Aminoalkylbis(phosphonates):: Their complexation properties in solution and in the solid state
Aminoalkylbis(phosphonates):: Their complexation properties in solution and in the solid state
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DOI：
10.1002/ejic.200600615
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发表时间：
2007-01-01
影响因子：
2.3
通讯作者：
Lukes, Ivan
中科院分区：
文献类型：
--
作者：
Kubicek, Vojtech;Kotek, Jan;Lukes, Ivan
合成了碳链α、γ、δ位含氨基的五种偕双膦酸盐，并通过电位测定法研究了它们的酸碱性质以及与Cu2+、Zn2+、Ca2+、Mg2+和Na+离子的络合性质。二价金属离子配合物的稳定常数的测定因沉淀物的形成而变得复杂。这些研究的结果表明α位置的羟基对配体的酸碱和络合性质的影响可以忽略不计。然而，α位氨基的存在降低了碱性，这导致双(膦酸盐)的络合能力较低。具有不同质子化程度的三种配体的晶体结构也已确定。氨甲基双（膦酸）的三铵盐的结构表明，质子与单质子化物质中的氮原子结合。帕米膦酸的 Cu2+ 配合物 [{Cu-2(H(2)pam)(2)}中心点 H2O](n) 的结构表明存在金属中心之间距离相对较短（2.99 埃）的二聚体单元。这些单元形成配位聚合物链。 （(c) Wiley-VCH Verlag GmbH & Co. KGaA，69451 魏因海姆，德国，2007 年）
Five geminal bis(phosphonates) containing an amino group in the alpha, gamma or delta position of the carbon chain have been synthesised and their acid-base and complexation properties with Cu2+, Zn2+, Ca2+, Mg2+ and Na+ ions studied by potentiometry. Determination of the stability constants of the complexes with divalent metal ions is complicated by the formation of precipitates. The results of these studies show a negligible effect of the hydroxo group in the a position on the acid-base and complexation properties of the ligands. The presence of an amino group in the alpha position, however, decreases the basicity, which results in a lower complexation ability of the bis(phosphonates). The crystal structures of the three ligands with different degrees of protonation have also been determined. The structure of the triammonium salt of aminomethylbis(phosphonic acid) shows that the proton is bound to the nitrogen atom in monoprotonated species. The structure of the Cu2+ complex of pamidronate [{Cu-2(H(2)pam)(2)}center dot H2O](n) shows the presence of dimeric units with a relatively short distance (2.99 angstrom) between the metal centres. These units form a coordination polymeric chain. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)