摘要:
                                Three amino(polyphenolic) ligands, N,N'-bis(5-tert-butyl-2-hydroxybenzyl)-1,2-diaminoethane 1, tris(5-tert-butyl-2-hydroxy-3-methylbenzyl)amine 3, its 3-chloro analogue 4 and their Zr-IV complexes have been synthesised. The crystal structure of the Zr-IV complex of tris (5-tert-butyl-3-chloro-2-hydroxybenzyl)amine, shows this to be [Zr(4-2H)(2)] in which both ligands exists in a zwitterionic form with one alkylarnmonium and three phenolate groups. The complexes are stable in a two phase, chloroform/water, system at high pH, but the zirconium is stripped at pH < 2.5. The pH value needed to strip 50% of the Zr-IV from the complex [Zr(1-4H)] of the tetraphenolic ligand is similar to 2.0 whilstthe complexes [Zr(3-2H)(2)]and [Zr(4-2H)(2)] of the triphenolic ligands are slightly more stable with pH(1/2) values of similar to 1.4. We were unable to use the ligands to extract zirconium from low pH aqueous zirconium oxychloride solutions into an organic phase under a variety of conditions. (c) 2007 Elsevier B.V. All rights reserved.