Spin crossover and reversible single-crystal to single-crystal transformation behaviour in two cyanide-bridged mixed-valence {(Fe2Fe2II)-Fe-III} clusters
Spin crossover and reversible single-crystal to single-crystal transformation behaviour in two cyanide-bridged mixed-valence {(Fe2Fe2II)-Fe-III} clusters
复制标题
两个氰化物桥混合价{(Fe2Fe2II)-Fe-III}簇中的自旋交叉和可逆单晶到单晶转变行为
DOI：
10.1039/c6dt03436e
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发表时间：
2016
影响因子：
4
通讯作者：
Li Dongfeng
中科院分区：
文献类型：
--
作者：
Zheng Chunyang;Xu Juping;Wang Feng;Tao Jun;Li Dongfeng
三氰基金属酸盐前体的反应，（Ph3PMe）[（Tp4-Me）Fe（CN）3·0.5CH3CN]（1）（Tp 4-Me =三（4-甲基-吡唑-1-基）硼酸酯）和（NBu 4）[（MeTp）Fe（CN）3]（MeTp =甲基三（吡唑基）硼酸酯），存在四齿tpa配体（tpa =三（2-吡啶甲基）胺）和Fe（ClO_4）_2·6H_2O得到了两个新的氰基桥联的混合价{FeIII_2FeII_2}分子正方形：[（Tp4-Me）FeIII（CN）3]2[FeII（tpa）]2·2ClO4·H2O（2·H2O）和[（MeTp）FeIII（CN）3]2[FeII（tpa）]2·2ClO4·CH3OH（3·CH3OH）。还得到了溶剂交换化合物3·CH_3OH，[（MeTp）Fe_III（CN）_3]_2[Fe_II（tpa）]_2·2ClO_4·2 H_2 O（3·2 H_2 O），以及它们的无溶剂形式（2和3）。所有化合物的自旋交叉（SCO）的属性确认通过详细的结构分析的Fe II中心和磁化率测量的协调环境。所有化合物在室温附近均表现出SCO行为（T1/2 = 320 K（2·H2O）; 302 K（2）; 292 K（3·CH 3OH）; 306 K（3·2 H2O）和290 K（3））以及由客体解吸和再吸收或溶剂交换诱导的可逆单晶到单晶（SC-SC）转变。可以通过脱水和再水化过程调节接近室温的转变温度。结构-性质分析揭示了扭曲的{Fe 4（μ-CN）4}核和弯曲的Fe-NC角的偏差在调节这些类似的混合价{FeIII 2FeII 2}配合物的转变温度中起着关键作用。
The reactions of tricyanometallate precursors, (Ph3PMe)[(Tp4-Me)Fe(CN)3·0.5CH3CN] (1) (Tp4-Me = tri(4-methyl-pyrazol-1-yl)borate) and (NBu4)[(MeTp)Fe(CN)3] (MeTp = methyltris(pyrazolyl)borate) with the presence of the tetradentate tpa ligand (tpa = tris(2-pyridylmethyl)amine) and Fe(ClO4)2·6H2O afford two new cyano-bridged mixed-valence {FeIII2FeII2} molecular squares: [(Tp4-Me)FeIII(CN)3]2[FeII(tpa)]2·2ClO4·H2O (2·H2O) and [(MeTp)FeIII(CN)3]2[FeII(tpa)]2·2ClO4·CH3OH (3·CH3OH). Solvent-exchange compounds of 3·CH3OH, [(MeTp)FeIII(CN)3]2[FeII(tpa)]2·2ClO4·2H2O (3·2H2O), and their solvent-free form (2 and 3) are also obtained, respectively. The spin crossover (SCO) properties of all compounds are confirmed by detailed structural analyses of the coordination environments of the FeII centres and magnetic susceptibility measurements. All compounds exhibit SCO behaviour near room temperature (T1/2 = 320 K for 2·H2O; 302 K for 2; 292 K for 3·CH3OH; 306 K for 3·2H2O and 290 K for 3) and reversible single-crystal to single-crystal (SC–SC) transformations induced by guest desorption and resorption or solvent exchange. The transition temperature close to room temperature can be tuned by the dehydration and re-hydration processes. The structure–property analysis discloses that the distorted {Fe4(μ-CN)4} core and deviations of bent ∠Fe−NC angles play a key role in tuning the transition temperature of these similar mixed-valence {FeIII2FeII2} complexes.