Synthesis and structure of tetranuclear orthometallated Pd(ii) complexes derived from bis-iminophosphoranes
作者:Raquel Bielsa、Rafael Navarro、Tatiana Soler、Esteban P. Urriolabeitia
DOI:10.1039/b718108f
日期:——
The reaction of Pd(OAc)2 with bis-iminophosphoranes Ph3PNCH2CH2CH2NPPh3 (1a), [C6H4(C(O)NPPh3)2-1,3] (1b) and [C6H4(C(O)NPPh3)2-1,2] (1c), gives the orthopalladated tetranuclear complexes [Pd(µ-Cl)C6H4(PPh2NCH2-κ-C,N)-2}}2CH2]2 (2a) [Pd(µ-OAc)C6H4(PPh2NC(O)-κ-C,N)-2}}2C6H4-1′,3′]2 (2b) and [Pd(µ-OAc)C6H4(PPh2NC(O)-κ-C,N)-2}}2C6H4-1′,2′]2 (2c). The reaction takes place in CH2Cl2 for 1a, but must be performed in glacial acetic acid for 1b and 1c. The process implies in all cases the activation of a C–H bond on a Ph ring of the phosphonium group, with concomitant formation of endo complexes. This is the expected behaviour for 1a, but for 1b and 1c reverses the exo orientation observed in other ketostabilized iminophosphoranes. The influence of the solvent in the orientation of the reaction is discussed. The dinuclear acetylacetonate complexes [Pd(acac-O,O′)C6H4(PPh2NCH2-κ-C,N)-2}}2CH2] (3a), [Pd(acac-O,O′)C6H4(PPh2NC(O)-κ-C,N)-2}}2C6H4-1′,3′] (3b) and [Pd(acac-O,O′)C6H4(PPh2NC(O)-κ-C,N)-2}}2C6H4–1′,2′] (3c) have been obtained from the halide-bridging tetranuclear derivatives. The X-ray crystal structure of [3c·4CHCl3] is also reported.
Pd(OAc)2 与双亚氨基磷烷 Ph3PNCH2CH2CH2NPPh3 (1a)、[C6H4(C(O)NPPh3)2-1,3] (1b) 和 [C6H4(C(O)NPPh3)2-1,2] (1c)反应,得到正钯化四核配合物 [Pd(µ-Cl)C6H4(PPh2NCH2-κ-C、N)-2}}2CH2]2 (2a) [Pd(µ-OAc)C6H4(PPh2NC(O)-κ-C,N)-2}}2C6H4-1′,3′]2 (2b) 和 [Pd(µ-OAc)C6H4(PPh2NC(O)-κ-C,N)-2}}2C6H4-1′,2′]2 (2c)。1a 的反应在 CH2Cl2 中进行,但 1b 和 1c 的反应必须在冰醋酸中进行。在所有情况下,反应过程都意味着膦基 Ph 环上的 C-H 键被活化,同时形成内络合物。这是 1a 的预期行为,但对于 1b 和 1c,在其他酮稳定亚氨基磷烷中观察到的外向性发生了逆转。本文讨论了溶剂对反应取向的影响。二核乙酰丙酮配合物 [Pd(acac-O,O′)C6H4(PPh2NCH2-κ-C,N)-2}}2CH2] (3a)、[Pd(acac-O,O′)C6H4(PPh2NC(O)-κ-C,N)-2}}2C6H4-1′、3′](3b)和[Pd(acac-O,O′)C6H4(PPh2NC(O)-κ-C,N)-2}2C6H4-1′,2′](3c)是从卤桥四核衍生物中得到的。同时还报告了 [3c-4CHCl3] 的 X 射线晶体结构。