Ghorai Samir, Mukherjee Chandan
Dalton Trans. 2014 Jan 14;43(2):394-7. doi: 10.1039/c3dt52072b.
Two radical-containing Ni(II) complexes having either parent salicylidene (complex 1) or 3,5-di-tert-butylsalicylidene (complex 2) in the ligand backbone were synthesized. Complex 2 underwent ligand centered C–H activation by aerial oxygen, forming the corresponding amide complex (2a). The UV-Vis/NIR spectral changes upon purging of molecular oxygen to 2 in CH2Cl2, alongwith ESI-MS analysis indicated the generation of Ni–oxygen/dioxygen species as the intermediate(s) for the amide formation. Interestingly, nonparticipation of the ligand centered π-radical in the oxidation process was observed.
合成了两种在配体主链中含有母体水杨醛（配合物1）或3,5-二叔丁基水杨醛（配合物2）的含自由基镍（II）配合物。配合物2通过空气中的氧气发生配体中心的C-H活化，形成相应的酰胺配合物（2a）。在二氯甲烷中向配合物2中通入分子氧时的紫外-可见/近红外光谱变化以及电喷雾电离质谱分析表明，生成了镍-氧/双氧物种作为酰胺形成的中间体。有趣的是，观察到配体中心的π自由基未参与氧化过程。
