Copolymerization Parameters of Itaconic Anhydride in Free-Radical Polymerization

The copolymerization of itaconic anhydride (M₁) with four different monomers (M₂), namely: vinyl acetate, 2-chloro-ethyl acrylate, acrylonitrile, and styrene, was studied. Values of r₁ and r₂ were determined for copolymerizations in benzene and for two of these systems, namely those with vinyl acetate and 2-chloroethyl acrylate. Values of r₁ and r₂ were also determined for copolymerizations in tetra-hydrofuran. The value of ri ranged from 0.53 to 4.8, but it was always very much greater than r2. The Q-e values for itaconic anhydride in all the systems studied were also calculated and the average values for Q₁ = 8.2, e₁ = 1.45 were determined.     

Reactions of 4-alkylidene (arylidene)-1-phenylpyrazolidine-3,5-dione

Reactions of 4-alkylidene(arylidene)-1-phenylpyrazolidine-3,5-dione with oxidizing (chromium trioxide/acetic acid) as well as with reducing (sodium borohydride/methanol) agents were carried out. Phenylhydrazine reacted with 4-arylidene-1-phenylpyrazolidine-3,5-diones via fission of exo C=C bond to give 1-phenylpyrazolidine-3,5-dione and the corresponding aryl hydrazones. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1335–1341, September, 2007.     

Rational design of biocompatible IPNs hydrogels containing carboxymethyl starch and trimethyl chitosan chloride with high antibacterial activity

Cellulose - Antimicrobial hydrogels have enticed a major concern for repairing soft tissues, particularly prohibiting bacterial infections that are frequently accompanied by impaired wound healing....     

Mesoporous carbons from self-assembled polymers

Polymer self-assembly provides a robust and cost-efficient nanomanufacturing platform for enabling a broad range of applications, such as microelectronics, drug delivery, and separation membranes. This review focuses on discussing the progress and opportunities of self-assembled polymer in the synthesis of mesoporous carbons (MCs), which have aroused significant research interests over the past decades. Specifically, we will discuss the two most established approaches for converting nanostructured polymers to MCs, including templating-based and direct pyrolysis-based methods. We will also review the fundamental ordering mechanisms and kinetics of these polymeric systems and discuss the recent development of engineering methods for providing on-demand control over the pore size and morphology of MCs. Additionally, this review article also includes a section focusing on the strategies to further functionalize these materials from self-assembled polymers to enhance their performance, such as chemical activation, heteroatom doping, introduction of nanoparticles into the carbon matrix, and enhancing graphitization degree of carbon walls. Finally, a brief perspective is provided about the emerging research opportunity in this exciting field.     

Effect of the formation of silver nano‐binuclear complex on the refinement of cytotoxic and antibacterial potency of coumarin Schiff base: Spectroscopy,thermal, X‐ray diffraction analyses and density functional theory calculations

A new Schiff base (SCH) was prepared using 8‐acetyl‐7‐hydroxy‐4‐methylcoumarin and sulfaclozine. Its silver complex was also synthesized. These compounds were subjected to elemental and spectral analyses. The silver complex was also subjected to thermogravimetric analysis, molar conductance measurements, scanning electron microscopy, energy‐dispersive X‐ray analysis and X‐ray diffraction measurements. The formula of the complex was determined as [(Ag₂SCH(NO₃)₂]. The molar conductance indicates its non‐electrolyte character. The electronic structure and nonlinear optical parameters of SCH and its complex were investigated theoretically at the B3LYP/GENECP level. The geometry of the studied complex is non‐planar as indicated from the dihedral angles between central Ag metal ion and coordinated centres of SCH. Density functional theory calculations were also carried out to calculate the global properties of hardness, global softness and electronegativity. The calculated energy gap between HOMO and LUMO energies shows that charge transfer occurs within the studied complex. The total static dipole moment, the mean polarizability, the anisotropy of the polarizability and the mean first‐order hyperpolarizability were calculated and compared with those of urea as a reference material. The results of the mean first‐order hyperpolarizability showed that SCH and its silver complex are excellent candidates as nonlinear optical materials. The compounds were screened for their antimicrobial effect against various species of bacteria and fungi. Their anticancer activities were evaluated in vitro against the human cancer cell line MCF‐7 (human breast adenocarcinoma).     

Impact of Intermolecular Non-Covalent Interactions in a CuI8PdII1 Discrete Assembly: Conformers’ Geometries and Stimuli-Sensitive Luminescence Properties

A new highly solid-state luminescent phase of a previously reported weakly luminescent Cu^I₈Pd^II₁ dicationic assembly is reported revealing the high geometrical versatility of this moiety that importantly alters its luminescent properties. This very minor new species B_c is based on a different conformer scaffold than the one encountered in the previously reported B_o form and, essentially differs from B_o by displaying shorter Cu^I-Cu^I intermetallic distances. DFT calculations allow concluding that the predominance in the solid-state of the weakly luminescent and less stable B_o phase is due to the extra stability induced by a larger number of intermolecular non-covalent π-CH interactions in its crystalline packing and not by the intrinsic stability of the Cu^I₈Pd^II₁ dicationic moiety. Calculations also revealed that a more stable conformation B_calc is expected in vacuum, which bears a different distribution of Cu^I-Cu^I intermetallic distances than the dications in B_o and B_c phases. Taking into account that the geometrical alterations are associated to drastic changes of luminescence properties, this confer to the Cu^I₈Pd^II₁ assembly high potentiality as stimuli-sensitive luminescent materials. Indeed, by applying mechanical or thermal stress to samples of B_o phase, new phases B_g and B_m , respectively, were obtained. Alterations of the solid-state photophysical properties of these new species compared to those recorded for B_o are reported together with a combined experimental and computed study of the structures/properties relationships observed in these phases.     

Functionalization of α-Aminonicotinonitrile: A New Entry for Synthesis of Pyrazolo[3,4-b]pyridine,Pyrido[2,3-d]pyrimidine,and 1,8-Naphthyridine Derivatives

Russian Journal of General Chemistry - Functionalization of α-aminopyridine to a new series of pyridine and fused pyridine derivatives has been achieved via its reaction with a variety of...     

Novel Triazole-, Oxadiazole-, and Pyrazole-Nicotinonitrile Hybrids: Synthesis,DFT Study,Molecular Docking,and Antimicrobial Activity

Russian Journal of General Chemistry - The present study is devoted to functionalization of ethyl 2-{[3-cyano-6-(4-cyanophenyl)-4-(2,4-dichlorophenyl)pyridin-2-yl]oxy}acetate (1) by triazole-,...     

Simultaneous determination of dimethoate and its metabolite omethoate in curry leaf using LC-MS/MS and risk assessment

This study presents the method development, validation, and simultaneous determination of dimethoate and its metabolite omethoate in curry leaf. Samples were extracted following modified quick, easy, cheap, effective, rugged, and safe extraction protocol and analyzed using liquid chromatography-tandem mass spectrometry. The limit of quantification in the matrix was 0.005 μg g⁻¹ for dimethoate and omethoate. Extraction using acetonitrile recorded the average recoveries in the range of 82.25 to 112.97% for dimethoate and 85.57 to 107.22% for omethoate at 0.005, 0.025 and 0.050 μg g⁻¹ fortification levels and relative standard deviation less than 5%. Similarly, the relative standard deviation values for intraday (Repeatability) and interday (Reproducibility) tests were less than 15%. Dissipation kinetics of dimethoate 30% emulsifiable concentrate at 200 and 400 g a.i h⁻¹ recorded initial deposits of 5.20 and 10.05 μg g⁻¹ and 0.33 and 0.48 μg g⁻¹ for dimethoate and omethoate, respectively, and half-life of 3.07 and 3.34 days. The estimated hazard index value found more than one at a day after dimethoate application. It is not safe for consumer health to use curry leaves in the initial days after application.