Chloride-Modulated Insertion Reactions of Dimethylallene across the Pd-C Bond in Palladium Methyl Complexes Bearing Potentially Terdentate Pyridylthioether Ligands

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• 作者：Luciano Canovese ; Fabiano Visentin ; Gavino Chessa ; Paolo Uguagliati ; Claudio Santo ; Giuliano Bandoli ; and Lucia Maini
• 刊名：Organometallics
• 出版年：2003
• 出版时间：August 4, 2003
• 年：2003
• 卷：22
• 期：16
• 页码：3230 - 3238
• 全文大小：160K
• 年卷期：v.22,no.16(August 4, 2003)
• ISSN：1520-6041

文摘

Palladium methyl complexes with potentially terdentate pyridylthioether (S-N-S(R) =2,6-bis(R-thiomethyl)pyridine, R = Me, t-Bu, Ph; N-S-N = 2[(2-pyridylmethylthio)methyl]pyridine) ligands have been prepared and characterized. Both the bidentate chloride[Pd(Me)(S-N-S(R))]Cl and the terdentate chloride-free [Pd(Me)(S-N-S(R))]⁺ species arepresent in solution and display a substantially different reactivity toward allene insertionacross the Pd-C bond. The structures of the complexes [Pd(Me)(S-N-S(t-Bu))]OTf and[Pd(Me)(S-N-S(t-Bu))]Cl were determined by X-ray diffraction. The chloride methylsubstrates [Pd(Me)(S-N-S(R))]Cl display an enhanced reactivity in solution with respectto the allene insertion, and this reactivity was traced back to the distortion of the maincoordination plane induced by the presence of an uncoordinated -CH₂-S-R group in position6 of the coordinating pyridine. The equilibrium position between the terdentate and thebidentate species can be modulated by addition of chloride ion, which therefore controls theoverall reactivity of the system.