Stability constants for some divalent metal ion/crown ether complexes in methanol determined by polarography and conductometry

Chen, L. and Bos, M. and Grootenhuis, P.D.J. and Christenhusz, A. and Hoogendam, E. and Reinhoudt, D.N. and Linden van der, W.E. (1987) Stability constants for some divalent metal ion/crown ether complexes in methanol determined by polarography and conductometry. Analytica Chimica Acta, 201 . pp. 117-125. ISSN 0003-2670

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Abstract:	Stability constants in methanol at 25.0°C were evaluated for the complexes of the divalent cations Ca2+, Ni2+, Zn2+, Pb2+, Mg2+, Co2+ and Cu2+ with the macrocyclic polyethers 15-crown-5 (15C5), 18-crown-6 (18C6), dicyclohexyl-18-crown-6 (DC18C6) and dibenzo-24-crown-8 (DB24C8). The log K values of the 1:1 complexes were generally in the range 2.1–4.2, which is low in comparison to the values of the corresponding crown ether/alkali metal ion complexes. M2L complexes were observed for the systems Pb2+/18C6, Pb2+/DC18C6, Ca2+/DC18C6 and Cu2+/D18C6, whereas ML2 complexes were found for Ca2+/18C6 and Cu2+/18C6. Within the series of complexes studied, there was no clear relationship between cation diameter and hole size.
Item Type:	Article
Copyright:	© 1987 Elsevier Science
Link to this item:	http://purl.utwente.nl/publications/69877
Official URL:	http://dx.doi.org/10.1016/S0003-2670(00)85330-1
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