Cyclopalladated azido dimers having various C,N-donor ligands, [Pd(μ-N3)(C,N-Ln)]2 (L1H = 2-(2â²-thienyl)pyridine; L2H = azobenzene; L3H = 3,3â²-dimethylazobenzene; L4H = N,Nâ²-dimethylbenzylamine; L5H = 2-phenylpyridine), underwent cleavage with tertiary (or chelating) phosphines to form the cyclopalladated [Pd(N3)(PR3)(C,N-L)], the Ï-bonded [Pd(N3)(PR3)2(C-L)], or the dinuclear-cyclopalladated [PdN3(PR3)(C,N-L)]2(μ-Pâ¼P) complexes. In particular, treating [Pd(μ-N3)(C,N-L)]2 with the basic chelating phosphine (depe or dmpe) produced the homoleptic bis(chelating) complex [Pd(C,N-Ln)2] (n = 1â3). Complex [Pd(N3)(PR3)(C,N-L4)] or [Pd(N3)(PR3)2(C-L4)] reacted with aryl isocyanides to selectively give the imidoyl [Pd(N3)(âCNâAr)(PR3)(N-L4)] or the imidoyl carbodiimido complex [Pd(NCNâAr)(âCNâAr)(PR3)(N-L4)], which was formed by the CNâAr insertion into the orthometallated PdâC bond on the phenyl moiety or the interaction into the PdâN3 bond of the supporting ligand. In addition, reactions of [Pd(N3)(PR3)2(C-Ln)] (n = 1, 2, 4) with RâNCS R = i-Pr, C6H4âNCS, (CH3)3Si} gave the S-coordinated tetrazoleâthiolato Pd(II) complexes. Finally, the catalytic activity of the cyclopalladated azido complexes was evaluated.
具有不同C,N供体
配体的环
钯化
叠氮化物二聚体,[Pd(μ-N3)(C,N-Ln)]2(L1H = 2-(2′-
噻吩基)
吡啶;
L2H =
偶氮苯;L3H = 3,3′-二甲基
偶氮苯;L4H = N,N′-二甲基
苄胺;L5H =
2-苯基吡啶),与叔烷基(或螯合)
磷配体发生断裂反应,形成环
钯化的[Pd(N3)(PR3)(C,N-L)]、σ-键合的[Pd(N3)(PR3)2(C-L)],或双核环
钯化的[PdN3(PR3)(C,N-L)]2(μ-P≡P)复合物。特别地,将[Pd(μ-N3)(C,N-L)]2与含碱的螯合
磷配体(depe或dmpe)反应,生成同配位的双(螯合)复合物[Pd(C,N-Ln)2](n = 1–3)。复合物[Pd(N3)(PR3)(C,N-L4)]或[Pd(N3)(PR3)2(C-L4)]与芳基
异氰酸酯反应选择性地产生
亚胺基复合物[Pd(N3)(–CN–Ar)(PR3)(N-L4)]或
亚胺基碳二
亚胺复合物[Pd(NCN–Ar)(–CN–Ar)(PR3)(N-L4)],后者是通过CN–Ar插入到与苯基部分的正位
金属化的Pd–C键或与支持
配体的Pd–N3键的相互作用形成的。此外,[Pd(N3)(PR3)2(C-Ln)](n = 1, 2, 4)与R–
NCS(R = i-Pr,
C6H4–
NCS, (
CH3)3Si)的反应生成了S配位的四氮杂环–
硫代
钯(II)复合物。最后,评估了环
钯化
叠氮化物复合物的催化活性。