Platinum-functionalized random copolymers for use in solution-processible, efficient, near-white organic light-emitting diodes

A near-white light-emitting polymer, consisting of hole transport (HT), electron transport (ET), and phosphorescent Pt functionalities, was prepared and utilized as the emissive layer in solution-processed OLEDs. The air-stable devices had a maximum external quantum efficiency of 4.6%.     

Determination of nineteen 4-alkylphenol endocrine disrupters in Geneva municipal sewage wastewater

A preconcentration technique, which involves liquid-liquid-liquid microextraction, was developed to determine phenoxy herbicides in bovine milk. A layer of organic phase was impregnated into the pores of a 3.5 cm long porous hollow fiber, while the internal volume of the fiber was filled with NaOH solution (the acceptor solution) that was connected directly to the needle of a microsyringe. The fiber was then immersed into 8 ml of acidified milk sample. When the sample solution was stirred, acidic analytes were extracted into the organic phase and back extracted simultaneously into the alkaline acceptor medium as the analytes were protonated at low pH and deprotonated at high pH. After extracting for a prescribed time, 5 microl acceptor solution was taken back into the syringe and injected directly into a HPLC system for quantification. The analytes were extracted quantitatively from the sample solution into the acceptor solution with a large enrichment factor of 900. Due to its low cost, the hollow-fiber extraction device was disposed of after a single extraction that eliminated the possibility of carry over effects. In addition, because a small volume of organic solvent was required and little waste is generated, the procedure is environmentally friendly, and is compatible with the "green chemistry" concept.     

Steric and electronic tuning of chiral bis(oxazoline) ligands with 3,3'-bithiophene backbone

[structure: see text] The role played by the electronic properties and the steric features of bis(oxazoline) ligands in the Cu(I)-catalyzed cyclopropanation of styrene effected with ethyl diazoacetate was investigated. Two pairs of new bis(oxazolines) displaying flexible and atropisomeric 3,3'-bithiophene backbones were synthesized and structurally and electronically characterized. For the first time, the electrochemical oxidative potential was used as a reliable index of the electronic density on the nitrogen atom of the chelating groups of new and, for comparative purposes, of already known bis(oxazolines). The Cu(I) complexes of the new ligands were prepared, and their enantioselection ability and catalytic efficiency were tested. This investigation suggests that steric factors and catalyst geometrical features are clearly more important than any consideration of the electronic properties of the chiral ligands.     

Structure, spectroscopic properties, and reversible solid-to-solid reactions of metal complexes of 5-nitro-pyrimidin-2-olate

In searching for coordination polymers containing the highly polarized 5-nitro-pyrimidin-2-olate ligand (NP), a number of species containing 3d transition metals have been prepared and characterized, namely Co(NP)2(H2O)4, [Co(NP)2]n, Ni(NP)2(H2O)4, [Ni(NP)2]x, and [Zn(NP)2]n. Their structures have been determined by X-ray powder diffraction methods. The hydrated compounds contain mononuclear M(NP)2(H2O)4 units interconnected by means of a three-dimensional (3D) network of hydrogen bonds. The homoleptic species, at variance from the already known metal(II) pyrimidin-2-olate ones, crystallize as two-dimensional (2D) slabs, where the metal coordination is of the MN3O kind. The electron-withdrawing nitro group, never bound to the metal ion, is likely to influence the observed stereochemistry through steric and dipolar effects within the crystal lattice. The thermal, spectroscopic, and magnetic properties of these species are presented. The M(NP)2(H2O)4/[M(NP)2]x,n systems interconvert reversibly upon dehydration/rehydration processes.     

Synthesis, characterization and colour determination using CIELAB colour space of stilbene dyes

The synthesis of six new symmetrical disazo direct dyes containing 4,4′-diaminostilbene-2,2′-disulphonic acid as middle component and N-(2-chlorophenyl)-2-hydroxybenzamide, N-(3-chlorophenyl)-2-hydroxybenzamide, N-(4-chlorophenyl)-2-hydroxybenzamide, N-(2-bromophenyl)-2-hydroxybenzamide, N-(3-bromophenyl)-2-hydroxybenzamide, N-(4-bromophenyl)-2-hydroxybenzamide as coupling components is presented. The synthesized dyes were analyzed by thin layer chromatography, electronic spectra and HPLC technique. Their structures were elucidated by FT/IR and 13C-NMR spectroscopy. The CIELAB (1976) colour space was used in all the colour measurements for the six disazo stilbene dyes under the CIE recommended illuminants: D65 (natural day light), A (tungsten light), F2 (fluorescent light) and the standard 10° observer, respectively. The colour differences: ΔEab* and ΔECMC were calculated against one standard. The results reveal a good colouring power of the new azo-stilbene dyes.     

Health benefits of pistachios consumption

The health benefits of nuts, mainly in relation to the improvement of dysmetabolic conditions such as obesity, type 2 diabetes mellitus and the related cardiovascular diseases, have been widely demonstrated. Compared to other nuts, pistachios have a lower fat and caloric content, and contain the highest levels of unsaturated fatty acids, potassium, γ-tocopherol, phytosterols and xanthophyll carotenoids, all substances that are well known for their antioxidant and anti-inflammatory actions. This variety of nutrients contributes to the growing body of evidence that the consumption of pistachios improves health, leading to a greater potential of healthy antioxidant and anti-inflammatory activity, glycemic control, and endothelial function. The present review examines the nutrients and phytochemicals present in pistachios as well as the potential health benefits of including pistachios in a diet.     

Efficiency of the dry–wet method for the MALDI‐MSI analysis of latent fingermarks

Matrix‐assisted laser desorption/ionisation mass spectrometry imaging (MALDI‐MSI) has proven to be a powerful analytical tool to investigate problems in several fields of life science. A novel application is in the field of forensics, particularly in the analysis of latent fingermarks. This technology enables images of the fingermark ridge detail and additional intelligence to be simultaneously obtained. Although several methods are available to deposit the MALDI matrix, to make the technology forensically operational, another deposition approach was devised and reported, namely the ‘dry–wet’ method. In the present study, the efficiency of the dry–wet method was evaluated and compared with the conventional spray coat methodology. Results indicate that the dry–wet method is superior for all the donors' typologies in terms of ion signal intensity and clarity of the ridge details. To underpin the reasons of this efficiency, scanning electron microscopy analyses were carried out in parallel to MALDI‐MSI experiments using matrices of different particle size. Results have confirmed that the particle size plays an important role in the efficiency of the method as higher quality images and higher intensity spectra are produced as the matrix particle size decreases. Copyright © 2013 John Wiley & Sons, Ltd.     

Matrix assisted laser desorption ionisation ion mobility separation mass spectrometry imaging of ex-vivo human skin

Matrix assisted laser desorption ionisation ion mobility separation mass spectrometry imaging (MALDI-IMS-MSI) has been employed to image the distribution of proteins in ex-vivo human skin. Using a “bottom-up” proteomics approach employing “on-tissue” digestion the distribution of abundant skin proteins; collagen, keratin, decorin and serum albumin could be mapped. Images have been recorded at 150 and 30 μm spatial resolution. Multivariate statistical analysis of the data has been employed to associate specific proteins with layers of the skin. The improved specificity given by the use of ion mobility separation in mass spectrometric imaging has been demonstrated by separation of peptide ions from phospholipids.     

Toward block copolymers from nonliving isospecific single‐site catalytic systems

Ethene/1‐olefin blocky copolymers were obtained through nonliving insertion copolymerizations promoted by an isospecific single site catalyst. Propene or 4‐methyl‐1‐pentene were copolymerized with ethene with metallocenes endowed with different stereospecificity in propene polymerization: (i) aspecific “constrained geometry” half‐sandwich complex, {η¹:η⁵‐([tert‐butyl‐amido)dimethylsilyl](2,3,4,5‐tetramethyl‐1‐cyclopentadienyl)}titanium dichloride [Me₂Si(Me₄Cp)(N‐^tBu)TiCl₂] ( CG ), (ii) moderately isospecific rac‐ethylenebis(indenyl)zirconium dichloride [rac‐(EBI)ZrCl₂] ( EBI ), (iii) slightly more isospecific hydrogenated homologue, rac‐ethylenebis(tetrahydroindenyl)zirconium dichloride [rac‐(EBTHI)ZrCl₂] ( EBTHI ), (iv) highly iso‐specific rac‐[methylenebis(3‐tert‐butyl‐1‐indenyl)]zirconium dichloride [rac‐H₂C‐(3‐^tBuInd)₂ZrCl₂] ( TBI ), (v) most isospecific rac‐[isopropylidene‐bis(3‐tert‐butyl‐cyclopentadienyl)]zirconium dichloride [rac‐Me₂C‐(3‐^tBuCp)₂ZrCl₂] ( TBC ). Copolymerizations were described by a 2^nd order Markovian copolymerization model and data are proposed to correlate the formation of 1‐olefin sequences with catalytic site isospecificity, made by the cooperation of organometallic complex and growing chain. Blocky copolymers were prepared over wide ranges of compositions: with any of the isospecific metallocenes when 4‐methyl‐1‐pentene was the 1‐olefin and only with the highly isospecific ones ( TBI , TBC ) when propene was the comonomer. A penultimate unit effect was observed with TBI as the metallocene, whereas a 1^st order Markov model described the ethene/propene copolymerization from TBC . A moderately isospecific metallocene, such as EBI , is shown to be able to prepare blocky ethene copolymers with 4‐methyl‐1‐pentene. These results pave the way for the synthesis of new ethene based materials. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2063–2075, 2010