Copper-bispidine coordination chemistry:: Syntheses, structures, solution properties, and oxygenation reactivity
Copper-bispidine coordination chemistry:: Syntheses, structures, solution properties, and oxygenation reactivity
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DOI：
10.1021/ic011114u
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发表时间：
2002-10-21
影响因子：
4.6
通讯作者：
Walter, O
中科院分区：
文献类型：
--
作者：
Börzel, H;Comba, P;Walter, O
本文合成了以2，4-取代（2-吡啶基或4-甲基-2-吡啶基）-3，7-二氮杂双环[3.3.1]壬酮为骨架的两个单核和四个双核四齿配体的铜（I）和铜（II）配合物，并对其进行了结构、光谱和电化学分析。除了两个铜（I）化合物为四配位和一个非配位的吡啶外，其余的铜（I）化合物均为四方锥结构。其它铜（I）结构具有两个吡啶供体、共配体（NCCH 3）和一个与铜中心共面的叔胺（N3）和另一个轴向配位的胺（N7）（Cu-N3 > Cu-N7，约2.25埃对2.20埃）。具有吡啶供体的铜（II）化合物具有类似的结构，但轴向胺具有与铜（II）中心的较弱键（Cu-N3 < Cu-N7，约2.03埃对2.30埃）。具有甲基化吡啶供体的结构也是正方锥体，其中共配体（Cl-或NCCH 3）在平面内。对于NCCH 3，观察到与其他铜（II）络合物相同的结构类型，并且对于体积较大的Cl-，共配体反式为N7，导致正方形金字塔结构，其中吡啶供体旋转出基面，并且轴向胺和面内胺之间只有很小的差异（2.15，2.12埃）。这些结构上的差异，由刚性bispidine骨干，导致光谱和电化学性质和反应性的大的变化。铜（I）配合物与吡啶取代的bispidine配体的氧化导致相对稳定的μ-过氧-二铜（II）配合物;通过连接两个供体组，这些过氧化合物在室温下稳定长达1小时。过氧络合物的稳定化在很大程度上归因于四方锥配位几何结构，其中基底结合在基底平面中，这是由刚性bispidine主链强制执行的结构基序。稳定性和结构性质也被认为与光谱（UV-vis和拉曼）和电化学性质相关。
Copper(I) and copper(II) complexes of two mononucleating and four dinucleating tetradentate ligands with a bispidine backbone (2,4-substituted (2-pyridyl or 4-methyl-2-pyridyl) 3,7-diazabicyclo[3.3.1]nonanone) have been prepared and analyzed structurally, spectroscopically, and electrochemically. The structures of the copper chromophores are square pyramidal, except for two copper(I) compounds which are four-coordinate with one noncoordinated pyridine. The other copper(I) structures have the two pyridine donors, the co-ligand (NCCH3) and one of the tertiary amines (N3) in-plane with the copper center and the other amine (N7) coordinated axially (Cu-N3 > Cu-N7, approximately 2.25 Angstrom vs 2.20 Angstrom). The copper(II) compounds with pyridine donors have a similar structure, but the axial amine has a weaker bond to the copper(II) center (Cu-N3 < Cu-N7, approximately 2.03 Angstrom vs 2.30 Angstrom). The structures with methylated pyridine donors are also square pyramidal with the co-ligands (Cl- or NCCH3) in-plane. With NCCH3 the same structural type as for the other copper(II) complexes is observed, and with the bulkier Cl- the co-ligand is trans to N7 leading to a square pyramidal structure with the pyridine donors rotated out of the basal plane and only a small difference between axial and in-plane amines (2.15, 2.12 Angstrom). These structural differences, enforced by the rigid bispidine backbone, lead to large variations in spectroscopic and electrochemical properties and reactivities. Oxygenation of the copper(I) complexes with pyridine-substituted bispidine ligands leads to relatively stable mu-peroxo-dicopper(II) complexes; with a preorganization of the dicopper chromophores, by linking the two donor sets, these peroxo compounds are stable at room temperature for up to 1 h. The stabilization of the peroxo complexes is to a large extent attributed to the square pyramidal coordination geometry with the substrate bound in the basal plane, a structural motif enforced by the rigid bispidine backbone. The stabilities and structural properties are also seen to correlate with the spectroscopic (UV-vis and Raman) and electrochemical properties.