Synthesis and Characterization of Binary Clusters to Controllable Binary Nanoparticles "The New Role of Zintl Anions"

Abstract

Zintl anions are best described as polyatomic main group clusters (i.e. E73-; E = P, As, Sb) with structures characteristic of isoelectronic clusters (i.e. hydrocarbon and borohydride clusters). Combining these main group clusters and transition-metal precursors (Ni(COD)2; COD = cyclooctadiene, and Pd(PCy3)2; PCy3 = tricyclohexyl phosphine) with very labile ligands allows for the isolation of novel binary molecular clusters. The freedom these structures experience due to the absence of organic ligands lends itself to the very unique structure growth the binary clusters exhibit. Direct oxidation of these binary molecular clusters results in the formation of binary phases (i.e. PdAs2, NiAs, NiAs2). More control of the phase-specific binaries obtained can be achieved by controlling the reaction of the precursors, eliminating the need to isolate the clusters. Binary nanoparticles are in the forefront of heterogeneous catalyst development and application, making this an area of intense investigation. Structural characteristics of the binary clusters, [As@Ni12@As20]3-, [(Ni2Sb2)(Sb7)2]4-, [Ni5Sb17]4-, [Pd7As16]4- and [Pd2(E7)2]4- (E = P, As), and evidence for the formation of phase-specific binary nanoparticles (Ni5As2, Ni11As8, NiAs and NiAs2) under very mild conditions will be presented.