Carborane Substituents Promote Direct Electrophilic Insertion over Reduction–Metalation Reactions |
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Authors: | Dr Wing Y Man Dr David Ellis Dr Georgina M Rosair Prof Alan J Welch |
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Institution: | Institute of Chemical Sciences, Heriot-Watt University, Edinburgh, UK |
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Abstract: | Two‐electron reduction of 1,1′‐bis(o‐carborane) followed by reaction with Ru(η‐mes)Cl2]2 affords 8‐(1′‐1′,2′‐closo‐C2B10H11)‐4‐(η‐mes)‐4,1,8‐closo‐RuC2B10H11]. Subsequent two‐electron reduction of this species and treatment with Ru(η‐arene)Cl2]2 results in the 14‐vertex/12‐vertex species 1‐(η‐mes)‐9‐(1′‐1′,2′‐closo‐C2B10H11)‐13‐(η‐arene)‐1,13,2,9‐closo‐Ru2C2B10H11] by direct electrophilic insertion, promoted by the carborane substituent in the 13‐vertex/12‐vertex precursor. When arene=mesitylene (mes), the diruthenium species is fluxional in solution at room temperature in a process that makes the metal–ligand fragments equivalent. A unique mechanism for this fluxionality is proposed and is shown to be fully consistent with the observed fluxionality or nonfluxionality of a series of previously reported 14‐vertex dicobaltacarboranes. |
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Keywords: | bis(carboranes) fluxionality metalation metallacarboranes two-electron reduction |
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