An Unusual Cobalt Azide Adduct That Produces a Nitrene Species for Carbon–Hydrogen Insertion Chemistry

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• 作者：Lauren N. Grant ; Maria E. Carroll ; Patrick J. Carroll ; Daniel J. Mindiola
• 刊名：Inorganic Chemistry
• 出版年：2016
• 出版时间：August 15, 2016
• 年：2016
• 卷：55
• 期：16
• 页码：7997-8002
• 全文大小：395K
• 年卷期：0
• ISSN：1520-510X

文摘

A family of Co(II) complexes supported by the bulky, dianionic bis(pyrrolyl)pyridine pincer ligand pyrr₂py [pyrr₂py^2– = 3,5-^tBu₂-bis(pyrrolyl)pyridine] are reported in this work. These compounds include 1-OEt₂, 1·toluene, and 1-N₃Ad (Ad = 1-adamantyl), the latter which is prepared via addition of N₃Ad to 1-OEt₂ [1 = (pyrr₂py)Co]. While complexes 1-OEt₂ and 1-N₃Ad are four-coordinate systems having a Co(II) ion confined in a cis-divacant octahedral geometry, complex 1·toluene possesses a Co(II) ion in a T-shaped environment where the toluene is interstitial and intercalated between two (pyrr₂py)Co molecules. Complex 1-N₃Ad is notable in that the organic azide binds to the metal through γ-N in a κ¹ fashion. Photolysis of 1-N₃Ad results in N₂ extrusion and formation of C–H insertion product [(pyrrpypyrrNHAd)Co] (2). We propose complex 2 form via insertion of the nitrene (NAd) into one ^tBu C–H bond, thus resulting in a pincer ligand having a pendant secondary amine. Complexes 1-OEt₂, 1·toluene, and 1-N₃Ad and C–H insertion product 2 have been structurally characterized, and in the case of 1-OEt₂, we also present electrochemical data.