The rich chemistry of transition-metal (TM) carbyne complexes has fueled their application in a wide range of fields, from synthetic chemistry to materials science. The isomeric forms of these complexes are monometal-substituted carbenes and have so far been detected only in the gas phase. In this article, we describe the synthesis of crystalline monometal-substituted free carbenes. To isolate these molecules, we selected a bulky π-donor substituent and a closed-shell electron-rich TM center as the substituents around the carbene center. This combination allows these metallocarbenes to exhibit a nucleophilic carbenic character with a high-lying highest occupied molecular orbital (HOMO) arising from the metal substituent. Additionally, we report a formal rearrangement of the metallocarbene to a zwitterionic species containing a carbyne anion, which makes these free compounds not only synthetic astonishments but also attractive for the development of novel subvalent carbon-transfer reactions.

过渡金属 (TM) 卡炔配合物的丰富化学特性推动了它们在从合成化学到材料科学等广泛领域的应用。这些配合物的异构形式是单金属取代的卡宾，迄今为止仅在气相中检测到。在本文中，我们描述了结晶单金属取代的游离卡宾的合成。为了分离这些分子，我们选择了一个庞大的 π- 供体取代基和一个闭壳富电子 TM 中心作为卡宾中心周围的取代基。这种组合使这些金属卡宾表现出亲核卡宾特性，具有由金属取代基产生的高位最高占据分子轨道 (HOMO)。此外，我们报告了金属卡宾正式重排为含有卡宾阴离子的两性离子物质，