In this paper, the reactivity of cobalamin towards S-oxidized cysteine derivatives (sulfenic, sulfinic, sulfonic and S-sulfate) is analyzed and compared to the reactivity towards related nitrogen, oxygen and sulfur-based ligands, focusing on the concept of linkage isomerism. UV-Vis spectra complemented by DFT and TD-DFT calculations show that cysteine and its oxidized derivatives do yield adducts, with a preference for binding to the cobalt through the sulfur.

A new equation for the determination of activation energy of chemical oscillations was obtained in the reaction of methanol oxidation on a Pd catalyst. The maximum temperature, TM, of oscillations depends on the arrangement of the same quantity of the catalyst in the reactor, with the other experimental conditions kept constant.

Dihedral angles are predicted from vicinal coupling constant 3JHH[Hz] with 3-sphere approach, sphere or torus trigonometric equations of circle 1, 2 and circle inversion 3-5 for all cis-, trans-ee, trans-aa stereochemistry. The existence of circle inversion was demonstrated with conformational analysis on five and six membered rings. The sign and the stereochemistry result from vicinal coupling constant under trigonometric equations confirmed by algebraic equations, Hopf and Lie algebra theory. 3-Sphere, a hypersphere in 4D enable for all stereochemistry calculation dihedral angles under magnetic wave (NMR data -3JHH[Hz]), and all isomers from only one vicinal coupling constant.

The present research reports the ultrasonic assisted synthesis of ferroelectric cellulose-barium titanate composites (C/BT). As proved by wide angle X-ray diffraction (WAXD) and by scanning electronic microscopy (SEM), the composites consist of perovskite-type barium titanate particles (BT) of 400- 600 nm, disposed around the cellulose microfibers. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and wide angle X-ray diffraction (WAXD) revealed the modifications of structure/morphologies of the prepared sample as compared to pristine cellulose, with direct consequences on the polymer crystalline domains, on the uniformity of BT dispersion and on the dielectric properties of the composites. The composites obtained by ultrasonic treatment possess high dielectric constants (58.6-140.5), better breakdown strengths (8.9-17.7 kV/mm) and energy storage densities (2.6-9.0 J/cm3) as compared to BT particles, as well as very low dielectric losses (0.27-3 x 10-4) at industrial frequencies (50-55 Hz), the values being dependent on the content of barium titanate and on the preparation parameters.

The multilayer (10 layers) Al doped ZnO (AZO) thin films were deposited on glass substrate by sol-gel & dipping method. X-Ray diffraction measurements showed that the AZO films were polycrystalline with a hexagonal wurtzite structure. The morphological properties of the films were analyzed by atomic force microscopy showing continuous and homogeneous film, completely covering the substrates. The thickness, optical constants, optical band gap (Eg) and transmittance (T) of AZO films were assessed by spectroscopic ellipsometry on UV-vis-NIR spectral range. The AZO film has high transmittance above 80% in the visible region and the optical band-gap energy around 3.7 eV. The electrical characteristics regarding conductivity, mobility and carrier concentrations, were measured by Hall Effect measurements (van der Pauw method). The bulk carrier concentration of the AZO film with 10 layers was found to be 1.16x1019 cm-3. The vibrational bands were obtained by Raman analysis. Defects due to oxygen vacancies in the prepared AZO films were evidenced by photoluminescence spectroscopy (PL). The optical and electrical properties of the AZO thin films proved the possibility to be used in optoelectronic applications.

Reaction of Ph3Bi[O(O)CC5H4N‐3]2 (1) in CHCl3 and AgClO4 in ethanol, in 1:1 molar ratio, afforded the isolation of colorless crystals of a coordination compound which was proved to be [Ag(EtOH){Ph3Bi[O(O)CC5H4N-3]2}(ClO4)]•CHCl3 (2•CHCl3) by single-crystal X-ray diffraction. A 1D coordination polymer is formed based on bridging triphenylbismuth(V) di(nicotinate) between silver atoms, with trans Ag−N dative bonds [2.183(4), 2.196(5) Å]. Additional Ag•••O interactions are established between the coinage metal atom and an ethanol molecule [2.58(3) Å] as well as a perchlorate anion [2.746(6) Å], respectively. Its supramolecular architecture, based on a variety of non-covalent interactions, i.e. O−H•••O, C−H•••O or C−H•••Cl hydrogen bonds, π•••π , C−H•••π, C−Cl•••π interactions, as well as Ag•••O and Ag•••Cl contacts, is discussed.

The interactions between four native and modified beta-cyclodextrins and a benzimidazolium bromide salt were analyzed through UV-Vis and NMR Spectroscopy. The new benzimidazolium salt was obtained by simple and efficient conversion of N-1 substituted 5,6-dimethylbenzimidazole with phenacyl bromide in acetone. In all cases, the complexes stoichiometry was 1:1, as determined from UV-Vis titrations. Based on the values for association constants, the strength of the interactions with benzimidazolium bromide was weakest with the methyl substituted beta-cyclodextrin and strongest with the sulfobutylether substituted beta-cyclodextrin. Through-space NOE experiments were used to investigate the structural aspects of inclusion process. The obtained NOE correlations indicate coexistence of two inclusion modes: one with the phenacyl group inside the cyclodextrin cavity and the second one with dimethyl-substituted benzene ring inside the cavity. The imidazole ring and the ethyl substituent have been proven to remain outside the cyclodextrin cavity in both inclusion modes.

New catalysts were synthesized by immobilization of Cu(II) and Mn(III) biomimetic complexes onto mesoporous SBA-15 silica, amino-functionalized SBA-15, montmorillonite and Al-pillared montmorillonite supports. [Cu(acac)(phen)(OH2)](ClO4) and [Cu(acac)(Me2bipy)](ClO4) copper complexes and [Mn(III)(valen)(H2O)(CH3CN)](ClO4)∙CH3CN manganese complex supported on silica pore surface or intercalated into the interlayer spaces of clays, were characterized by X-ray diffraction, N2 adsorption-desorption, TGA-DTA analysis, IR and UV-Vis spectroscopy. These results have confirmed the structural stability of the mesoporous hosts and successful anchoring of the metal complexes over the supports. In order to verify the biomimetic comportment, catalytic activities of the free and immobilized complexes and that of Trametes versicolor laccase, immobilized on the same supports, were tested by oxidation with air of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), the most used substrate for estimation of specific activity of laccases. The supported complexes were more active than the free ones. Furthermore, the stability tests for the most active heterogeneous catalyst confirmed that the best support was NH2-SBA-15.

Zn(1-x)CuxO (x = 0, 1, 3, 5%) nanocrystals were synthesized via a hydrothermal method at 150°C for 24 h. The structural, morphological, optical and photocatalytic properties of the samples were investigated, and found to be dependent on the content of the copper dopant. The UV photocatalytic activities of Zn(1-x)CuxO nanocrystals were evaluated by the photodecomposition of the methyl orange (MO) dye. The nanocrystals with a Cu content of 5% exhibited the highest UV photocatalytic activity with a photodegradation efficiency of 94% during 120 min as compared to that of pure ZnO with 73%. The enhancement of the photocatalytic activity of Zn0.95Cu0.05O originates from the better separation of the photogenerated electron-hole pairs.