Lanthanoid Complexation by a Tris-Tetrazole-Functionalised Calix[4]arene
The synthesis and characterization of 5,11,17,23-tetra-tert-butyl-25-hydroxy-26,27,28-tris(tetrazol-5-ylmethoxy)calix[4]arene is reported. Purification of the macrocycle required the use of preparative HPLC techniques. The macrocycle was found to be a poorer ligand for complexation of lanthanoid cat...
| Main Authors: | , , , , , , |
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| Format: | Journal Article |
| Published: |
Wiley - V C H Verlag GmbH
2016
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| Online Access: | 833 http://hdl.handle.net/20.500.11937/44728 |
| Summary: | The synthesis and characterization of 5,11,17,23-tetra-tert-butyl-25-hydroxy-26,27,28-tris(tetrazol-5-ylmethoxy)calix[4]arene is reported. Purification of the macrocycle required the use of preparative HPLC techniques. The macrocycle was found to be a poorer ligand for complexation of lanthanoid cations than the bis(tetrazole) analogue, but somewhat more effective than the tetrakis(tetrazole)-substituted derivative. Two metal complexes of the tris(tetrazole)-calixarene were structurally characterised. A polymeric sodium salt of the tris(tetrazole)-calixarene was isolated from a solution containing yttrium and a sodium acetate buffer. A praseodymium complex was isolated in the presence of an ammonium acetate buffer, where the calixarene acts as a unidentate ligand, bound to the metal atom through one tetrazole N-atom. Increasing the amount of buffer resulted in the crystallisation of a metal-free ammonium salt of the calixarene. |
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