Activation of C–H and C–Br bonds in cyclopalladation reactions of Schiff base ligands: Influence of the benzylidene ring substituents
作者:Leticia Naya、Digna Vázquez-García、Margarita López-Torres、Alberto Fernández、José M. Vila、Nina Gómez-Blanco、Jesús J. Fernández
DOI:10.1016/j.jorganchem.2007.11.051
日期:2008.2
Reaction of Pd(AcO)2 with the Schiff base ligands 2-Br-4,5-(OCH2O)C6H2C(H)N(Cy) (a) and 4,5-(OCH2CH2)C6H3C(H)N(Cy) (b) leads to the cyclometallated compounds [Pd2-Br-4,5-(OCH2O)C6HC(H)N(Cy)-C6,N}(μ-O2CMe)]2 (1a) and [Pd4,5-(OCH2CH2)C6H2C(H)N(Cy)-C6,N}(μ-O2CMe)]2 (1b), respectively, via C–H activation. Treatment of a with Pd2(dba)3 gave [Pd4,5-(OCH2O)C6H2C(H)N(Cy)-C2,N}(μ-Br)]2 (6a), via C–Br activation
Pd(AcO)2与席夫碱配体2-Br-4,5-(OCH 2 O)C 6 H 2 C(H)N(Cy)(a)和4,5-(OCH 2 CH 2)C 6 H 3 C(H)N(Cy)(b)生成环化金属化合物[Pd 2-Br-4,5-(OCH 2 O)C 6 HC(H)N(Cy)-C6,ñ }(μ-O 2 CME)] 2(1A)和[钯4,5-(OCH 2 CH 2)C 6 H ^ 2 C(H)N(CY) - C6,ñ}(μ-O 2 CME)] 2(图1b),分别通过C-H活化。用Pd 2(dba)3处理a得到[Pd 4,5-(OCH 2 O)C 6 H 2 C(H)N(Cy)-C2,N }(μ-Br)] 2(6a) ,通过C–Br激活。1a和1b与氯化钠水溶液的复分解反应得到相应的具有桥接的氯化物配体2a和2b的环钯二聚体, 分别。用叔三和二膦以适当的摩尔比处理卤素桥连化合物,得到单核和双核化合物3a