Palladium Complexes of a P₂C Ligand Containing a Central Carbene Moiety

Palladium(II) complexes of the PCHP pincer ligand were prepared from PdCl2, a “proto-pincer” P2CH2, and base. The resulting (PCHP)PdCl was converted to (PCHP)PdOTf. (PCHP)PdCl did not react with NaN(SiMe3)2 but produced (PCHP)PdR (R = Me, Et, Ph) upon reaction with the corresponding organolithium, Grignard, or organozinc reagent. Trityl cation abstracted a hydride from (PCHP)PdCl to yield cationic Pd carbene complex (P2C)PdCl. Analysis of the structural data points to minimal π-interaction between the carbene center and palladium.以二氯化钯（PdCl₂）、“前钳形”配体P₂CH₂与碱为原料，制备得到PCHP钳形配体的二价钯配合物。所得的(PCHP)PdCl可转化为(PCHP)PdOTf。 (PCHP)PdCl与六甲基二硅基胺钠（NaN(SiMe₃)₂）不发生反应，但可与相应的有机锂试剂、格氏试剂或有机锌试剂反应，生成(PCHP)PdR（R = Me、Et、Ph）。 三苯甲基正离子可从(PCHP)PdCl中夺取氢负离子，得到阳离子钯卡宾配合物(P₂C=)PdCl。 对结构数据的分析显示，该卡宾中心与钯之间仅存在极弱的π相互作用。