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81.
Pyrrolyl and thienyl derived sulfonamides and their metal [cobalt(II), copper(II), nickel(II) and zinc(II)] complexes were synthesized and characterized by elemental analyses, molar conductances, magnetic moments, IR, 1H NMR, 13C NMR and electronic spectral data. These compounds were screened for in‐vitro antibacterial activity against four Gram‐negative (Escherichia coli, Shigella flexeneri, Pseudomonas aeruginosa and Salmonella typhi) and two Gram‐positive (Bacillus subtilis and Staphylococcus aureus) bacterial strains, and for in‐vitro antifungal activity against Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani and Candida glaberata. The results of these studies revealed that all compounds showed significant to moderate antibacterial activity; however, the zinc complexes were shown to be the most active against various species. The brine shrimp bioassay was also carried out to study their in vitro cytotoxic properties of all the synthesized ligands and their metal complexes. Only two compounds ( 14 and 19 ) displayed potent cytotoxic activity as LD50 = 5.5637 × 10?4 and 4.4023 × 10?4 M ml?1 respectively, against Artemia salina. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
82.
F. Tietz I. Arul Raj M. Zahid A. Mai D. Stver 《Progress in Solid State Chemistry》2007,35(2-4):539-543
An overview on the variation of the thermal expansion, the electrical conductivity as well as non-stoichiometry of the oxide content as a function of composition within the quasi-ternary system La0.8Sr0.2MnO3−δ–La0.8Sr0.2CoO3−δ–La0.8Sr0.2FeO3−δ in air is presented. The various powders were synthesized under identical conditions. The DC electrical conductivity values of the compositions at 800 °C in air vary in a wide range from 15 to 1338 S cm−1. The magnitude of electrical conductivity of the perovskites is mainly determined by the percentage of cobalt in the compositions. A similar behaviour was observed for the measured thermal expansion coefficients between room temperature and 1000 °C in air, increasing from 10.9 to 19.4 × 10−6 K−1 as a function of cobalt content. Changes in the oxygen stoichiometry of the materials were characterized by temperature-programmed oxidation measurements. 相似文献
83.
The attenuation and dispersion of commercially available all-plastic step-index optical fiber are the major factors limiting the maximum achievable transmission distance and bit rate; this article explores these limits. Calculations predict that ∼ 500 Mb/s transmission over 100 m of standard 0.47 NA step-index PMMA POF at 650 nm is feasible, and recent experimental results at up to 400 Mb/s are briefly described. The implications of having a lower loss, higher bandwidth POF, for example, perfluorinated, graded-index PMMA, arc discussed. 相似文献
84.
Giamblanco N Yaseen M Zhavnerko G Lu JR Marletta G 《Langmuir : the ACS journal of surfaces and colloids》2011,27(1):312-319
The dynamic adsorption of human serum albumin (HSA) and plasma fibronectin (Fn) onto hydrophobic poly(hydroxymethylsiloxane) (PHMS) and the structures of adsorbed protein layers from single and binary protein solutions were studied. Spectroscopic ellipsometry (SE) and quartz crystal microbalance with dissipation monitoring (QCM-D) together with atomic force microscopy (AFM) were used to measure the effective mass, thickness, viscoelastic properties, and morphology of the adsorbed protein films. Adsorbed HSA formed a rigid, tightly bound monolayer of deformed protein, and Fn adsorption yielded a thick, very viscoelastic layer that was firmly bound to the substrate. The mixed protein layers obtained from the coadsorption of binary equimolecular HSA-Fn solutions were found to be almost exclusively dominated by Fn molecules. Further sequential adsorption experiments showed little evidence of HSA adsorbed onto the predeposited Fn layer (denoted as Fn ? HSA), and Fn was not adsorbed onto predeposited HSA (HSA ? Fn). The conformational arrangement of the adsorbed Fn was analyzed in terms of the relative availability of two Fn domains. In particular, (4)F(1)·(5)F(1) binding domains in the Hep I fragment, close to the amino terminal of Fn, were targeted using a polyclonal antifibronectin antibody (anti-Fn), and the RGD sequence in the 10th segment, in the central region of the molecule, was tested by cell culture experiments. The results suggested that coadsorption with HSA induced the Fn switch from an open conformation, with the amino terminal subunit oriented toward the solution, to a close conformation, with the Fn central region oriented toward the solution. 相似文献
85.
Max Deimling Manuel Kirchhof Barbara Schwager Yaseen Qawasmi Alex Savin Dr. Tina Mühlhäuser Dr. Wolfgang Frey Dr. Birgit Claasen Dr. Angelika Baro Prof. Thomas Sottmann Prof. Sabine Laschat 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(40):9464-9476
The role of liquid confinement on the asymmetric Rh catalysis was studied using the 1,2-addition of phenylboroxine ( 2 ) to N-tosylimine 1 in the presence of [RhCl(C2H4)2]2 and chiral diene ligands as benchmark reaction. To get access to Rh complexes of different polarity, enantiomerically pure C2-symmetric p-substituted 3,6-diphenylbicyclo[3.3.0]octadienes 4 and diastereomerically enriched unsymmetric norbornadienes 5 and 6 carrying either the Evans or the SuperQuat auxiliary were synthesized. A microemulsion containing the equal amounts of H2O/KOH and toluene/reactants was formulated using the hydrophilic sugar surfactant n-octyl β-d -glucopyranoside (C8G1) to mediate the miscibility between the nonpolar reactants and KOH, needed to activate the Rh–diene complex. Prominent features of this organized reaction medium are its temperature insensitivity as well as the presence of water and toluene-rich compartments with a domain size of 55 Å confirmed by small-angle X-ray scattering (SAXS). Although bicyclooctadiene ligands 4 a , b , e performed equally well under homogeneous and microemulsion conditions, ligands 4 c , d gave a different chemoselectivity. For norbornadienes 5 , 6 , however, microemulsions markedly improved conversion and enantioselectivity as well as reaction rate, as was confirmed by kinetic studies using ligand 5 b . 相似文献
86.
Biologically active triazole Schiff bases ( L 1 L 3 ) derived from the reaction of 3‐amino‐1,2,4‐triazole with chloro‐, bromo‐ and nitro‐ substituted salicylaldehydes and their Zn(II) complexes (1–3) have been synthesized and characterized by their physical, spectral and analytical data. Triazole Schiff bases potentially act as tridentate ligands and coordinate with the Zn(II) metal atom through salicylidene‐O, azomethine‐N and triazole‐N. The complexes have the general formula [M(L‐H)2], where M = zinc(II) and L = ( L 1 – L 3 ), and observe an octahedral geometry. The Schiff bases and their Zn(II) complexes have been screened for in‐vitro antibacterial, antifungal and brine shrimp bioassay. The biological activity data show the Zn(II) complexes to be more potent antibacterial and antifungal than the parent simple Schiff bases. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
87.
Ahmed I. Khodair Adel M. Attia Eman A. Gendy Yaseen A. M. M. Elshaier Mohammed A. El‐Magd 《Journal of heterocyclic chemistry》2019,56(6):1733-1747
Glycosylation of small molecule‐based drugs can dramatically improve the biological activities of the parent scaffold. In the current study, S‐glycosides and N‐glycosides of polyfunctionalized pyridine‐biphenyl system tethered with benzotriazole moiety were designed and synthesized. S‐Glycosides of pyridine‐2‐thione derivatives 5a – h and N‐glycosides of pyridine‐2‐one derivatives 9a , b were synthesized by a facile, convenient, and high‐yielding procedure. The epimers glucose and galactose, acetylated or deacetylated, were used to form the glycone part. The structures of these compounds were confirmed by microanalysis and spectroscopic data (IR, 1 H–NMR, and 13C‐NMR). The anticancer activities of the target compounds, in comparison with standard cisplatin, were assessed by MTT assay against MCF7 cell line. Compounds 4f , 4g , 5f , and 5h exhibited the highest cytotoxic effect on MCF7. The anticancer effect of these four compounds induced the apoptosis as evident by the up‐regulated expression of the apoptotic genes Bax and p53 and down‐regulated expression of the anti‐apoptotic gene BCl2. S‐Glycoside derivatives are more active than N‐glycosides. Moreover, the nontoxic doses of the tested compounds were evaluated in MA104, FRHK4, BGM, Hep2, and Vero cells. Compounds 4a – d and 5a – d were also evaluated for their antiviral effect against HSV‐1, HAV, and rotavirus Wa strain. The compounds' results showed less, moderated, and high antiviral activities. The docking study for these compounds with MDM2 revealed that deacetylated galactose is important for binding with the receptor as it facilitates the formation of hydrogen bond in the receptor. Rapid overlay of chemical structures analysis was employed to understand the compounds' similarity on the basis of their shape structure using the Tanimoto scores. 相似文献
88.
Cubic liquid crystalline nanoparticles (cubosomes) of bicontinuous nature with internal networks of water channels have received great interests in nanomedicine applications, particularly as potential vehicle for loading and release of therapeutic agents. These nanoparticles have been most commonly produced using monoolein and phytantriol. In this study, we explore the use of a Guerbet branched chain glycolipid, namely 2-hexyl-decyl-β-D glucopyranoside (β-Glc?OC10C6), as a new and alternative material for cubosomes production. The fully hydrated glycolipid assumes a reverse bicontinuous cubic liquid crystal phase of an Ia3d space group with lattice parameter of ca. 74 Å, as confirmed using a small-angle X-ray scattering. Dynamic light scattering and a conventional transmission electron microscopy were used to investigate the average size and morphology of the cubosomes. The effectiveness of Poloxamer 407 (stabiliser typically used in other cubosome systems against aggregations and particle coalescence) in providing steric stabilisation of the glycolipid cubosomes was assessed through visual assessment. 相似文献
89.
Latifa Mouni Mehmet Akkurt S. Ö. Yıldırım Taibi Ben Hadda Zahid H. Chohan 《Journal of chemical crystallography》2010,40(2):169-172
Abstract
The title copper complex, Cu[CH3CO–CH=C(CH3)N(CH2–CH2)N(CH3)C=CHCO CH3], has been synthesized by the reaction of ligand, 4-[2-(1-methyl-3-oxo-but-1-enylamino)-ethylamino]-pent-3-en-2-one (ONNO) and copper chloride. The structure of the synthesized complex was determined by IR, NMR, mass spectroscopic data and X-ray crystallography. The structure was solved in monoclinic, space group P21/n with a = 10.971 (4), b = 8.988 (3), c = 12.830 (5) ?, β = 93.512 (5), V = 1,262.7 (6) ?3, Z = 4 and with R int = 0.047. The geometry around the copper atom displays a distorted square-planner structure by coordinating with two oxygen atoms from carbonyl moiety and two nitrogen heteroatom from the central moiety of the ligands and thus established two 6-membered rings and one 5-membered ring. The two nitrogen atoms form two anionic–cationic bonds to complete the coordination sphere around the copper metal atom. 相似文献90.
Javid Hussain Nausheen Bukhari Hidayat Hussain Sajjad Haider Zahid Hassan 《Helvetica chimica acta》2010,93(7):1428-1431
Phlomisamide ( 1 ), a new ceramide, and a new stigmasterol derivative, phlomisteriod ( 2 ), have been isolated from Phlomis cashmeriana. Their structures were elucidated by comprehensive analysis of their 1D‐ (1H‐ and 13C‐NMR) and 2D‐NMR (COSY, HMQC, HMBC), and HR‐EI‐MS data. 相似文献