99Tc NMR as a promising technique for structural investigation of biomolecules: theoretical studies on the solvent and thermal effects of phenylbenzothiazole complex

The phenylbenzothiazole compounds show antitumor properties and are highly selective. In this paper, the ⁹⁹Tc chemical shifts based on the (^99mTc)(CO)₃(NNO) complex conjugated to the antitumor agent 2‐(4′‐aminophenyl)benzothiazole are reported. Thermal and solvent effects were studied computationally by quantum‐chemical methods, using the density functional theory (DFT) (DFT level BPW91/aug‐cc‐pVTZ for the Tc and BPW91/IGLO‐II for the other atoms) to compute the NMR parameters for the complex. We have calculated the ⁹⁹Tc NMR chemical shifts of the complex in gas phase and solution using different solvation models (polarizable continuum model and explicit solvation). To evaluate the thermal effect, molecular dynamics simulations were carried, using the atom‐centered density matrix propagation method at the DFT level (BP86/LanL2dz). The results highlight that the ⁹⁹Tc NMR spectroscopy can be a promising technique for structural investigation of biomolecules, at the molecular level, in different environments. Copyright © 2014 John Wiley & Sons, Ltd.     

Efficient Detection of Phthalate Esters in Human Saliva via Fluorescence Spectroscopy

The detection of phthalates in human biologic fluids remains an important research objective because it provides an important measure of an individual’s exposure to this class of compounds, which have known deleterious health effects. Moreover, the ability to accomplish such detection in fluids that are easy to collect, such as saliva and urine, provides additional practical advantages. Reported herein is the application of cyclodextrin-promoted fluorescence energy transfer and fluorescence modulation to accomplish precisely such detection: the development of sensitive and selective florescence-based detection methods for phthalates in saliva, an easily collectable human biologic fluid. Such saliva-based detection methods occur with high levels of selectivity (100% differentiation) and sensitivity (limits of detection as low as 0.089?µM), and provide significant potential in the development of practical phthalate detection devices.     

Supramolecular Assemblies for Electronic Materials

This work presents a synergy between organic electronics and supramolecular chemistry, in which a host–guest complex is designed to function as an efficacious electronic material. Specifically, the noncovalent recognition of a fullerene, phenyl-C₆₁-butyric acid methyl ester ( PC₆₁BM ), by an alternating perylene diimide ( P )-bithiophene ( B ) conjugated macrocycle ( PBPB ) results in a greater than five-fold enhancement in electron mobility, relative to the macrocycle alone. Characterization and quantification of the binding of fullerenes by host PBPB is provided alongside evidence for intermolecular electronic communication within the host–guest complexes.     

Bismuth(III) Flavonolates: The Impact of Structural Diversity on Antibacterial Activity,Mammalian Cell Viability and Cellular Uptake

A series of homoleptic and heteroleptic bismuth(III) flavonolate complexes derived from six flavonols of varying substitution have been synthesised and structurally characterised. The complexes were evaluated for antibacterial activity towards several problematic Gram-positive (Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant Enterococcus (VRE)) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacteria. The cell viability of COS-7 (monkey kidney) cells treated with the bismuth flavonolates was also studied to determine the effect of the complexes on mammalian cells. The heteroleptic complexes [BiPh(L)₂] (in which L=flavonolate) showed good antibacterial activity towards all of the bacteria but reduced COS-7 cell viability in a concentration-dependent manner. The homoleptic complexes [Bi(L)₃] exhibited activity towards the Gram-positive bacteria and showed low toxicity towards the mammalian cell line. Bismuth uptake studies in VRE and COS-7 cells treated with the bismuth flavonolate complexes indicated that Bi accumulation is influenced by both the substitution of the flavonolate ligands and the degree of substitution at the bismuth centre.     

Exact Meromorphic Stationary Solutions of the Real Cubic Swift‐Hohenberg Equation

We show that all meromorphic solutions of the stationary reduction of the real cubic Swift‐Hohenberg equation are elliptic or degenerate elliptic. We then obtain them all explicitly by the subequation method, and one of them appears to be a new elliptic solution.     

Selective MAO-B inhibitors: a lesson from natural products

Monoamine oxidases (MAOs) are mitochondrial bound enzymes, which catalyze the oxidative deamination of monoamine neurotransmitters. Inside the brain, MAOs are present in two isoforms: MAO-A and MAO-B. The activity of MAO-B is generally higher in patients affected by neurodegenerative diseases like Alzheimer’s and Parkinson’s. Therefore, the search for potent and selective MAO-B inhibitors is still a challenge for medicinal chemists. Nature has always been a source of inspiration for the discovery of new lead compounds. Moreover, natural medicine is a major component in all traditional medicine systems. In this review, we present the latest discoveries in the search for selective MAO-B inhibitors from natural sources. For clarity, compounds have been classified on the basis of structural analogy or source: flavonoids, xanthones, tannins, proanthocyanidins, iridoid glucosides, curcumin, alkaloids, cannabinoids, and natural sources extracts. MAO inhibition values reported in the text are not always consistent due to the high variability of MAO sources (bovine, pig, rat brain or liver, and human) and to the heterogeneity of the experimental protocols used.     

Novel Copolymers of Styrene. 16. Halogen Ring-Disubstituted Methyl 2-Cyano-3-Phenyl-2-Propenoates

Electrophilic trisubstituted ethylenes, ring-disubstituted methyl 2-cyano-3-phenyl-2-propenoates, RPhCH?C(CN)CO₂CH₃, where R is 2,5-dichloro, 3,5-dichloro, 2,3-difluoro, 3-chloro-2-fluoro, 3-chloro-4-fluoro, 4-chloro-3-fluoro, 2-chloro-5-nitro, and 2-chloro-6-nitro were prepared and copolymerized with styrene. The monomers were synthesized by the piperidine catalyzed Knoevenagel condensation of ring-disubstituted benzaldehydes and methyl cyanoacetate, and characterized by CHN analysis, IR, ¹H and ¹³C-NMR. All the ethylenes were copolymerized with styrene (M₁) in solution with radical initiation (ABCN) at 70°C. The compositions of the copolymers were calculated from nitrogen analysis and the structures were analyzed by IR, ¹H and ¹³C-NMR. The order of relative reactivity (1/r₁) for the monomers is 4-Cl-3-F (4.87) > 2,3-F₂ (4.49) > 3-Cl-4-F (3.50) > 3-Cl-2-F (2.96) > 2-Cl-5-NO₂ (2.02) > 2,5-Cl₂ (1.54) > 2-Cl-6-NO₂ (1.00) > 3,5-Cl₂ (0.41). Relatively high T_g of the copolymers in comparison with that of polystyrene indicates a decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 200–500ºC range with residue (1.5–34.5% wt), which then decomposed in the 500-800ºC range.