Heteroatomic Deltahedral Zintl Ions of Group 14 and their Alkenylation

Reported is the synthesis of Ge9-xSnx heteroatomic deltahedral Zintl ions and their alkenylation by reactions with alkynes. The nine-atom clusters are made either by extraction from mixed Ge/Sn precursors with nominal composition K4Ge9−xSnx or by dissolution of mixtures of the corresponding binary precursors K4Ge9 and K4Sn9 in solvents with high dielectric constants such as DMF, DMSO, and acetonitrile. Reactions of the heteroatomic clusters with alkynes such as Me3SiCCSiMe3, HCCCpr (Cpr = cyclopropyl), and HCCPh in ethylenediamine resulted in the following structurally characterized compounds with alkenylated heteroatomic clusters: [K-(2,2,2-crypt)]3[GeSn8-CHCH2]·en·tol (1), triclinic, P1̅, a = 13.9220(3) Å, b = 14.9788(3) Å, and c = 21.5892(5) Å, α = 94.2580(10)°, β = 98.5210(10)°, and γ = 98.4890(10)°, V = 4382.31(16) Å3, Z = 2; [K-(2,2,2-crypt)]4[Ge2Sn7(CHCH2)2]2·en (2), monoclinic, P21/c, a = 48.1883(15) Å, b = 12.1551(4) Å, and c = 21.4824(7) Å, β = 90.052(2)°, V = 12583.0(7) Å3, Z = 4; [K-(2,2,2-crypt)]3[GeSn8-CHCHCpr]·en (3), monoclinic, P21/c, a = 17.9132(9) Å, b = 22.7967(11) Å, and c = 21.6922(12) Å, β = 98.409(2)°, V = 8763.0(8) Å3, Z = 4; [K-(2,2,2-crypt)]3[Ge2Sn7-CHCHPh]·2en (4), monoclinic, P21/n, a = 13.2583(5) Å, b = 47.0565(17) Å, and c = 15.9978(6) Å, β = 111.536(2)°, V = 9284.1(6) Å3, Z = 4. The potassium countercations of the divinyl-substituted cluster in 2 were exchanged for tetrapropylammonium cations, and the resulting compound was also crystallized and structurally characterized: [Pr4N]4[Ge2Sn7(CHCH2)2]2 (5), triclinic, P1̅, a = 11.6757(8) Å, b = 18.8150(16) Å, and c = 21.0608(17) Å, α = 112.327(3)°, β = 91.550(3)°, and γ = 91.892(3)°, V = 4273.5(6) Å3, Z = 2. All clusters were also characterized in solution by electrospray mass spectrometry.