Journal of Inorganic Chemistry The latest articles from Hindawi Publishing Corporation © 2016 , Hindawi Publishing Corporation . All rights reserved. Complexation of Oxovanadium(IV) and Dioxouranium(VI) with Synthesized 1,2-(Diimino-4′-antipyrinyl)-1,2-diphenylethane Schiff Base: A Thermodynamic, Kinetic, and Bioactivity Investigation Sun, 28 Dec 2014 00:10:05 +0000 We report the comparative synthetic methodologies and characterization of a tetradentate Schiff base ligand 1,2-(diimino-4′-antipyrinyl)-1,2-diphenylethane (DE). The target synthesis of oxovanadium(IV) and dioxouranium(VI) complexes (vanadyl and uranyl) with the (DE) ligand was also attempted to envisage the effect of metal ion steric factor on complexation process through solution phase thermodynamic and kinetic studies. The thermodynamic stabilities of synthesized vanadyl and uranyl (DE) complexes are discussed in light of their solution phase thermodynamic stability constants obtained by electroanalytical method. A comparative kinetic profile of vanadyl and uranyl complexation with DE is also reported. The complexation reaction proceeds with an overall 2nd order kinetics with both metal ions. Temperature dependent studies of rate constants present an activation energy barrier of ca. 40.913 and 48.661 KJ mol−1, for vanadyl and uranyl complexation, respectively, highlighting the metal ion steric and ligand preorganization effects. The synthesized Schiff base ligand and its vanadyl and uranyl complexes were screened for biocidal potential as antibacterial, antifungal, and anthelmintic agents with the results compared to corresponding reference drugs. Shabnum Bashir, Syed Raashid Maqsood, Ghulam Mustafa Peerzada, Badruddin Khan, and Masood Ahmad Rizvi Copyright © 2014 Shabnum Bashir et al. All rights reserved. Synthesis and Characterization of Rutile Pigments with Cr and Nb Tue, 02 Sep 2014 09:54:08 +0000 Rutile pigments (where , 0.05, 0.10, 0.20, 0.30 and 0.50) prepared by solid-state reaction are investigated. Chromium is chromophore (coloring ion) and niobium is counterion (charge-compensating element for electroneutrality). The effect of composition (x), calcination temperature (850, 900, 950, 1000, 1050, 1100 and 1150°C), and starting titanium compounds (anatase TiO2, hydrated anatase paste, TiOSO42H2O, and hydrated Na2Ti4O9 paste) on their color properties into organic matrix and particle size distribution was observed. According to the highest chroma C and visual color evaluation, yellow and orange pigments were selected as in color the most interesting. They have concentration or 0.10 and are prepared from anatase TiO2 and TiOSO42H2O at temperature 1050°C. Jan Večeřa, Iveta Šedová, Petr Mikulášek, and Petra Šulcová Copyright © 2014 Jan Večeřa et al. All rights reserved. Optical Properties of Al- and Zr-Doped Rutile Single Crystals Grown by Tilting-Mirror-Type Floating Zone Method and Study of Structure-Property Relationships by First Principle Calculations Sun, 17 Aug 2014 08:12:20 +0000 High quality and transparent single crystals of undoped rutile TiO2, Al-doped rutile (Al : TiO2), and Zr-doped rutile (Zr : TiO2) have been grown successfully by tilting-mirror-type floating zone (TMFZ) using travelling solvent floating (TSFZ) technique. The effect of doping on the electronic and optical properties of rutile has been studied experimentally as well as by simulation calculations. The effect of doping on the quality of crystals was also investigated by observing optical micrograph and measuring etch pits density that reveals the presence of defects. Undoped rutile crystals were dark blue and comprised many low-angle grain boundaries. Al+3 and Zr+4 ions pin down the migration of dislocations during the cooling and create oxygen vacancies. Doping of the impurities would improve the electronic and optical properties of rutile. The elastic properties might be changed for doping of the impurities in the rutile crystals. Md. Abdur Razzaque Sarker Copyright © 2014 Md. Abdur Razzaque Sarker. All rights reserved. Copper(II) Complexes of 2-(Methylthiomethyl)anilines: Spectral and Structural Properties and In Vitro Antimicrobial Activity Wed, 16 Apr 2014 11:30:05 +0000 Copper(II) complexes of 2-(methylthiomethyl)anilines (1a–1f) have been obtained and characterized by elemental analyses, IR, electronic spectra, conductivity, and X-ray crystallography. The complexes (2a–2f) have the structural formula [CuCl2L] with the bidentate ligand coordinating through sulfur and nitrogen. The single crystal X-ray diffraction data reveal that the copper complex (2f) has a tetragonally distorted octahedral structure with long Cu–Cl equatorial bonds. Magnetic susceptibility measurements indicate the availability of one unpaired electron in the complexes and the conductivity measurements in DMF show their behaviour as nonelectrolytes. The solid reflectance spectra and the electronic spectra of the complexes in DMSO were determined. The ligands and their copper complexes were screened for in vitro antimicrobial activity against S. aureus, B. subtilis, E. coli, and C. albicans. The methoxysubstituted complex (2c) showed more promising antibacterial activity against S. aureus and B. subtilis than other compounds at the concentration tested. Temitope E. Olalekan, Denzil R. Beukes, Bernardus Van Brecht, and Gareth M. Watkins Copyright © 2014 Temitope E. Olalekan et al. All rights reserved. Spectroscopic Characterization, In Vitro Cytotoxicity, and Antioxidant Activity of Mixed Ligand Palladium(II) Chloride Complexes Bearing Nucleobases Tue, 01 Apr 2014 07:10:22 +0000 Mixed-ligand palladium(II) chloride complexes bearing the nucleobases, adenine (Ad), cytosine (Cyt), and guanine (Gua), have been synthesized and characterized by UV-vis spectrophotometric methods, magnetic susceptibility, molar conductivity, elemental analysis, FTIR, and 1H-NMR. The complexes were found to have the composition cis-[PdCl2(Gua)(Cyt)], cis-[PdCl2(Ad)(Cyt)], and cis-[PdCl2(Ad)(Gua)]. A four-coordinated square-planar geometry is proposed for these Pd(II) complexes based on magnetic evidence and electronic spectra. The complexes as well as the free nucleobase ligands were tested for their in vitro cytotoxicity on human promyelocytic leukemia (HL60) and human histiocytic leukemia (U937) cell lines. cis-[PdCl2(Ad)(Gua)] showed IC50 values of 11.29 ± 2.91 and 8.31 ± 1.44 μM against HL60 and U937, respectively, which was higher than that of the positive control (curcumin) against U937. The complexes also showed significant antioxidant activity when tested against 2,2-diphenyl-1-picrylhydrazylradical (DPPH). Samuel Tetteh, David K. Dodoo, Regina Appiah-Opong, and Isaac Tuffour Copyright © 2014 Samuel Tetteh et al. All rights reserved. Synthesis and Characterisation of New Symmetrical Binucleating Ligands and Their Binuclear Copper(II) Complexes Thu, 02 Jan 2014 14:59:47 +0000 New symmetrical binucleating ligands N,N-bis[2-hydroxy-5-methyl-3-(4-methyl-piperazinomethyl)benzyl]-alkylamines L1 and L2 and their copper(II) complexes [Cu2L(X)2]·2H2O, where X = CH3COO−, C6H5COO−, Cl−, and , were prepared and characterised. All the complexes undergo quasi-reversible reduction at negative potential (E = −0.48 to −1.02 V). The acetate and benzoate complexes undergo a two-step single electron transfer at –0.48 to –0.60 V and −0.9 to −1.02 V. The chloro and perchlorate complexes undergo a single step two-electron transfer at −0.55 to −0.75 V. Variable temperature magnetic studies show the presence of weak exchange interaction for acetate (−2 J around 25 to 40 cm−1) and benzoate (−2 J around 45 to 55 cm−1) bridged complexes and no exchange interaction is found for chloro and perchlorate complexes. ESR spectra of chloro and perchlorate complexes are like mononuclear copper(II) complexes with hyperfine splitting (A = 165 ± 5, = 2.17–2.23, and = 2.05–2.10). The ESR spectra of acetate and benzoate complexes are like binuclear copper(II) complexes with broad signal ( = 2.2). K. Jothivenkatachalam and S. Chandra Mohan Copyright © 2014 K. Jothivenkatachalam and S. Chandra Mohan. All rights reserved. Computational Study on the Intramolecular Carbene-CO Coupling in M(CH2)(CO)3 Radicals (M = Co, Rh, Ir) Sun, 29 Dec 2013 17:58:48 +0000 The intramolecular carbene-carbonyl coupling has been investigated for the simple M(CH2)(CO)3 (M = Co, Rh, Ir) radical complexes at the DFT PBEPBE/TZVP level of theory. The coupling is predicted to be very fast for the cobalt-containing system, but it is still feasible for the systems based on the other two metals. The back-way reaction, that is, the conversion of the ketene complex into carbonyl-carbene complex, cannot be excluded from the Ir-containing system in CH2Cl2, and it is even favored in gas phase. The intermolecular ketene formation by the addition of external CO onto the CH2 moiety is the favored pathway for the Ir-complex. The Laplacian distribution, as well as the natural spin density distribution of all the species, being involved in the reaction, gives explanation for the significant difference between the nature of the Co-complex and the Rh- and Ir-systems. Gábor Tollár and Tamás Kégl Copyright © 2013 Gábor Tollár and Tamás Kégl. All rights reserved. Synthesis and Characterisation of First Generation Luminescent Lanthanide Complexes Suitable for Being Adapted for Uptake via the Mannose Receptor Wed, 18 Dec 2013 18:36:20 +0000 With the aim of directing lanthanide complex uptake via the mannose receptor, a first generation of luminescent lanthanide complexes has been developed with an α-D-mannose targeting motif. Four complexes were produced to investigate photophysical properties and determine the effect of the coordinated mannose residue on emission intensity. The free hydroxyls of the α-D-mannose residue quenched lanthanide phosphorescence due to their close proximity, though they did not bind the lanthanide centre as observed by q-values ≈1.0 for all complexes between pH 3 and 10. Fluorescent emission was found to vary significantly with pH, though phosphorescent emission was relatively insensitive to pH. This lack of pH sensitivity has the potential to provide stable emission for the visualisation of the endosome-lysosome system where acidic pH is often encountered. Robert Brooks, Zhangli Du, Glenn Borlace, Douglas Brooks, and Sally Plush Copyright © 2013 Robert Brooks et al. All rights reserved. Synthesis, Characterization, and Electrochemical Behaviour of Cobalt(II) and Nickel(II) Complexes with Chelating Ligand 4,4′-(Biphenyl-4,4′-diyldinitrilo)dipentan-2-one Tue, 03 Sep 2013 08:50:29 +0000 4,4′-Diaminobiphenyl reacts with 2,4-pentanedione in absolute ethanol in a molar ratio 1 : 2 to form mainly the product of [1 + 2] condensation, 4,4′-(biphenyl-4,4′-diyldinitrilo)dipentan-2-one (H2L). The Schiff base was used as tetradentate chelating ligand to coordinate and chlorides leading to complexes where the ratio of metal ligand was found to be 2 : 1 or 2 : 2. All the synthesized products were characterized by elemental analysis, infrared, electronic, and mass spectroscopy, 1H NMR, and DSC. The electrochemical behaviour of the ligand and its complexes in DMF is also investigated. Lakhdar Sibous, Embarek Bentouhami, and Mustayeen Ahmed Khan Copyright © 2013 Lakhdar Sibous et al. All rights reserved. Oxovanadium(IV) Complexes with Nitrogen Donors: Synthesis, Characterisation, and Biological Activities Mon, 26 Aug 2013 15:02:09 +0000 Some oxovanadium(IV) complexes of SA/SSA and 5, 10, 15, and 20-meso-tetraphenylporphyrin (H2tpp) with unidentate and bidentate nitrogen donors have been synthesized and characterized by elemental analysis, conductivity measurements, magnetic susceptibility, UV-Vis, IR, mass spectroscopy, TGA/DTA, and 1H, 13C and 51V NMR studies to investigate the steric and electronic effects of axial ligands on the properties of porphyrins. On the basis of these studies, it has been investigated that the axial ligands bind to the sixth coordination site of the vanadium ion to form a relatively stable six-coordinate-porphyrin complex where as in the case of SA/SSA complexes the nitrogen donors bind to the equatorial position giving square pyramidal geometry. The in vitro cytotoxicity against human cancer cell lines and antimicrobial activities of the synthesized compounds have been done against various fungal and bacterial pathogens. The [VO(SA/SSA)L/L-L] complexes were found to possess higher antibacterial, antifungal activity and in vitro cytotoxicity against human cancer cell lines than VO(tpp)L complexes. Gauri D. Bajju, Puja Sharma, Ashu Kapahi, Madhulika Bhagat, Sujata Kundan, and Deepmala Gupta Copyright © 2013 Gauri D. Bajju et al. All rights reserved. A Novel Approach to Prepare Well-Defined Silica-Supported Polyoxometalate Species by Reaction with a Chlorinated Support Thu, 22 Aug 2013 11:27:44 +0000 Polyoxometalates were grafted covalently on SBA-15 by a two-step procedure. The dehydroxylated mesoporous silica was first modified by reaction with methyltrichlorosilane in presence of triethylamine. The resulting solid was fully characterized and contained a mixture of mono- and digrafted species . These surface Si–Cl bonds can react with lacunary polyoxometalates as in solution, yielding to a ≡Si–O–POM linkage. However, solid state MAS NMR shows that only the digrafted species react with the polyoxometalate. This new grafting method opens the way to the synthesis of a new class of catalysts which could operate in solution without leaching. Eva Grinenval, Jean-Marie Basset, and Frédéric Lefebvre Copyright © 2013 Eva Grinenval et al. All rights reserved. Synthesis, Crystal Structures, and Magnetic Properties of Ternary M(II)-Dicyanamide-hydroxypyridine Complexes Wed, 05 Jun 2013 10:11:07 +0000 Three two-dimensional (2D) and 3D supramolecular coordination architectures based on ternary M(II)-dicyanamide-2-hydroxypyridine systems, [Co(hmpH)2(dca)2] (1), [Cu(hmpH)2(dca)2] (2), and [Mn(hepH)2(dca)2] (3) (dca = dicyanamide, hmpH = 2-(hydroxymethyl)pyridine, hepH = 2-(hydroxyethyl)pyridine), have been synthesized. 1 is a mononuclear Co(II) complex. The mononuclear units are interlinked into a 2D (4,4) hydrogen-bonded layer via O–H⋯N hydrogen bonds between the hydroxyl groups and the noncoordinating nitrile ends. These 2D layers are further extended into a 3D supramolecular architecture via the interlayer pyridyl-pyridyl stacking interaction. 2 has a 1D coordination chain structure formed by the double 1,5-dca bridged dinuclear [Cu2(1,5-dca)2(hmpH)2] unit and the 1,3-dca bridges via weak Cu–N coordination, and these 1D coordination chains are further extended into 2D hydrogen-bonded layers via strong O–H⋯N hydrogen-bonding interaction between the hydroxyl groups and the noncoordinating nitrile ends. 3 is a 2D (4,4) coordination network made of 1D [Mn(hepH)(1,5-dca)] helical chain units and interchain double (1,5-dca) bridges. Pairs of [Mn(hepH)(1,5-dca)] helical chains are interlinked by the double (1,5-dca) bridges into a racemic coordination layer structure, which is further extended into a 3D hydrogen-bonded network. Magnetic studies reveal that weak antiferromagnetic exchange occurs in 3. Ling-Ling Zheng Copyright © 2013 Ling-Ling Zheng. All rights reserved.