Studies on Unusual Properties and New Functions Occurred by the Interaction among Heavy Transition Metal Atoms

多核过渡金属配合物中金属间的相互作用主要受中心金属离子的性质、氧化态和几何构型的影响。由于多核过渡金属配合物的氧化还原性质可以通过改变金属离子的氧化态来控制，从而有可能分离出混合价化合物，因此多核过渡金属配合物的氧化还原性质受到了人们的广泛关注。为了研究具有金属-金属相互作用的分子对外界刺激如磁场、电势、辐射激发或热的响应，我们合成了吡唑类和吡啶硫醇类多核配合物，并研究了它们的性质。以下是我们的结果摘要。(1)以分子内氢键为前体[Pd_2（μ-Rpz）_2（Rpz）_2（Rpzh）_2]（R=3-叔丁基）合成了Pd_2M '_2型四核配合物（M' = Ag，Au）。HT-[Pd_2（μ-3-t-Bupz）_2（3-t-Bupz）_2（3-t-Bupz）]反应的详细研究 ...更多信息 H）_2]与Ag^I离子和Au^I配合物的反应，分离出了四核配合物的两种键合异构体：头对头异构体（HH异构体）和头尾异构体（HT异构体）。由于在高温下观察到了键合异构体的容易的立体化学重排，因此随后进行了^1H NMR光谱分析。(2)为了合成环铂三聚体中的Pt-Pt键，最适合的配合物可能是吡唑桥联的三核铂（II）配合物[Pt_3（μ-pz）_6]（pz =吡唑基）。为了回答环铂三聚体中是否能形成Pt-Pt直接键的问题，我们进行了[Pt_3（μ-Pz）_6]的氧化反应，首次成功地分离和表征了双电子氧化物[Pt_3Br_2（μ-Pz）_6]，并对其电子光谱进行了归属。非常有趣的是，氧化物种在溶液中表现出“价态脱陷”行为。结果表明，在溶液状态下，Br^-以缔合方式通过溶剂DMF分子与Br配位的Pt中心或Br^-与未配位的Pt原子的结合而发生价态脱陷. (3)虽然迄今为止已经合成了几种ESBO-Ⅳ配合物，但它们都是抗磁性的。我们成功地合成了一个吡啶-2-硫醇盐的ESBO双（IV）配合物，它具有温度依赖的磁性，表明存在^3（δδ^*）激发三重态。少

The metal-metal interaction in polynuclear transition metal complex is mainly governed by the nature, oxidation state and geometry of the central metal ion. Because the extent of metal-metal interaction can be controlled by the change of oxidation state of metal ions and therefore there is possibility to isolate mixed-valent compounds, the redox properties of polynuclear transition metal complexes have attracted much attention. In order to study the response of molecules with metal-metal interactions towards external stimuli such as magnetic field, electric potential, excitation by radiation, or heat, we have synthesized polynuclear complexes of pyrazolates and pyridinethiols, and studied their properties. Followings are the summary of our results.(1) The precursor with intramolecular hydrogen bonding, [Pd_2(μ-Rpz)_2(Rpz)_2(Rpzh)_2] (R=3-t-butyl), gave tetranuclear complexes of Pd_2M'_2 type (M' = Ag, Au). The detailed study on the reaction of HT-[Pd_2(μ-3-t-Bupz)_2(3-t-Bupz)_2(3-tBupz … More H)_2] with Ag^I ion and Au^I complex enabled is to isolate two linkage isomers of tetranuclear complexes, head-to-head isomer (HH isomer) and head-to-tail isomer (HT isomer). Because a facile stereochemical rearrangement of the linkage isomers was observed at elevated temperature, it was followed by ^1H NMR spectroscopy.(2) To synthesize Pt-Pt bonds in cyclic platinum trimer, the best-fit complex is probably the pyrazolato-bridged trinuclear platinum(II) complex, [Pt_3(μ-pz)_6] (pz = pyrazolate). In order to give an answer to the question whether direct Pt-Pt bond can be formed in the cyclic platinum trimer or not, we have conducted the oxidation of [Pt_3(μ-pz)_6] and succeeded, for the first time, the isolation and characterization of the two-electron oxidized species, [Pt_3Br_2(μ-Pz)_6], as well as the assignment of the electronic spectra of them. Very interestingly, the oxidized species show "valence-detrapping" behavior in solution. We concluded that the valence-detrapping occurs in the solution state in associative manner via either approach of solvent DMF molecule to the Br-coordinated Pt center or approach of Br^- to the uncoordinated Pt atom in the presence of excess Br^- anion.(3) Although several ESBO rhenium(IV) complexes have been synthesized so far, they are all diamagnetic. We have succeeded in the synthesis of an ESBO rhenium(IV) complex of pyridine-2-thiolate, which exhibits temperature-dependent magnetic properties showing the existence of ^3(δδ^*) excited triplet state. Less