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

Abstract

Reactions of nine-atom deltahedral clusters (Zintl ions) of germanium, Ge₉<i>ⁿ</i>^- (<i>n</i> = 2, 3, 4), with alkyl chlorides, RCl\n(R = <i>^t</i>Bu, <i>ⁿ</i>Bu, <i>^s</i>Bu, <i>^t</i>Am), yielded the corresponding dialkylated dimers of Ge₉ clusters [R−Ge₉−Ge₉−R]^4-. The <i>^t</i>Bu\nderivative with [K(2,2,2-crypt)]⁺ countercations was characterized in the solid state by single-crystal X-ray diffraction\nas [K(2,2,2-crypt)]₄[<i>^t</i>Bu−Ge₉−Ge₉−<i>^t</i>Bu]·7en (monoclinic, <i>C</i>2/<i>c</i>, <i>a</i> = 35.0914(10) Å, <i>b</i> = 24.8161(6) Å, and <i>c</i> =\n16.8782(5) Å, β = 94.0136(17)°, <i>V</i> = 14662.0(7) ų, and <i>Z</i> = 4) and in solution by ¹H and ¹³C NMR. All species\nwere also characterized in solution by electrospray mass spectrometry in the negative-ion mode. These are the\nfirst main group deltahedral clusters functionalized with purely organic substituents.