Structures and properties of weakly associated polyoxometalate-transition metal complexes

本研究项目旨在合成聚氧乙烯酸盐与过渡金属离子的配合物，分析其晶体结构，然后检查其结构特有的物理化学性质。首先，研究了首次合成并表征的[Cu_2（OH）_2（OH_2）_6][Cu_2（OH_2）_8][V_<10>O_<28>]-4（CH_3）_2CO的磁性。该化合物在[V_ O_ ]^核的两侧有两对Cu^&lt;2+&gt;阳离子<10><28><6->，它们之间的距离分别为2.89和3.37 μ m。这些对中的未成对电子没有耦合，每个Cu^2+原子都是一个独立的自旋中心。第二，合成了[V_<10>O_<28>]^<6->与Cu^&lt;2+&gt;、NH_4^+、K^+、Rb^+的复盐，并测定了它们的晶体结构。在这些晶体中，与阳离子配位的水分子通过氢键将氢原子支撑在[V_<10>O_<28>]^<6->核上并稳定单质子化物种[HV 关于我们 <10><28>^<5->.在这些晶体中，首先明确地确定了单质子化十钒酸根阴离子上质子的精确位置。此外，对<11><39><8->Na^+和胍盐阳离子结晶的[SiW_O_]^的结构测定表明，该化合物具有<11><39><8->由Na^+阳离子连接的新型螺旋结构，尽管过渡金属没有掺入到该化合物中。它的结构表明，它将显示非线性光学特性的可能性，因此照射波长为800 nm的脉冲激光，导致观察到二次谐波产生。在进行这些研究的同时，研究人员还在两个同步加速器设施安装和升级了衍射仪：高能加速器研究组织的SPring-8和光子工厂。这些工作有助于对上述非线性光学活性硅钨酸盐晶体进行精确的结构分析，以及对具有纳米尺寸环状的混合价钼巨团簇的分子生长和分子间凝聚的结构解释。少

This research project aims at synthesizing complexes of polyoxometalates with transition metal ions, analyzing their crystal structures, and then examining the physicochemical properties that are specific to their structures. First, the magnetic properties of [Cu_2(OH)_2(OH_2)_6][Cu_2(OH_2)_8][V_<10>O_<28>]-4(CH_3)_2CO, which was first synthesized and characterized by the investigator, were investigated. The compound has two pairs of Cu^<2+> cations on the two sides of the [V_<10>O_<28>]^<6-> core, which are separated by 2.89 Å and 3.37 Å, respectively. The unpaired electrons of these pairs were not coupled and each Cu^<2+> atom works as an independent spin center. Second, double salts of [V_<10>O_<28>]^<6-> with Cu^<2+> and NH_4^+, K^+ or Rb^+ were synthesized and their crystal structures were determined. In these crystals, a water molecule coordinating to the cation supports a hydrogen atom on the [V_<10>O_<28>]^<6-> core via hydrogen bond and stabilizes a monoprotonated species, [HV … More _<10>_O<28>]^<5->. In these crystals, the precise location of the protons on the monoprotonated decavanadate anion was first determined unambiguously. Also, the structure determination of [SiW_<11>O_<39>]^<8-> crystallized with Na^+ and guanidinium cations revealed that the compound exhibits a novel screw structure of [SiW_<11>O_<39>]^<8-> linked by Na^+ cation, although transition metals were not incorporated into the compound. Its structure indicated a possibility that it would show non-linear optical properties and thus pulsed laser light with the wavelength of 800 nm was irradiated, resulting in the observation of second harmonic generation. In parallel with these studies, the investigator has installed and upgraded diffractometers at two synchrotron facilities : SPring-8 and Photon Factory of High Energy Accelerator Research Organization. These efforts have profited the precise structure analyses of abovementioned NLO active silicotungstate crystals as well as the structural elucidation of the molecular growth and intermolecular condensation of mixed valence molybdenum giant clusters with nanometer sized ring shape. Less