Alkylation of Deltahedral Zintl Clusters: Synthesis of [R−Ge₉−Ge₉−R]^4- (R = <i>^t</i>Bu, <i>^s</i>Bu, <i>ⁿ</i>Bu, <i>^t</i>Am) and Structure of [<i>^t</i>Bu−Ge

Reactions of nine-atom deltahedral clusters (Zintl ions) of germanium, Ge9n- (n = 2, 3, 4), with alkyl chlorides, RCl (R = tBu, nBu, sBu, tAm), yielded the corresponding dialkylated dimers of Ge9 clusters [R−Ge9−Ge9−R]4-. The tBu derivative with [K(2,2,2-crypt)]+ countercations was characterized in the solid state by single-crystal X-ray diffraction as [K(2,2,2-crypt)]4[tBu−Ge9−Ge9−tBu]·7en (monoclinic, C2/c, a = 35.0914(10) Å, b = 24.8161(6) Å, and c = 16.8782(5) Å, β = 94.0136(17)°, V = 14662.0(7) Å3, and Z = 4) and in solution by 1H and 13C NMR. All species were also characterized in solution by electrospray mass spectrometry in the negative-ion mode. These are the first main group deltahedral clusters functionalized with purely organic substituents.