Tabakcı, MustafaMemon, ShahabuddinYılmaz, MustafaRoundhill, D. Max2020-03-262020-03-262003Tabakcı, M., Memon, S., Yılmaz, M., Roundhill, D. M., (2003). Synthesis and Extraction Studies of a Versatile Calix[4]arene-Based "Proton-switchable Extractant" for Toxic Metals and Dichromate Anions. Journal of Inclusion Phenomena and Macrocyclic Chemistry, 45(3-4), 265-270.1388-31271573-1111https://hdl.handle.net/20.500.12395/18574The article describes the syntheses and extraction properties of a new calixarene based extractant 5, which has been synthesized from 5,11,17,23-tetra-tert-butyl-25,27-bis(chlorocarbonyl-methoxy)-26,28-dihydroxycalix[4]arene (4) by treatment with isoniazid (isonicotinic acid hydrazide) in the presence of pyridine. The compound 5 was converted to its methyl iodide salt (6) by refluxing 5 with methyl iodide in acetonitrile. In this synthesis it was thought to explore the role of pyridinium sites in the extraction of HCr2O7-/Cr2O72- anions. The complexing properties of 5 toward selected alkali/transition metal cations and HCr2O7-/Cr2O72- anions are reported. It has been observed that receptor 5 does not extract alkali metal cations but shows an excellent selectivity toward transition metals. The protonated pyridinium form of 5 is an effective form for transferring the HCr2O7-/Cr2O72- anions from an aqueous into a dichloromethane layer.eninfo:eu-repo/semantics/openAccessCalixareneSolvent extractionAlkali and transition metalsDichromate anionsArticle453-4265270Q3WOS:000183943500013Q2