Lanza Santo, Bruno Giuseppe, Nicolò Francesco, Callipari Giovanna, Tresoldi Giuseppe
Dipartimento di Chimica Inorganica, Chimica Fisica e Chimica Analitica Villaggio S. Agata, Salita Sperone 31, 98166 Messina, Italy.
Inorg Chem. 2003 Jul 28;42(15):4545-52. doi: 10.1021/ic034233d.
Bischelate platinum(II) complexes of the type [Pt(H-R(2)-N(2)C(2)S(2))(2)] (H-R(2)-N(2)C(2)S(2)(-) = dialkyl-dithioxamidate) are ditopic receptors which, after coordination of the first Pd(eta(3)-allyl)(+) moiety, induce the orientation of the second palladium-allyl fragment. Thus, a series of trimetallic complexes of formula bis-(eta(3)-allyl)-palladium(II) kappa-S,S-kappa-S',S'-Pt-kappa-N,N-Pd-kappa-N',N'-Pd') has been prepared in which the allyl fragments are oriented toward the same side of the molecular plane. We have also prepared the trimetallic complex using a dithioxamide obtained from the racemic phenylethylamine. Only two isomers were produced in equimolar ratio: the racemate that has four homochiral alkyl substituents and the mesoform containing the meso-dithioxamide that has homochiral substituents on the same side of molecular plane. Under the effect of the temperature, the trimetallic Pd-Pt-Pd complexes undergo rapid allyl isomerization; the mechanism of the isomerization, which is similar to that found by us in an analogue Pt-Pd bimetallic complex, is discussed. The crystal and molecular structure of bis-(eta(3)-allyl)-palladium(II) kappa-S,S-kappa-S',S'-Pt-kappa-N,N-Pd-kappa-N',N'-Pd') has been reported.
[Pt(H-R(2)-N(2)C(2)S(2))(2)]类型的双螯合铂(II)配合物（H-R(2)-N(2)C(2)S(2)(-) = 二烷基二硫代草酰胺酸根）是双位点受体，在第一个Pd(η(3)-烯丙基)(+)部分配位后，会诱导第二个钯-烯丙基片段的取向。因此，已制备了一系列通式为双-(η(3)-烯丙基)-钯(II) κ-S,S-κ-S',S'-Pt-κ-N,N-Pd-κ-N',N'-Pd')的三金属配合物，其中烯丙基片段朝向分子平面的同一侧。我们还使用从外消旋苯乙胺得到的二硫代草酰胺制备了三金属配合物。仅以等摩尔比生成了两种异构体：具有四个同手性烷基取代基的外消旋体和含有在分子平面同一侧具有同手性取代基的内消旋二硫代草酰胺的内消旋体。在温度的影响下，三金属Pd-Pt-Pd配合物会发生快速的烯丙基异构化；讨论了异构化的机理，其与我们在类似的Pt-Pd双金属配合物中发现的机理相似。已报道了双-(η(3)-烯丙基)-钯(II) κ-S,S-κ-S',S'-Pt-κ-N,N-Pd-κ-N',N'-Pd')的晶体和分子结构。
