Synthesis of PtSn4 and Ir3Sn7 intermetallic nanoparticles from bimetallic Zintl cluster precursors

Controlled I2 oxidations of preformed Zintl clusters [Pt2Sn9(PPh3)]2− and [Sn9Ir(cod)]3−, give well ordered tin-rich intermetallic nanoparticles (NPs) of PtSn4 and Ir3Sn7, respectively. The intermetallics were characterized by HR-TEM and XRD analysis. Both clusters have strong structural similarities with the final intermetallic, which appears to be an important factor in determining the phase of the resulting intermetallic NP. Despite the 1:9 (Ir:Sn) atomic ratio of the [Sn9Ir(cod)]3− cluster, ordered Ir3Sn7 NPs were formed instead of the compositionally-similar IrSn4 phases. PtSn4 is difficult to prepare and isolate due to the formation of other known Pt–Sn phases, such as PtSn, PtSn2 and Pt3Sn.

Intermetallic nanoparticles of PtSn4 and Ir3Sn7 can be prepared directly from the intermetallic Zintl cluster anions [Pt2Sn9(PPh3)]2− and [Sn9Ir(cod)]3−, respectively. The close structural similarities between the clusters and intermetallic phases facilitate the low temperature transformations.Figure optionsDownload as PowerPoint slide