Phase formation in the NaF-KF-AlF3 system, in the vicinity of the K2NaAl3F12 composition, has been studied. The samples have been prepared by melting the starting components at 650 °C. A new phase has been revealed, which appeared to be a low-temperature form of the well-known K2NaAl3F12 ternary fluoride obtained by the hydrothermal synthesis method. The high-temperature form melts at 598 °C and is stable in a narrow temperature region of about 15 deg below the melting point. Thermal analysis, high temperature X-ray diffraction, IR-spectroscopy, X-ray fluorescence, and X-ray powder diffraction crystal structure analysis have been applied to study the composition, crystal structure, and thermal properties of the low-temperature phase. The crystal structure consists of trigonal-hexagonal two-dimensional (2D) grids built from the [AlF6] octahedra connected via vertices. The 2D grids have a specific wave-like conformation with a wavelength of 11.88 Å and an amplitude of 0.46 Å. There is a shift of the adjacent grids relative to each other. Because of this shift, the space between the grids changes. The shift leads to the formation of pores adapted to potassium and sodium ions. The reasons for the wave-like structure of layers are discussed. It is shown that the two polymorphic forms differ in the order of cation occupations.

The salt [NH 3 (CH 2 ) 2 SS(CH 2 ) 2 NH 3 ] [CuCl 4 ] was obtained by crystallization after adding CuCl 2 to cystamine (Cysta), solved in hydrochloric acid. The assumption of conserved disulfide connection (S-S) in the compound, made on the basis of infrared spectroscopy, is further supported by the crystal structure determined from X-ray powder diffraction data. The compound has an ionic structure. [CuCl 4 ] 2− and CystaH 2 2+ ions package in the form of inorganic and organic layers in the cell, interconnected through the formation of hydrogen bonds via NH 3 -groups and chlorine atoms of the complex [CuCl 4 ] 2− . Inorganic layers are additionally stabilized in the parquet package of [CuCl 4 ] 2− ions which provides a Cu-distorted octahedral coordination. CystaH 2 [CuCl 4 ] is stable in air up to 200°C. Thermal decomposition occurs in several stages, accompanied by breaking of S-S bonds, releasing of the organic component and yielding CuO.

The complex [Cu(en) 2 (H 2 O)](sy) 2 (en)(H 2 O) 2 has been synthesized and characterized by its electronic and vibrational spectra. The molecular structure of the complex has been determined by X-ray diffraction methods. The complex crystallizes in the orthorhombic space group Pnma with unit-cell parameters a = 10.7236 (5), b = 20.4660(10), c = 14.4523(11)Å and Z = 4. In the cation, the Cu(II) ion has a distorted square pyramidal coordination with two bidendate (en) ligands forming the basal plane and a H 2 O molecule in the apical position. The complex cations and syringate anions constitute chains along the b axis in -A-B-A-fashion. The members of the chains are linked by through N-H···O hydrogen bonds. The (en) molecules are responsible for connecting adjacent layers.

Seven new phases containing hexachloroplatinate [PtCl 6 ]2− and trans-1,2-dl-diammoniumcyclohexane 1,2-C 6 H 10 (NH 3 ) 2 2+ ions were obtained by crystallization from solutions with minor variation of synthesis conditions. The compounds can be applied as precursors for the synthesis of effective anticancer drug tetraplatin ([PtC 6 H 10 (NH 2 ) 2 Cl 4 ]). The phase diversity was achieved by alterations including solvent acidity, crystallization rate, temperature, type of solvent, and the reagents ratio. The compounds were characterized by chemical and thermal analysis, IR, and 1 H NMR spectroscopy. Crystal structures of the five compounds were determined by X-ray powder diffraction technique. The phases have ionic structures involving H 2 O, HCl molecules, or Cl − ions as supplementary species in the lattices. It helps to arrange some frames additionally interconnected by hydrogen bonds between ions and solvent molecules. It was suggested that crystal lattices adapted associated particles presented in solutions. It results in observed variety of the crystal structures. Besides the basic interest the obtained results are important for tetraplatin synthesis control.

No abstract

No abstract