Organic–inorganic hybrids consisting of organic cations and polyanions are promising functional materials due to their various compositions and structures. An important aspect of these materials is the interactions between the organic and inorganic components, which not only produce the final structures, but also influence the properties. Here, we investigated the interactions between organic cations and polyanions using protonated 2-aminopyridinium (Hap) as the cation, and successfully obtained two polyoxometalate-based hybrids, namely (C5H7N2)4[Mo8O26], (I), and (C5H7N2)2[NiMo6O16(OH)2CH3C(CH2O)3}2]·4H2O, (II). In the crystal structure of (I), every Hap cation links with two polyanions by donating one or two N—H...O hydrogen bonds, and every polyanion is surrounded by eight Hap cations via terminal or bridging O atoms. Conversely, in compound (II), every Hap cation only links with one polyanion decorated by a triol ligand; this organic–inorganic component further assembles via uncoordinated water molecules. In the extended structures, Hap plays a key role, not only providing a counter charge, but also acting as `glue' linking polyanions in the role of hydrogen-bond donors. In both compounds, as the nodes of the supramolecular network, the polyanions exhibit an ordered two-dimensional arrangement due to strong hydrogen bonds and electrostatic interactions between the organic and inorganic parts. The electrochemistry of compound (I) shows that redox sourcing from polyanions is a surface-controlled process. Conversely, the magnetic behaviour of compound (II) indicates dominant antiferromagnetic properties.
由有机阳离子和聚阴离子组成的有机-无机杂化物因其不同的组成和结构而成为前景广阔的功能材料。这些材料的一个重要方面是有机成分和无机成分之间的相互作用,这种相互作用不仅会产生最终的结构,还会影响其性能。在此,我们以质子化的 2-aminopyridinium (Hap) 为阳离子,研究了有机阳离子与聚阴离子之间的相互作用,并成功获得了两种基于聚氧化金属酸盐的混合物,即 (C5H7N2)4[Mo8O26], (I) 和 (C5H7N2)2[NiMo6O16(OH)2CH3C(CH2O)3}2]-4H2O, (II)。在化合物(I)的晶体结构中,每个 Hap 阳离子通过提供一个或两个 N-H...O 氢键与两个多阳离子相连,每个多阳离子通过末端或桥接 O 原子被八个 Hap 阳离子包围。相反,在化合物(II)中,每个 Hap 阳离子只与一个由三醇配体装饰的多阴离子相连接;这种有机-无机成分通过非配位水分子进一步组装。在扩展结构中,Hap 起着关键作用,它不仅提供反电荷,还充当连接多阴离子的 "胶水",扮演氢键供体的角色。在这两种化合物中,聚阴离子作为超分子网络的节点,由于有机部分和无机部分之间的强氢键和静电作用,呈现出有序的二维排列。化合物(I)的电化学特性表明,多阴离子的氧化还原来源是一个表面控制过程。相反,化合物 (II) 的磁性表现则显示出主要的反铁磁特性。