The bis‐chelate tin complex 1, based on the 4,6‐di‐tert‐butyl‐N‐(tert‐butyl)‐ortho‐aminophenol ligand and representing the first example of a redox‐isomeric compound in main‐group chemistry, is synthesized and characterized by X‐ray diffraction analysis. Complex 1 exists in two electromeric forms in nonpolar solvents: a diamagnetic pseudotetrahedral (AP)₂Sn^IV (1a) and a paramagnetic tetragonal‐pyramidal structure of low‐valence tin (imSQ)₂Sn^II (1b) (where AP and imSQ are the dianionic and radical‐anionic forms of the ligand, respectively). The reversible redox‐isomeric rearrangement between 1a and 1b is investigated in solution by means of magnetochemistry, EPR spectroscopy, UV/Vis spectroscopy, and ¹¹⁹Sn Mössbauer spectroscopy. This interconversion can be quenched by an addition of a strong donor ligand, such as pyridine (Py), resulting in an octahedral complex (AP)₂Sn^IV(Py)₂ (2) that does not undergo redox isomerism.

中文翻译：

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主族化学中的氧化还原异构现象：含邻氨基苯醌配体的锡配合物

双-螯合锡复合1的基础上，4,6-二-叔丁基- ñ - （叔丁基） -邻氨基苯酚配体和表示主基团化学的氧化还原异构体化合物的第一实例中，通过X射线衍射分析合成并表征。配合物1在非极性溶剂中以两种电子形式存在：抗磁性伪四面体（AP）₂ Sn ^IV（1a）和低价锡（imSQ）₂ Sn ^II（1b）的顺磁性四方锥体结构）（其中AP和imSQ分别是配体的二阴离子和自由基-阴离子形式）。通过磁化学，EPR光谱，UV / Vis光谱和¹¹⁹ SnMössbauer光谱研究溶液中1a和1b之间可逆的氧化还原异构体重排。可以通过添加强供体配体（例如吡啶（Py））来淬灭这种相互转化，从而得到不经历氧化还原异构现象的八面体络合物（AP）₂ Sn ^IV（Py）₂（2）。