Bis(2‐aminopyridinium) maleate

Two cyclic eight‐membered hydrogen‐bonded rings exist in the title compound, 2C₅H₇N₂⁺·C₄H₂O₄²⁻, involving the 2‐amino­pyridinium and maleate ions. The dihedral angle between the two pyridinium rings hydrogen bonded to the maleate ion is 74.80 (4)°. The maleate anion lies on a twofold axis and is linked to the pyridinium cations by intermolecular N—H⃛O hydrogen bonds. The heterocycle is fully proton­ated, which enables amino–imino tautomerization.     

Methyl (±)‐1‐ethyl‐2‐hydroxy‐4‐(4‐methoxybenzoyl)‐5‐(4‐methoxyphenyl)‐3‐oxo‐2,3‐di­hydro‐1H‐pyrrole‐2‐acetate

The title compound, C₂₄H₂₅NO₇, is a racemic mixture of 2,3‐di­hydro‐1H‐pyrrol‐3‐ones. It crystallizes in the triclinic system, space group P1, with Z = 2. The asymmetric unit contains two enantiomorphic mol­ecules and the structure is stabilized by hydrogen‐bond contacts.     

2,4‐[2,2′‐Methylenebis(4‐nitrophen­oxy)]‐2,4,6,6‐tetrachlorocyclo‐2λ5,4λ5,6λ5‐triphosphazatriene (ansa)

The title compound, C₁₃H₈Cl₄N₅O₆P₃, consists of a non‐planar trimeric phosphazene ring and a bulky 2,2′‐methylenebis(4‐nitrophenoxy) side group which predominantly determines the molecular shape. With respect to the corresponding values in the reference compound N₃P₃Cl₆, the endocyclic angle around one P atom is the same, but the exocyclic angle is increased, while the endocyclic and exocyclic angles about another P atom are both decreased. This situation is different from that in other reported phosphazene derivatives.     

In Vitro and In Silico Investigation of Diterpenoid Alkaloids Isolated from Delphinium chitralense

This study reports the isolation of three new C₂₀ diterpenoid alkaloids, Chitralinine A–C (1–3) from the aerial parts of Delphinium chitralense. Their structures were established on the basis of latest spectral techniques and single crystal X-rays crystallographic studies of chitralinine A described basic skeleton of these compounds. All the isolated Compounds (1–3) showed strong, competitive type inhibition against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) in comparison to standard allanzanthane and galanthamine however, chitralinine-C remained the most potent with IC₅₀ value of 11.64 ± 0.08 μM against AChE, and 24.31 ± 0.33 μM against BChE, respectively. The molecular docking reflected a binding free energy of −16.400 K Cal-mol⁻¹ for chitralinine-C, having strong interactions with active site residues, TYR334, ASP72, SER122, and SER200. The overall findings suggest that these new diterpenoid alkaloids could serve as lead drugs against dementia-related diseases including Alzheimer’s disease.     

Vortex-assisted magnetic solid phase extraction of Pb and Cu in some herb samples on magnetic multiwalled carbon nanotubes

This study is the development of a new solid phase extraction method based on using magnetic multiwalled carbon nanotubes impregnated with 1-(2-pyridylazo)2-naphthol (PAN) for separation, preconcentration, and flame atomic absorption spectrometric determination of Pb(II) and Cu(II). Optimization of the method was done by investigating pH effect, amount of magnetic multiwalled carbon nanotubes impregnated with PAN, eluent type and volume, matrix effects, and volume of the sample. The optimum adsorbent amount was found to be 75 mg and the optimum pH value was found as 5.5. The detection limits were 16.6 μg L^-1 for Pb(II) and 18.9 μg L^-1 for Cu(II). The relative standard deviations (RSD%) were less than 4%. Two certified reference materials: SPS-WW2 wastewater and NCS-DC73349 (bush branches and leaves) were used to test the validation of the method. The method was successfully applied to the analysis of Pb(II) and Cu(II) ions in daisy, mint, paprika, sage, rosemary, daphne leaves, heather, green tea, andViburnum opulussamples.     

A Highly Selective Poly(thiophene)‐graft‐Poly(methacrylamide) Polymer Modified ITO Electrode for Neuron Specific Enolase Detection in Human Serum

In this study, an impedimetric immunosensor based on polymer poly(thiophene)‐graft‐poly(methacrylamide) polymer (P(Thi‐g‐MAm)) modified indium tin oxide (ITO) electrode is developed for the detection of the Neuron Specific Enolase (NSE) cancer biomarker. First, the P(Thi‐g‐MAm) polymer is synthesized and coated on the ITO electrode by using a spin‐coating technique. P(Thi‐g‐MAm) polymer acts as an immobilization platform for immobilization of NSE‐specific monoclonal antibodies. Anti‐NSE antibodies are utilized as biosensing molecules and they bind to the amino groups of P(Thi‐g‐Mam) polymer via glutaraldehyde cross‐linking. Spin‐coating technique is employed for bioelectrode fabrication and this technique provides a thin and uniform film on the ITO electrode surface. This bioelectrode fabrication technique is simple and it generates a suitable platform for large‐scale loadings of anti‐NSE antibodies. This immunosensor exhibits a wide linear detection range from 0.02 to 4 pg mL^?1 and with an ultralow detection limit of 6.1 fg mL^?1. It reveals a good long‐term stability (after 8 weeks, 78% of its initial activity), an excellent reproducibility (1.29% of relative standard deviation (RSD)), a good repeatability (5.55% of RSD), and a high selectivity. In addition, the developed immunosensor is proposed as a robust diagnostic tool for the clinical detection of NSE and other cancer biomarkers.     

Calixarenes: recent progress in supramolecular chemistry for application in cancer therapy

Journal of Inclusion Phenomena and Macrocyclic Chemistry - Cancer is one of the leading causes of death worldwide, and the limited success of currently used anticancer drugs is a driving force for...     

Synthesis,structures, photophysical properties,and catalytic characteristics of 2,9-dimesityl-1,10-phenanthroline (dmesp) transition metal complexes

The syntheses of the 2,9-dimesityl-1,10-phenanthroline ( dmesp ) metal complexes, [Cu(dmesp)(MeCN)]PF₆ ( 1 ), [Cu(dmesp)₂]PF₆ ( 2 ), Fe(dmesp)Cl₂ ( 3 ), Co(dmesp)Cl₂ ( 4 ), Ni(dmesp)Cl₂ ( 5 ), Zn(dmesp)Cl₂ ( 6 ), Pd(dmesp)MeCl ( 7 ), Cu(dmesp)Cl ( 8 ), and Pd(dmesp)₂Cl₂ ( 9 ), in good to high yields are described. These complexes were characterized by ¹H and ¹³C NMR spectroscopy, HR–MS (ESI and/or APPI), and elemental analysis (CHN). The solid-state structures of complexes 1 – 8 were determined by single-crystal X-ray analysis and their photophysical properties were also characterized. To demonstrate the versatility of this new platform, complexes 3 – 5 , 8 , and 9 were employed in the catalytic oligomerization of ethylene using modified methyl aluminoxane (MMAO) as the cocatalyst, where Co(II) and Ni(II) complexes ( 4 and 5 , respectively) were found to exhibit moderate selectivity for catalytic dimerization of ethylene to butenes over tri- or tetramerization. Complex 8 is an effective catalyst of both the commonly encountered “click” reaction and amine arylation chemistries. Complexes 6 and 9 were found to be excellent catalysts for Friedel-Crafts alkylation and Suzuki-Miyaura coupling, respectively.     

Construction of amperometric biosensor modified with conducting polymer/carbon dots for the analysis of catechol

Phenolic compounds used in food industries and pesticide industry, are environmentally toxic and pollute the rivers and ground water. For that reason, detection of phenolic compounds such as catechol by using simple, efficient and cost-effective devices have been becoming increasingly popular. In this study, a suitable and a novel matrix was composed using a novel conjugated polymer, namely poly[1-(5-(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b']dithiophen-2-yl)furan-2-yl)-5-(2-ethylhexyl)-3-(furan-2-yl)-4H thieno[3,4-c]pyrrole-4,6(5H)-dione] (PFTBDT) and carbon dots (CDs) to detect catechol. PFTBDT and CDs were synthesized and the optoelectronic properties of PFTBDT were investigated via electrochemical and spectroelectrochemical studies. Laccase enzyme was immobilized onto the constructed film matrix on the graphite electrode. The proposed biosensor was found to have a low detection limit (1.23 μM) and a high sensitivity (737.44 μA/mM.cm⁻²) with a linear range of 1.25–175 μM. Finally, the applicability of the proposed enzymatic biosensor was evaluated in a tap water sample and a satisfactory recovery (96–104%) was obtained for catechol determination.