Synthesis and characterization of organopalladium complexes containing a fluoro ligand
Synthesis and characterization of organopalladium complexes containing a fluoro ligand
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DOI：
10.1021/om9708440
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发表时间：
1998-04-27
期刊：
影响因子：
2.8
通讯作者：
Grushin, VV
中科院分区：
文献类型：
--
作者：
Pilon, MC;Grushin, VV
本文报道了含氟配体[（Ph_3P）（2）Pd（F）R]有机钯配合物的合成。已经开发了两种通用的合成策略：（i）用TREAT HF（[（HF）（3））中和羟基钯二聚体[（Ph 3 P）（2）Pd-2（R）（2）（μ-OH）（2）]（R = Me或Ph）。NEt 3]）;（ii）在苯中超声促进[（Ph 3 P）（2）Pd（I）R]与AgF之间的交换。用TREAT HF进行合成时，不可使用过量的HF源;否则，会形成相应的二氟化物[（Ph 3 P）（2）Pd-（FHF）R]。在5-10%的相应有机碘化物RI存在下进行I/F交换有利于所需氟络合物的纯度。所有配合物1-10已经通过各种方法充分表征。[（Ph 3 P）（2）Pd（F）R]中的氟配体在低极性的无水介质中是惰性的。然而，在痕量水的存在下，观察到F配体交换。没有发生Pd-F键的不可逆水解，因为[（Ph 3 P）（2）Pd（F）R]仍然是系统中唯一可观察到的（NMR）物质。对不同[（Ph_3P）（2）Pd（F）R]在CH_2Cl_2中的水饱和溶液进行了VT NMR研究，揭示了H_2O促进的F配体交换过程的推/拉型“两亲性”机理. Pd-F键断裂可能涉及水对金属中心的亲核攻击，伴随着氟配体和H2O之间形成氢键。
The synthesis of organopalladium complexes containing a fluoro ligand, [(Ph3P)(2)Pd(F)R], is described. Two general synthetic strategies have been developed: (i) neutralization of hydroxo palladium dimers, [(Ph3P)(2)Pd-2(R)(2)(mu-OH)(2)] (R = Me or Ph), with TREAT HF ([(HF)(3) . NEt3]) in the presence of PPh3 and (ii) the ultrasound-promoted exchange between [(Ph3P)(2)Pd(I)R] and AgF in benzene. It is essential for the synthesis with TREAT HF that no excess of the HF source is used; otherwise, the corresponding bifluorides, [(Ph3P)(2)Pd-(FHF)R], are formed instead. Conducting the I/F exchange in the presence of 5-10% of the corresponding organic iodide, RI, is beneficial for purity of the desired fluoro complexes. All complexes 1-10 have been fully characterized by a variety of methods. The fluoro ligand in [(Ph3P)(2)Pd(F)R] is inert in anhydrous media of low polarity. However, in the presence of trace amounts of water, F ligand exchange is observed. No irreversible hydrolysis of the Pd-F bond takes place as [(Ph3P)(2)Pd(F)R] remains the only observable (NMR) species in the system. VT NMR studies of various [(Ph3P)(2)Pd(F)R] in CH2Cl2 saturated with water have been conducted, revealing a push/pull-type, "ambiphilic" mechanism of the H2O-promoted F ligand-exchange process. The Pd-F bond cleavage likely involves nucleophilic attack of water on the metal center, concomitantly occurring with the formation of a hydrogen bond between the fluoro ligand and H2O.