Examination of Template Structural Effects on CEC Chiral Separation Performance of Molecule Imprinted Polymers Made by a Generalized Preparation Protocol

Some acidic chiral templates were used to prepare open tubular (OT) molecule imprinted polymer (MIP) capillary columns to explore the effects of molecular structures of templates on chiral recognition capabilities and to verify the feasibility of the general MIP preparation protocol introduced in the previous study. The templates are phenyl carboxylic acids and their derivatives. Optimization was carried out for chiral separation of template enantiomers for each MIP column through varying pH and composition of eluent. It was found that the preparation protocol can be successfully applied for the appropriate templates with functional groups fulfilling the three-points interaction rule. The chiral separation performances were quite satisfactory for MIPs of such templates although they are yet inferior to the separation performances of the MIP columns fabricated with the templates of profen drugs (2-arylpropionic acids with a large substituent on the phenyl ring). Subtle variations of the template molecular structures have been found to be critical to enhance chiral recognition ability of the resultant MIP column.     

Physical properties of small water clusters in low and moderate electric fields

Likely candidates for the lowest minima of water clusters (H(2)O)(N) for N ≤ 20 interacting with a uniform electric field strength in the range E ≤ 0.6 V/? have been identified using basin-hopping global optimization. Two water-water model potentials were considered, namely TIP4P and the polarizable Dang-Chang potential. The two models produce some consistent results but also exhibit significant differences. The cluster internal energy and dipole moment indicate two varieties of topological transition in the structure of the global minimum as the field strength is increased. The first takes place at low field strengths (0.1 V/? 10) usually forming helical structures.     

Correlating the scattered intensities of P3HT and PCBM to the current densities of polymer solar cells

Grazing-incidence X-ray diffraction and rocking scans have quantified the structure of poly(3-hexylthiophene) and [6,6]-phenyl-C(61)-butyric acid methyl ester in the active layers of organic solar cells. Our study reveals that the device J(SC) correlates with the local structural development of pure PCBM and, to second order, the extent of out-of-plane P3HT π-stacking.     

A facile method to tune zeolite L crystals with low aspect ratio

We demonstrate an alternative route to tune the morphology of zeolite L crystals using C(2)H(5)OH as the co-solvent in the synthesis gel. A low aspect ratio (0.2 to 0.4) of zeolite L crystals was obtained at lower synthesis temperature (150 °C) and shorter synthesis duration (3 days).     

From microscopic insights of H2 adsorption to uptake estimations in MOFs

The adsorption of hydrogen in MOFs takes place mainly close to the inorganic secondary building unit (IBU). The adsorption capacities on MIL-88, UiO-66, MIL-47 and MFU-1 were investigated. Quantum chemical calculations at the ab initio HF/MP2 theoretical level were employed to estimate the maximum uptake of H(2) molecules per metallic centre. Extrapolating the results on small clusters to the unit cell of each particular MOF, the H(2) uptakes (gravimetric and volumetric) were estimated. The loading of hydrogen per metal atom (H(2) molecules/M-atom) and the density of metal atoms (M-atoms ?(-3)) were defined as useful parameters to assess hydrogen storage properties and to estimate the optimum density that the material should have to be a good H(2) adsorbent. It was found that values above 3 H(2) molecules/M-atom and around 0.004 M-atoms ?(-3) for MOFs with densities around 0.7-1.0 g cm(-3) are required to reach the 2015 storage targets.     

Determination of the enantiomeric excess of α-hydroxy acids

This work describes a convenient and accurate method for optical purity determination of α-hydroxy acids. Their derivatization with commercially available valine methyl ester affords diastereoisomers easily separable by HPLC using achiral C₁₈ columns.     

An Identification Problem for First-Order Degenerate Differential Equations

We study a first-order identification problem in a Banach space. We discuss the nondegenerate and mainly the degenerate case. As a first step, suitable hypotheses on the involved closed linear operators are made in order to obtain unique solvability after reduction to a nondegenerate case; the general case is then handled with the help of new results on convolutions. Some applications to partial differential equations motivate this abstract approach.Communicated by I. GalliganiWork partially supported by MIUR (Ministero dell’ Istruzione, dell’ Università e dalla Ricerca), Project PRIN 2004011204 “Analisi Matematica nei Problemi Inversi,” and by the University of Bologna Funds for Selected Research Topics.     

Flow-injection spectrofluorimetric determination of paracetamol

A flow-injection spectrofluorimetric determination of paracetamol is reported, based on the oxidation of the analyte with potassium hexacyanoferrate(III) immobilized on an anion-exchange resin, the fluorescence being enhanced with N,N′-dimethylformamide. Concentrations of paracetamol in the range 0.04–17.60 mg l^?1 are determined with a relative standard deviation of 1.5%. The injection rate is 25 samples h^?1. The influence of foreign species and the determination of paracetamol in several pharamaceutical formulations are also reported.     

Synthesis and some chemical transformations of 3-ferrocenyl-3-phenylcyclopropene

Crystalline 3-ferrocenyl-3-phenylcyclopropene was obtained by dehydrobromination of 2-bromo-l-ferrocenyl-l-phenylcyclopropane with potassiumtert-butoxide in dimethyl sulfoxide. The compound synthesized undergoes catalytic hydrogenation to l-ferrocenyl-I-phenylcyclopropane, reacts with 1,3-diphenylisobenzofuran to give the expected product of stereospecific [4+2[-cycloaddition and 3-ferrocenylindene, and also undegoes opening of the small ring on treatment with superacids to give 3-ferrocenylindene as the major product. The data of single crystal X-ray diffraction analysis of 1-ferrocenyl-l-phenylcyclopropane and the diene adduct of 3-ferrocenyl-3-phenylcyclopropene with 1,3-diphenylisobenzofuran are given.     

A study of transverse and longitudinal momentum correlations in proton diffraction dissociation at 14 GeV/c

We present data on momentum correlations both in and out of the production plane for the reactions π⁺p→π_f⁺(π⁺n) and π^?p→π_f^?(π^?Δ⁺⁺). The dissociation products show strikingly similar transverse momentum distributions which in terms of exchange models suggest an equal amount of pion and baryon exchange. For both reactions, we find an approximate factorization in the projectile frame between the transverse momentum of π_f and the longitudinal momenta of the dissociation products. Exchange models predict this result equally in both reactions, but it appears much more clearly in the Δ reaction. Finally, we relate the observed longitudinal and transverse momentum distributions in a way suggested by an isotropic decay model.