Mononuclear and binuclear Zn(II), Cd(II) and Hg(II) complexes of orthohydroxybenzeneazoethylacetoacetate isonicotinoyl hydrazone (H₃L), have been synthesized and characterized by elemental analyses, IR, ¹H NMR and VIS-UV spectra, conductance and thermal analyses. The ligand behaves as tetradentate in mononuclear complexes and hexadentate in binuclear complexes. The molar conductance of the complexes has been discussed.

Five new tetracarboxylato-bridged dinuclear nickel(II) complexes of the formula [Ni₂(PMTA)L₄], where L denotes 4,7-diphenyl-1,10-phenanthroline (Ph₂-phen); 2,9-dimethyl-1,10-phenanthroline (Me₂-phen); diaminoethane (en); 1,3-diaminopropane (pn) and 1,2-diaminopropane (ap); and PMTA represents the tetraanion of pyromellitic acid, have been synthesized and characterized by elemental analyses, molar conductivity and room temperature magnetic moment measurements, and by spectroscopy. It is proposed that these complexes have PMTA-bridged structures and consist of two nickel(II) ions in a distorted octahedral environment. The complexes [Ni₂(PMTA)(Ph₂-phen)₄] (1) and [Ni₂(PMTA)(Me₂-phen)₄] (2) were further characterized by variable temperature magnetic susceptibility measurements (4~300 K) and the observed data were treated in terms of two theoretical models, giving the exchange integrals J = -2.85 cm^-1 for (1 and -1.96 cm^-1 for (2. The result indicates that there is a very weakly antiferromagnetic spin-exchange interaction between two the Ni(II) ions within each molecule.

Six new µ-oxamido heterodinuclear complexes, [Cu(Me₂oxpn)Fe(L)₂]SO₄, have been synthesized from the planar monomeric fragment [Cu(Me₂oxpn)], where Me₂oxpn denotes N,N'-bis(3-amino-2,2-dimethylpropyl)oxamido dianion and L represents 1,10-phenanthroline (phen); 5-nitro-1,10-phenanthroline (NO₂-phen); 5-chloro-1,10-phenanthroline(Cl-phen);5-bromo-1,10-phenanthroline(Br-phen);5-methyl-1,10-phenan- throline (Me-phen) and 2,2'-bipyridine (bpy). Based on the elemental analyses, spectroscopic studies, magnetic moments (at room temperature) and molar conductivity measurements, extended oxamido-bridged structures consisting of a copper(II) and an iron(II) ions, which have a square planar environment and an octahedral environment, respectively, are proposed for these complexes. The [Cu(Me₂oxpn)Fe(bpy)₂]SO₄ (1) and [Cu(Me₂oxpn)Fe(phen)₂]SO₄ (2) complexes have been characterized by variable temperature magnetic susceptibility (4.2~300 K) and the observed data were least-squares fitted to the susceptibility equation derived from the spin Hamiltonian including single-ion zero-field interaction for the iron(II) ion, H = -2J S₁^.S₂-S_Z1², giving the exchange integrals J = -15.8 cm^-1 for (1) and J = -17.6 cm^-1 for (2). These results indicated that the spin coupling between the adjacent copper(II) and iron(II) ions through oxamido-bridge in both complexes (1) and (2) is antiferromagnetic.

Six dinuclear Fe^III complexes involving tetradentate Schiff bases N,N'-bis(salicyl-
idene)ethylenediamine (salenH₂) or bis(salicylidene)o-phenylenediamine (salophH₂) with 2,6-pyridinedicarboxylic acid (2,6-dicarpyH₂), thiodiglycolic acid (tdgaH₂) or 3,3'-thiodipropionic acid (3,3'-tdpaH₂) have been synthesized and characterized by elemental analysis, IR spectroscopy and conductivity measurements. The magnetic behaviour of all complexes has been studied between 77-298 K. The dicarboxylic acids form bridges between paramagnetic centers and weak antiferromagnetic intramolecular exchanges were found. Thus, the complexes can be characterized as high spin distorted octahedral iron(III), except for [{Fe(saloph)}₂(2,6-dicarpy)], where S₁ = S₂ = 3/2 spin-exchange model complies best with experimental data and the iron(III) has probably square-pyramidal coordination mode. The HDW S₁ = S₂ = 5/2 spin-exchange model with (H = -2S₁ S₂) was applied in the case of the other complexes. The antiferromagnetic coupling parameters J vary in the range of -1.06 to -5.87 cm^-1.

The thermal decomposition of M₂^ICrO₄ (where M^I = Li, Na, K, Rb, Cs, Ag, Tl), M^IICrO₄ (where M^II = Mg, Ca, Sr, Ba), M₂^III(CrO₄)₃ (where M^III = La, Nd) has been investigated. Mechanisms of individual stages of the thermal decomposition have been proposed on the basis of morphological classification. The effect of cationic counterions on the decomposition of chromates(VI) is described.

Tetradentate open-chain Schiff base ligands R-salen (R-salen are N,N'-ethylenebis(R-salicylideneiminato) dianions) and fluoride anions F^- coordinate to the iron(III) central atom in methanol forming the complexes trans-[Fe(R-salen)(CH₃OH)F]. The complexes are redox stable in the dark. Photoexcitation into their intraligand or ligand-to-metal charge transfer excited states leads to the photoreduction of Fe(III) to Fe(II), as a product of metanol oxidation the radical ^.CH₂OH was identified. The final products of the redox processes, Fe(II) and CH₂O, are formed in a 2:1 molar ratio. The efficiency of the photoredox processes is strongly wavelength dependent and influenced by the peripheral groups R of the tetradentate ligands. A mechanism of deactivation processes is proposed and the influence of the peripheral groups R on the photoredox efficiency and electrochemical properties of the complexes is discussed.

The complexes of light lanthanides (La-Eu) with 2,6-dihydroxybenzoic acid have been prepared and their IR spectra and thermal decomposition have been investigated. The complexes Ln(C₇H₅O₄)₃^.nH₂O, where n = 4 for La-Sm and n = 6 for Eu, when heated lose te crystallization water molecules in one (La-Pr), two (Nd, Sm) or three (Eu) steps and then anhydrous compounds decompose to Ln₂O₃, CeO₂ and Pr₆O₁₁ with intermediate formation of unstable Ln(C₇H₅O₄)(C₇H₄O₄), except of lanthanum complex, which forms additionally La₂O₂CO₃.

Three polypeptide fragments of flagellin protein were synthesized using the solid-phase method. The immunogenicity of the peptides was tested. All the peptides exhibit high immunological activity.

Statherin is a 43-amino acid residue phosphominiprotein present in human parotid and submandibular saliva. It may take part in transport of calcium and phosphate and most probably is partly responsible for the protection and recalcification of tooth enamel. The solid phase synthesis of statherin and its three shortened analogues: (1-15)statherin, [Ser², Ser³](1-15)statherin and [Asp², Asp³](1-15)statherin is presented. It was established that polyclonal antibodies directed against three shortened analogues showed affinity to synthetic statherin and statherin in saliva.

An essential development is presented, of our new method of quantitative estimation of the energetic heterogeneity of adsorbent and catalysts surfaces, from Temperature Programmed Desorption spectra, based on the Statistical Rate Theory of Interfacial Transport. That method, presented in a series of our recent publications, involved a necessity of estimating, in other than TPD experiments, of certain adsorption parameters which are necessary to calculate the adsorption energy distribution. This was a serious inconvenience of that new method. In this paper, it is shown for the first time, that these parameters can be determined in the same TPD experiment, by applying variable heating rate.

New superacid catalysts have been obtained by the action of BCl₃ vapours on silicaalumina (87% SiO₂). The mechanism and kinetics of pentane isomerization is discussed.

The effect of carboxylic acids of different strength on polarographic behaviour of p-chloronitrobenzene in N,N-dimethylformamide has been investigated. In the presence of each acid a pre-wave appeared at a more positive potential than the original one, which was associated with the cathodic reduction of a hydrogen-bonded adduct, formed between the nitrocompound and the acid molecules in the double layer of the electrode. A linear correlation has been found between E_1/2 and pK_HA^DMF (pK_HA^DMF refers to the value of the pK_a measured in N,N-dimethylformamide, whereas E_1/2 = E_1/2^{pre wave} - E_1/2^{original wave}). Measurements in a solvent series in the presence of benzoic acid (BA) led to the correlation between E_1/2 and pK_BA (the symbol pK_BA denotes the value measured in a given solvent). The slopes of regression lines are discussed in terms of the double layer effect on the basicity of the -NO₂ group.

A home-made Electrochemical Scanning Tunneling Microscope/Scanning Tunneling Microscope (ESTM/STM) has been used for investigations of the anodic oxidation of polycrystalline nickel, being controlled by cyclic voltammetry and coulometry. A surface fragment with a ± 10% accuracy at the scale of 4800 nm × 4800 nm and 100 nm × 100 nm was observed. The best compact and relatively smooth layers of nickel oxides have been obtained in a concentrated (c = 10.0 mol dm^-3) sulphuric acid solution. In a diluted electrolyte (c = 0.1 mol dm^-3), the formation of the NiO_x islands is possible.

Isotherms and heats of adsorption were measured for n-pentane, cyclopentane, furane and tetrahydrofurane adsorbed separately on NaX zeolite. Molar integral and differential adsorption heats as well as adsorption entropies have been calculated. Two energetical parameters have been determined for each adsorption system.

The homogeneous decomposition of various asymmetric dialkyl peroxides ROOR' (R = C₆H₅C(CH₃)₂; R' = Et, Pr, Bu, Buⁱ, Bu^s, Bu^t, n-heptyl, n-dodecyl and allyl) is examined by the measurement of autooxidation of isopropylbenzene in the presence of peroxides as initiators. Rate constants and activation parameters are determined and the size effect and type of alkyl group R' on stability of O-O bond is discussed.

Oxidative dehydrogenation of isobutane has been studied at 250°C for a series of chromium oxde-TiO₂ (anatase) samples containing 5-50 Cr at per nm² of the support surface and for pure chromia. The catalysts have been characterized by XPS, Raman, ESR spectroscopies and by probe reactions for acido-basic properties and the catalyst oxygen reactivity. The maximum activity and selectivity to isobutene have been observed for a catalyst containing 1 theoretical monolayer of the chromia phase on titania. Higher selectivity to isobutene for this catalyst as compared with unsupported chromia or catalysts with higher Cr loading has been ascribed to lower acidity and lower reactivty of oxygen.

The crystals of cobalt furoate {bis(µ-furan-2-carboxylato-O,O')-(µ-furan-2-carboxylato-O,O,O')-(furan-2-carboxylato-O)-bis[diaquacobalt(II)] dihydrate} are isostructural with the crystals of zinc furoate. They contain dimeric molecules. Two independent metal ions are connected to each other by three carboxylate bridges (one O:O,O and two O:O) from furan-2-carboxylate anions. The distorted octahedral environments of metal ions differ in the way of binding one of the furan-2-carboxylate ligands: monodentate in the case of Co(1) [Zn(1)]; bidentate in the case of Co(2) [Zn(2)]. The heteroring oxygen atoms do not coordinate directly the metal ions; their electrondonor properties manifest themselves by formation of O_water-H^...O_furan contacts. Both structures exhibit intermolecular hydrogen bonds involving all O_water atoms, and also weak contacts to carbon atoms from furan rings as donors. Carbonyl and furan oxygen atoms and electron of the furan rings are proton acceptors in these hydrogen bonds.

Copper(II) complexes Cu₂L₄(NO₃)₄ (a) and CuL₄(NO₃)₂ (b), where L is 1-allylimidazole, have been synthesized and characterized by elemental analysis, IR, FTIR, near IR, VIS, magnetic and crystallographic measurements. In centrosymmetric binuclear complex (a) the nitrate anions are linked to the Cu(II) cations through bidentate oxygen atoms. In complex (b) the Cu(II) cation occupies a symmetry centre and is tetragonal-bipyramid coordinated.