A series of crystalline phases composed of trimetallic 3d-5d-5d′ {Fe₉[Re(CN)₈]_6−x[W(CN)₈]_x(MeOH)₂₄}·yMeOH (x = 1 (1), 2 (2), 3 (3), 4 (4) and 5 (5); y = 10–15) clusters were obtained by altering the octacyanidometalate composition. The temperature dependent studies involving SC XRD, SQUID magnetic measurements, IR spectroscopy and ⁵⁷Fe Mössbauer spectroscopy revealed reversible phase transition with the retention of single crystal character in each congener. The transition was assisted by reversible spin-crossover (SCO) ^HSFe^II ↔ ^LSFe^II transition at the central Fe1(II) site for Fe₉Re₅W₁ (1), Fe₉Re₄W₂ (2), Fe₉Re₃W₃ (3) and Fe₉Re₂W₄ (4). In contrast, the tungsten-rich congener Fe₉Re₁W₅ (5) exhibited nontrivial behavior with the SCO transition being stopped halfway through the cooling process, to be completed with single electron transfer (ET) from the external Fe2(II) center towards one of the neighboring W(V) sites. The critical temperature T_c of SCO has been systematically increased from 193 K (1) to 247 K (4). All experimental data indicate the domination of the Fe(II)–W(V) valence states in all crystals 1–5, however, with increasing quantity of [W(CN)₈]³⁻ (and decreasing quantity of [Re(CN)₈]³⁻), the valence equilibrium Fe(II)–W(V) ↔ Fe(III)–W(IV) was systematically shifted to the right, starting from congener 3. The overall electronic configuration at low temperatures and variable amounts and location of spin carriers along the whole series suggest the remarkable competition between magnetic super-exchange Fe(II)–CN–W(V) interactions and intermolecular interactions. The observed behavior is in line with the information collected previously for the bimetallic congeners Fe₉Re₆ and Fe₉W₆, to shed light on the role of the mixed tri-metallic composition in changing the properties observed for the relevant bimetallic cyanido-bridged skeletons.

中文翻译：

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三金属磁性氰基桥联簇中定点SCO和金属间ET之间的相变调整

由三金属3d-5d-5d'{Fe ₉ [Re（CN）₈ ] _{6− x} [W（CN）₈ ] _x（MeOH）₂₄ }· y MeOH（x = 1（1）组成的一系列晶相，2（2），3（3），4（4）和5（5；y = 10–15）团簇是通过改变八氰基金属酸盐的组成获得的。温度相关的研究涉及SC XRD，SQUID磁测量，红外光谱和⁵⁷FeMössbauer光谱显示了可逆的相变，并在每个同类物中保留了单晶特征。过渡是由可逆旋交叉（SCO）辅助^HS的Fe ^II ↔ ^LS的Fe ^II在中央FE1（过渡II）的网站的Fe ₉重新₅ w ^ ₁（1），铁₉重新₄ w ^ ₂（2），铁₉ Re ₃ W ₃（3）和Fe ₉ Re ₂ W ₄（4）。相比之下，富钨同类Fe ₉ Re ₁ W ₅（5）表现出非平凡的行为，SCO转变在冷却过程中途停止，要通过从外部Fe2（II）中心进行单电子转移（ET）来完成朝向相邻的W（V）网站之一。SCO的临界温度T _c已从193 K（1）逐渐增加到247 K（4）。所有实验数据表明，所有晶体1-5中Fe（II）–W（V）价态占优势。但是，随着[W（CN）₈ ] ^{3−的增加}（和[Re（CN）₈ ] ^{3−的减少}），价态平衡Fe（II）–W（V）↔Fe（III）– W（IV）从同类3开始系统地向右移动。低温下的整体电子结构以及整个系列中自旋载流子的数量和位置都不同，这表明磁性超交换Fe（II）–CN–W（V）相互作用和分子间相互作用。观察到的行为与先前针对双金属同类物Fe ₉ Re ₆和Fe ₉ W ₆收集的信息相符，以阐明混合三金属成分在改变相关双金属氰基桥联反应中观察到的性质中的作用。骨骼。