Synthesis and Reactivity of the Imido-Bridged Metallothiocarboranes CpCo(S2C2B10H10)(NSO2R)

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• 作者：Wei Zhong ; Qiwu Yang ; Yi Shang ; Guifeng Liu ; Haitao Zhao ; Yizhi Li ; Hong Yan
• 刊名：Organometallics
• 出版年：2012
• 出版时间：September 24, 2012
• 年：2012
• 卷：31
• 期：18
• 页码：6658-6668
• 全文大小：663K
• 年卷期：v.31,no.18(September 24, 2012)
• ISSN：1520-6041

文摘

The reactions of the 16-electron half-sandwich complex CpCo(S₂C₂B₁₀H₁₀) (1) (Cp: cyclopentadienyl) with sulfonyl azides (p-toluenesulfonyl azide, TsN₃; methanesulfonyl azide, MsN₃) in refluxing dichloromethane or at ambient temperature lead to imido-bridged adducts CpCo(S₂C₂B₁₀H₁₀) (NSO₂R) (2a, R = 4-MePh; 2b, R = Me) which can convert to the tetraazadiene cobalt complexes CpCoN₄(SO₂R)₂ (3a, R = 4-MePh; 3b, R = Me) in the presence of excess azide if heated. The reactions of 1 with acyl azides (methyl azidoformate and benzoyl azide) lead to CpCo(S₂C₂B₁₀H₁₀)(CONR) (4a, R = OMe; 4b, R = Ph) with a newly-generated five-membered metallacyclic ring Co鈥揝鈥揘鈥揅鈥揙. Complexes 2a and 2b show further reactivity toward alkynes to give rise to the insertion products CpCo(S₂C₂B₁₀H₁₀)(R₁C鈺怌R₂) (NSO₂R) (R₁ = COOMe, R₂ = H, R = 4-MePh, 5a, R = Me, 5b; R₁ = R₂ = COOMe, R = 4-MePh, 6a, R = Me, 6b; R₁ = COOMe, R₂ = Ph, R = 4-MePh, 8a, R = Me, 8b) formed by alkyne addition to a Co鈥揝 bond to generate a Co鈥揅鈥揅鈥揝 four-membered ring and CpCo(S₂C₂B₁₀H₁₀)(R₁C鈺怌R₂NSO₂R) (R₁ = H, R₂ = Ph, R = 4-MePh, 7a, R = Me, 7b; R₁ = COOMe, R₂ = Ph, R = 4-MePh, 9a, R = Me, 9b) formed by alkyne insertion into a Co鈥揘 bond to generate a Co鈥揅鈥揅鈥揘鈥揝 five-membered ring. In the case of PhC鈮CO₂Me, the products with insertion into both Co鈥揝 and Co鈥揘 bonds are isolated. Interestingly, if tert-butylacetylene is used, CpCo(S₂C₂B₁₀H₁₀)(R₁R₂C鈺怌NSO₂R) (R₁ = tBu, R₂ = H, R = 4-MePh, 10a, R = Me, 10b) are generated by insertion of terminal carbon into a Co鈥揘 bond to form four-membered ring Co鈥揅鈥揘鈥揝. The insertion pathways of these reactions have been discussed on the basis of DFT calculations. All the new complexes were fully characterized, and X-ray structural analyses were performed for 2a, 3a, 3b, 4a, 4b, 5a, 6a, 7a, 7b, 8a, 9a, 9b, and 10b.