The reduction chemistry of thorium complexes is less explored compared to that of their uranium counterparts. Here, we report the synthesis, characterization, and reduction chemistry of two thorium(IV) complexes, (^AdTPBN₃)ThCl (1) and (^DtbpTPBN₃)ThCl(THF) (4) [^RTPBN₃ = 1,3,5-[2-(RN)C₆H₄]₃C₆H₃; R = 1-adamantyl (Ad) or 3,5-di-tert-butylphenyl (Dtbp); THF = tetrahydrofuran], supported by tripodal tris(amido)arene ligands with different N-substituents. Reduction of 1 with excessive potassium in n-pentane yielded a double C–C coupling product, [(^AdTPBN₃)ThK(Et₂O)₂]₂ (3), featuring a unique tetraanionic tricyclic core. On the other hand, reduction of 4 with 1 equiv of KC₈ in hexanes/1,2-dimethoxyethane (DME) afforded a single C–C coupling product, [(^DtbpTPBN₃)Th(DME)]₂ (5), with a dianionic bis(cyclohexadienyl) core. The solid- and solution-state structures of dinuclear thorium(IV) complexes 3 and 5 were established by X-ray crystallography and NMR spectroscopy. In addition, reactivity studies show that 3 and 5 can behave as thorium(II) and thorium(III) synthons to reduce organic halides. For instance, 3 and 5 are able to reduce 4 and 2 equiv of benzyl chloride, respectively, to regenerate 1 and 4 with concomitant formation of dibenzyl. Reversible C–C couplings under redox conditions provide an alternative approach to exploiting the potential of thorium arene complexes in redox chemistry.

中文翻译：

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钍三(酰胺基)芳烃配合物的还原：可逆双和单 C-C 偶联


与铀对应物相比，钍络合物的还原化学研究较少。在这里，我们报告了两种钍(IV)络合物的合成、表征和还原化学，( ^Ad TPBN ₃ )ThCl (1) 和 ( ^Dtbp TPBN ₃ )ThCl(THF) (4) [ ^R TPBN ₃ = 1,3,5-[2-(RN)C ₆ ] ₃ C ₆ H ₃ ; R = 1-金刚烷基 (Ad) 或 3,5-二叔丁基苯基 (Dtbp)； THF = 四氢呋喃]，由具有不同 N-取代基的三足三（酰胺基）芳烃配体支持。在正戊烷中用过量的钾还原 1，得到双 C-C 偶联产物 [( ^Ad TPBN ₃ )ThK(Et ₂ O) < b14> ] ₂ (3)，具有独特的四阴离子三环核心。另一方面，在己烷/1,2-二甲氧基乙烷 (DME) 中用 1 当量的 KC ₈ 还原 4，得到单一 C-C 偶联产物，[( ^Dtbp TPBN ₃ )Th(DME)] ₂ (5)，具有双阴离子双(环己二烯基)核。通过X射线晶体学和核磁共振波谱建立了双核钍(IV)配合物3和5的固态和溶液态结构。此外，反应性研究表明3和5可以作为钍(II)和钍(III)合成子来还原有机卤化物。例如，3和5能够分别还原4和2当量的苄基氯，再生1和4，同时形成二苄基。氧化还原条件下的可逆 C-C 偶联为开发钍芳烃配合物在氧化还原化学中的潜力提供了另一种方法。