摘要：

Recently we have started to study the synthesis and structural analysis of copper complexes containing heavier elements of Group 15.[1] Despite the extensive amount of work that has been carried out in the area of transition-metal complexes of heavier Group 15 elements, there are only a few accounts of antimony- or bismuth-containing copper complexes.[2] Most of these complexes are adducts of copper(I) salts with tertiary stibanes or bismuthines ER3 (E=Sb, Bi; R=aryl or alkyl) as terminal ligands.[3] The first copper(I) antimonide complex [{Mes2SbCu(PMe3)2}2] (Mes=2,4,6-trimethylphenyl) was prepared by the metathesis reaction of Mes2SbLi with CuCl.[4] Our approach to the syntheses of copper(I) antimonides reported herein involves the reaction of Sb(SiMe3)3 with copper(I) salts in the presence of tertiary phosphines (see Scheme 1).[1] By this approach we have already synthesized the copper-antimony clusters [Cu10(Sb3)2(SbSiMe3)2(dppm)6], [Cu17Sb8(dppm)7], and [Cu20Sb10(PCy3)8] (dppm=1,2-bis-(diphenylphosphino)methane, Cy=cyclohexyl).[1a],[c] The different ratio of Cu:Sb present in complexes 2 and 3 suggests copper atoms in the oxidation states 0, +i, or +II. UV/Vis studies and magnetic measurements on these type of compounds, however, did not confirm the presence of metal centers in various oxidation states and instead showed that these compounds are best described as phosphine-stabilized molecular copper-antimony alloys. On our way towards the selective synthesis of molecular alloys and the correlation of their properties with those of CuSb phases which have similar Cu:Sb ratios, we report herein the structure of an intermediate copper-antimony cluster and the two largest molecular CuSb alloys belonging to this class of compounds.[5] The structures of the complexes were established by X-ray crystallography and the results assessed with structures obtained from DFT studies.

展开