Dynamic Uptake and Release of Water in the Mixed-Metal EDTA Complex M3[Yb(EDTA)(CO3)] (M = K, Rb, Cs)

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• 作者：Khai-Nghi Truong ; Paul Müller ; Richard DronskowskiUlli Englert
• 刊名：Crystal Growth & Design
• 出版年：2017
• 出版时间：January 4, 2017
• 年：2017
• 卷：17
• 期：1
• 页码：80-88
• 全文大小：594K
• ISSN：1528-7505

文摘

Ethylenediaminetetraacetic acid (H₄EDTA) acts as a multidentate ligand toward ytterbium nitrate in the presence of M₂CO₃ (M = K, Rb, Cs). All structurally characterized compounds are three-dimensional coordination polymers with eight-coordinated ytterbium and three alkali metal cations in the asymmetric unit. In the presence of potassium cations, two different phase pure reaction products can be obtained. From a water-containing solution, first a water-deficient compound with composition K₃[Yb(EDTA) (CO₃)](H₂O)·H₂O precipitates. When kept in the reaction mixture, this kinetic product transforms into the more water-rich mixed-metal coordination network K₃[Yb(EDTA)(CO₃)](H₂O)₄·2H₂O; alternatively, the conversion can be achieved by isolating the water-deficient product and immersing it into a water-containing solvent. The reverse reaction, partial dehydration, may be induced by prolonged drying in a desiccator, vacuum treatment, or heating. For the heavier alkali cations Rb⁺ and Cs⁺, only one crystalline structure type is found; it is isomorphous to the water-rich potassium derivative. Dehydration leads to amorphous products.