2D → 3D corrugated structure self-assembled from 4,4′-methylenebis(N-(pyridin-2-ylmethylene)aniline and terephthalic acid: Crystal structure and selective anion separations via anion exchange

A new flexible cationic Zn(II)metal organic framework, {[Zn₂(BDC)_1.5(L)(DMF)]NO₃·DMF·solvent}_n, MOF 1 , which is a corrugated two-dimensional network, was synthesized by self-assembly of Zn(NO₃)₂.6H₂O with 4,4′-methylenebis(N-(pyridin-2-ylmethylene)aniline as a neutral ligand and terephthalic acid in dimethyl formamide (DMF) as solvent and characterized by X-ray diffraction. Because of the presence of uncoordinated nitrate (NO₃⁻) ions in the channels, the compound was employed for ion-exchange applications. We report a detailed study of the host–guest interaction for a cationic metal–organic framework (MOF) that can reversibly capture nitrate. The recrystallization of the MOF was evaluated by monitoring the anion exchange dynamics using a combination of powder X-ray diffraction and Fourier transform infrared spectra with various kinds of foreign anions. This MOF showed fast and highly efficient Cr₂O₇²⁻ and CrO₄²⁻, N₃⁻, MnO₄⁻, and SCN⁻ exchange. The trapping capacities of Cr₂O₇²⁻, CrO₄²⁻, N₃⁻, MnO₄⁻, and SCN⁻ were 105,138, 44,104, and 25mg/g at 25°C after 3h, respectively, and there was good recyclability for capturing N₃⁻ and SCN⁻. {[Zn₂(BDC)_1.5(L)(DMF)]NO₃}_n exhibited anion exchange selectivity of SCN⁻ in a solution containing a mixture of 0.025mmol N₃⁻, SCN⁻, CrO₄⁻²⁻, Cr₂O₇²⁻, and MnO₄⁻ for 3h and exhibited anion exchange selectivity for SCN⁻ and Cr₂O₇²⁻ in a solution containing a mixture of 0.001mmol N₃⁻, SCN⁻, CrO₄²⁻, Cr₂O₇²⁻, and MnO₄⁻.     

Synthesis and labeling of p-NH2-Bn-DTPA-(Dabcyl-Lys6,Phe7)-pHBSP with 99mTc as a radiopeptide scintigraphic agent to detect cardiac ischemia

Journal of Radioanalytical and Nuclear Chemistry - Myocardial ischemia and infarction represent a major health burden worldwide, but their immediate diagnosis can reduce mortality and healthcare...     

Free vibration of composite plates with mixed boundary conditions based on higher-order shear deformation theory

A global higher-order shear deformation theory is devised to obtain the governing equations of composite plates under dynamic excitation. The time-harmonic solution leads to an eigenvalue problem for the natural frequencies of plates. The eigenvalue problem for rectangular plates is converted to a set of homogenous algebraic equations using differential quadrature method. The formulation of the problem allows direct application of various boundary conditions. Therefore, rectangular plates with mixed boundary conditions are also considered. To show the validity of results, the fundamental natural frequencies of composite plates with different boundary conditions and those of isotropic plates with mixed boundary conditions are compared against the results available in the literature.     

Synthesis and characterization of platinum nano sized particles by laser ablation in C<Subscript>2</Subscript>H<Subscript>6</Subscript>O<Subscript>2</Subscript> solution

Platinum nano sized particles (Pt NPs) are superior catalysts for many intentions, such as glucose sensors, cancer therapy, gas sensors, etc. Here, Pt NPs were produced by pulsed laser ablation in C₂H₆O₂ solution using Q-switched Nd:YAG laser, for the first time. Then, the influence of the laser fluence during synthesis of them was investigated; and they were characterized by UV–vis spectroscopy, TEM, FE-SEM, XRD, FT-IR, and Raman spectroscopy. The results showed that with increasing laser fluence, the mean particle size of the spherical NPs enhanced. Meanwhile, they had a polycrystalline cubic structure. Correspondingly, the plasmon peak position of generated NPs in the absorption spectra shifted from 257 to 266 nm, with a rise of laser fluence. The IR and Raman spectroscopy was used to achieve the information about the surface state of Pt NPs. We propose that the optimum adjusted laser fluence is an important factor to increase the ablation efficiency.     

Effects of polymer adsorption on the effective viscosity in microchannel flows: phenomenological slip layer model from molecular simulations

Molecular simulations (Dissipative Particle Dynamics - DPD) were used to quantify the effect of polymer adsorption on the effective shear viscosity of a semi-dilute polymer solution in microchannel Poseuille flow. It is well known that polymer depletion layers develop adjacent to solid walls due to hydrodynamic forces, causing an apparent wall slip and reduced effective viscosity (increased total flow rate). We found that depletion layers also developed in the presence of hydrodynamically rough adsorbed layers on the wall. Polymer-polymer (steric) repulsion between flowing and adsorbed polymer expanded the depletion layer compared to no-adsorption cases, and the effective viscosity was reduced further. Desorption occurred for higher shear rates, reducing the repulsion effect and shrinking the depletion layers. A phenomenological algebraic model for the depletion layer thickness, including a shear modified adsorption isotherm, was developed based on the simulation data. The depletion layer model can be used together with the effective viscosity model we developed earlier.     

The effects induced by proton irradiation on structural characteristics of nuclear graphite

A grade TSX graphite was irradiated by a 2.5 MeV proton and a dose of 1.47 × 10¹⁸ ion cm⁻² at 330 K. The displacement per atom under this irradiation condition was about 0.02. The lattice parameter, crystallite size and the vacancies density in the graphite was measured before and after irradiation. It was found that the proton irradiation led to an increase in the volume of the sample. The volume change in the irradiated sample was confirmed by atomic force and scanning electron microscopes observations as increased roughness and pore size. Also, FTIR results showed that graphite is slightly oxidized by irradiation.

     

[2,2'-Bipyridine]-1,1'-diium perchlorate as a new and efficient dicationic organic salt for the promotion of the synthesis of bis(4-hydroxycoumarin), 5-arylidene barbituric acid and pyrano[2,3-d]pyrimidinone derivatives in water

Research on Chemical Intermediates - A simple and convenient procedure for the synthesis of 5-arylidene barbituric acid, pyrano[2,3-d]pyrimidinone and 4-hydroxycoumarin derivatives using...     

Survey reactivity of 2-aminopyridine and Meldrum’s acid in the presence of aryl glyoxals or aryl aldehydes; ethyl 2-(3-aryl imidazo[1,2-a]pyridin-2-yl)acetates versus ethyl 3-aryl-3-(pyridin-2-ylamino)propanoates

Research on Chemical Intermediates - The aim of present investigation is survey reactivity of 2-aminopyridine and Meldrum’s acid in the presence of aryl glyoxals or aryl aldehydes. The ethyl...     

Competitive binding affinity of two lanthanum(III) macrocycle complexes toward DNA and bovine serum albumin in water

In the present study, two water-soluble lanthanum(III) hexaaza Schiff base complexes were synthesized and characterized and also theoretically investigated. The interactions of these complexes with DNA and bovine serum albumin (BSA) were studied using different spectroscopic assessments and docking simulation analysis. The DNA docking studies suggested that these two complexes are able to interact with DNA through the minor groove, and also the binding affinity is in the order of La(L¹) > La(L²). Furthermore, the spectral titration was carried out and viscosity measurements were taken. In this regard, protein-binding studies revealed that these complexes quench the intrinsic fluorescence of BSA, and indicated that the possible binding site is located on the vicinity of Trp 213, which is further validated by docking simulation analysis. The in vitro anticancer activities of these complexes indicated that the La(L¹) complex is more effective than the other one and also exhibits a better interaction with DNA.