Carbon−Hydrogen Bond Cleavage Reaction in 5-Coordinate Bis(2,6-dimethylbenzenethiolato)ruthenium(II) Complexes

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• 作者：Masafumi Hirano ; Sayaka Togashi ; Muneaki Ito ; Yuko Sakaguchi ; Nobuyuki Komine ; Sanshiro Komiya
• 刊名：Organometallics
• 出版年：2010
• 出版时间：July 26, 2010
• 年：2010
• 卷：29
• 期：14
• 页码：3146-3159
• 全文大小：1154K
• 年卷期：v.29,no.14(July 26, 2010)
• ISSN：1520-6041

文摘

A series of bis(2,6-dimethylbenzenethiolato)ruthenium(II) complexes, Ru(SC₆H₃Me₂-2,6-κ¹S)₂(TRIPHOS-κ³P,P′,P′′) (2a), Ru(SC₆H₃Me₂-2,6-κ¹S)₂(TDPME-κ³P,P′,P′′) (2b), trans-Ru(SC₆H₃Me₂-2,6-κ¹S)₂(DPPE-κ²P,P′)₂ (3c) and Ru(SC₆H₃Me₂-2,6-κ¹S)₂(PMe₃)₃ (2d) are prepared. Treatment of 2a with PMe₃ in benzene at 50 °C results in the sp³ C−H bond cleavage reaction of the ortho methyl in thiolato group to give a stereochemical mixture of thiaruthenacycle complex Ru[SC₆H₃(CH₂-2)(Me-6)-κ²S,C](TRIPHOS-κ³P,P′,P′′)(PMe₃) (1a) in 70% yield ([(OC-6−34)-1a]/[(OC-6−25)-1a] = 80/20) with concomitant liberation of 2,6-dimethylbenzenethiol. Similar treatment of 2d with PMe₃ in benzene at room temperature rapidly produced cis-Ru[SC₆H₃(CH₂-2)(Me-6)-κ²S,C](PMe₃)₄ (1d) quantitatively. Treatment of 2b with PMe₃ results in the formation of 1d by the C−H bond cleavage reaction and ligand displacement reaction. The C−H bond cleavage reaction does not occur from 3c under these conditions. Treatment of 2d with PMe₃ in methanol does not give 1d at all but yields cis-Ru(SC₆H₃Me₂-2,6-κ¹S)₂(PMe₃)₄ (3d), which is not responsible for formation of 1d, suggesting importance of coordinative unsaturation for the C−H bond cleavage reaction. The kinetic study suggests that present C−H bond cleavage reaction proceeds by a concerted mechanism.