Chalkogen-Verbrückte Derivate des Pentamethylcyclopentadienylrhenium-Halbsandwich-Fragments (Cp★Re): Bildung und Molekülstruktur der Selenkomplexe Cp★ 2Re 2(μ-Se 4) 2 und Cp★ 2Re 2O 2(μ-Se) 2

Abstract

Starting from the halfsandwich compound Cp★Re(O)Cl 2, the chalcogen-bridged binuclear complexes Cp★ 2Re 2(μ-E 4) 2 (E  S, Se), Cp★ 2Re 2O 2(μ-E)(μ-E 2)(E  S, Se) and Cp★ 2Re 2O 2(μ-E) 2 (E  Se, Te) have been prepared by reaction with oligochalcogenides and subsequent chalcogen abstraction using tertiary phosphanes, PR 3. The molecular structures in the crystalline state of three selenium compounds have been determined by X-ray structure analyses; in contrast to the oxo complexes, the oxygen-free compounds Cp★ 2Re 2(μ-E 4) are distinguished by a strong intramolecular ReRe interaction ( d(ReRe) 2.692 (1)Å in Cp★ 2Re 2(μ-Se 4) 2, d(Re … Re) 4.32 Å and 3.77 Å in Cp★ 2Re 2O 2(μ-Se) (μ-Se 2) and Cp★ 2Re 2O 2(μ-Se) 2, respectively). The reactions of Cp★Re(O)Cl 2 with either Na 2S 4 or (NEt 4) 2Se 6 lead initially to the mononuclear cyclo-tetrachalcogenide compounds Cp★Re(O)(E 4) (E  S, Se), which can then be converted into the binuclear complexes. However, Cp★ 2Re 2O 2(μ-Te) 2 was directly formed in the reaction between Cp★Re(O)Cl 2 and (N nBu 4) 2Te 5.