X-Ray Diffraction and Mössbauer Spectroscopy Studies of Pressure-Induced Phase Transitions in a Mixed-Valence Trinuclear Iron Complex.
X-Ray Diffraction and Mössbauer Spectroscopy Studies of Pressure-Induced Phase Transitions in a Mixed-Valence Trinuclear Iron Complex.
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混合价三核铁配合物中压力诱导相变的 X 射线衍射和穆斯堡尔谱研究。
DOI：
10.1002/chem.201600718
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
B. Iversen
中科院分区：
文献类型：
--
作者：
S. R. Madsen;H. P. Gunnlaugsson;S. Moggach;E. Eikeland;Lai;O. Leupold;J. Overgaard;B. Iversen
用单晶X射线衍射分析和同步辐射穆斯堡尔谱学研究了混合价态配合物Fe3O（cyanoacetate）6（H2O）3（1），压力分别为5.3（1）GPa和8（1）GPa。 在4.0（1）GPa的压力下，晶体结构得到了细化。 在此压力范围内，1经历两次压力诱导相变。在约3GPa下的第一相变是等对称的，并且涉及50%的氰基乙酸酯配体的60°旋转。 在4GPa附近的第二相变使对称性从菱面体降低到三斜。 穆斯堡尔谱表明配合物在第二次相变后变成部分价态俘获。这种缓慢的压力诱导的价态俘获与化合物1在环境压力下从130 K冷却至120 K时观察到的非常突然的价态俘获相反。
The mixed-valence complex Fe3 O(cyanoacetate)6 (H2 O)3 (1) has been studied by single-crystal X-ray diffraction analysis at pressures up to 5.3(1) GPa and by (synchrotron) Mössbauer spectroscopy at pressures up to 8(1) GPa. Crystal structure refinements were possible up to 4.0(1) GPa. In this pressure range, 1 undergoes two pressure-induced phase transitions. The first phase transition at around 3 GPa is isosymmetric and involves a 60° rotation of 50 % of the cyanoacetate ligands. The second phase transition at around 4 GPa reduces the symmetry from rhombohedral to triclinic. Mössbauer spectra show that the complex becomes partially valence-trapped after the second phase transition. This sluggish pressure-induced valence-trapping is in contrast to the very abrupt valence-trapping observed when compound 1 is cooled from 130 to 120 K at ambient pressure.