Kunishita Atsushi, Kubo Minoru, Ishimaru Hirohito, Ogura Takashi, Sugimoto Hideki, Itoh Shinobu
Department of Chemistry, Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan.
Inorg Chem. 2008 Dec 15;47(24):12032-9. doi: 10.1021/ic801568g.
The structure and H(2)O(2)-reactivity of a series of copper(II) complexes supported by tris[(pyridin-2-yl)methyl]amine (TPA) derivatives having a phenyl group at the 6-position of pyridine donor group(s) [(6-phenylpyridin-2-yl)methyl]bis[(pyridin-2-yl)methyl]amine (Ph(1)TPA), bis[(6-phenylpyridin-2-yl)methyl][(pyridin-2-yl)methyl]amine (Ph(2)TPA), and tris[(6-phenylpyridin-2-yl)methyl]amine (Ph(3)TPA) have systematically been examined to get insights into the aromatic substituent (6-Ph) effects on the coordination chemistry of TPA ligand system. The X-ray crystallographic analyses have revealed that Cu(II)(TPA)(CH(3)CN)(2) (CuTPA) and Cu(II)(Ph(3)TPA)(CH(3)CN)(2) (3) exhibit a trigonal bipyramidal structure, whereas Cu(II)(Ph(1)TPA)(CH(3)CN)(2) (1) shows a slightly distorted square pyramidal structure and Cu(II)(Ph(2)TPA)(CH(3)CN)(2) (2) has an intermediate structure between trigonal bipyramidal and square pyramidal. On the other hand, the UV-vis and ESR data have suggested that all the copper(II) complexes have a similar trigonal bipyramidal structure in solution. The redox potentials of CuTPA, 1, 2, and 3 have been determined as E(1/2) = -0.34, -0.28, -0.16, and -0.04 mV vs Ag/AgNO(3), respectively, demonstrating that introduction of each 6-Ph group causes positive shift of E(1/2) about 0.1 V. Notable difference in H(2)O(2)-reactivity has been found among the copper(II) complexes. Namely, CuTPA and 1 afforded mononuclear copper(II)-hydroperoxo complexes CuTPA-OOH and 1-OOH, respectively, whereas complex 2 provided bis(mu-oxo)dicopper(III) complex 2-oxo. On the other hand, copper(II) complex 3 was reduced to the corresponding copper(I) complex 3(red). On the basis of the H(2)O(2)-reactivity together with the X-ray structures and the redox potentials of the copper(II) complexes, the substituent effects of 6-Ph are discussed in detail.
一系列由三[（吡啶-2-基）甲基]胺（TPA）衍生物支撑的铜（II）配合物，其吡啶供体基团的6位带有苯基[（6-苯基吡啶-2-基）甲基]双[（吡啶-2-基）甲基]胺（Ph(1)TPA）、双[（6-苯基吡啶-2-基）甲基][（吡啶-2-基）甲基]胺（Ph(2)TPA）和三[（6-苯基吡啶-2-基）甲基]胺（Ph(3)TPA），对其结构和与H₂O₂的反应活性进行了系统研究，以深入了解芳基取代基（6-Ph）对TPA配体体系配位化学的影响。X射线晶体学分析表明，Cu(II)(TPA)(CH₃CN)₂（CuTPA）和Cu(II)(Ph(3)TPA)(CH₃CN)₂（3）呈现三角双锥结构，而Cu(II)(Ph(1)TPA)(CH₃CN)₂（1）显示出略微扭曲的四方锥结构，Cu(II)(Ph(2)TPA)(CH₃CN)₂（2）具有介于三角双锥和四方锥之间的中间结构。另一方面，紫外可见光谱和电子顺磁共振数据表明，所有铜（II）配合物在溶液中具有相似的三角双锥结构。已测定CuTPA、1、2和3的氧化还原电位分别为E(1/2) = -0.34、-0.28、-0.16和-0.04 mV（相对于Ag/AgNO₃），表明引入每个6-Ph基团会使E(1/2)正向移动约0.1 V。在铜（II）配合物中发现了H₂O₂反应活性的显著差异。即，CuTPA和1分别生成单核铜（II）-氢过氧配合物CuTPA-OOH和1-OOH，而配合物2生成双（μ-氧）二铜（III）配合物2-oxo。另一方面，铜（II）配合物3被还原为相应的铜（I）配合物3(red)。基于H₂O₂反应活性以及铜（II）配合物的X射线结构和氧化还原电位，详细讨论了6-Ph的取代基效应。
