Template synthesis and characterization of diaza dioxa macrocyclic nanosized cobalt(II) complex dispersed within nanocavity of zeolite-Y

Nanocavity microreactor containing 15- and 16-membered diaza dioxa Schiff-base cobalt(II) complexes “[Co(Et[15]N₂O₂)]²⁺, [Co(Pr[16]N₂O₂)]²⁺, [Co(Ph[15]N₂O₂)]²⁺ and [Co(Ch[15]N₂O₂)]²⁺” have been prepared by the template synthesis of diamine (1,2-diaminoethane, 1,3-diaminopropane, 1,2-diaminobenzene or 1,2-diaminocyclohexane) with [(1,3-bis(2-carboxyaldehydephenoxy)propane)cobalt]²⁺;[Co(BCAPP)]²⁺@NaY within the pores of zeolite-Y. The nanosized cobalt(II) complex were entrapped in the supercage of Y-zeolite by a three-step process in the liquid phase: (i) exchange of Co(II) ions with NaY in water solution, (ii) reaction of Co(II)–NaY with excess BCAPP in methanol; [Co(BCAPP)]²⁺@NaY; (iii) template synthesis of [Co(BCAPP)]²⁺@NaY with diamine. The new nanosized complex entrapped in the nanocavity of zeolite Y was characterized by several techniques: chemical analysis and spectroscopic methods (FT-IR, UV–Vis, XRD, BET, DRS, XPS, TGA).     

Thermal decomposition route for synthesis of Mn3O4 nanoparticles in presence of a novel precursor

The synthesis of manganese oxide (Mn₃O₄) nanoparticles by using thermal decomposition and its physicochemical characterization are being reported in present investigation. As a new precursor, [bis(2-hydroxy-1-naphthaldehydato)manganese(II)] complex was used in the presence of oleylamine (C₁₈H₃₇N) as both surfactant and solvent to control the size of resulting nanoparticle. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and Raman spectrum. Synthesized manganese oxide nanoparticles have a tetragonal structure with average size of 9–24 nm. The phase pure samples were characterized by using X-ray photoelectron spectroscopy (XPS) for Mn 2p level. The values of binding energies are consistent with the relative values are reported in the literature. As a comparison between two methods, the novel precursor thermally was treated in solid state reaction in different temperature, 400, 500, and 600 °C and the products were characterized by SEM images. Magnetic property of the as-prepared Mn₃O₄ nanoparticle shows a ferromagnetic behavior with high saturation magnetization and coercivity.     

Synthesis and characterization of hexagonal nano-sized nickel selenide by simple hydrothermal method assisted by CTAB

Nano-sized nickel selenide powders have been successfully synthesized via an improved hydrothermal route based on the reaction between NiCl₂·6H₂O, SeCl₄ and hydrazine (N₂H₄·H₂O) in water, in present of cetyltrimethyl ammonium bromide (CTAB) as surfactant, at various conditions. The products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and X-ray energy dispersive spectroscopy analysis. Effects of temperature, reaction time and reductant agent on the morphology, the particle sizes and the phase of the final products have been investigated. It was found that the phase and morphology of the products could be greatly influenced by these parameters. The synthesis procedure is simple and uses less toxic reagents than the previously reported methods. Photoluminescence (PL) was used to study the optical properties of NiSe samples.     

Charged Polymers in the Attractive Regime: A First-Order Transition from Brownian Scaling to Four-Point Localization

We study a quenched charged-polymer model, introduced by Garel and Orland in 1988 (Europhys. Lett. 6(7):597–601, 1988; Europhys. Lett. 6(4):307–310, 1988), that reproduces the folding/unfolding transition of biopolymers. We prove that, below the critical inverse temperature, the polymer is delocalized in the sense that: (1) the rescaled trajectory of the polymer converges to the Brownian path; and (2) the partition function remains bounded.     

Interaction of copper(II) complex of compartmental Schiff base ligand N,N'-bis(3-hydroxysalicylidene)ethylenediamine with bovine serum albumin

Circular dichroism (CD) spectroscopy, cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to investigate the interaction between copper(II) complex of compartmental Schiff base ligand (L), N,N'-bis(3-hydroxysalicylidene)ethylenediamine, and bovine serum albumin (BSA) in 0.1 mol dm(-3) phosphate buffer solution adjusted to physiological pH 7.0 containing 20% (w/w) dimethylsulfoxide at room temperature. CD spectra show that the interaction of the copper(II) complex with BSA leads to changes in the alpha-helical content of BSA and therefore changes in secondary structure of the protein with the slight red shift (2 nm) in CD spectra. From the voltammetric data, i.e. changes in limiting current with addition of BSA, the binding constant (K) of the interaction of copper(II) complex with BSA was found to be 1.96 x 10(4)dm(3)mol(-1). From the shifts in potential with the addition of BSA, the equilibrium constant ratio (K(2)/K(1)) for the binding of the oxidized Cu(II)L (K(1)) and reduced Cu(I)L (K(2)) species to BSA was found to be 3.77, which shows that the reduced form Cu(I)L is bound more strongly to BSA than the oxidized form Cu(II)L.     

Synthesis and characterization of NiO nanoclusters via thermal decomposition

Thermal decomposition process has been developed to synthesize nickel oxide (NiO) nanoclusters via the reaction between a new precursor, nickel oxalate [Ni(O₄C₂)(H₂O)₄] and oleylamine (C₁₈H₃₇N). The combination of triphenylphosphine (C₁₈H₁₅P) and C₁₈H₃₇N were added as surfactants to control the particle size. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA) and ultraviolet–visible (UV–Vis) spectroscopy. The synthesized NiO nanoclusters have a cubic structure with average size 2–10 nm.     

Pure cubic ZrO2 nanoparticles by thermolysis of a new precursor

Zirconia (ZrO₂) nanoparticles have been synthesized through the thermolysis of bis-aqua, tris-2-hydroxyacetophenato zirconium (IV) nitrate, [Zr(HAP)₃(H₂O)₂](NO₃), as a precursor in oleylamine (C₁₈H₃₇N) and triphenylphosphine (C₁₈H₁₅P). The combination of C₁₈H₃₇N and C₁₈H₁₅P was added to act as surfactants to control the particle size. C₁₈H₃₇N and C₁₈H₁₅P play an important role in preventing aggregation of ZrO₂ nanoparticles. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), photoluminescence spectroscopy (PL) and Fourier transform infrared (FT-IR) spectroscopy to depict the phase and morphology. The synthesized ZrO₂ nanoparticles have a cubic structure. The FT-IR spectrum showed the purity of obtained cubic phase ZrO₂ nanocrystals.     

Bright blue pigment CoAl<Subscript>2</Subscript>O<Subscript>4</Subscript> nanocrystals prepared by modified sol–gel method

Nanocrystalline films of magnetite have been prepared by a novel sol–gel route in which, a solution of iron (III) nitrate dissolved in ethylene glycol was applied on glass substrates by spin coating. Coating solution showed Newtonian behaviour and viscosity was found as 0.0215 Pa.s. Annealing temperature was selected between 291 and 350 °C by DTA analysis in order to obtain magnetite films. In-plane grazing angle XRD and TEM studies showed that magnetite phase was present upon annealing the films at 300 °C. The films had crack free surfaces and their thicknesses varied between ~10 and 200 nm. UV–Vis spectrum results showed that transmittance of the films increases with decreasing annealing temperature and increasing spinning rate. Up to 96% transmittance was observed between the wavelengths of 900–1,100 nm. Vibrating sample magnetometer measurements indicated that magnetite thin films showed ferromagnetic behavior and the saturation magnetization value was found as ~35 emu/cm³.