Formation and characterization of a reactive chromium(<scp>v</scp>)–oxo complex: mechanistic insight into hydrogen-atom transfer reactions
作者:Hiroaki Kotani、Suzue Kaida、Tomoya Ishizuka、Miyuki Sakaguchi、Takashi Ogura、Yoshihito Shiota、Kazunari Yoshizawa、Takahiko Kojima
DOI:10.1039/c4sc02285h
日期:——
acetonitrile based on analysis of the electron-transfer (ET) equilibrium between 1 and a one-electron donor, [RuII(bpy)3]2+ (bpy = 2,2′-bipyridine). The reorganization energy (λ) of 1 was also determined to be 1.03 eV in ET reactions from phenol derivatives to 1 on the basis of the Marcus theory of ET. The smaller λ value in comparison with that of an Fe(IV)–oxo complex (2.37 eV) is caused by the small
单核 Cr( V )–氧配合物,[Cr V (O)(6-COO − -tpa)](BF 4 ) 2 ( 1 ; 6-COO − -tpa = N , N -双(2-吡啶基甲基) -N- (6-羧基-2-吡啶基甲基)胺)是通过Cr( III )前体络合物与碘酰苯作为氧化剂反应制备的。1的表征是通过 ESI-MS 光谱、电子顺磁共振、紫外可见光谱和共振拉曼光谱实现的。根据对 1和单电子供体 [Ru II (bpy) 3 ] 2之间的电子转移 (ET) 平衡的分析,1 的还原电位 ( E red ) 在乙腈中相对于SCE为1.23 V + (bpy = 2,2′-联吡啶)。根据马库斯 ET 理论,在苯酚衍生物到 1的ET反应中,1 的重组能为 1.03 eV 。与 Fe( IV )-氧配合物 (2.37 eV)相比,较小的λ值是由于电子接受 LUMO 为1的 dπ 特性导致 ET 过程中结构变化