The facile carbon atom abstraction reaction by [(ⁱPr₃P)Ni]₅H₆ (1) with various terminal alkenes to give [(ⁱPr₃P)Ni]₅H₄(μ₅-C) (2) occurs via a common highly reactive intermediate [(ⁱPr₃P)Ni]₅H₄ (3), which was isolated by the reaction of 1 with norbornene. Temperature dependent ¹H and ³¹P{¹H} NMR chemical shifts of 3 are consistent with a thermally populated triplet excited state only 2 kcal mol⁻¹ higher energy than the diamagnetic ground state. Complex 3 catalyzes the dimerization of norbornene to stereoselectively provide exclusively (Z) anti-(bis-2,2'-norbornylidene).

中文翻译：

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打破键和打破规则：[(iPr3P)Ni]5H4 和催化立体有择降冰片烯二聚的惰性键激活

^{[( i} Pr ₃ P)Ni] ₅ H ₆ ( 1 ) 与各种末端烯烃容易发生碳原子抽取反应，得到 [( ⁱ Pr ₃ P)Ni] ₅ H ₄ (μ ₅ -C) ( 2 )通过常见的高活性中间体 [( ⁱ Pr ₃ P)Ni] ₅ H ₄ ( 3 )，通过 1 与降冰片烯的反应分离。温度相关¹ H 和³¹ P{ ¹H} NMR 化学位移 3 与热聚集的三重激发态一致，仅比抗磁基态的能量高2 kcal mol ^{-1 。}复合物 3 催化降冰片烯的二聚化，以立体选择性地专门提供 ( Z ) 抗 (bis-2,2'-norbornylidene)。