کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5230250 | 1383689 | 2007 | 5 صفحه PDF | دانلود رایگان |
The article describes the syntheses and complexation properties of new calixarene-based extractants, which have been synthesized from 5,11,17,23-tetra-tert-butyl-25,26,27-tris(chlorocarbonylmethoxy)-28-hydroxycalix[4]arene and 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrakis(chlorocarbonylmethoxy)calix[4]arene by treatment with isoniazid (isonicotinic acid hydrazide) in the presence of pyridine, respectively. p-tert-Butylcalix[4]arene teraamide was converted to its methyl iodide salt by refluxing with methyl iodide in acetonitrile. In this synthesis it was thought to explore the role of pyridinium sites in the extraction of HCr2O7â/Cr2O72â anions. The complexing properties of the extractants toward selected alkali/transition metal cations and HCr2O7â/Cr2O72â anions are reported. It has been observed that both receptors do not extract alkali metal cations but show excellent selectivity toward transition metals. The protonated pyridinium forms of the receptors are effective for transferring the HCr2O7â/Cr2O72â anions from an aqueous into a dichloromethane layer.
The article describes the synthesis and evaluation of alkali/transition metal cations and dichromate anion extraction abilities of new 'proton-switchable' tri- and tetra-substituted p-tert-butylcalix[4]arene amides (8 and 9) bearing pyridinium moieties.
Journal: Tetrahedron - Volume 63, Issue 29, 16 July 2007, Pages 6861-6865