Giuseppe Ciccarella

Use of readily available chiral compounds related to the betti base in the enantioselective addition of diethylzinc to aryl aldehydes

Abstract Readily available members of the family of chiral non-racemic aminonaphthols related to the Betti base 1 were tested as complexing agents in the catalytic enantioselective addition of diethylzinc to aryl aldehydes. The use of these bases gave high ee values (up to > 99%). The highest ee values were obtained with the tertiary aminonaphthol 2. An important role was played by the solvent. The effect of the nature and the position of the substituents on the aromatic ring of the aldehyde was also investigated.

Selective reactions on the tips of colloidal semiconductor nanorods

A strategy to access several types of Au-tipped dumbbell-like nanocrystal heterostructures is presented, which involves the selective oxidation of either PbSe or CdTe sacrificial domains, initially grown on CdSe and CdS nanorods, with a Au(III) ∶ surfactant complex. The formation of gold patches is supported by TEM, XRD and elemental analysis. This approach has allowed us to grow Au domains onto specific locations of anisotropically shaped nanocrystals for which direct metal deposition is unfeasible, as for the case of CdS nanorods. We believe that this strategy may be of general utility to create other types of complex colloidal nanoheterostructures, provided that a suitable sacrificial material can be grown on top of the starting nanocrystal seeds.

Photocatalytic degradation of 4-nitrophenol in aqueous suspension by using polycrystalline TiO2 samples impregnated with Cu(II)-phthalocyanine

In this paper, the preparation of polycrystalline TiO2 samples impregnated with a modified Cu(II)-phthalocyanine (TiO2–CuPc) is reported along with an investigation on the photocatalytic behavior of this system compared with bare TiO2 (both in the anatase and rutile form) and with TiO2 samples impregnated with not functionalized commercial phthalocyanine (TiO2–CuPc) or with metal free phthalocyanine (TiO2–Pc). The photocatalytic degradation of 4-nitrophenol (4-NP) was studied as a probe reaction. The presence of modified CuPc showed to be beneficial only for TiO2 (anatase) while the commercial not functionalized CuPc also slightly for both TiO2 (anatase) and TiO2 (rutile). The metal free Pc did not show any beneficial influence on the photoactivity. A tentative explanation of the beneficial effect due to the presence of the Cu(II)-phthalocyanines both on the initial reaction rate and on the mineralization process is provided by taking into account intrinsic electronic and physico-chemical properties.

THE BETTI BASE : ABSOLUTE CONFIGURATION AND ROUTES TO A FAMILY OF RELATED CHIRAL NONRACEMIC BASES

Abstract A detailed protocol for the resolution of the Betti base [i.e. 1-(α-aminobenzyl)-2-naphthol] was investigated and the absolute configuration of the two isomers was established by means of an X-ray diffractometric study. A series of optically active derivatives was also prepared. The list includes the N-benzyl- and the N,N,O-trimethyl derivatives. The N,N-dimethyl derivative was prepared in racemic form by means of the Betti reaction and was resolved into the two enantiomers with an extremely easy and efficient procedure. The O-methyl derivative was prepared in a racemic form and subjected to resolution. The configuration of each base was determined by correlation with the configuration of the Betti amine.

Surfactant-free synthesis of pure anatase TiO2 nanorods suitable for dye-sensitized solar cells

A non-aqueous, solvothermal method was applied to the synthesis of TiO2 nanorods in pure anatase crystal phase using Ti(IV)-isopropoxide. The use of benzyl alcohol as both solvent and reactant was investigated in combination with the addition of acetic acid to the reaction mixture. Various values of the AcOH : Ti(OiPr)4 molar ratio were realized in the synthesis and tested in order to obtain a significant dimensional and morphological control over the resulting TiO2 nanostructures, as well as to devise a simple and scalable synthetic protocol. On the basis of the experimental results, a substantially modified version of the well-established “benzyl alcohol route” was then designed and developed. X-ray diffractometry and transmission electron microscopy revealed that monodisperse anatase nanorods having a length of about 13–17 nm and a diameter of 5 nm can be obtained when AcOH and Ti(OiPr)4 are reacted in comparable proportions. Investigation of the characteristic parameters of dye-sensitized solar cells fabricated using the synthesized nanorods as photoanode revealed a power conversion efficiency of about 7.5% corresponding to an improvement of 28% with respect to a commercial spheroidal nanotitania (P25) based reference device.

Optochemical vapour detection using spin coated thin films of metal substituted phthalocyanines

Spin coated layers of metallophthalocyanines have been used as chemically interacting materials and a discussion concerning the data obtained with optical absorbance measurements in UV-Vis spectral range in controlled atmosphere is presented. Glass substrates coated with metallophthalocyanines show good sensitivity and selectivity depending on both the central metal ion of the molecules and the peripheral substituents of the macrocycles. A promising sensitivity towards tert-butylamine, diethylamine, dibutylamine, 2-butanone and acetic acid vapours has been monitored. Moreover, a structural characterisation by using scanning electron microscopy has been performed and a different morphology of the sensitive layers obtained from different materials has been evidenced.

Metallophthalocyanines thin films in array configuration for electronic optical nose applications

Abstract The interaction between some ambient reactive compounds and organic or inorganic thin layers can cause variations in the physical properties of the chemically interactive layers. Molecules in the gas phase, which are adsorbed onto the surface or absorbed in the bulk of the thin layer, generally modify the electrical or optical or mass properties of the gas-sensitive material giving rise to a number of different kinds of chemical sensors based on different working principles. This work reports and discusses the experimental results obtained with optical absorbance measurements in UV-Vis spectral range onto these optical sensitive layers in controlled atmosphere containing vapours. In particular, very interesting results have been obtained by optical absorption measurements carried out in the region of the typical Q band of phthalocyanines and a selectivity toward different vapours, depending both on the metal and the peripheral substituents of the macrocycle, was found. The as-manufactured sensors have been arranged in an array configuration and examples of applications for “electronic optical nose” to the analysis of some volatile organic compounds (VOC) which are of interest in food analysis are reported in this work.

Design and synthesis of fluorenone-based dyes: two-photon excited fluorescent probes for imaging of lysosomes and mitochondria in living cells

Three fluorenone-derived two-photon fluorescent probes (TK) targeting the lysosomes (TK-Lyso) and mitochondria (TK-Mito1 and TK-Mito2) were synthesized by introducing different diphenylamine moieties into the fluorenone core. The TK dyes showed high biocompatibility and long-term retention, low cytotoxicity, large Stokes shift and good fluorescence quantum yield. The results of the present work disclose a class of organic dyes with potential wide applications as specific and efficient probes for lysosomes and mitochondria in the study of various biological processes.

First disubstituted dibenzothiophene-5,5-dioxide monodispersed molecular materials for efficient blue-electroluminescence

This study reports on the first monodispersed molecular materials embodying the dibenzothiophene-5,5-dioxide core for the achievement of blue electroluminescence. The core has been functionalised in its 2,8- or 3,7-positions with dimethyl-fluorene (2,8-DBTOF and 3,7-DBTOF) or methyl-carbazole (2,8-DBTOC and 3,7-DBTOC) groups. The obtained compounds were characterised by 1H and 13C NMR, APCI-MS, thermal analysis (TGA and DSC) and cyclic voltammetry. Their optical and photophysical properties were investigated by UV and PL measurements as well as by time-dependent density-functional theory calculations. The materials were successfully employed as active layers in blue to purplish blue p-i-n OLED devices, that reached, in the case of 3,7-DBTOC, performances as high as 11 422 cd m−2 and 3.25 cd A−1.

Novel phthalocyanines containing cardanol derivatives

The synthesis and characterization of metal-free and metallo derivatives (Cu, Zn, Ni, Pd) of tetra-substituted phthalocyanines are described. The new compounds contain as a peripheral substituent 3-n-pentadecylphenol, a component of cardanol, which is a renewable organic source.