zn2+ ion was found to give the largest band shifts compared to other metal cations, indicating that Zn2+ ion (Ka = 18 760 M-1 for 1 and Ka = 19 930 M-1 for 2) was selectively encapsulated by the calix[4]azacrown cavity with assistance of the pendent indoaniline sidearm.
Original language | English |
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Pages (from-to) | 6514-6518 |
Number of pages | 5 |
Journal | Journal of Organic Chemistry |
Volume | 67 |
Issue number | 18 |
DOIs | |
Publication status | Published - 2002 Sept 6 |
Externally published | Yes |
ASJC Scopus subject areas
- Organic Chemistry