Two classes of cationic palladium(II) phosphine carboxylate complexes were isolated and characterized. Reactions of trans-[(R3P)(2)Pd(O2CR')(2)] (1) with [Li(OEt2)(2.5)][B(C6F5)(4)] in MeCN led to carboxylate abstraction and formation of trans-[(R3P)(2)Pd(O2CR')(MeCN)][B(C6F5)(4)] (2) in good to excellent yields. On the other hand, carboxylate abstraction reactions of 1 with [Me-2(H)NPh][B(C6F5)(4)] or p-toluenesulfonic acid (HOTs center dot H2O) in CH2Cl2 furnished the palladium cations [(R3P)(2)Pd(kappa(2)-O,O-O2CR')](+) (3). The reactions of 2 and 3 with Lewis bases were found to be different in some cases. For example, reactions of 2 with pyridine furnished the simple products of acetonitrile substitution, trans-[(R3P)(2)Pd(O2CR')(py)][B(C6F5)(4)]. In contrast, the reaction of 3e (R = Pr-i, R' = CH3) with CD3CN in the presence of excess sodium carbonate yielded a material derived from cyclometalation of one of the Pr-i arms of a (Pr3P)-Pr-i ligand. New complexes were characterized by elemental analyses and NMR (H-1, C-13, and P-31) spectroscopic methods and in two cases by single-crystal X-ray structural methods.
Synthesis and Reactivity of Cationic Palladium Phosphine Carboxylate Complexes
作者:Natesan Thirupathi、Dino Amoroso、Andrew Bell、John D. Protasiewicz
DOI:10.1021/om050356p
日期:2005.8.1
Simple routes to two new types of mononuclear cationicpalladium phosphine acetate complexes featuring κ1- or κ2-carboxylates have been developed, and the resulting materials have been characterized by single-crystal X-ray diffraction. In acetonitrile the complex [(iPr3P)2Pd(κ2O,O‘-OAc)]+ leads not to the independently prepared trans-[(iPr3P)2Pd(MeCN)(OAc)]+ but to reversible cyclometalation to form
简单路由到两个新类型的单核的阳离子钯膦配合物醋酸设有κ的1 -或κ 2个-carboxylates被开发出来,并且所得到的材料的特点是单晶X射线衍射。在乙腈络合物[(我镨3 P)2的Pd(κ 2 ø,ö “-OAc)] +引线不将独立制备的反式- [(我镨3 P)2的Pd(MeCN中)(OAC)] +但可逆环金属化以形成[(我镨3 P)(乙腈)钯(κ 2C,P- C(Me)2 P i Pr 2)] +。
The Impact of Palladium(II) Reduction Pathways on the Structure and Activity of Palladium(0) Catalysts
作者:Carolyn S. Wei、Geraint H. M. Davies、Omid Soltani、Jacob Albrecht、Qi Gao、Charles Pathirana、Yi Hsiao、Srinivas Tummala、Martin D. Eastgate
DOI:10.1002/anie.201210252
日期:2013.5.27
Two roads diverged: The mechanism of in situ PdII catalyst activation to generate an active LnPd0} catalyst from an air‐stable PdII precursor was examined using the standard conditions of a Miyaura borylation reaction. Two pathways for catalyst activation exist under these conditions, producing two structurally and chemically distinct LnPd0} complexes (see scheme).
两条道路分歧:使用Miyaura硼化反应的标准条件,研究了原位Pd II催化剂活化从空气稳定的Pd II前体生成活性L n Pd 0 }催化剂的机理。在这些条件下存在两种催化剂活化途径,产生两种结构和化学上不同的L n Pd 0 }配合物(参见方案)。