New blue-violet diamagnetic diindium(III) triphthalocyanine and paramagnetic indium(III) diphthalocyanine complexes have been obtained in crystalline form. The UV- -VIS, IR and far IR spectra of the In₂Pc₃ and InPc₂ complexes are presented here for the first time. The spectroscopic data of the both In(III) complexes are discussed in terms of characteristic group frequencies and compared with other phthalocyanines. An empirical vibrational assignment of the observed fundamentals are given. The absorption electronic spectra indicate the proximity of the HOMO and LUMO of the Pc ligand in energy.

(Ph₄P)₂ReCl₆^.2CH₃CN 1 crystallizes as colourless single crystals from the acetonitrile solution of (Ph₄P)₂ReCl₆ in ether. The crystals are monoclinic in space group P2₁/c with unit cell constants of a = 9.5507(12) ; b = 19.724(3) ; c = 15.033(2) ; = = 90^o; ß = 8.451(14)^o; V = 2801.1(7) ³; Z = 2. In the octahedral anion the Re-Cl bond lengths are 2.368 in average. The FIR region indicates two deformation bands (Cl-Re-Cl) at 162 cm^-1 (F_2g) and 175 cm^-1 (F_1u) and stretching band niu(Re-Cl) at 309 cm^-1 (F_1u). For 1 very weak antiferromagnetic super-exchange is observed; the effective magnetic moment at room temperature is 3.57 B.M.

The interactions between the components in the ternary Zr-Ag-In system were studied. An isothermal section at 870 K was established by X-ray analysis. Two unknown ternary compounds have been found: ZrAg_0.4In_2.6-AuCu₃ structure type (space group Pm3m, a = 4.3644(4) ) and Zr₅AgIn₃-Hf₅CuSn₃ structure type (space group P6₃/mcm, a = 8.735(3) , c = 5.948(2) ). Their crystal structures were determined by powder X-ray analysis.

The autocatalytic oxidation of PPh₃ with dioxygen in the systems containing some iron compound and NCS^- anions in acetonitrile leads to the formation of the complex [Fe(NCS)₃(OPPh₃)₃], where OPPh₃ is triphenylphosphine oxide. The complex is also formed by direct interaction of Fe(NCS)₃ with OPPh₃. This high-spin iron(III) complex acts as an oxidation catalyst of PPh₃. On the basis of elemental analysis, spectral data and X-ray powder diffraction have been proved that the samples of the complex have not only the same composition but possess the same crystal structure irrespective of the preparation method.

Co(II) complexes with a group of diastereoisomeric dipeptides consisting of alanine and leucine in various chiral forms have been studied in aqueous solution. The equilibria were determined by potentiometric and spectrophotometric methods, using least-squares fitting procedures. The results were compared with those for glycine dipeptides containing only one asymmetric atom.

In the presence of catalytic amounts of Rh₂(OAc)₄ in toluene, dimethyl diazomalonate (1) decomposed with evolution of N₂ to form a carbenoid of type 8 which reacted with carboxamides 2 and toluenesulfonamide (4) to give 2-(acylamino)- and 2-(sulfonylamino)malonates 3 and 5, respectively. In an analogous reaction, -diazo ketone 6 and 4 yielded N-(2-oxo-1,2-diphenylethyl)toluenesulfonamide (7).

Flash vacuum pyrolysis of 2-phenyl-1,3-oxazol-5(4H)-one (5) at 600^oC/1.5^.10^-3 Torr proceeded via CO₂-elimination to give 3-phenyl-2H-azirine (6) as the only detectable product which was isolated in 34% yield. Under similar conditions, 4,4-dimethyl-1,3- thiazole-5(4H)-thiones 7a and 7b yielded isomeric 1,4,2-dithiazole derivatives 8a,b as main products. Desulfurization leads to 2-(2-propylidene)-1,3-thiazetes 9 as minor products, and in the case of 7a, disulfide 10a is formed as a second minor product.

The reactions of selected allylic acetates with methanol, ethanol, n-propyl alcohol, isopropyl alcohol and tert-butyl alcohol in the presence of catalytic amounts of cerium(III) chloride are described. Allylic alkyl ethers, bis-allylic ethers and 1,3-dienes were obtained depending on the structure of the acetates.

The synthesis of chiral 2,2'-diselenobisbenzoates (3) from 2-aminobenzoic acid and chiral alcohols was elaborated. Similar method was applied for the preparation of chiral 2,2'-diselenobisbenzenesulfonates (4) from 2-aminobenzenesulfonic acid. Ester 3a was an efficient catalyst for chemoselective hydrogen peroxide oxidation of sulfides into sulfoxides but no stereoselectivity of the reaction was observed.

The reaction between anion generated from (methylthio)acetyliron complex (1) and four stereoisomeric dialdo-1,4-furanoses was performed. Each aldehyde led to mixtures (6-8) of stereoisomeric aldols. Aldols were separated and their configuration was determined. Decomplexation of these products was studied with oxidative (NCS, Cl₂, I₂, CuCl₂) and reducing (BH₃^.Me₂S and NaBH₄) reagents. Sugar derivatives were isolated and their structures were deduced.

2-Pyridinecarboxaldehyde (pyad) has been oxidized by Cr₂O₇^2- ion at pH range 0-1 to 2-pyridinecarboxylic acid (pyac). The produced Cr(III) exists in the form of three complex ions: [Cr(pyac)(H₂O)₄]²⁺, [Cr(pyac)₂(H₂O)₂]⁺ and [Cr(H₂O)₆]³⁺. The reaction follows unusual mixed fourth-order rate law: first-order on concentrations of H_aq⁺ and Cr(VI) and second-order on concentration of the aldehyde. Mechanism of the reaction has been discussed.

To explain the mechanism of the influence of fluorine substituent on the FdUMP activity in thymidylate synthase reaction, the aromaticity based on X-ray determined structures, factor analysis applied to structural data from CSD and ab initio RHF calculations were employed. It was found that fluorine substitution dearomatizes the pyrimidine ring, stabilizing the local double C(5)=C(6) bond and making them more susceptible to nucleophilic addition from the thymidylate synthase side. The effect of local strain occurs in the ipso region in relation to the substituent. The effect is rather asymmetrical: the C(5)=C(6) bond is more strongly affected by the substituent than the C(4)-C(5) bond. This suggests a possibility of a further affinity increase of FdUMP system regarding the enzyme.

Lipophilic calix[4]resorcinarenes, derived from lauryl aldehyde and resorcinol, are strongly adsorbed on the modified silica gel RP-18 during HPLC. This technique leads to the column with an excellent time stability and good reproducibility at the retention characteristics of substituted phenols as analytes.

The resistance changes in diffusion limited electrode processes are given and compared with experimentally determined by high frequency resistometry (HFR) combined with potentiostatic, galvanostatic and cyclic voltammetry methods. The general shape of resistance-time dependence is similar to current time transients in potentiostatic and potential time transients in galvanostatic experiments. The resistance-potential depen-dence in cyclic resistometry exhibits a sigmoidal shape, similar to the convolutive CV current function. The greatest change of the electrolyte resistance takes place near the electrode surface. High frequency resistometry provides independent parameters to those obtained from other electrochemical methods.

The solid-liquid equilibrium (SLE), of 11 binary mixtures of n-alkanes (octadecane, nonadecane, eicosane, heneicosane, docosane, tricosane, tetracosane, pentacosane, hexa-
cosane, heptacosane, octacosane) in ethyl tert-butyl ether, (ethyl 1,1-dimethylethyl ether, ETBE) have been determined from 275 K to the melting temperature of n-alkane. Results of solubility are compared with values calculated by Wilson, NRTL and UNIQUAC equations utilizing parameters from SLE. The existence of solid-solid first order phase transition in hydrocarbons has been considered in the solubility calculations. The best correlation of the solubility data has been obtained by the NRTL equation, where the average root-mean-square deviation of the solubility temperatures is 0.84 K.

In the crystals of trans-diaquobis(mu-3-aminopyrazine-2-carboxylato-N,O,O,O)strontium(II) the Sr ion is eightfold coordinated: by two aminopyrazinate (APZA) ligands via their (N,O) bonding moieties [Sr-O 2.5189(15) , Sr-N 2.7280(18) ], two other carboxylate oxygen atoms donated by the adjacent APZA molecules [Sr-O 2.5989(16) ] bridging the Sr(APZA)₂ units into molecular ribbons and two water molecules [Sr-O 2.5556(18) ]. The ribbons are interconnected by hydrogen bonds involving the water molecules and the carboxylate oxygens [O-H...O 2.71(1) ], as well as the amino group nitrogen atoms and the heteroring nitrogen atoms [N-H...N 3.08(1) ].

The low-temperature crystal structures of 4-methylphenyl[2.2]paracyclophane (1), C₂₃H₂₂, orthorhombic, Pbca, a = 12.880(2), b = 7.4234(12), c = 34.425(6) , Z = 8; 2,6-dimethylphenyl[2.2]-paracyclophane (2), C₂₄H₂₄, orthorhombic, P2₁2₁2₁, a = 8.593(3), b = 12.550(4), c = 15.745(4) , Z = 4, and 2,4,5-trimethylphenyl[2.2]paracyclophane (3), C₂₅H₂₆, monoclinic, P2₁/c, a = 13.737(2), b = 17.883(2), c = 15.230(2) , ß = 103.423(8), Z = 8 (two independent molecules) have been determined. Surprisingly, only small differences from the normal paracyclophane structure were found in the three sterically hindered species; the paracyclophane rings are mutually rotated and twisted by a few degrees, and the torsion angle between paracyclophane and aryl rings is slightly increased in 2 and 3 compared to 1.

X-ray crystal study of the 2-(1,4,5,6-tetrahydropyrimidin-2-yl)phthalazinone-1 hydroiodide showed different hydrogen bonding network and packing than those observed in the crystals of two other phthalazinones-1, comprising either smaller (4,5-dihydro-
imidazolyl) or larger (4,5,6,7-tetrahydrodiazepinyl) ring substituent in position 2 and having very similar crystal structures.

The crystals of cis-tetraquobis(pyrazine-2-carboxylato-O,N)calcium(II) contain monomeric molecules, in which the calcium ion has a distorted dodecahedral coordination, formed by four water molecules (mean Ca-O = 2.441 , two oxygen atoms from monodentate carboxylic groups of two pyrazinic acid molecules (mean Ca-O = 2.458 ) and two nitrogen atoms located next to the above carboxylic groups (mean Ca-N = 2.619 ). In the crystals of cis-tetraquobis(pyrazine-2-carboxylato-O,N)strontium(II) the coordination of the Sr²⁺ ion is identical with that of the calcium complex, the corresponding mean distances being Sr-O(water) 2.572 , Sr-O 2.588 , Sr-N 2.751 . The monomeric molecules of both compounds are linked via a network of hydrogen bonds.