Replacement of H₂O and/or OH^-ligands in the [Rh₂(O₂^-)(OH)₂(H₂O)_n]³⁺ cation by carboxylate ions: RCO₂^- (R = C₂H₅, C₃H₇, C₄H₉, (CH₃)₃), glycine, L-aspartic acid and L-proline have been studied by electronic and ESR spectra. Two new superoxo rhodium(III) carboxylates formulated as [Rh₂(O₂^-)(OH)(RCO₂)₄]_n, (R = C₂H₅(1), C₃H₇(2)), have been synthesized in the reaction between the rhodium(III) superoxo hydroxide, assumed to be [Rh₂(O₂^-)(OH)_2+m(H₂O)_n-m] with RCO₂H. Reaction products were characterized by elemental analysis, UV-VIS, IR, ESR spectroscopies and magnetic susceptibility measurements. The results indicated the formation both the superoxo rhodium(III) carboxylates and amino-carboxylates, containing the [Rh₂(O₂^-)]⁵⁺ core of higher stability in the compounds with the amino-carboxylic acid anions.

The title compounds were prepared and their solubility in water at 295 K (10^-2-10^-1 mol/dm³), the IR spectra and X-ray diffractograms complexes were recorded, and their thermal decomposition in air was investigated. During heating the hydrated complexes (Co, Ni, Cd) lose crystallization water molecules in one step and the anhydrous compounds decompose to oxides (Co, Ni, Zn: 5 and 10 K/min and Cu: 5 K/min heating rate) or to gaseous products (Cu: 10 K/min, Cd: 5 and 10 K/min heating rate).

The optically pure title compound was obtained from (+)--pinene (e.e. = 70%) via myrtenyl bromide and corresponding 1,5-hexadiene.

Reaction of 2-aminopyridine 1-oxide 1a with 2-fluoropyridine 5a in DMF at 140°C gave 2-(2-pyridylamino)pyridine 1-oxide 6 (41%) along with bis(2-pyridyl)amine 7 (5%). However, heating in melt of 1a with 2-chloropyridine 5b or 2-bromopyridine 5c in the presence of dry potassium carbonate at 175°C provided 3-(2-pyridylamino)-2(1H)-pyridone 9 as cine substitution product. Compound 9 results from the nucleophilic attack of the N-oxide on the carbon atom bearing halogen to give corresponding cation 17, which rearranges to cine substitution product 9 via anhydro-base 18.

DBU/MgCl₂ mediated reaction between nitroarenes and some CH acids bearing leaving group lead to 2,1-benzisoxazole derivatives under aprotic conditions. Ortho- directing effect was observed.

A convenient synthesis of -substituted vinylphosphonates based on the reaction of readily available S-(-oxoalkyl)dithiophosphates and Se-(-oxoalkyl)selenophosphates with sodium dialkyl phosphites is described.

Proline-rich protein (PRP), isolated from ovine colostrum, possesses strong immunotropic activity. The nonapeptide (Val-Glu-Ser-Tyr-Val-Pro-Leu-Phe-Pro) and the hexapeptide (Tyr-Val-Pro-Leu-Phe-Pro) PRP fragments revealed biological activity similar to that of the native protein. Seeking for analogues of PRP fragments with constrained structure, two cyclic peptides were synthesized by the solid phase method:
Cys-Val-Glu-Ser-Tyr-Val-Pro-Leu-Phe-Pro-Cys and
Ac-Glu-Tyr-Val-Pro-Leu-Phe-Pro-Lys-NH₂. Immunotropic activity of both peptides in murine system was the same as for the linear nonapeptide, whereas all three peptides were practically inactive in human system, where resistance to hydrocortisone and induction of two cytokinins IFN and TNF were used as indicators, respectively.

The first total synthesis of enantiomerically enriched (+)- and (-)-corydalisol (1) has been performed by addition of lithiated optically pure 1,3-dithiane 3b to hydrastinine chloride (2a), followed by desulfurization, separation of diastereomers and reduction with lithium aluminum hydride.

Stoichiometry and stability constants of -cyclodextrin (-CD) complexes of several aromatic ketones and the corresponding thioketones were determined by the spectrophotometric and solubility methods. The solubility method with high-performance liquid chromatography (HPLC) detection of the solute concentration proved to be very convenient in determination of the stability constant for the least soluble thioketone. The formation constants were correlated with 1-octanol-water partition coefficients, which vary over more than five orders of magnitude for compounds studied. The hydrophobic interaction and dispersion forces were found to be the most important sources of the complex stability. Relatively strong hydrogen bonds between the ketone molecules and water destabilize their -cyclodextrin complexes. Stoichiometry of all -cyclodextrin complexes studied was found to be 1:1. The synthesis of a new alkyl derivative of 4H-1-benzopyran-4-one and 4H-1-benzopyran-4-thione was described.

The calix[4]resorcinarene-coated RP-18 phases were found to be useful beds for HPLC separation of thymine, cytosine and uracil. Typical lipophilic calix[4]resorcinarene prepared from lauryl aldehyde and resorcinol was used.

The solubility of substituted pyrazaboles: 1,3,5,7-tetramethylpyrazabole (TMP) and 1,3,5,7-tetramethyl-4,4,8,8-tetraphenylpyrazabole (TMTFP) in methanol, ethanol, 2-propanol, tert-butanol and toluene have been determined by a dynamic method at temperatures ranging from the boiling point of the solvent to 285 K. Introduction of the substituents to a pyrazabole molecule strongly decreases the solubility in alcohols. The results have been correlated by the Wilson, UNIQUAC and UNIQUAC ASM equations. The best results were obtained for UNIQUAC ASM equation with the average root mean square deviation = 1.5 K.

The potential dependence of the formal partial charge number for cadmium(II) underpotential deposition (upd) on platinum was obtained, using electrochemistry and piezoelectric microgravimetry. The comparison of this dependence with the formal partial charge number, calculated on the basis of earlier proposed mechanism of cadmium(II) upd, supports this mechanism, according to it the electrosorption valency for the cadmium(II) adsorption on platinum equals 1 and 2.

The Cu₂Si(Ge,Sn)Te₃-HgTe systems were investigated using differential thermal, X-ray phase and microstructural analysis. Existence of the quaternary Cu₂HgSiTe₄ and Cu₂HgGeTe₄ phases, which melt congruently at 898 and 805 K respectively, have been established in Cu₂SiTe₃-HgTe and Cu₂GeTe₃-HgTe systems. The Cu₂HgSnTe₄ phase is a part of solid solution on the basis of Cu₂SnTe₃ in Cu₂SnTe₃-HgTe section. The solid solution on the basis of Cu₂SiTe₃ contains 7 mol% HgTe and the one on the basis of Cu₂GeTe₃ contains 12 mol% HgTe. The solid solubility in HgTe at 670 K is 2.5 mol% Cu₂SiTe₃, 4 mol% Cu₂GeTe₃ and 5.5 mol% Cu₂SnTe₃.

ZSM-5 zeolite modified with Tl has been investigated with XRD, IR and XPS spectroscopies. Thallium Tl⁺ ions were introduced in the exchange reaction in water medium, accompanied by exchange of Na⁺ with H⁺. From XPS results follows that more likely thallium atoms have been incorporated to the ZSM-5 zeolite lattice as TI³⁺ species, strongly polarized by framework-forming elements, than as TI⁺ species. All TIHNa-ZSM-5 zeolite samples catalyzed ammoxidation of m-xylene. X-ray diffractograms before and after ammoxidation proved the preservation of the ZSM-5 zeolite structure.

During the hydrogenation of acetylene-ethylene mixtures on palladium catalysts, the rate of acetylene disappearance and the concentration of carbon dissolved in the bulk palladium increase similarly for samples metal crystallite size << 25 nm. Such a positive correlation supports the hypothesis that carburization of palladium is responsible for the increase of the rate of acetylene disappearance during againg of the catalyst. The maximum concentration of carbon in palladium at the steady-state depends on the temperature of the reaction and on the crystallite size. This concentration increases with carburization temperature and decreases with the increase of Pd crystallite size. The presence of supersaturated solution of carbon in Pd at 50°C is possible, due to a diffusion-hindered frozen state in the bulk. The catalytic properties of such a sample match the behavior of partially carburized Pd catalyst at steady-state conditions. This result strongly suggests that, in both cases, concentrations of surface carbon are similar.

The dielectric relaxation studies of trioctylmethylammonium chloride (TOMAC) in pure state and in n-heptane, iso-octane and 1,4-dioxane solutions have been performed in the frequency range 100 kHz to 36 GHz at 20°C and 50°C. The dielectric spectra have been formally described as a sum of the conductivity and two relaxational contributions. The viscosity dependence of the relaxation time, corresponding to the contribution appearing in low frequency region, shows full analogy to the "limiting" behaviour of many electrolyte solutions.

The adsorption of nitrobenzene on the surface of magnesium oxide has been studied by TPD and ESR methods. The high temperature activation of MgO reveals the presence of low coordinated oxygen ions (LC), which are the one-electron donor (reducing) sites of MgO surface, resulting in the formation of different nitrobenzene anion radicals. The corner O_3C^2- and probably the edge O_4C^2- lattice ions are the source of single electrons to the adsorbed nitrobenzene molecules. Depending on adsorption temperature and surface coverage, there are visible at least three forms of NB radicals in ESR spectra with different values of the hyperfine splitting (A_||^N). These forms differ in thermal stability. The small variations of particular A_||^N value was attributed to the different chemical environment of the low coordinated adsorption sites on MgO surface.

The charge-transfer complexation reaction between iodine and dibenzopyridino-18-crown-6 (DBPY18C6) has been investigated spectrophotometrically in chloroform solution at different temperatures. The resulting complex was formulated as (DBPY18C6...I⁺)man I₃^-. The enthalpy and entropy of the complex formation were evaluated from the temperature dependence of the formation constant. The resulting charge-transfer complex is both enthalpy and entropy stabilized. The rate constants at various temperatures and the activation parameters were evaluated.

The crystal structure of the title solvate has been determined by X-ray diffraction with R = 0.065. The 1,3-dithiane ring presents a chair conformation, the substituents at C(2), C(4) and C(5) are all in equatorial positions and the molecular ratio of the solvate is 1:1.

The crystal structure of 7,8-dimethoxy-3-oxo-3a,4,5,9-tetrahydroisoquinolino-[1,2b] thiazolidine has been investigated by X-ray diffraction methods. Crystals are monoclinic, space group P2₁/c, a = 19.789(2), b = 7.454(1), c = 8.917 , = 100.43(1)°, Z = 4. The structure was solved by direct methods and refined to R = 0.0329 for 2110 observed reflections. The sum of three bond angles around N atom is 359.3(3)°, showing its near planar surrounding. The tetrahydroisoquinoline moiety is composed of the planar aromatic ring and hydrogenated heterocyclic ring having the conformation of non-ideal sofa. The next condensed heterocyclic five-membered ring accepts the form of envelope.This is the first published crystal structure of tetrahydroisoquinoline moiety fused with sulfur containing five-membered ring.

• Nomenclature of Organometallic Compounds of the Transition Elements
• Definitions of Terms for Diffusion in the Solid State
• Classification and Use of Terms for Amplification and Related Reactions