Strucural Conversion of Sulfur-Bridged Polynuclear Complexes by Metal Replacement Reaction

研究表明，在金属离子的辅助下，含有两个或三个硫酸盐配体的八金属配合物形成了一系列具有多个手性中心的S桥联多核配合物。人们注意到，这些多核配合物的结构高度依赖于金属离子与八面体配合物的配位几何构型。为了更好地了解这种类型的S桥联结构的性质特征，有必要对由(三)或(双)硫醇配合物单元组成的类似的S桥联多核配合物进行研究。在本研究中，我们发现了新型的S桥联的Co^&lt；Ⅲ&gt；Ag^I_3Co^&lt；Ⅲ&gt；五核配合物[Ag_3{Co(Aet)_3}_2]^&lt；3&gt；和[Ag_3{Co(L-CyS-N，S)_3}_2，^&lt；3-gt；是由Fac(S)-[Co(aEt或L-Cys-N，S)_3]^&lt；0或3-&gt；与线形Ag^反应而成。在Co^&lt；III&gt；Ag^i_3Co^；Ⅲ&gt；结构中，来自两个面(S)-[Co(AET或L-Cys-N，S)_3]^&lt；0或3-gt；单元的两个硫代S原子分别与三个Ag原子配位，使得S-Ag-S三个键形成一个三螺旋结构，另一方面，S桥联的Co^&lt；三核配合物[Ni{Co(Aet)_2(En)}_2]Cl_4与Na_2[PdCI_4]按1：1的比例反应得到S桥联的Co^&lt；III&gt；Pd^&lt；II&gt；Co^&lt；III&gt；双核配合物，[PdCl2{Co(Aet)_2(En)}]Ci。在Co^&lt；III&gt；Pd^&lt；II&gt；Co^&lt；III&gt；结构中，Pd^&lt；II&gt；原子由两个顺(S)-[Co(Aet)_2(En)]^单元中的四个S原子配位，而Co_t；结构除了一个八面体单元中的两个S原子外，还有两个氯原子配位。

The aggregation of octaetal complexes with two or three thiolate ligands assisted by metal ions has been shown to form a variety of S-bridged polynuclear complexes containing several chiral centers. It has been noted that the structures of these polynuclear complexes are highly dependent on the coordination geometry of metal ions incorporated with the octahedral complexes. In order to better understand the properties characteristic of the S-bridged structure of this type, it is necessary to investigate analogous S-bridged polynuclear complexes composed of (tris)- or (bis)thiolato complex-units.In this study, we have found that the novel S-bridged Co^<III>Ag^I_3Co^<III> pentanuclear complexes, [Ag_3{Co(aet) _3}_2] ^<3+> and [Ag_3{Co(L-cys-N,S) _3}_2, ] ^<3->, were prepared by reacting fac(S)-[Co(aet or L-cys-N,S) _3] ^<0or3-> with linear Ag^+. In the Co^<III>Ag^I_3Co^<III>structure, the two thiolato S atoms from two fac(S)-[Co(aet or L-cys-N,S) _3] ^<0or3-> units coordinate to each of three Ag atoms, such that the three S-Ag-S linkages form a triple helical structure, On the other hand, the reaction of an S-bridged Co^<III>Ni^<II>Co^<III> trinuclear complex, [Ni{Co(aet) _2 (en)}_2]Cl_4, with Na_2 [PdCI_4 ] in a ratio of 1 : 1 gave an S-bridged Co^<III>Pd^<II>Co^<III> trinuclear complex, [Pd{Co(aet) _2 (en)}_2]Cl_4, while the corresponding 1 : 2 reaction produced an S-bridged Co^<III>Pd^<II> dinuclear complex, [PdCl_2{Co(aet) _2 (en)}]CI.In the Co^<III>Pd^<II>Co^<III> structure the Pd^<II> atom is coordinated by four S atoms from two cis(S)-[Co(aet) _2 (en)] ^+ units, while the Pd_<II> atom in the Co_<III>Pd_<II> structure is coordinated by two Cl atoms besides two S atoms from one octahedral unit.