Assembly of metal-metal bonds through small-size clusters

金属-金属键合的铂和钯小分子簇作为多相催化剂表面的最小模型越来越受到人们的关注；通过改变合成策略和有机配体的选择，可以改变催化剂的结构、性质和反应活性。报道了双(二苯基膦甲基)苯基膦(DPMP)通过双铂前驱体系统地合成了同金属和异三金属铂簇合物。[Pt2(Rnc)6]^&lt；2+&gt；(RNC=芳香族异氰酸酯)与DPMP反应，得到了一种[Pt2(Dpmp)2(Rnc)2]^&lt；2+&gt；(syn-1和anti-2)的异构体。Syn-1和anti-2的不同反应活性允许获得同核和异三核簇的多种聚集体。前者(syn-1)经Pt0、Pt2、Pd0、Pd2+、Rh、Ir、Ir、Au、Au、Ag1和Cu1处理后转变为多种铂-铂-M簇合物，线形-[Pt2(Dpmp)2(Rnc)2]^lt；2+&gt；(M=铂，Pd)，asym-A-frame-[Pt_2MCl_2(dpmp)_2(RNC)_2]^&lt；2+&gt；(M=铂，钯)，T-形-[铂_2MCl(Dpmp)_2(Rnc)_2]^&lt；2+&gt；(M=Ir，Rh)，Y-形-[铂_2m(Dpmp)_2(Rnc)_2]^&lt；3+&gt；(M=Au，Ag)，菱形-[铂_2CuX(Dpmp)_2]^&lt；2+&gt；(X=Cl，Br，I)。含Pt0和Pd^0物种的络合物ANTI-2处理后得到了铂-铂-铂和铂-钯-铂A-骨架簇合物。有趣的是，另一个金属的插入位置受两个非配位膦单元1和2的排列所调节。还制备了双核和三核钯、钼与DPMP的配合物并进行了表征。

Metal-metal bonded small-size clusters of platinum and palladium have been of increasing interest as minimal models for the surface of heterogeneous catalysts ; structures, properties, and reactivities are able to be modified by varying the synthetic strategy and the choice of organic ligands. Systematic syntheses of homo- and heterotrimetallic platinum clusters through diplatinum precursors with bis (diphenylphosphino m ethyl) phenyl phosphine (dpmp) are reported. The reaction of [Pt_2(RNC)_6]^<2+> (RNC=aromatic isocyanide) with dpmp afforded an isomeric mixture of syn- and anti-[Pt_2(dpmp)_2(RNC)_2]^<2+> (syn-1 and anti-2). The differential reactivity of syn-1 and anti-2 allows an access to versatile aggregations of homo and hetero trinuclear clusters. The former (syn-1) was transformed by treatment with Pt^0, Pt^<II>, Pd^0, Pd^<II>, Rh^I, Ir^I, Au^I, Ag^I, and Cu^I species to a wide variety of Pt-Pt-M clusters, linear-[Pt_2(dpmp)_2(RNC)_2]^<2+> (M=Pt, Pd), asym-A-frame-[Pt_2MCl_2(dpmp)_2(RNC)_2]^<2+> (M=Pt, Pd), T-shape-[Pt_2MCl(dpmp)_2(RNC)_2]^<2+> (M=Ir, Rh), Y-shape-[Pt_2M(dpmp)_2(RNC)_2]^<3+> (M=Au, Ag), and rhombic-[Pt_2CuX(dpmp)_2]^<2+> (X=Cl, Br, I). Treatment of complex anti-2 with Pt^0 and Pd^0 species gave Pt-Pt-Pt and Pt-Pd-Pt A-frame clusters. The inserted position of an additional metal was interestingly regulated by the arrangements of two uncordinate phosphine units of 1 and 2. Di- and trinuclear plladium and molybdenum complexes with dpmp were also prepared and characterized.