Institute of Chemistry, Far Eastern Branch of Russian Academy of Sciences, 159 Prosp00-Letiya Vladivostoka, 690022 Vladivostok, Russia.
Molecules. 2022 Dec 2;27(23):8489. doi: 10.3390/molecules27238489.
To understand how polyethyleneimine (PEI), as a ligand, affects structure and properties of the transition metals hexacyanoferrates (HCFs) immobilized in cross-linked PEI matrix, we have synthesized Cu(II), Zn(II), and Fe(III) HCFs via successive ion-exchange reactions with metal salts and K[Fe(CN)] or K[Fe(CN)]. The structure and properties of the obtained materials in comparison with the crystalline HCF analogs were investigated with FT-IR, Mössbauer, and UV-Vis spectroscopy. Complete reduction of Fe(III) to Fe(II) by PEI in HCF(III) was confirmed. When synthesis was performed at pH favoring binding of precursor metal ions by PEI, cyano-bridged hybrids rather than polymer-HCFs composites were formed. Although the obtained hybrids did not demonstrate sorption activity toward cesium ions, known for crystalline HCFs, they are of interest for the other applications. SQUID measurements revealed a significant difference in magnetic properties of PEI-HCFs hybrids in comparison with crystalline HCFs. Due to the Fe(III) to Fe(II) reduction in HCF ions, Cu(II) and Fe(III) HCFs(III) lost the molecular magnets properties in PEI matrix, but magnetic ordering, including ferromagnet-antiferromagnet interactions, was observed in all hybrids over the broad temperature range.
为了了解配体聚乙烯亚胺（PEI）如何影响固载在交联 PEI 基质中的过渡金属六氰合铁酸盐（HCFs）的结构和性质，我们通过金属盐与 K[Fe(CN)]或 K[Fe(CN)]的连续离子交换反应合成了 Cu(II)、Zn(II)和 Fe(III) HCFs。通过傅里叶变换红外光谱、穆斯堡尔光谱和紫外可见光谱对所得到的材料的结构和性质与晶态 HCF 类似物进行了研究。证实了 PEI 将 HCF(III)中的 Fe(III)完全还原为 Fe(II)。当在有利于 PEI 结合前体金属离子的 pH 下进行合成时，形成了氰基桥联的杂化物而不是聚合物-HCF 复合材料。尽管所得到的杂化物对铯离子没有表现出与晶态 HCFs 相同的吸附活性，但它们对其他应用具有吸引力。SQUID 测量表明，PEI-HCFs 杂化物的磁性能与晶态 HCFs 有显著差异。由于 HCF 离子中的 Fe(III)还原为 Fe(II)，Cu(II)和 Fe(III) HCFs(III)在 PEI 基质中失去了分子磁体性质，但在所有杂化物中，在宽温度范围内观察到磁有序，包括铁磁-反铁磁相互作用。
