Three adducts have been prepared from Hg(CN)2 and square planar MII(CN)42- transition metal cyanides (M = Pt, Pd, or Ni, with d8 electron shell) as solids. The structure of the compounds K2PtHg(CN)6·2H2O (1), Na 2PdHg-(CN)6·2H2O (2), and K 2NiHg(CN)6·2H2O (3) have been studied by single-crystal X-ray diffraction, XPS, Raman spectroscopy, and luminescence spectroscopy in the solid state. The structure of K2PtHg(CN) 6·2H2O consists of one-dimensional wires. No CN- bridges occur between the heterometallic centers. The wires are strictly linear, and the Pt(II) and Hg(II) centers alternate. The distance dHg-Pt is relatively short, 3.460 Å. Time-resolved luminescence spectra indicate that Hg(CN)2 units incorporated into the structure act as electron traps and shorten the lifetime of both the short-lived and longer-lived exited states in 1 compared to K2[Pt(CN) 4]·2H2O. The structures of Na2PdHg-(CN) 6·2H2O and K2NiHg(CN) 6·2H2O can be considered as double salts; the lack of heterometallophilic interaction between the remote Hg(II) and Pd(II) atoms, 4dHg-Pd = 4.92 Å, and Hg(II) and Ni(II) atoms, d Hg-Ni = 4.61 Å, is apparent. Electron binding energy values of the metallic centers measured by XPS show that there is no electron transfer between the metal ions in the three adducts. In solution, experimental findings clearly indicate the lack of metal-metal bond formation in all studied Hg II-CN--MII(CN)42- systems (M = Pt, Pd, or Ni).
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry