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This contribution reports the synthesis, characterization, 1H NMR, optical absorption and fluorescence properties of a bis(salicylaldiminato)Zinc(ii) Schiff base complex, 1, having dipodal, alkyl ammonium bromide derivatized side chains in the salicylidene rings. The comparison of 1H NMR and optical spectroscopic properties of 1with those of the closely related amphiphilic alkyl derivative allowed getting insights into the nature of species in solutions. Present data suggest the existence of ZnBr interactions, thus avoiding intermolecular ZnO interactions, as usually occur in the absence of other coordinating species. SEM images of samples obtained by drop-casting from dichloromethane solutions of 1reveal the existence of branched nanostructures, consistent with intermolecular ZnBr interactions. The present approach thus suggests a new method to unique supramolecular architectures for coordination metal complexes. [ABSTRACT FROM AUTHOR]

Praseodymium aluminum oxide (PrAlOx) thin films have been grown by metal organic chemical vapor deposition (MOCVD) using two different multimetal sources consisting of mixtures of aluminum acetylacetonate (Al(acac)3) with two praseodymium precursors, namely, the praseodymium hexafluoroacetylacetonate diglyme adduct (Pr(hfa)3·diglyme) and the praseodymium tetramethylheptanedionate (Pr(tmhd)3). Smooth and amorphous films have been deposited on Si(100) substrates. Their chemical composition and microstructure, investigated by EDX measurements and TEM analyses, are deeply affected by the nature of the precursor mixture. Optimal structural and compositional properties are achieved with a Al(acac)3−Pr(hfa)3·diglyme mixture. Annealing procedures at 900 °C under an inert ambient atmospher do not affect the film crystallization. Preliminary electrical characterizations indicate a dielectric constant of about 12. [ABSTRACT FROM AUTHOR]

A novel approach based on a molten multicomponent precursor source has been applied for the MOCVD fabrication of high-quality CaCu3Ti4O12(CCTO) thin films on various substrates. The adopted in situ strategy involves a molten mixture consisting of Ca(hfa)2·tetraglyme, Ti(tmhd)2(O-iPr)2, and Cu(tmhd)2Hhfa 1,1,1,5,5,5-hexafluoro-2,4-pentanedione; tetraglyme 2,5,8,11,14-pentaoxapentadecane; Htmhd 2,2,6,6-tetramethyl-3,5-heptandione; O-iPr isopropoxide precursors. Film structural and morphological characterizations have been carried out by several techniques X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and in particular the energy filtered TEM mapping and X-ray energy dispersive (EDX) analysis in TEM mode provided a suitable correlation between nanostructural properties of CCTO films and deposition conditions and/or the substrate nature. Correlation between the nanostructure and optical/dielectric properties has been investigated exploiting spectroscopic ellipsometry. [ABSTRACT FROM AUTHOR]

A hybrid approach of colloidal lithography and metalorganic chemical vapour deposition (MOCVD) has been used to fabricate ZnO nanowire bundles and nanoholes by using a silver metalorganic precursor as the growth catalyst. [ABSTRACT FROM AUTHOR]

A simple and effective approach to fabricate extensive 3D ZnO nanoarchitectures on alkaline etched (100) Si substrates is presented. Textured silicon micropattern drives ZnO 1D growth on all the {111} exposed faces, resulting in sea sponge-likeZnO nanoarchitectures. The obtained 3D nanostructured ZnO is the result of a perfectly ordered array of continuous and crystalline ZnO nanorods, grown on the silicon pyramid {111} faces. The substrate orientation and the relative roughness, intrinsically derived by the alkaline silicon texturization, drive the preferential growth of one-dimensional ZnO nanorods. The ZnO nanorods photoluminescence spectra show, at room temperature, a narrow ultraviolet (UV) emission peak at 3.28 eV and a broad unstructured green band emission at 2.57 eV. These luminescence emissions are attributed to the near band-edge exciton transitions and to the defect emission, respectively. This original approach to fabricate high surface area ZnO nanoarchitectures presents the advantages of well established and reproducible methodologies of semiconductors industrial manufacturing (silicon micromachining and chemical vapor deposition), thus representing an easy scaling up solution to fabricate new ZnO-based nanomaterials. [ABSTRACT FROM AUTHOR]

The diglyme [CH3O(CH2CH2O)2CH3] adduct of the magnesium bis-hexafluoroacetyl-acetonato [Mg(hfa)2·2H2O·2diglyme] has been synthesized in a single-step reaction. It has been characterized by elemental analyses, IR spectroscopy, and 1H and 13C NMR. Single-crystal X-ray diffraction studies provide evidence of a mononuclear hexa-coordinated complex with an octahedral structure for the Mg(hfa)2·2H2O moiety and diglyme coordinated in the outer sphere (triclinic system, space group= P1̅; a= 8.952(3) Å, b= 9.036(3) Å, c= 11.98(1) Å, α = 110.44(5)°, β = 108.64(4)°, γ = 97.06(3)°, Z= 1). The “thermal robustness” and mass transport properties of the adduct have been investigated by thermogravimetric analysis and chemical vapor deposition experiments. Thermal analysis data revealed high volatility and good thermal stability with a residue left lower than 1%. The Mg(hfa)2·2H2O·2diglyme has been successfully applied to the low-pressure metal-organic chemical vapor deposition (MOCVD) of MgF2films. The good quality of the deposited films indicates that the adduct is a very attractive single-source precursor for deposition of MgF2films. [ABSTRACT FROM AUTHOR]

Spontaneous self-assembly of calix[4]arenes bearing four 2′-deoxythymidine or 2′-deoxyadenosine nucleotide pendants is investigated using 1H NMR, exchange NMR, and diffusion ordered NMR spectroscopies and dynamic light scattering. In aqueous medium, the nucleotide−calixarene conjugates, by noncovalent interactions involving both nucleobases and calixarene skeleton, form dimers which self-organize in micelles by increasing the concentration. Microscopic images (scanning electron microscopy and transmission electron microscopy) show that the nucleobase affects the aggregate morphology in the solid state. [ABSTRACT FROM AUTHOR]