Bisvinylated [R–Ge9–Ge9–R] 4– cluster dimers

Abstract

The syntheses, crystal structures, and NMR and Raman spectroscopic characterization of two compounds with a new member of the organically functionalized dimeric Ge-9-Ge-9 polyanion [R-Ge-9-Ge-9-R] 4-with R=CH=CH2 are presented. [K([2.2.2] crypt)](4)[(CH2=CH)-Ge-9-Ge-9-(CH=CH2)]center dot 1.76 en (1) was synthesized either at elevated temperature by the reaction of K4Ge9 and bis(trimethylsilyl) acetylene in ethylenediamine or at ambient temperature in the presence of Pt(PPh3)(4). [K([18]crown-6)](4)[(CH2=CH)-Ge-9-Ge-9-(CH=CH2)]center dot 4 en (2) was obtained from the prefabricated monomeric bisvinylated Ge-9 cluster [Ge-9(CH=CH2)(2)](2-) and an ethylenediamine solution of the intermetallic compound K4.79Co0.79Sn9. The reductive cleavage of one or two vinyl groups from [Ge-9(CH=CH2)(2)](2-) - a prerequisite for the latter reaction - could be shown by reacting a solution of the divinylated [Ge-9(CH=CH2)(2)](2-) anion in liquid ammonia with elemental potassium, which resulted in the formation of the ligand-free Ge-9(4-) cluster in the new compound [K-5(OH)]Ge-9(NH3)(11) (3).