Controlled Synthesis of Ternary II-II-VI Nanoclusters and the Effects of Metal Ion Distribution on Their Spectral Properties

The reaction of [(3,5-Me2-C5H3N)2Zn(ESiMe3)2] (E = Se, Te) with cadmium(II) acetate in the presence of PhESiMe3 and PnPr3 at low temperature leads to the formation of single crystals of the ternary nanoclusters [ZnxCd10-xE4-(EPh)12(PnPr3)4] [E = Se, x = 1.8 (2a), 2.6 (2b); Te, x = 1.8 (3a), 2.6 (3b)] in good yield. The clusters [Zn3Hg7Se4(SePh)12(PnPr3)4] (4) and [Cd3.7Hg6.3Se4(SePh)12(PnPr3)4] (5) can be accessed by similar reactions involving [(3,5-Me2-C5H3N)2Zn(SeSiMe3)2] or [(N,Nʹ-tmeda)Cd(SeSiMe3)2] (1) and mercury(II) chloride. The metal silylchalcogenolate reagents are efficient delivery sources of {ME2} in cluster synthesis, and thus, the metal ion content of these clusters can be readily moderated by controlling the reaction stoichiometry. The reaction of cadmium acetate with [(3,5-Me2-C5H3N)2Zn(SSiMe3)2], PhSSiMe3, and PnPr3 affords the larger nanocluster [Zn2.3Cd14.7S4(SPh)26(PnPr3)2] (6). The incorporation of Zn(II) into {Cd10E} (E = Se, Te) and Zn(II) or Cd(II) into {Hg10Se} nanoclusters results in a significant blue shift in the energy of the first "excitonic" transition. Solid-state thermolysis of complexes 2 and 3 reveals that these clusters can be used as single-source precursors to bulk ternary ZnxCd1-xE materials as well as larger intermediate clusters and that the metal ion ratio is retained during these reactions.