Kinetic study of metal-metal bonded rhenium complexes

本项目的目的是利用铼配合物了解氧化态与反应活性之间的关系，以及金属与金属相互作用与氧化还原性能之间的关系。铼是具有多种氧化态的最通用的元素，因此它的配合物是研究金属配合物氧化还原性能的最合适的材料。在北海道大学制备了多种重要的配合物，国外同行对其反应性进行了研究。此外，纽卡斯尔大学的sayse11博士和奥兰奥兰州自由大学的botha博士分别在北海道大学呆了3个月，为项目的重大进展做出了贡献。通过使用N，N，N， o和N，N， o型螯合配体，我们分离出了几种具有不完全螯合配体的单核铼(V)配合物。这些配合物的x射线结构测定揭示了这些螯合配体的络合形成步骤，这些信息是通过取代不稳定的金属离子无法获得的。双核铼双氧桥配合物在两个相邻的氧化态（III，IV）和（IV，IV）中被分离出来。它们的结构和氧化还原研究表明了Re-Re键序与氧化还原反应之间的相关性。对六核硫化铼簇的研究也揭示了Re-Re键的特征性质。六苯乙烯簇[Re_6S_8(H_2O)_6]_<2+>簇与Cl^-或NCS^-的反应异常缓慢。单核铼（III）配合物的显著惰性难以理解，应考虑金属-金属键的影响。这种惰性性质使我们制备了部分取代的[Re_6S_8（吡啶）_<6-n>Cl_n]^<(2-n)+>(n=1-3)。对吡啶衍生物配体与六芳鎓配合物的进一步研究表明，六芳鎓中心的配体之间存在一定的氧化还原相互作用。我们还研究了一些双核钌（III）配合物与氧化物和乙酸桥的氧化还原反应。氧化桥的质子化作用显著地改变了二钌部分的氧化还原电位。质子偶联氧化还原反应与某些酶的活性中心有关。少

The purpose of this project is to understand the correlation between the oxidation states and reactivity and that of metal-to-metal interaction and redox properties by using rhenium complexes. Rhenium is the most versatile element with respect to its variety of oxidation states, and thus its complexes are the most appropriate to study redox preperties of metal complexes. Various important complexes have been prepared at Hokkaid Universty, and their reactivities have been studied by the foreign colleagues. Also, Dr.Sayse11 of the University of Newcastle-upon-Tyne and Dr.Botha of the University of Orange-Free-State, stayd at Hokkaido University for 3 months each and contributed to significant progress of the project.By using N,N,N,O-and N,N,O-type chelating ligands, we have isolated several mononuclear rhenium (V) complexes having incompletely chelated ligands. X-Ray structural determination of these complexes revealed complex formation steps of these chelating ligands, information which … More is impossible to obtain by using substitution labile metal ions. Dinuclear rhenium doubly oxo-bridged complexes have been isolated in two neighboring oxidation states, (III,IV) and (IV,IV). Their structural and redox studies show the correlation between the Re-Re bond-order and redox reactions. Study on hexanuclear rhenium sulfide clusters also revealed characteristic properties of Re-Re bond. The hexarhenium cluster, [Re_6S_8(H_2O)_6]_<2+> clusters, shows unexpectedly slow anation reactions with Cl^- or NCS^-. The remarkable inertness is difficult to understand for mononuclear rhenium (III) complexes and the effect of metal-metal bond should be taken into account. This inert nature enabled us to prepare partially substituted species of the type, [Re_6S_8(pyridine)_<6-n>Cl_n]^<(2-n)+>(n=1-3). Further studies to prepare the hexarhenium (III) complexes with pyridine derivative ligands show some redox interaction between the ligands at hexarhenium center.We have also studied redox reactions of some dinuclear ruthenium (III) complexes with oxide and acetate bridges. Protonation at the oxide bridge remarkable change the redox potentials of the diruthenium moiety. Relevance of the proton-coupled redox reactions to some enzyme dimetal active centers have been suggested. Less