Total assignment of the 1H and 13C NMR spectra of benzo[f][1]benzothieno[2,3-c]quinoline by inverse-detected two-dimensional NMR techniques

The proton and carbon nmr spectra of benzo[f][1]benzothieno[2,3-c]quinoline have been totally assigned using a combination of 2D nmr methods including concerted use of HMQC (heteronuclear multiple quantum correlation) and HMBC (heteronuclear multiple bond correlation) experiments.     

Synthesis,structural elucidation,characterization and theoretical DFT study of 1‐(o‐tolyl)biguanidium chloride

The structure of the new salt 1‐(o‐tolyl)biguanidium chloride, C₉H₁₄N₅⁺·Cl^?, has been determined by single‐crystal X‐ray diffraction. The salt crystallizes in the monoclinic space group C2/c. In this structure, the chloride and biguanidium hydrophilic ions are mostly connected to each other via N—H…N and N—H…Cl hydrogen bonds to form layers parallel to the ab plane around y = and y = . The 2‐methylbenzyl groups form layers between these layers around y = 0 and y = , with the methyl group forming C—H…π interactions with the aromatic ring. Intermolecular interactions on the Hirshfeld surface were investigated in terms of contact enrichment and electrostatic energy, and confirm the role of strong hydrogen bonds along with hydrophobic interactions. A correlation between electrostatic energy and contact enrichment is found only for the strongly attractive (N—H…Cl^?) and repulsive contacts. Electrostatic energies between ions reveal that the interacting biguanidium cation pairs are repulsive and that the crystal is maintained by attractive cation…Cl^? dimers. The vibrational absorption bands were identified by IR spectroscopy.     

Resistivity–viscosity relationship in liquid–liquid critical mixtures with added ions

Precise resistivity ρ (Ω cm) and viscosity η (10⁻² P) measurements for isobutyric acid–water (IBAW) critical mixtures with added K⁺ and Cl⁻ ions have been performed in the Arrhenius temperature domain of the electrolyte. From the activation energy, the resistivity–viscosity relation reveals a fraction power character over the whole range of parameters investigated. To analyze our data we have used an exponential formula derived from the equivalent Arrhenius law: ρ/T is proportional to (η/T)^R, where R = E_ρ/E_η is the ratio between the resistivity and viscosity activation energies. In the case of the pure system (IBAW), the value of R is in vicinity of 1, but when the salt is added, the ratio R shows dependence on the (K⁺, Cl⁻) concentrations: 0.6 < R < 1. The domain of the validity of R is in conformity with the theoretical prediction. The Coulombic interaction is the origin of the deviation.     

Transport and separation of Ag(+) and Zn(2+) by donnan dialysis through a monovalent cation selective membrane

Donnan Dialysis of Ag⁺ and Zn²⁺ was investigated through a cation exchange membrane (CMS Neosepta) when a proton concentration difference was maintained between the two sides of the membrane. Developed for the production of brine from sea water, CMS Neosepta showed a higher permeability to monovalent than to bivalent cations. Several physico-chemical parameters have been determined (electrical resistance, membrane potential, sorption of electrolytes, Zn²⁺ and Ag⁺ diffusion coefficients). The flux of Ag⁺ and the diffusion potential in the membrane increase with HNO₃ concentrations. Ag⁺ and Zn²⁺ can be separated because of the preferential membrane transfer for Ag⁺.     

More on Ordinary Differential Equations Which Yield Periodic Solutions of Delay Differential Equations

We construct a Poincaré operator for the system where λ is a real parameter, x ³, x = (x₁, x₂, x₃), [formula], and ƒ is an odd C² function such that ƒ′(0) = 1, xƒ(x) > 0, for x ≠ 0. We also consider the case where ƒ is C¹. We will express F in linearized form, that is, F(x) = Ax + G(x), where A is the linearized part of F around zero and G(x) = o(|x|) near zero. Fixed points of the Poincaré operator correspond to periodic solutions of the functional differential equation

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where T is the period of x.     

Synthesis of W‐doped TiO2 by low‐temperature hydrolysis: Effects of annealing temperature and doping content on the surface microstructure and photocatalytic activity

A series of tungsten‐doped Titania photocatalysts were synthesized using a low‐temperature method. The effects of dopant concentration and annealing temperature on the phase transitions, crystallinity, electronic, optical, and photocatalytic properties of the resulting material were studied. The X‐ray patterns revealed that the doping delays the transition of anatase to rutile to a high temperature. A new phase W_yTi_1‐yO₂ appeared for 5.00 wt% W‐TiO₂ annealed at 900 °C. Raman and diffuse reflectance UV–Vis spectroscopy showed that band gap values decreased slightly up to 700 °C. X‐ray photoelectron spectroscopy showed that surface species viz. Ti³⁺, Ti⁴⁺, O^2?, oxygen‐vacancies, and adsorbed OH groups vary depending on the preparation conditions. The photocatalytic activity was evaluated via the degradation of methylene blue using LED white light. The degradation rate was affected by the percentage of dopants. The best photocatalytic activity was achieved with the sample labeled 5.00 wt% W‐TiO₂ annealed at 700 °C.     

Chemical compounds from Phoenician juniper berries (Juniperus phoenicea)

Natural chemical compounds are a widely researched topic worldwide because of their potential activity against cerebrovascular diseases. Chemicals from Juniperus phoenicea berries are reported in this study. Lipids (11%) from seeds are mainly unsaturated (86%). Minerals are also quantified like Na (63.8?mg per 100?g?DW) or K (373.9?mg per 100?g?DW). Total reduced sugars are ca 192.6?mg?g(-1)?DW. Polyphenols and flavonoids from berries are highly present with an average of 1764?±?174.3?mg gallic acid per 100?g?DW and 890?±?47.6?mg rutin per 100?g?DW, respectively. Mean free radical scavenging activities, determined by DPPH and ABTS, are 1337?±?126.2?mM TEAC per 100?g?DW and 1105.7?±?95.9?mM TEAC per 100?g?DW, respectively. All findings improve the possible presence of biologically active fractions in phytocomplex that could be used as such and/or extracted for the formulation of supplements and/or ingredients for the pharmaceutical industry.     

2,4-Dioxo(dimercapto)-1,5-benzodiazepino-13-couronne-2, Nouveau Macrocycle Complexant de L'ion Ag +

We describe herein the synthesis of new macrocycles 5 et 6 derived from 1,5-benzodiazepine-2,4-dione in a heterogenous media using phase transfer catalysis conditions. A crystallographic study by x-ray of 5 was carried out to confirm the structure suggested; moreover the macrocycle 6 presents chelating properties with respect to the ion Ag + easily observed by IR and UV spectroscopies.     

Dirichlet-to-Neumann semigroup acts as a magnifying glass

The first aim of this paper is to illustrate numerically that the Dirichlet-to-Neumann semigroup represented by P. Lax acts as a magnifying glass. In this perspective, we used the finite element method for discretizing of the correspondent boundary dynamical system using the implicit and explicit Euler schemes. We prove by using the Chernoff’s Theorem that the implicit and explicit Euler methods converge to the exact solution and we use the (P1)-finite elements to illustrate this convergence through a FreeFem++ implementation which provides a movie available online. In the Dirichlet-to-Neumann semigroup represented by P. Lax the conductivity \(\gamma \) is the identity matrix \(I_n\) , but for a different conductivity \(\gamma \) , the authors of Cornean et al. (J Inverse Ill-posed Prob 12:111–134, 2006) supplied an estimation of the operator norm of the difference between the Dirichlet-to-Neumann operator \(\Lambda _\gamma \) and \(\Lambda _1\) , when \(\gamma =\beta I_n\) and \(\beta =1\) near the boundary \(\partial \Omega \) (see Lemma 2.1). We will use this result to estimate the accuracy between the correspondent Dirichlet-to-Neumann semigroup and the Lax semigroup, for \(f\in H^{1/2}(\partial \Omega )\) .