Towards More Sustainable Schiff Base Carboxylate Anodes for Sodium-Ion Batteries.

Bismine sodium salt (BSNa), a Schiff base with two sodium carboxylates, has shown promising electrochemical performance as an anode material. However, its synthesis involves toxic reagents and generates impurities, requiring significant solvent use for purification. This study introduces a novel synthetic method using sodium hydroxide as the sole reagent, which acts as both a base and Na source in the ion exchange step.

Peptide-biphenyl hybrid-capped AuNPs: stability and biocompatibility under cell culture conditions.

In this study, we explored the biocompatibility of Au nanoparticles (NPs) capped with peptide-biphenyl hybrid (PBH) ligands containing glycine (Gly), cysteine (Cys), tyrosine (Tyr), tryptophan (Trp) and methionine (Met) amino acids in the human hepatocellular carcinoma cell line Hep G2. Five AuNPs, Au[(Gly-Tyr-Met)2B], Au[(Gly-Trp-Met)2B], Au[(Met)2B], Au[(Gly-Tyr-TrCys)2B] and Au[(TrCys)2B], were synthesised. Physico-chemical and cytotoxic properties were thoroughly studied.

Chemical applications of neural networks: aromaticity of pyrimidine derivatives.

Neural networks are computational tools able to apprehend non-linear relationships between different parameters, having the capacity to order a large amount of input data and transform them into a graphical pattern of output data. We have previously reported their use for the quantification of the aromaticity through the Euclidean distance between neurons. In this article, we apply the method to a variety of pyrimidine derivatives with electron-donor and electron-withdrawing groups as substituents, with capacity to produce push-pull compounds.

Preparation and characterization of gold nanoparticles capped by peptide-biphenyl hybrids.

Gold nanoparticles were prepared using peptide-biphenyl hybrids (PBHs) as capping agents. AuNPs were characterized by different techniques including UV-Vis, TEM, EDX, FT-IR, elemental analysis, (1)H NMR and (13)C CP/MAS NMR spectroscopy. TEM analysis showed that AuNPs present diameters in the range of 1.

Biological and chemical studies on aryl hydrocarbon receptor induction by the p53 inhibitor pifithrin-α and its condensation product pifithrin-β.

Aims: Pifithrin α (PFTα), an inhibitor of the p53 protein, is regarded as a lead compound for cancer and neurodegenerative disease therapy. There is some evidence that this compound activates the aryl hydrocarbon receptor (AhR) in a complete independent way of the p53 inhibition and that it is easily converted to its condensation product pifithrin β (PFTβ). The aim of this study was to explore the ability of PFTα and of PFTβ to induce a variety of AhR mediated processes.

Substituent effects on the aromaticity of carbocyclic five-membered rings.

The influence of the substituent nature, as well as the number and position of the substituents, on the aromaticity/antiaromaticity of a comprehensive set of derivatives of cyclopentadienyl anion, cyclopentadiene and cyclopentadienyl cation has been analyzed. The aromaticity/antiaromaticity of substituted cyclopentadienyl derivatives has been measured using energetic, magnetic and structural criteria to take into account the multidimensional character of aromaticity. Furthermore, the Euclidean distance values (d(j)) for all compounds have been estimated using the neural network developed previously.

X-ray diffraction, solution structure, and computational studies on derivatives of (3-sec-butyl-2,3-dihydro-1H-isoquinolin-4-ylidene)acetic acid: compounds with activity as calpain inhibitors.

A thorough experimental and computational study of derivatives of (3-sec-butyl-2,3-dihydroisoquinolin-4-ylidene)acetic acid was performed. Some of these compounds are calpain inhibitors and could be useful as therapeutic agents, since this enzyme is a Ca(2+)-dependent cysteine protease involved in a wide variety of metabolic and physiological processes, whose over-activation is associated to several pathological conditions. To gain a better understanding of the structure-activity relationships, a structural analysis was carried out with (1)H and (13)C NMR spectroscopy and DFT calculations together with the X-ray diffraction data of three compounds.

A universal scale of aromaticity for pi-organic compounds.

Aromaticity is an essential concept in chemistry, invented to account for the stability, reactivity, molecular structure, and properties of many organic and inorganic compounds. In recent years, numerous methods to quantify aromaticity based on the energetic, magnetic, structural, and electronic properties of molecules have been proposed but none of them is universal. The inability of establishing a universal scale of aromaticity based on a single parameter is due to the multidimensional character of this phenomenon.

Decabromobiphenyl (PBB-209) activates the aryl hydrocarbon receptor while decachlorobiphenyl (PCB-209) is inactive: experimental evidence and computational rationalization of the different behavior of some halogenated biphenyls.

In rat H4IIE cells permanently transfected with a luciferase gene under the control of AhR, incubation with PBB-209 led to a statistically significant increase of luminescence. In this system, PCB-209 only caused a small induction of luciferase activity. In a fish cell line, only PBB-209 was able to provoke an induction of ethoxyresorufin- O-deethylase activity.

Neural networks as a tool to classify compounds according to aromaticity criteria.

Aromaticity is a fundamental concept in chemistry, with many theoretical and practical implications. Although most organic compounds can be categorized as aromatic, non-aromatic, or antiaromatic, it is often difficult to classify borderline compounds as well as to quantify this property. Many aromaticity criteria have been proposed, although none of them gives an entirely satisfactory solution.

Activation of the aryl hydrocarbon receptor by carbaryl: Computational evidence of the ability of carbaryl to assume a planar conformation.

It has been accepted that aryl hydrocarbon receptor (AhR) ligands are compounds with two or more aromatic rings in a coplanar conformation. Although general agreement exists that carbaryl is able to activate the AhR, it has been proposed that such activation could occur through alternative pathways without ligand binding. This idea was supported by studies showing a planar conformation of carbaryl as unlikely.

Peptide-biphenyl hybrids as calpain inhibitors.

Calpain is a cysteine protease that is activated by Ca2+. The over-activation of calpain, which occurs on increasing Ca2+ concentration, causes a variety of diseases. This paper reports experimental results on the inhibition of calpain I (mu-calpain) by peptide-biphenyl hybrids.

Induction of cytochrome P4501A (CYP1A) by clotrimazole, a non-planar aromatic compound. Computational studies on structural features of clotrimazole and related imidazole derivatives.

The classical pathway for induction of cytochrome P4501A (CYP1A) by xenobiotics is ligand binding to the aryl hydrocarbon receptor (AhR). High-affinity AhR ligands are planar polyaromatic molecules such as the prototypic ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The present work investigated the ability of the imidazole derivative, clotrimazole [1-(2'chlorotrityl)imidazole, CLO], to induce CYP1A in cultured rainbow trout (Oncorhynchus mykiss) hepatocytes at the catalytic activity (determined as 7-ethoxyresorufin-O-deethylase, EROD) and at the transcriptional level.

Solid-phase combinatorial synthesis of peptide-biphenyl hybrids as calpain inhibitors.

[structure: see text] The combinatorial parallel synthesis of peptide-biphenyl hybrids on solid support using state of the art of peptide synthesis is reported. Key steps were the N to C addition of an amino moiety, hydrolysis of the methyl ester, and the absence of cross-linked compounds when the 2,2'-diamino-1,1'-biphenyl was incorporated. When tested for activity as calpain inhibitors, some of the compounds exhibited IC(50) values in the nanomolar range.

Differences in retention of dioxin-like compounds and organochlorinated insecticides on an immunochromatographic column. Interpretation and applicability.

The retention of organochlorinated compounds on an immunochromatographic column is studied. The compounds considered are usually found together in real samples of environmental concern, and include chlorinated biphenyls, chlorinated dibenzo-p-dioxins, chlorinated dibenzofurans, and organochlorinated insecticides. The different retention observed for different compounds is interpreted in light of the structural similarities of the compound studied with that used as a hapten to raise the antibodies employed as ligands in the immunochromatographic column.

Studies on aromatic compounds: inhibition of calpain I by biphenyl derivatives and peptide-biphenyl hybrids.

With the objective to understand structural features responsible for the biological activity, novel nonelectrophilic biphenyl derivatives and peptide-biphenyl hybrids have been synthesized and evaluated as calpain I inhibitors. The preliminary results indicate that the presence of additional aromatic rings (besides the biphenyl system) makes these compounds potent calpain inhibitors with IC50 values in the nanomolar range.

Induction of CYP1A by the N-imidazole derivative, 1-benzylimidazole.

Xenobiotics can induce cytochrome P4501A (CYP1A) by ligand binding to the aryl hydrocarbon receptor (AhR). Typical AhR ligands are polycyclic aromatic compounds with planar molecular conformation. The present work investigated the ability of the N-imidazole derivative, 1-benzylimidazole (BIM), to induce CYP1A in rainbow trout hepatocytes.

Computational studies on biphenyl derivatives. Analysis of the conformational mobility, molecular electrostatic potential, and dipole moment of chlorinated biphenyl: searching for the rationalization of the selective toxicity of polychlorinated biphenyls (PCBs).

With the objective to understand how the pattern and degree of chlorination influence on the properties of the title molecules, a computational study on biphenyl and all the chlorinated biphenyls (from 1 to 10 chlorine atoms, 209 congeners) has been undertaken. The study includes conformational searches (and further refinement by molecular dynamics simulations) and the ab initio calculation of the molecular electrostatic potential (MEP) and the dipole moments for all the congeners. The most significant property is the MEP, finding a good correlation between the MEPs and the substitution pattern on chlorinated biphenyls.