Synthesis,spectral characterization and biological studies of transition metal(II) complexes with triazole Schiff bases

New metal based triazoles (1–12) have been synthesized by the interaction of novel Schiff base ligands (L¹–L³) with the Co(II), Ni(II), Cu(II) and Zn(II) metal ions. The Schiff base ligands and their all metal(II) complexes have been thoroughly characterized using various physical, analytical and spectroscopic techniques. In vitro bacterial and fungal inhibition studies were carried out to examine the antibacterial and antifungal profile of the Schiff bases in comparison to their metal(II) complexes against two Gram‐positive, four Gram‐negative and six fungal strains. The bioactivity data showed the metal(II) complexes to have more potent antibacterial and antifungal activity than their uncomplexed parent Schiff bases against one or more bacterial and fungal species. Copyright © 2012 John Wiley & Sons, Ltd.     

Petra,Osiris, and Molinspiration Together as a Guide in Drug Design: Predictions and Correlation Structure/Antibacterial Activity Relationships of New N-Sulfonyl Monocyclic β-Lactams

We report in this article the design and calculated molecular properties of 18 new mono-cyclic β-lactams 4–21, on the basis of one hypothetical antibacterial pharmacophore structure designed to interact with both of Gram-positive bacteria and Gram-negative bacteria. The in vitro biological evaluation of these compounds allowed us to point out new potential non-nucleoside hits, with MIC values in the range of 2–8 μg/mL active against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa. A correlation structure/antibacterial activities relationship of these monocyclic β-lactams is described.

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.     

Sulfonamide‐derived compounds and their transition metal complexes: synthesis,biological evaluation and X‐ray structure of 4‐bromo‐2‐[(E)‐{4‐[(3,4‐dimethylisoxazol‐5 yl)sulfamoyl]phenyl} iminiomethyl] phenolate

Sulfonamide‐derived new ligands, 4‐({[(E)‐(5‐bromo‐2‐hydroxyphenyl)methylidene]‐amino}methyl)benzenesulfonamide and 4‐bromo‐2‐((E)‐{4‐[(3,4‐dimethylisoxazol‐5‐yl)sulfamoyl]phenyl}iminiomethyl)phenolate and their transition metal [cobalt(II), copper(II), nickel(II) and zinc(II)] complexes were synthesized and characterized. The nature of bonding and structure of all the synthesized compounds were deduced from physical (magnetic susceptibility and conductivity measurements), spectral (IR, ¹H and ¹³C NMR, electronic, mass spectrometry) and analytical (CHN analysis) data. The structure of the ligand, 4‐bromo‐2‐((E)‐{4‐[(3,4‐dimethylisoxazol‐5‐yl)sulfamoyl]phenyl} iminiomethyl)phenolate was also determined by X‐ray diffraction method. An octahedral geometry was suggested for all the complexes. In order to evaluate the biological activity of the ligands and the effect of metals, the ligands and their metal complexes were screened for in vitro antibacterial, antifungal and cytotoxic activity. The results of these studies revealed that all compounds showed moderate to significant antibacterial activity against one or more bacterial strains and good antifungal activity against various fungal strains. Copyright © 2011 John Wiley & Sons, Ltd.     

Synthesis,characterization and biological studies of oxovanadium(IV) complexes with triazole‐derived Schiff bases

A series of triazole‐derived Schiff bases (L¹–L⁵) and their oxovanadium(IV) complexes have been synthesized. The chemical structures of Schiff bases were characterized by their analytical (CHN analysis) and spectral (IR, ¹H and ¹³C NMR and mass spectrometry) data, and oxovanadium(IV) complexes were elucidated by their physical (magnetic susceptibility and conductivity), analytical (CHN analysis), conductance measurements and electronic spectral data. The molar conductivity data indicate the oxovanadium(IV) complexes to be non‐electrolyte. The Schiff bases act as bidentate and coordinate with the oxovanadium(IV)‐forming stoichiometry of a complex as [M (L‐H)₂] where M = VO and L = L¹–L⁵ in a square‐pyramidal geometry. The agar well diffusion method was used for in vitro antibacterial screening against E. coli, S. flexenari, P. aeruginosa, S. typhi, S. aureus and B. subtilis and for antifungal activity against T. longifucus, C. albican, A. flavus, M. canis, F. solani and C. glaberata. The biological activity data show the oxovanadium(IV) complexes to be more antibacterial and antifungal than the parent Schiff bases against one or more bacterial and fungal strains. Copyright © 2009 John Wiley & Sons, Ltd.     

Structure of 2-[(Phenyl)-(3,5-Dimethyl-Pyrazol-1-yl)-Methyl]-Malonic Acid Diethyl Ester

Abstract  

The titled new functionalized ligand of type 2-[(phenyl)-(3,5-dimethyl-pyrazol-1-yl)-methyl]-malonic acid diethyl ester (4) is prepared in good yield through condensation of 3,5-dimethyl-pyrazole, with 2-arylidene-malonic acid diethyl esters 3. The structure of 4 was determined by spectral (IR, ¹H and ¹³C NMR), elemental analyses and X-ray diffraction data. The title compound (4) crystallizes in the monoclinic space group P2₁/a, with a = 7.9253 (2), b = 17.1299 (5), c = 13.4522 (4) ?, β = 90.220 (2)°, V = 1,826.25 (9) ?³, Z = 4 and with R _int = 0.021. The molecular conformation shows two possible pockets ready to coordinate two metal atoms. The crystal structure of (4) is stabilized by inter-molecular C–H⋯O and C–H⋯N hydrogen bonding.     

Retracted: Synthesis,characterization and reactivity towards first‐row d‐transition metals and biological significance of new pyridinyl derived N‐substituted sulfonamides

Retraction: The following article from the Journal of Applied Organometallic Chemistry , ‘Synthesis, characterization and reactivity towards first‐row d‐transition metals and biological significance of new pyridinyl derived N‐substituted sulfonamides’ by Muhammad M. Naseer and Zahid H. Chohan, published online on 20 July 2007 in Wiley Interscience ( www3.interscience.wiley.com ), has been retracted by agreement between the authors, the journal Editor in Chief, Peter J. Craig and John Wiley & Sons, Ltd. The retraction has been agreed at the authors' request.     

Metal‐based isatin‐bearing sulfonamides: their synthesis,characterization and biological properties

A new series of antibacterial and antifungal isatin bearing sulfonamides and their cobalt (II), copper (II), nickel (II) and zinc (II) metal complexes have been synthesized, characterized and screened for their in vitro antibacterial activity against Bacillus cereus, Corynebacterium diphtheriae, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, Salmonella typhi, Shigilla dysentriae and Staphylococcus aureus and for in vitro antifungal activity against Trichophyton schoenleinii, Candid glabrata, Pseudallescheria boydii, Candida albicans, Aspergillus niger, Microsporum canis and Trichophyton mentagrophytes. The results of these studies revealed that all compounds showed moderate to significant antibacterial activity. The brine shrimp bioassay was also carried out to study their in vitro cytotoxic properties. Only three compounds, 2, 11 and 22 displayed potent cytotoxic activity as LD₅₀ = 1.56 × 10^?7, 1.59 × 10^?7 and 1.67 × 10^?7 M /ml respectively, against Artemia salina. Copyright © 2006 John Wiley & Sons, Ltd.     

Cosmic ray nuclei of chargeZ⩾3 during the period of low solar activity

A detailed study of the composition and energy spectra of heavy nuclei of charge Z?3 in the primary cosmic rays has been made during the period of low solar activity, using two stacks of nuclear emulsions exposed in balloon flights from Fort Churchill, Canada, in June 1963. Each of the stacks was composed of 120 nuclear emulsions of three different sensitivities and was exposed at about 3·5 g. cm.^?2 of residual air for about 11.1 hr. Reliable resolution of charges of nuclei from lithium to oxygen was obtained; for heavier nuclei, charge groups were determined. From the analysis of 793 tracks of nuclei with Z?3, results on the following aspects were obtained:

1. The differential energy spectra of L (Z=3–5), M (Z=6–9) and H (Z=10–28) nuclei were measured in the energy intervel 150–600 MeV/nucleon; integral fluxes were obtained for energy >600 MeV/nucleon;
2. The energy dependence of the L/M ratio at the top of the atmosphere was determined; the ratios were obtained as 0·45 ± 0·06 and 0·29 ± 0·03 in the energy intervals of 200–575, and >575 MeV/nucleon respectively;
3. Relative abundances of individual nuclei of Li, Be, B, C, N and O at the top of the atmosphere were determined as 36, 29, 55, 100, 60 and 106 respectively in the energy interval 150–600 MeV/nucleon; corresponding values were also obtained for energy >600 MeV/nucleon.
4. The differential fluxes of multiply charged nuclei measured by us and by other investigators were used to determine the solar modulation between solar maximum to solar minimum. It was found that solar modulation of the fluxes of M and He nuclei were consistent with Rβ dependence and that the modulation parameter Δη between 1965 and 1957 was about 1·1.

The implications of these results are discussed.     

Quenching of tryptophan fluorescence in various proteins by a series of small nickel complexes

A series of twelve anionic, cationic, and neutral nickel(II) complexes have been synthesized and characterized. The interaction of these complexes with bovine serum albumin (BSA), human serum albumin (HSA), lysozyme (Lyso), and tryptophan (Trp) has been studied using steady-state fluorescence spectroscopy. Dynamic and static quenching constants have been calculated, and the role played in quenching by the ligand and complex charge investigated. The nickel complexes showed selectivity towards the different proteins based on the environment surrounding the Trp residue(s). Only small neutral complexes with hydrophobic ligands effectively quenched protein fluorescence via static quenching, with association constants ranging from 10(2) M(-1) (free Trp) to 10(10) M(-1) (lysozyme), indicating a spontaneous and thermodynamically favorable interaction. The number of binding sites, on average, was determined to be one in BSA, HSA and free Trp, and two in lysozyme.