A New Synthetic Methodology in the Preparation of Bimetallic Chalcogenide Clusters via Cluster-to-Cluster...

A decanuclear silver chalcogenide cluster, [Ag₁₀(Se){Se₂P(OPr)₂}₈] (2) was isolated from a hydride-encapsulated silver diisopropyl diselenophosphates, [Ag₇(H){Se₂P(OPr)₂}₆], under thermal condition. The time-dependent NMR spectroscopy showed that 2 was generated at the first three hours and the hydrido silver cluster was completely consumed after thirty-six hours. This method illustrated as cluster-to-cluster transformations can be applied to prepare selenide-centered decanuclear bimetallic clusters, [Cu_xAg_10-x(Se){Se₂P(OPr)₂}₈] (x = 0-7, 3), via heating [Cu_xAg_7-x(H){Se₂P(OPr)₂}₆] (x = 1-6) at 60 °C. Compositions of 3 were accurately confirmed by the ESI mass spectrometry. While the crystal 2 revealed two un-identical [Ag₁₀(Se){Se₂P(OPr)₂}₈] structures in the asymmetric unit, a co-crystal of [Cu₃Ag₇(Se){Se₂P(OPr)₂}₈]_0.6[Cu₄Ag₆(Se){Se₂P(OPr)₂}₈]_0.4 ([3a]_0.6[3b]_0.4) was eventually characterized by single-crystal X-ray diffraction. Even though compositions of 2, [3a]_0.6[3b]_0.4 and the previous published [Ag₁₀(Se){Se₂P(OEt)₂}₈] (1) are quite similar (10 metals, 1 Se^2-, 8 ligands), their metal core arrangements are completely different. These results show that different synthetic methods by using different starting reagents can affect the structure of the resulting products, leading to polymorphism.