Study of the Structure and Reactions of Bis(μ-Oxalato)tetramminediplatinum(II) in Aqueous Chloride Solutions

A comparison study of the bis(-oxalato)tetramminediplatinum(II) dimer [Pt₂(NH₃)₄(-C₂O₄)₂] and the oxalatodiammineplatinum(II) chelate [Pt(NH₃)₂C₂O₄] is performed. The kinetics and mechanism of substitution of C₂O^2– ₄ for Cl^– in aqueous chloride solutions are studied by photoelectronic spectroscopy, gravimetry, and chemical phase analysis within the 1.0–6.7 pH range at 75°C. The rate constants of substitution and the equilibrium constants for a two-step protonation for the dimeric and chelate complexes are calculated. Their solubility in 1 M KCl at 75°C; is determined. The unit cell parameters for [Pt₂(NH₃)₄(-C₂O₄)₂] are determined: a = 3.858 Å, b = 10.704 Å, c = 6.795 Å, = 94.35°. The IR spectra of [Pt(NH₃)₂C₂O₄], [Pt₂(NH₃)₄(-C₂O₄)₂], and their deuterated analogs are studied.     

Synthesis of functionally substituted isoxazole and isothiazole derivatives

Acylation of benzene and toluene with 5-phenyl- and 5-(p-tolyl)isoxazole-3-carbonyl chlorides gave 5-phenyl(or p-tolyl)isoxazol-3-yl phenyl(or p-tolyl)ketones which were reduced to the corresponding alcohols with sodium tetrahydridoborate in propan-2-ol. Selective reduction of the carboxy group in 4,5-dichloroisothiazole-3-carboxylic acid was achieved by the action of BH₃, and the aldehyde group in 4-formyl-2-methoxyphenyl 5-arylisoxazole-3-carboxylates and 4,5-dichloroisothiazole-3-carboxylates was reduced to hydroxymethyl group with sodium triacetoxyhydridoborate in benzene. Acylation of the resulting hydroxymethyl derivatives with 5-arylisoxazole- and 4,5-dichloroisothiazole-3-carbonyl chlorides afforded the corresponding esters containing two azole fragments in their molecules.     

Influence of temperature gradients on the composition of crystallization products of ammonium chloroplatinum(IV) and chlorohodium(III) complex salts

The influence of temperature gradients on the particle size and component composition of solid phases in heterogeneous systems of ammonium chloroplatinum(IV) and chlorhodium(III) complex salts was studied. A Benard cell was implemented as applied to not only homogeneous but also heterogeneous systems. Two contributions to the cocrystallization of rhodium with platinum are distinguishable and kinetically resolved: the formation of nonequilibrium solid solutions by ammonium chlorometalates and equilibrium Ostwald ripening. The elucidation of both factors helps in finding crystallization parameters for minimizing the rhodium contamination of platinum in refining practice.     

Physicochemical Properties and Structure of the Bone Matrix in Simulated Tuberculous Osteitis

Technical Physics - The physicochemical properties and structure of the bone matrix are studied in a case of simulated tuberculous osteitis without treatment and after a full course of specific...     

Reversible adsorption deformation of layered adsorbents at high pressures and temperatures

Isotherms of excessive adsorption of N₂ and Ar on three montmorillonite samples (natural sodium (NaMt) and ion-exchange pyridinium (PyMt) and polyhydroxyaluminum (PGAMt)) were measured in the pressure interval from 0.1 to 60 MPa and at temperatures 303, 343, 373, and 400 K. The results of measurements showed the inverse temperature dependence of the measured isotherms of excessive adsorption at elevated pressures and temperatures: for the isotherms at higher temperatures the amounts adsorbed exceed the values measured at lower temperatures. The deformation of montmorillonites with the temperature increase results in an increase in the adsorption volume of the adsorbent.