Chromogenic indoaniline armed-calix[4]azacrowns.
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 (K(a) = 18 760 M(-)(1) for 1 and K(a) = 19 930 M(-1) for 2) was selectively encapsulated by the calix[4]azacrown cavity with assistance of the pendent indoaniline sidearm.
Department of Chemistry, Konyang University, Nonsan 320-711, Korea, Korea. jongskim@konyang.ac.kr
Jong Seung
JS
Kim
Ok Jae
OJ
Shon
Seung Hwan
SH
Yang
Jong Yeol
JY
Kim
Moon Jib
MJ
Kim