Crystal and molecular structure of a new gadolinium nitrate complex with furancarboxylic acid and dipyridyl

The gadolinium nitrato complex with α-furancarboxylic acid (FA) and 2,2′-dipyridyl (Dipy) has been synthesized. According to X-ray diffraction results, the complex is composed of the [Gd(FA)₂(NO₃)(Dipy)]₂ dimers. The crystals are triclinic: a = 9.942(2) Å, b = 10.231(2) Å, c = 11.037(2) Å, α = 85.50(3)°, β = 75.71(3)°, γ = 69.82(3)°, Z = 1. Two gadolinium atoms are linked by four carboxylate groups of furancarboxylic acid molecules. Each gadolinium atom is coordinated to seven oxygen atoms (five belonging to the FA carboxyl groups and two belonging to the bidentate nitrate group) and to two nitrogen atoms (from Dipy).     

Mechanism of formation of doubly charged fragments from bis-benzyltetrahydroisoquinolines under electron impact

Some bis-benzyltetrahydroisoquinolines [α,α′-di-N,N-(1-benzyl-1,2,3,4-tetrahydroisoquinoline)-p-xylene and various substituted analogues] give rise to very abundant doubly charged fragment ions under electron impact, corresponding to the loss of the two benzyl groups. Substituent effects, ionization and appearance energy measurements and metastable transitions show that these doubly charged ions are formed (at least in part) from singly charged precursors by a heterolytic cleavage (charge separation).     

Asymmetric aza-Henry reactions from N-p-tolylsulfinylimines

[reaction: see text] N-Sulfinylimines derived from aromatic or aliphatic aldehydes and ketones react with nitromethane and NaOH in a highly diastereoselective manner under mild conditions. In the presence of TBAF, the reaction rates are strongly increased and the stereoselectivity is inverted. This method provides enantiomerically pure beta-nitroamines derived from enolizable aldimines and ketimines, which so far are hardly accessible by aza-Henry reactions.     

Preparation and characterization of bionanocomposite films based on wheat starch and reinforced with cellulose nanocrystals

Cellulose - In recent times, the attention of scientific community has been focusing on the replacement of petroleum-based polymers by others more environmentally friendly. In this sense,...     

An efficient method for the synthesis of nitropiperidones

A three step efficient strategy for the synthesis of substituted 5-nitropiperidones in high de, employing Michael addition of N-p-tolylsulfinyl beta-nitroamines to alpha,beta-unsaturated esters, hydrolysis of the sulfinyl group, and cyclization of the resulting free amines, has been developed. A very simple experimental procedure involving mild conditions and only one chromatographic purification are the main features of the process.     

Bioprocess Design for the Microbial Production of Natural Phenolic Compounds by Debaryomyces hansenii

Debaryomyces hansenii NRRL Y-7426 metabolised ferulic acid into different phenolic compounds using a factorial design where glucose concentration (in the range of 1?C20?g/L), peptone concentration (2?C20?g/L) and yeast extract concentration (0.2?C10?g/L) were the independent variables. The interrelationship between dependent and operational variables was well fitted (R ²?>?0.95) to models including linear, interaction and quadratic terms. Depending on the glucose and nitrogen concentrations, which redirected the metabolism, the major degradation products were 1,226.2?mg 4-vinyl guaiacol/L after 72?h (molar yield of 86.0?%), 1,077.8?mg vanillic acid/L after 360?h (molar yield of 91.1?%) or 1,682.6?mg acetovanillone/L after 408?h (molar yield of 98.8?%) in fermentations carried out with 2,000?mg ferulic acid/L. Other metabolites such as vanillin, vanillyl alcohol or 4-ethylguaiacol were present in lower amounts.     

Nanophotonic lab-on-a-chip platforms including novel bimodal interferometers, microfluidics and grating couplers

One of the main limitations for achieving truly lab-on-a-chip (LOC) devices for point-of-care diagnosis is the incorporation of the "on-chip" detection. Indeed, most of the state-of-the-art LOC devices usually require complex read-out instrumentation, losing the main advantages of portability and simplicity. In this context, we present our last advances towards the achievement of a portable and label-free LOC platform with highly sensitive "on-chip" detection by using nanophotonic biosensors. Bimodal waveguide interferometers fabricated by standard silicon processes have been integrated with sub-micronic grating couplers for efficient light in-coupling, showing a phase resolution of 6.6 × 10(-4)× 2π rad and a limit of detection of 3.3 × 10(-7) refractive index unit (RIU) in bulk. A 3D network of SU-8 polymer microfluidics monolithically assembled at the wafer-level was included, ensuring perfect sealing and compact packaging. To overcome some of the drawbacks inherent to interferometric read-outs, a novel all-optical wavelength modulation system has been implemented, providing a linear response and a direct read-out of the phase variation. Sensitivity, specificity and reproducibility of the wavelength modulated BiMW sensor has been demonstrated through the label-free immunodetection of the human hormone hTSH at picomolar level using a reliable biofunctionalization process.     

Decarboxylation of Ferulic Acid to 4-Vinyl Guaiacol by <Emphasis Type="Italic">Streptomyces setonii</Emphasis>

4-Vinyl guaiacol (3-methoxy 4-hydroxystyrene) can be obtained by decarboxylation of ferulic acid by the strain Streptomyces setonii ATCC 39116. The formation of this metabolite was favoured by microaerobic conditions and the culture medium employed, increasing progressively the product concentration from 543.3 up to 885.1 mg/l when aeration level was diminished, reaching a highest volumetric productivity of 70.4 mg/l h and a product yield of 1.11 mol/mol. The identity of the metabolite was confirmed by gas chromatography–mass spectrometry. A metabolic study of ferulic acid and the main degradation products (ferulic acid, 4-vinyl guaiacol, protocatechuic acid, vanillyl alcohol, vanillic acid and vanillin) suggested that ferulic acid was the only substrate capable to be transformed into 4-vinyl guaiacol by this strain of S. setonii.