Dehydration of Octacyanido-Bridged NiII-WIV Framework toward Negative Thermal Expansion and Magneto-Colorimetric Switching
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- 作者：Mateusz Reczyński ; Szymon Chorazy ; Beata Nowicka ; Barbara Sieklucka ; Shin-ichi Ohkoshi
- 刊名：Inorganic Chemistry
- 出版年：2017
- 出版时间：January 3, 2017
- 年：2017
- 卷：56
- 期：1
- 页码：179-185
- 全文大小：442K
- ISSN：1520-510X
文摘
An inorganic three-dimensional [NiII(H2O)2]2[WIV(CN)8]·4H2O (1) framework undergoes a single-crystal-to-single-crystal transformation upon thermal dehydration, producing a fully anhydrous phase NiII2[WIV(CN)8] (1d). The dehydration process induces changes in optical, magnetic, and thermal expansion properties. While 1 reveals typical positive thermal expansion of the crystal lattice, greenish-yellow color, and paramagnetic behavior, 1d is the first ever reported octacyanido-based solid revealing negative thermal expansion, also exhibiting a deep red color and diamagnetism. Such drastic shift in the physical properties is explained by the removal of water molecules, leaving the exclusively cyanido-bridged bimetallic network, which is accompanied by the transformation of the octahedral paramagnetic [NiII(H2O)2(NC)4]2– to the square-planar diamagnetic [NiII(NC)4]2– moieties.