Lichen based biomonitoring of air quality in Havana City west side

Summary An epiphytic lichen (Physcia alba sp.) grown over Roystonea regia tree was used as biomonitor of air quality in the Havana City west side. During the survey, 81 sampling sites were selected according to traffic and industry conditions. The concentration for 14 elements (Mg, Al, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Cd and Pb) was determined by flame atomic absorption spectrometry (FAAS) and anodic stripping voltammetry (ASV). Contents of Cu, Zn, Cd and Pb obtained by both techniques were compared. Several biological reference materials (RM's) were analyzed in order to assure the quality of analytical results. Some pollution sources were identified using principal component analysis. A total of 5 factors were achieved, of which 4 could be interpreted in terms of anthropogenic pollution sources. However, the expected correlation between traffic influence and lead concentration in lichen could not be demonstrated. The factor values patterns are presented.     

One teflon-like channelled nanoporous polymer with a chiral and new uninodal 4-connected net: sorption and catalytic properties

Zn(C17H8F6O4) is the first example of a fluoro-lined nanotube organo-inorganic 3D polymeric chiral structure, which possesses two different types of isolated channels, one of them being laid out with a double spiral of CF3-groups from the ligand molecule; the structure is a new uninodal 4-connected net that only exists when bent ligands connect the centres, and the compound exhibits selective sorption and catalytic chiral recognition properties.     

Unprecedented asymmetric induction through configurationally stable lithium N-(alpha-methylbenzyl)phosphinamides. A new entry to enantiomerically pure gamma-aminophosphinic acids and esters

The first examples of configurationally stable N-benzyl-N-phosphinoyl carbanions are described. Their applications to the synthesis of homochiral gamma-aminophosphinic acids and esters via highly enantioselective dearomatising reactions are shown.     

Efficient methods for the synthesis of 2-hydroxyphenazine based on the Pd-catalyzed N-arylation of aryl bromides

[reaction: see text] Substituted diphenylamines can be synthesized by Pd(0)-catalyzed N-arylation using o-nitroanilines and nitro-substituted aryl bromides for a substrate. Cyclization of the diphenylamines by various methods, including the intramolecular Pd(0)-catalyzed N-arylation, produces 2-methoxyphenazine which can easily be deprotected to give 2-hydroxyphenazine. This phenazine is required to synthesize methanophenazine, a novel redoxactive cofactor isolated from methanogenic archaea.     

High-resolution retinal images obtained by deconvolution from wave-front sensing

A new concept for high-resolution ophthalmoscopy is presented. The method is an alternative to the use of adaptive optics. It is based in deconvolving a retinal image from simultaneously acquired multiple ocular wave-front aberration and aberration-distorted fundus images. A computer simulation of the procedure using actual ocular wave-front aberration data that shows the validity of the method is first presented. Experimental results obtained from an artificial eye serve both to probe the method in a situation similar to the real eye and to introduce the required preprocessing of the retinal images. Finally, results from a real human retina are presented, and the potential of the technique is discussed.     

Tris(benzocyclobutadieno)triphenylene and its lower biphenylene homologues by palladium-catalyzed cyclizations of 2,3-didehydrobiphenylene

[reaction: see text] The Pd-catalyzed cycloaddition of didehydrobiphenylenes 2a,b, generated from the corresponding 3-(trimethylsilyl)-2-biphenylenyl triflates with fluoride, furnishes the C3-symmetric trimers 1a,b in which the embedded triphenylene unit is distorted to increase the aromaticity of the central benzene ring. Cocyclization of 2a,b with dimethyl acetylenedicarboxylate provides the phenanthrene- and naphthalenecarboxylic ester analogues, depending on the catalyst used.     

Diastereoselective tandem 6-exo carbolithiation intramolecular ring opening in (-)-8-aminomenthol-derived perhydrobenzoxazines. A new synthesis of enantiopure 4-substituted tetrahydro isoquinolines and 2-azabenzonorbornanes.

Aryllithiums prepared by bromine-lithium interchange in chiral 2-(o-bromophenyl)-substituted perhydro-1,3-benzoxazines participate in the intramolecular 6-exo carbolithiation reaction with unactivated double bonds attached to the nitrogen substituent of the heterocycle. When the reaction time is extended or no TMEDA is used, the cyclized lithium intermediates react intramolecularly with the N,O-acetal system leading to 2-azabenzonorbornane derivatives. The reactions are highly stereoselective and constitute a high-yielding synthesis of enantiopure 4-substituted tetrahydroisoquinolines or 7-substituted 2-azabenzonorbornanes.     

NMR data visualization,processing, and analysis on mobile devices

Touch‐screen computers are emerging as a popular platform for many applications, including those in chemistry and analytical sciences. In this work, we present our implementation of a new NMR ‘app’ designed for hand‐held and portable touch‐controlled devices, such as smartphones and tablets. It features a flexible architecture formed by a powerful NMR processing and analysis kernel and an intuitive user interface that makes full use of the smart devices haptic capabilities. Routine 1D and 2D NMR spectra acquired in most NMR instruments can be processed in a fully unattended way. More advanced experiments such as non‐uniform sampled NMR spectra are also supported through a very efficient parallelized Modified Iterative Soft Thresholding algorithm. Specific technical development features as well as the overall feasibility of using NMR software apps will also be discussed. All aspects considered the functionalities of the app allowing it to work as a stand‐alone tool or as a ‘companion’ to more advanced desktop applications such as Mnova NMR. Copyright © 2015 John Wiley & Sons, Ltd.