In contrast to naturally occurring F₂, O₂ and N₂, diatomic C₂ is an intriguing species that has only been observed indirectly in the gas phase, and because of its high reactivity has eluded isolation in the condensed phase. It has previously been stabilized in L→C₂←L compounds but the bonding situation of the central C₂ in this motif differs remarkably from that of free C₂. Here we have prepared and structurally characterized diatomic C₂ as a monoligated complex L→C₂ using a bulky phosphine ligand bearing two imidazolidin-2-iminato groups (L is (NHC^R=N)₂(CH₃)P, where NHC^R is an N-heterocyclic carbene). The compound is stable in solution at ambient temperature and has also been isolated in the solid state. Reactivity studies, in combination with quantum chemical analysis, suggest that the two carbon atoms of the L→C₂ complex both have carbene character. The complex underwent intermolecular C–H bond activation upon thermolysis and exhibited hydroalkoxylation-like reactivity with methanol.

与天然存在的 F ₂、O ₂和 N ₂相比，双原子 C ₂是一种有趣的物质，只能在气相中间接观察到，并且由于其高反应性而无法在凝聚相中分离。它以前已在 L→C ₂ ←L 化合物中稳定，但该基序中中心 C _{2的键合情况与游离 C 2}的键合情况显着不同。在这里，我们使用带有两个咪唑啉-2-亚氨基的庞大膦配体制备双原子 C ₂并在结构上表征为单配位络合物 L→C _{2 (L 是 (NHC} ^R =N) ₂(CH ₃ )P，其中 NHC ^R是 N-杂环卡宾)。该化合物在环境温度下在溶液中是稳定的，并且也以固态分离。与量子化学分析相结合的反应性研究表明，L→C ₂配合物的两个碳原子都具有卡宾特性。该复合物在热解时经历了分子间 C-H 键活化，并与甲醇表现出类似加氢烷氧基化的反应性。