Reaction of Pentaphenylphosphorus with Hexachloroplatinic Acid

Tetraphenylphosphonium hexachloroplatinate (1) was synthesized by the interaction of pentaphenylphosphorus with hexachloroplatinic acid in acetone. The recrystallization of complex 1 from dimethylsulfoxide gave tetraphenylphosphonium dimethylsulfoxidopentachloroplatinate (2). The compounds have been characterized by IR-spectroscopy and X-ray analysis. The absorption bands characterizing stretching vibrations of the phenyl groups are present in the IR spectra, recorded on a Shimadzu IRAffinity-1S Fourier spectrometer in the 4000–400 cm–1 area in KBr pellets. According to the X-ray analysis, the compound unit cell parameters are: triclinic syngony, space group (1, 2), а = 10.205(10), b = 10.970(15), c = 12.160(11) Å (1), а = 7.7667(4), b = 13.3069(7), c = 14.2562(7) Å (2), a = 73,65(4)°, β = 80.64(3)°, g = 77.48° (1), a = 80.972(4)°, β = 88.205(4)°, g = 89.199(4)° (2), V = 1272(2) Å3 (1), 1454.38(13) Å3 (2). The crystals of complexes 1 and 2 consist of the tetrahedral tetraphenylphosphonium cations and octahedral anions. In cations the phosphorus atoms have a slightly distorted tetrahedral environment (the CPC angles are 107.8(3)-113.2(3)° (1), 105.9(3)–112.9(3)° (2), the P-C distance is 1.785(6)-1.805(6) Å (1), 1.783(7)–1.791(6) Å (2). Platinum atoms in the anions of complexes 1 and 2 are hexacoordinated. In complex 2 the dimethyl sulfoxide ligand is coordinated with the Pt atom via the sulfur atom 2.290(2) Å. Complete tables of coordinates of atoms, bond lengths and valence angles are deposited at the Cambridge Structural Data (CCDC 1865783, 829586 http://www.ccdc.cam.ac.uk).

Preparation of Sub-Micrometre Size Platinum Particles via Chemical Reduction of Hexachloroplatinic Acid in Aqueous Solution

The sub-micrometre size platinum particles via chemical reduction of hexachloroplatinic acid in aqueous solution was investigated by UV-Visible Spectroscopy, Transmission Electron Microscopy, X-ray diffraction and FTIR Spectroscopy. Hydrazine hydrate was used as the reducing agent, and polyvinylpyrrolidone (PVP-K30) was used for stabilizing the particles. By varying the amount of PVP-K30 the average diameter of the platinum particles could be adjusted. The TEM and XRD results revealed that the final sub-micrometre size Pt particles were the result of an aggregation of small (~5 nm) nanoparticles. The UV-Visible Spectroscopy and FTIR Spectroscopy investigations indicates the mechanism of anti-aggregation of Pt particles by the steric effect of PVP-K30.