title: Diazo-coupled calix[4]arenes for qualitative analytical screening of metal ions.
abstract: New chromogenic diazophenylcalix[4]arenes 1 and 2 were synthesized in cone conformation. Compound 1 with the ortho-carboxyl groups in CH(3)CN solution preferentially binds with alkaline earth and transition metal ions, whereas no significant changes in absorption spectra are observed in the presence of alkali metal ions. While 2 with the ortho-ester groups shows selective complexation properties towards transition metal ions over alkali and alkaline earth metal ions. The detection of metal ions gives rise to bathochromic shifts in the absorption spectra (from orange/yellow to red), which is clearly visible even to the naked eye. According to the selective color changes using both receptors upon cation complexation, one can set up a qualitative analytical routine to screen alkali, alkaline earth, and transition metal ions.
authors: Department of Chemistry, Seoul National University, Seoul 151-747, Republic of Korea.
authors: Tae Hyun
authors: TH
authors: Kim
authors: Su Ho
authors: SH
authors: Kim
authors: Le Van
authors: le V
authors: Tan
authors: Yunyan
authors: Y
authors: Dong
authors: Hasuck
authors: H
authors: Kim
authors: Jong Seung
authors: JS
authors: Kim
mesh_terms: D047250:Calixarenes / Q000737:chemistry*; D003116:Color; D003979:Diazonium Compounds / Q000737:chemistry*; D008670:Metals / Q000032:analysis*; D008672:Metals, Alkali / Q000032:analysis; D008673:Metals, Alkaline Earth / Q000032:analysis; D010636:Phenols; D013057:Spectrum Analysis; D013329:Structure-Activity Relationship; D028561:Transition Elements / Q000032:analysis
chemical_list: D003979:Diazonium Compounds; D008670:Metals; D008672:Metals, Alkali; D008673:Metals, Alkaline Earth; D010636:Phenols; D028561:Transition Elements; C121325:calix(4)arene; D047250:Calixarenes