Transition-Metal Complexes of Pyrrole Pigments. XXII. Photoredox Behavior of Oxo(tetra-p-tolylporphinato)molybdenum(V) Complexes
Transition-Metal Complexes of Pyrrole Pigments. XXII. Photoredox Behavior of Oxo(tetra-p-tolylporphinato)molybdenum(V) Complexes
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吡咯颜料的过渡金属络合物。
DOI：
10.1246/bcsj.59.1839
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发表时间：
1986
影响因子：
4
通讯作者：
Y. Murakami
中科院分区：
文献类型：
--
作者：
Y. Matsuda;Toshihiko Takaki;Y. Murakami
研究了5，10，15，20-四对甲苯基卟啉的氧钼(V)配合物[MoV(X)(TTP)]在可见光照射下的光化学还原反应。[MoVo(X)(TTP)]的辐照导致Mo-X键的均裂断裂，生成[MoIVO(TTP)]和轴向配体(X)生成的自由基物种。还原速度受控于Mo-X键的性质，轴向键的离子性质较少的络合物在均解过程中更具活性。轴向烷氧基配体的体积对反应活性有两种截然相反的影响：(I)轴向配体与赤道TTP之间的排斥作用加速了Mo-X键的均裂；(Ii)由轴向配位键光化学裂解产生的自由基物种从配位球上扩散的速度随着轴向配体与赤道TTP的体积增大而逐渐减缓。
Photochemical reduction of oxomolybdenum(V) complexes of 5,10,15,20-tetra-p-tolylporphine, [Mov(X)(ttp)], was investigated under irradiation with the visible light in benzene, where X stands for an axial ligand placed trans to the oxo group. Irradiation of [MovO(X)(ttp)] resulted in a homolytic cleavage of the Mo–X bond to afford [MoIVO(ttp)] and a radical species generated from the axial ligand (X). The reduction rate was controlled by the nature of the Mo–X bond, and a complex with less ionic character of the axial bond was more reactive in the homolysis process. The bulkiness of the axial alkoxo ligands may provide two different effects which are opposite to each other on the reactivity: (i) The repulsive interaction between an axial ligand and the equatorial ttp accelerates the homolysis of the Mo–X bond; (ii) the diffusion rate of the radical species, generated by the photochemical cleavage of the axial coordinate bond, from the coordination sphere is progressively retarded as the bulkiness of the al...