Metal chelates of salicyl-4-aminoantipyrine

The formation constants of salicyl-4-amino-2,3-dimethyl-1-phenyl-3-pyrazoline-5-one (SAAP) complexes with 3d transition metal ions [Cu(II), Ni(II), Co(II), Zn(II) and Mn(II)] have been determined in 60% ethanol-water medium ofμ = 0.1M (NaCl) at 25°C. It is observed that the formation constants for chelates with 3d transition metals follow the order Mn(II) < Co(II) < Ni(II) < Zn(II) < Cu(II). The effects of metal ions, ionic radii, electronegativities and ionization potentials on chelate formation constants are discussed. Complexes of UO₂(II) and Pd(II) have been synthesized and characterised by elemental analysis, electrolytic conductance, IR spectra and magnetic measurements. The ligand forms the complexes PdLCl and UO₂L₂,2H₂O, where L is a uninegatively charged tridentate ligand (ONO donor sets).     

Fused pyridines by a tandem aza‐wittig / heterocyclization strategy: Synthesis of 1,2,4‐triazolo[1,5‐a]pyridines and pyrido[1,2‐b][1,2,4]triazines

The iminophosphorane 1‐amino‐6‐(triphenylphosphoranylideneamino)‐2‐oxo‐4‐phenyl‐1,2‐dihydro‐pyridine‐3,5‐dicarbonitrile 2 prepared from 1,6‐diaminopyridine 1 reacts with heterocumulenes such as carbon disulfide and phenylisocyanate, and with acid chlorides, acid anhydrides and haloketones to give directly the title compounds in an one‐pot aza‐Wittig / heterocyclic‐ring closure process with good yields.     

In vitro antimicrobial evaluation and in silico studies of coumarin derivatives tagged with pyrano-pyridine and pyrano-pyrimidine moieties as DNA gyrase inhibitors

Molecular Diversity - Several coumarin-containing substitute nitrogen heterocycles have recently received considerable importance due to their diverse pharmacological properties. One-pot and rapid...     

Metal complexes of chalcone analogue: Synthesis,characterization, DNA binding,molecular docking and antimicrobial evaluation

A novel chalcone, namely 5‐(4‐(dimethylamino)phenyl)‐1‐(thiophen‐2‐yl)penta‐2,4‐dien‐1‐one, DMATP, and its complexes with nickel(II), vanadium(III), palladium(II) and platinum(II) metal ions were synthesized and characterized using a set of chemical and spectroscopic tools including elemental analysis, electrical conductance, magnetic susceptibility and spectral techniques. The interactions of the synthesized chalcone and its metal complexes with DNA were studied using steady‐state absorption and emission techniques as well as viscosity and electrochemical measurements. The obtained results confirm DNA intercalation. Additionally, theoretical studies were performed for all the investigated compounds using DFT/B3LYP calculations. The optimized geometries are found to be in good agreement with the suggested experimental structures. The bond lengths, bond angles, chemical reactivity, energy components, binding energy and dipole moment were evaluated. Also, theoretical infrared intensities and thermodynamic parameters for all compounds were calculated. Molecular docking calculations show that the Ni(II) complex exhibits the highest DNA binding activity, which agrees well with the experimental results. Finally, the compounds were screened for antimicrobial activity using several microorganisms.     

Reactions with Hydrazonoyl Halides 63: Synthesis and Anticancer Activity of Some New 1,3,4-Thiadiazoles, 1,3,4-Selenadiazoles,and 1,2,4-Triazolo[4,3-a]pyrimidines

2,3-Dihydro-1,3,4-thiadiazoles, 2,3-dihydro-1,3,4-selenadiazoles, and triazolino[4,3-a]pyrimidines containing benzoxazole or benzothiazole moieties were prepared from the reaction of each of ethyl 3-aza-3-(benzoxazol-2-ylamino)-2-chloroprop-2-enoate and ethyl 3-aza-3-(benzothiazolo-2-ylamino)-2-chloroprop-2-enoate with each of potassium thiocyanate, potassium selenocyanate, alkyl carbodithioate, and pyrmidine-2-thione derivatives. All the newly synthesized compounds were confirmed by elemental analysis, spectral data, and alternative route synthesis whenever possible. Some of the newly synthesized compounds were screened toward certain cancer tumors.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Symmetric multilayer slab waveguide structure with a negative index material: TM case

The present paper deals with the theoretical modeling of symmetrical multilayer planar waveguide structure. One of the layers is considered as a negative refractive index material. We take the appropriate field distributions for p-polarization and impose the boundary conditions to derive the mode equation and other necessary formulae for the proposed structure. The effect of the negative-index layer on the modal refractive index, power flow, and penetration depth of the waveguide is studied. Also, we compare our computed results with those obtained for a similar conventional four-layer structure. It is observed that the presence of the negative-index material reduces the power flowing in the guiding layer and enhances the power flowing in the surroundings.     

Molecular Complexes of Crown Ethers: Part 8. Effect of Surfactant on the Charge Transfer Complexes of 18C6 with Picric Acid in the Presence of Alkali Metal Ions

The interaction of 18-crown-6 (CE) with picric acid(PA) was studied in the UV-Visible region in 1,2-dichloroethane (DCE) at 298.2 K. The effect of the surfactant Triton X-100 was studied, and it was found to have a pronounced effect on the interaction of 18-crown-6 with picric acid. The effect of the alkali metal cations, especially Na and K on the complex matrix donor–acceptor surfactant was studied. It is found that the extraction of the insoluble solid NaCl and KCl to the organic phase increased by more than 8-fold in the presence of the complex. The interaction of the alkali metals ions, i.e., Li, Na, K, Cs and Rb with the systems Donor–Acceptor and Donor–Acceptor–Triton were studied. It is found that the stability of the complexes formed between the system CE + Triton + Picric acid and the alkali metals ions depends on the ratio between the crown ether radius and the alkali metal radius.     

A Facile Access to Polysubstituted Bipyrazoles and Pyrazolylpyrimidines

3‐(Pyrazol‐3‐yl)‐3‐oxo‐propanenitrile derivative reacts with several nitrogen nucleophiles to give bipyrazole, pyrazolyloxazole, and pyrazolylpyrimidine derivatives. The structures of the products were confirmed on the basis of their elemental and spectral analyses.