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首页> 外文期刊>Dalton transactions: An international journal of inorganic chemistry >Coordination properties of cyclam (1,4,8,11-tetraazacyclotetradecane) endowed with two methylphosphonic acid pendant arms in the 1,4-positions
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Coordination properties of cyclam (1,4,8,11-tetraazacyclotetradecane) endowed with two methylphosphonic acid pendant arms in the 1,4-positions

机译：在1,4-位带有两个甲基膦酸侧链的环素（1,4,8,11-四氮杂环十四烷）的配位性能

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摘要

The title ligand, 1,4,8,11-tetraazacyclotetradecane-1,4-diyl-bis(methylphosphonic acid) (H(4)te(2)p(1,4), H4L), was prepared by an optimized synthetic approach and its complexing properties towards selected metal ions were studied by means of potentiometry. The ligand forms a very stable complex with copper(II) (log beta(CuL) = 27.21), with a high selectivity over binding of other metal ions (e. g. log beta(ZnL) = 20.16, log beta(NiL) = 21.92). The crystal structures of two intermediates in the ligand synthesis and two forms of the nickel(II) complex (obtained by crystallization at different pH) were determined. From acid solution, the crystals of trans-O, O-[Ni(H3L)] Cl center dot H2O were isolated. In such complex species, one phosphonate pendant arm is double-and the second arm is monoprotonated. The isolation of such species demonstrates a high kinetic inertness of the complex. The central metal ion is surrounded by four in-plane nitrogen atoms (in the ring configuration III) and two oxygen atoms of pendant moieties in the apical positions of octahedral coordination sphere. From neutral solution, the crystals of {trans-O, O-[Ni(H2L)]}(3)center dot 5H(2)O were isolated. The molecular structures of the complex units found in this structure are analogous to that found in trans-O, O-[Ni(H3L)] Cl center dot H2O.
机译：通过优化的合成方法制备了标题配体1,4,8,11-四氮杂环十四烷-1,4-二基-双（甲基膦酸）（H（4）te（2）p（1,4），H4L）电位法研究了该方法及其对所选金属离子的络合性能。配体与铜（II）形成非常稳定的络合物（log beta（CuL）= 27.21），对其他金属离子的结合具有很高的选择性（例如log beta（ZnL）= 20.16，log beta（NiL）= 21.92） 。确定了配体合成中两种中间体和两种形式的镍（II）配合物（通过在不同pH下结晶获得）的晶体结构。从酸性溶液中分离出反式-O，O- [Ni（H3L）] Cl中心点H2O的晶体。在这种复杂的物种中，一个膦酸酯侧链是双链的，第二个是单质子化的。此类物质的分离证明了该复合物的高动力学惰性。中心金属离子在八面体配位球体的顶端被四个面内氮原子（呈环状结构III）和两个悬垂基团的氧原子包围。从中性溶液中分离出{反式-O，O- [Ni（H 2 L）]}（3）中心点5H（2）O的晶体。在该结构中发现的复杂单元的分子结构与在反式-O，O- [Ni（H3L）] Cl中心点H2O中发现的类似。

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