Speciation of Copper(II) Complexes in an Ionic Liquid Based on Choline Chloride and in Choline Chloride/Water Mixtures
Speciation of Copper(II) Complexes in an Ionic Liquid Based on Choline Chloride and in Choline Chloride/Water Mixtures
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DOI：
10.1021/ic202341m
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发表时间：
2012-05-07
影响因子：
4.6
通讯作者：
Van Deun, Rik
中科院分区：
文献类型：
--
作者：
De Vreese, Peter;Brooks, Neil R.;Van Deun, Rik
当氯化胆碱与二水合氯化亚铜（II）以1：2的摩尔比混合时，形成具有离子液体性质的深共熔溶剂。EXAFS和UV-vis-near-IR光学吸收光谱已被用来比较铜离子在该离子液体中的配位球与0.1 M的CuCl 2中心点2 H（2）O在溶剂中的溶液中的铜离子的配位球，具有不同的氯化胆碱和水的摩尔比。EXAFS数据表明，在离子液体中存在三个氯离子和一个水分子与铜离子配位的物种，以及两个氯分子和两个水分子与铜离子配位的物种。另一方面，在不含氯化胆碱的水溶液中形成完全水合的铜（II）离子，并且在具有超过50重量%氯化胆碱的氯化胆碱水溶液中形成四氯铜（II）络合物。在具有0和50重量%之间的氯化胆碱的溶液中，出现混合的氯水性络合物。在室温下静置时，在离子液体中形成CuCl 2中心点2 H（2）O和Cu（choline）Cl-3的晶体。Cu（choline）Cl-3是胆碱阳离子与过渡金属离子配位的第一个例子。用分子或离子液体溶剂合成了[胆碱]（3）[CuCl_4][Cl]和[胆碱]（4）[Cu_4Cl_（10）O]晶体，并测定了它们的晶体结构。
A deep-eutectic solvent with the properties of an ionic liquid is formed when choline chloride is mixed with copper(II) chloride dihydrate in a 1:2 molar ratio. EXAFS and UV-vis-near-IR optical absorption spectroscopy have been used to compare the coordination sphere of the cupric ion in this ionic liquid with that of the cupric ion in solutions of 0.1 M of CuCl2 center dot 2H(2)O in solvents with varying molar ratios of choline chloride and water. The EXAFS data show that species with three chloride ions and one water molecule coordinated to the cupric ion as well as species with two chloride molecules and two water molecules coordinated to the cupric ion are present in the ionic liquid. On the other hand, a fully hydrated copper(II) ion is formed in an aqueous solution free of choline chloride, and the tetrachlorocuprate(II) complex forms in aqueous choline chloride solutions with more than 50 wt % of choline chloride. In solutions with between 0 and 50 wt % of choline chloride, mixed chloro aquo complexes occur. Upon standing at room temperature, crystals of CuCl2 center dot 2H(2)O and of Cu(choline)Cl-3 formed in the ionic liquid. Cu(choline)Cl-3 is the first example of a choline cation coordinating to a transition-metal ion. Crystals of [choline](3)[CuCl4][Cl] and of [choline](4)[Cu4Cl10O] were also synthesized from molecular or ionic liquid solvents, and their crystal structures were determined.