Synthesis, structure, theoretical studies, and ligand exchange reactions of monomeric, T-shaped arylpalladium(II) halide complexes with an additional, weak agostic interaction
Synthesis, structure, theoretical studies, and ligand exchange reactions of monomeric, T-shaped arylpalladium(II) halide complexes with an additional, weak agostic interaction
复制标题
DOI：
10.1021/ja037928m
复制
发表时间：
2004-02-04
影响因子：
15
通讯作者：
Hartwig, JF
中科院分区：
文献类型：
--
作者：
Stambuli, JP;Incarvito, CD;Hartwig, JF
一系列单体芳基钯（II）配合物LPd(Ph)X (L = 1-AdP(t)BUu, (PBu3)-Bu-t或Ph(5)FcP(t)Bu(2) (Q-phos)；制备了含有单个膦配体的X = Br， I, OTf)。在1等量的磷化氢存在下，芳基溴或芳基碘化物氧化加成到大体积、试验基磷化氢的双连接钯(O)配合物或Pd(dba)(2) （dba =二苄基丙酮）上，可以得到相应的芳基钯（II）配合物，收率很高。相比之下，氯化苯在双连接钯(O)配合物上的氧化加成不会产生芳基钯（II）配合物。三氟化苯酯对PdL2 (L = 1-AdP（t)Bu(2)， PBu3或Q-phos）的氧化加成也不会形成芳基钯（II）配合物。三酸银与(1-AdP(t)Bu(2))Pd(Ph)Br反应生成相应的芳基三酸钯，收率较高。苯基溴和碘化物对Pd(Q-phOS)(2)的氧化加成比Pd(1-AdP(t)Bu(2))(2)或Pd((PBu3)-Bu-t)(2)的氧化加成要快。用x射线衍射对几种芳基钯配合物进行了表征。所有芳基钯（II）配合物都是t形单体。苯基配体的反式影响最大，位于开放配位的反式位置。配合物似乎是通过金属与位于钯中心第四配位的配体C-H键的弱有机相互作用而稳定的。根据密度泛函理论，钯-氢键的强度取决于辅助配体对钯的给体性质。
A series of monomeric arylpalladium(II) complexes LPd(Ph)X (L = 1-AdP(t)BUu, (PBu3)-Bu-t, or Ph(5)FcP(t)Bu(2) (Q-phos); X = Br, I, OTf) containing a single phosphine ligand have been prepared. Oxidative addition of aryl bromide or aryl iodide to bis-ligated palladium(O) complexes of bulky, trial kylphosphines or to Pd(dba)(2) (dba = dibenzylidene acetone) in the presence of 1 equiv of phosphine produced the corresponding arylpalladium(II) complexes in good yields. In contrast, oxidative addition of phenyl chloride to the bis-ligated palladium(O) complexes did not produce arylpalladium(II) complexes. The oxidative addition of phenyl triflate to PdL2 (L = 1-AdP(t)Bu(2), PBu3, or Q-phos) also did not form arylpalladium(II) complexes. The reaction of silver triflate with (1-AdP(t)Bu(2))Pd(Ph)Br furnished the corresponding arylpalladium(II) triflate in good yield. The oxidative addition of phenyl bromide and iodide to Pd(Q-phOS)(2) was faster than oxidative addition to Pd(1-AdP(t)Bu(2))(2) or Pd((PBu3)-Bu-t)(2). Several of the arylpalladium complexes were characterized by X-ray diffraction. All of the arylpalladium(II) complexes are T-shaped monomers. The phenyl ligand, which has the largest trans influence, is located trans to the open coordination site. The complexes appear to be stabilized by a weak agostic interaction of the metal with a ligand C-H bond positioned at the fourth-coordination site of the palladium center. The strength of the Pd...H bond, as assessed by tools of density functional theory, depended upon the donating properties of the ancillary ligands on palladium.