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Synthesis of a Pyrene-Derived Schiff Base and Its Selective Fluorescent Enhancement by Zinc and Aluminum Ions  [PDF]
Ping-Feng Hsu, Yun Chen
International Journal of Organic Chemistry (IJOC) , 2018, DOI: 10.4236/ijoc.2018.82016
Abstract: An efficient pyrene-Schiff base fluorescent sensor PySb was synthesized and evaluated for its fluorescence response to metal ions. Sensor PySb exhibits an “off-on-type” mode with high selectivity to Zn2+ and Al3+ in ethanol (470 nm) and in dimethyl sulfoxide (458 nm) respectively. The originally non-fluorescent PySb, due to photo-induced electron transfer (PET) from imine moiety, is turned on after binding with the cations. The stoichiometric ratio between PySb and Zn2+ is 1:2; moreover, the limit of detection (LOD) and bonding constant were 2.39 × 10-8 M and 2 × 109 M-1 respectively, as obtained from titration experiments.
Synthesis, Characterization, and Biological Activity of Some Transition Metal Complexes Derived from Novel Hydrazone Azo Schiff Base Ligand  [PDF]
C. Anitha,S. Sumathi,P. Tharmaraj,C. D. Sheela
International Journal of Inorganic Chemistry , 2011, DOI: 10.1155/2011/493942
Abstract: A series of metal(II) complexes ML where M = VO(II), Co(II), Ni(II), Cu(II), and Zn(II) have been synthesized from azo Schiff base ligand (N′E)-N′-(5-((4-chlorophenyl)diazenyl)-2-hydroxybenzylidene)-2-hydroxybenzohydrazide and characterized on the basis of elemental analyses, electronic, IR, and 1H NMR spectra, magnetic susceptibility and also by aid of scanning electron microscopy (SEM), X-ray powder diffraction, fluorescence spectral studies, and molar conductivity measurements. Conductivity measurements reveal that the complexes are nonelectrolytes. Spectroscopy and other analytical studies reveal distorted square planar geometry for copper, square-pyramidal geometry for oxovanadium, and tetrahedral geometry for other complexes. Redox behavior of the copper(II) complex has been studied with cyclic voltammetry, and the biological activities of the ligand and metal complexes have been studied against several microorganisms by the well diffusion method. All synthesized compounds can serve as potential photoactive materials as indicated from their characteristic fluorescence properties. The second harmonic generation (SHG) efficiency of the ligand was measured and found to be higher than that of urea and KDP. The SEM image of the copper(II) complex implies that the size of the particles is 50?nm. 1. Introduction Azo Schiff base metal complexes have been studied extensively for years due to the synthetic flexibilities of these Schiff base ligands and their selectivity as well as sensitivity towards the transition metal ions [1]. Among the ligand systems, hydrazide and hydrazones occupy special place because transition metal complexes of these ligands developed due to their chelating capability, structural flexibility, interesting electrical as well as magnetic properties [2, 3], and, nowadays, they are extensively being used for their promising applications in the treatment of several diseases and also been used as synthetic and analytical reagents [4], as polymer-coating pigment and fluorescent materials [5–9]. Moreover, these ligands exhibit keto-enol tautomerism [10–14] bearing unusual coordination numbers. In the present paper, we report the synthesis and characterization of VO(II), Co(II), Ni(II), Cu(II), and Zn(II) complexes of azo Schiff base derived from the condensation of 5-(4-chloro-phenylazo)-2-hydroxy benzaldehyde with 2-hydroxybenzohydrazide in a mole ratio of (1?:?1), respectively, and, due to the rich chemistry of vanadium metal [15, 16], we also aimed to prepare and characterize the vanadyl complex of hydrazone derivative. 2. Experimental
Synthesis and Characterization of Chiral Nitrobenzaldehyde - Schiff Base Ligands  [PDF]
Wen Tao Gao,Zhuo Zheng
Molecules , 2003, DOI: 10.3390/81100788
Abstract: Three chiral nitrobenzaldehyde/Schiff base ligands (2a-c) were prepared by the reaction of ortho, meta, and para-NO2 substituted benzaldehydes (1a-c) with (1R,2R)-(-)-1,2-diaminocyclohexane. The structures of ligands 2a-c were characterized by IR, 1H-NMR, 13C-NMR and elemental analysis.
Acoustical properties of Schiff base solutions in dmf
Baluja,S.; Vaishnani,K.P.; Gajera,R.; Kachhadia,N.;
Latin American applied research , 2010,
Abstract: density, ultrasonic velocity and viscosity of schiff bases have been studied in dimethyl formamide at 308.15 k. from the experimental data, various acoustical parameters such as specific impedance (z), isentropic compressibility (?s), rao's molar sound function (rm), van der waals constant (b), relaxation strength (r), intermolecular free length (lf), internal pressure (p), solvation number (sn) etc. have been evaluated, which helps in understanding the molecular interactions occurring in these solutions.
Acoustical properties of Schiff base solutions in dmf  [cached]
S. Baluja,K.P. Vaishnani,R. Gajera,N. Kachhadia
Latin American applied research , 2010,
Abstract: Density, ultrasonic velocity and viscosity of Schiff bases have been studied in dimethyl formamide at 308.15 K. From the experimental data, various acoustical parameters such as specific Impedance (Z), isentropic compressibility (?s), Rao's molar sound function (Rm), Van der Waals constant (b), relaxation strength (r), intermolecular free length (Lf), internal pressure (p), solvation number (Sn) etc. have been evaluated, which helps in understanding the molecular interactions occurring in these solutions.
Synthesis and antibacterial activity of some Schiff base complexes
Journal of the Serbian Chemical Society , 2006,
Abstract: Two Schiff bases were synthesized from raceacetophenone: 1) ADS1: 4-ethyl-6-{(E)-1-[(3-nitrophenyl)imino]ethyl}benzene-1,3-diol and 2) ADS3: 4-ethyl-6-{(E)-1-[(2-nitrophenyl)imino]ethyl}benzene-1,3-diol. Then their metal complexes were formed. The metals selected for the preparation of complexes were copper, nickel, iron and zinc. Hence, in total 8 metal complexes were synthesized and screened for antibacterial activity against some clinically important bacteria, such as Pseudomonas aeruginosa, Proteus vulgaris, Proteus mirabilis, Klebsiella pneumoniae and Staphylococcus aureus. The in vitro antibacterial activity was determined by the Agar Ditch technique using DMF (polar) and 1,4-dioxane (non polar) as solvents. The Schiff bases showed greater activity than theirmetal complexes; themetal complexes showed differential effects on the bacterial strains investigated and the solvent used, suggesting that the antibacterial activity is dependent on the molecular structure of the compound, the solvent used and the bacterial strain under consideration. The Schiff base ADS3 in the polar solvent DMF showed better antibacterial activity towards the investigated bacterial strains. Amongst the four metals, Zn showed the best antibacterial activity followed by Fe in 1,4-dioxane while Ni followed by Zn and Fe showed the best antibacterial activity in DMF. P. vulgaris was the most resistant bacteria.
Characterization, XPS and Toxicological Study of Organothallium (III) Compounds with Schiff Base Ligands  [PDF]
Gyanendra Kumar Gaur, Shekhar Srivastava
Crystal Structure Theory and Applications (CSTA) , 2012, DOI: 10.4236/csta.2012.13018

Many Organothallium Compounds have been used in medicine, industry and antibacterial activity. Optical properties are among the most fascinating and useful properties of many complexes and have been extensively studied using a variety of optical spectroscopic techniques. A basic understanding of the optical properties and related spectroscopic techniques is essential for characterization about semiconductors, insulators or metal. Optical properties are related to other properties and functionalities (e.g. electronic, magnetic, and thermal) that are of fundamental importance to many technological applications, such as energy conversion, chemical analysis, biomedicine, opto-electronics, communication, and radiation detection. The fundamental importance of Thallium is the ability to accept electrons due to empty d-orbitals and thus establish additional bonds (σ bond and π bond) in chemistry. The Thallium metal, which has outer electronic configuration 6 s2, 6 p1 shows oxidation states of Thallium (III) and Thallium (I). This research paper explains that Thallium (III) and Thallium (I) accepts lone pairs from various bi-dentate tetra-dentate Schiff base ligands due to p-orbital and vacant d-orbital. This research paper explains the Characterization, XPS and Toxicological Study of Or- ganothallium (III) Compounds with Schiff base ligands by physiochemical technique. X-Ray photoelectron spectrogra- phy (XPS) study of Thallium (III) complexes with Schiff Base ligands also reported in this paper. XPS study shows a single symmetrical peak without any splitting in photoelectron peak, which confirms diamagnetic nature of all prepared molecular adducts. All prepared complexes with Schiff base ligands show toxicological effect.

Precision analysis for standard deviation measurements of single fluorescent molecule images  [PDF]
Michael C. DeSantis,Shawn H. DeCenzo,Je-Luen Li,Y. M. Wang
Quantitative Biology , 2009, DOI: 10.1364/OE.18.006563
Abstract: Standard deviation measurements of intensity profiles of stationary single fluorescent molecules are useful for studying axial localization, molecular orientation, and a fluorescence imaging system's spatial resolution. Here we report on the analysis of the precision of standard deviation measurements of intensity profiles of single fluorescent molecules imaged using an EMCCD camera. We have developed an analytical expression for the standard deviation measurement error of a single image which is a function of the total number of detected photons, the background photon noise, and the camera pixel size. The theoretical results agree well with the experimental, simulation, and numerical integration results. Using this expression, we show that single-molecule standard deviation measurements offer nanometer precision for a large range of experimental parameters.

WANG Yuming,MENG Zhaofu,WANG Zhao,

金属学报 , 1986,
Abstract: The crystallization of amorphous Ni_(83)Cr_7Fe_3Si_4B_3 alloy was investigated under dynamic heating and isothermal annealing conditions. An identical crystallization and unaltered phases are revealed under both treatments. However, the initial crystallization is mainly due to the nucleation of crystals under dynamic heating, while the crystal growth plays a major role under isothermal annealing. It has also been measured that the microhardness approached its highest value just before the specimen being totally crystallized.
Crystallization process of Ni-base metallic glasses  [PDF]
T. Poloczek,S. Griner,R. Nowosielski
Journal of Achievements in Materials and Manufacturing Engineering , 2006,
Abstract: Purpose: The paper presents a crystallization process of Ni68,7Cr6,6Fe2,65Si7,8B14C0,25 metallic glasses. The Ni68,7Cr6,6Fe2,65Si7,8B14C0,25 metallic glasses were produced by the CBMS method for two different conditions of the casting, with different cooling rate.Design/methodology/approach: The crystallization of Ni68,7Cr6,6Fe2,65Si7,8B14C0,25 metallic glasses by method differential thermal analysis (DTA), internal friction (IF), X-ray diffraction and transmission electron microscopy (TEM) were studied. For calculation of activation energy of crystallization processes was used modified Kissingers formula.Findings: The investigation showed, that the conditions of vitrification (different, but higher than critical cooling rate) influence for different course elementary crystallization processes during thermal activation.Research limitations/implications: The differences in temperature of beginning of elementary crystallization processes of alloy, the activation energy of crystallization process as a function of thickness of strip were disclosed.Practical implications: The calculation values of activation energy of crystallization processes can used for analysis of thermal stability of metallic glasses.Originality/value: The paper presents, that the conditions of vitrification influence for different course elementary crystallization processes during thermal activation.
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