Synthesis,spectral, structural,Hirshfeld surface and DFT studies on bis(N-(4-fluorobenzyl)-N-(2-phenylethyl)dithiocarbamato-S,S′)zinc(II) and its use for the preparation of ZnS and ZnO nanoparticles

Two new complexes, bis(N-(2-phenylethyl)-N-(4-fluorobenzyl)dithiocarbamato-S,S′)zinc(II) (1) and bis(N-(2-phenylethyl)-N-(4-chlorobenzyl)dithiocarbamato-S,S′)zinc(II) (2), have been synthesized and characterized by various physicochemical techniques. Structure of 1 has been determined by single crystal X-ray diffraction. Complex 1 is a dimer. Zinc atom is four coordinated with a distorted tetrahedral environment. Geometry optimization, geometrical parameters, molecular electrostatic potential (MEPs) and frontier molecular orbital analysis of dimeric and monomeric structures of 1 have been carried out by DFT methods and compared with the experimental X-ray diffraction data. The noncovalent interactions in the complex 1 have been analyzed using Hirshfeld surface analysis. 1 and 2 have been used as single source precursors for the preparation of zinc sulfide and zinc oxide nanoparticles. As-prepared zinc sulfides and zinc oxides have been characterized by powder X-ray diffraction (PXRD), scanning electron microscope (SEM), UV–vis absorption, photoluminence and energy dispersive X-ray spectroscopy (EDS). X-ray diffraction study reveals that zinc sulfides and zinc oxides are composed of rhombohedral and hexagonal phases, respectively. Photocatalytic activities of zinc sulfides and zinc oxides were evaluated by degradation of rhodamine B in aqueous solution under UV light irradiation. The results demonstrated the capability of zinc sulfides and zinc oxides as photocatalyst under UV irradiation to degrade the dye.     

Effect of functionlization of N,N-dibenzyldithiocarbamate: synthesis,spectral and structural studies on bis(N-benzyl-N-(4-methoxybenzyl)dithiocarbamato-S,S′)zinc(II) and bis(N-benzyl-N-(4-cholrobenzyl)dithiocarbamato-S,S′)cadmium(II) and their use for the preparation of MS (M = Zn,Cd)

Bis(N-benzyl-N-(4-methoxybenzyl)dithiocarbamato-S,S′)zinc(II) (1) and bis(N-benzyl-N-(4-chlorobenzyl)dithiocarbamato-S,S′)cadmium(II) (2) have been prepared and characterized by elemental analysis, IR and NMR (¹H and ¹³C) spectroscopy and single-crystal X-ray analysis. Complexes 1 and 2 exist as monomer and dimer, respectively. Crystal structures of 1 and 2 confirm the presence of four coordinated zinc in a distorted tetrahedral arrangement and five coordinated cadmium in a distorted square pyramid arrangement, respectively. Both the complexes are further stabilized by various interactions such as C–H···S, C–H···N, C–H···O and C–H···π (chelate). C–H···O interaction leads to the formation of dimer in complex 1. In complex 2, C–H···π (chelate) interaction runs in opposite directions which results in the polymeric chain. ZnS and CdS have been prepared from 1 and 2, respectively, and characterized by powder X-ray diffraction, SEM, UV–Vis and fluorescence spectroscopy. The X-ray diffraction pattern confirms the wurtzite phase of as-prepared ZnS and CdS.     

Synthesis,characterization, thermal constant and relaxation of gadolinium(III), iron(III) and manganese(II) chelates of diethylenetriamine-bis-inositol-N,N′,N″-triacetic acid

The reaction of the bicyclic anhydride of diethylenetraiamine-pentaacetic acid (DTPAA) with inositol gave diethylenetriamine-inositol-biester-N,N^′,N″-triacetic acid (DTPA-BI) (1). (1) was characterized by FAB-MS, ¹HNMR, IR and elemental analysis. Its chelates of Gd(III), Fe(III) and Mn(II) holding promise of magnetic resonance imaging (MRI) were synthesized. Gd(III) complex was obtained from Gd₂O₃ and the acid form of (1). Thermodynamic stability constant and relaxation of Gd(III) complex with DTPA-BI were determined. The spin–lattice relaxivity (R₁=5.6 l mmol⁻¹ s⁻¹) of chelate was slightly larger than that of [GdDTPA]²⁻. The results showed that the complex is a prospective MRI agent, although thermodynamic stability constant of DTPA-BI K_[GdDTPA-BI]⁻=10^18.2 was a little less than that of [GdDTPA]²⁻ (K_[GdDTPA]²⁻=10^20.73).     

Synthesis,characterization and crystal structure of (cis-P,P′-diphenyl-1,4-diphospha-cyclohexane)molybdenum(0)tetracarbonyl

The preparation of the novel (cis-P,P′-diphenyl-1,4-diphospha-cyclohexane)molybdenum(0)tetracarbonyl complex is described. The spectral data and X-ray structure of the title complex are reported. The results of the crystallographic work show a distorted octahedral complex around the metal center, the first of its kind reported for the P,P′-diphenyl-1,4-diphospha-cyclohexane ligand.     

Synthesis,structure, and properties of two novel copper(II) complexes, [Cu(phen)(L)2]·6H2O and [Cu(phen)3]·(ClO4)2

Two novel copper(II) complexes, namely [Cu(phen)(L)₂]·6H₂O (1) and [Cu(phen)₃]·(ClO₄)₂ (2) have been synthesized under mild condition (HL = 5-methyl-1H-pyrazole-3-carboxylic acid, phen = 1,10-phenanthroline). We report the structural evidence of discrete water decamer conformation in the solid state. These units are found to act as supramolecular glue in the aggregation of mononuclear copper(II) complex to give a three-dimensional network through hydrogen-bonding. The preliminary investigation on the thermal behavior and the anion exchange property of the complexes are presented.     

Electrical conductance and apparent molar volumes of Al(ClO4)3, Be(ClO4)2, and Cu(ClO4)2 in N,N-dimethylacetamide solutions at 25°C

Equivalent conductances and apparent molar volumes of Al(ClO₄)₃, Be(ClO₄)₂, and Cu(ClO₄)₂ in N,N-dimethylacetamide at 25°C are reported. The limiting equivalent conductances, the first step association constants, and the apparent molar volumes at infinite dilution are derived and discussed in terms of influence of nature of cation on the properties of DMA-solvated cations.     

Advantageous mechanochemical synthesis of copper(Ⅰ)selenide semiconductor,characterization,and properties

Copper(I)selenide-nanocrystalline semiconductor was synthesized via one-step mechanochemical synthesis after 5 min milling in a planetary ball mill.The kinetics of synthesis was followed by X-ray powder diffraction analysis and specific surface area measurements of milled 2Cu/Se mixtures.The X-ray diffraction confirmed the orthorhombic crystal structure of Cu₂Se with the crystallite size～25 nm.The surface chemical structure was studied by X-ray photoelectron spectroscopy,whereby the binding energy of the Cu 2p and Se 3d signals corresponded to Cu⁺and Se^2?oxidation states.Transmission electron microscopy revealed agglomerated nanocrystals and confirmed their orthorhombic structure,as well.The optical properties were studied utilizing ultraviolet-visible spectroscopy and photoluminescence spectroscopy.The direct bandgap energy 3.7 eV indicated a blue-shift phenomenon due to the quantum size effect.This type of Cu₂Se synthesis can be easily adapted to production dimensions using an industrial vibratory mill.The advantages of mechanochemical synthesis represent the potential for inexpensive,environmentally-friendly,and waste-free manufacturing of Cu₂Se.     

Reactive sintering behavior and enhanced densification of (Ti,Zr)B2–(Zr,Ti)C composites

Reactive hot pressing was used to prepare (Ti,Zr)B₂–(Zr,Ti)C composites from equimolar ZrB₂ and TiC powders. The reaction and solid-solution coupling effect and enhanced densification in ZrB₂-50 mol.% TiC were proposed as contrasted to conventional consolidation of TiB₂-50 mol.% ZrC. The (Ti,Zr)B₂–(Zr,Ti)C composite sintered at a temperature as low as 1750 °C exhibited negligible porosity and average grain sizes of 0.30 μm for (Ti,Zr)B₂ and 0.36 μm for (Zr,Ti)C. Complete reaction and rapid densification of ZrB₂-50 mol.% TiC was achieved at 1800 °C for only 10 min. The densification mechanism was mainly attributed to material transport through lattice diffusion of Ti and Zr atoms with an activation energy of 531 ± 16 kJ/mol. This study revealed for the first time novel insights into rapid densification of refractory fine-grained diboride–carbide composites by reactive hot pressing at relatively low temperatures.     

Optical,electrical, mechanical,and thermal properties and non-isothermal decomposition behavior of poly(vinyl alcohol)–ZnO nanocomposites

Iranian Polymer Journal - Poly(vinyl alcohol) (PVA) nanocomposites incorporated with ZnO nanofiller were prepared and examined to study the influence of nanofiller on their properties. All the...     

orthovanadate (SO) and erythro

rate. The results suggested that the slower senescence rate of peach fruit was closely related to the higher peak value and longer duration of Ca2 -ATPase activity in microsomal membrane, with     

Theoretical investigation of molecular interactions between sulfur ylide and hypohalous acids (HOX,X═F,Cl, Br,and I)

In the present study, the complexes of sulfur ylide (SY) with hypohalous acids (HOX; X═F, Cl, Br, and I) were theoretically studied using the MP2/aug-cc-pVTZ computational level. Four types of structures were obtained for these complexes including two kinds of hydrogen bonds (HBs) (SY: HOX─I and SY: HOX─II) and two kinds of halogen bonds (SY: XOH─I and SY: XOH─II). According to the energetic results, the SY:XOH─I complexes are stronger for X═Br and I, while the SY:HOX─I complexes are favorable for X═Cl and Br; also, the SY:HOX─II complexes are stronger than SY:XOH─II except for SY:IOH─II, which is stronger than its counterpart (SY:HOI─II). Moreover, on comparing SY:HOX─I and II HBs complexes, the former is more stable than the latter, while between the SY:XOH─I and II halogen bond complexes (X═Cl, Br, and I), the SY:XOH─I ones are more stable. The strength, properties, and nature of interactions were also analyzed using the natural bond orbital and atoms in molecules theories.     

Enzymatic synthesis,thermal and crystalline properties of a poly(β–amino ester) and poly(lactone-co-β–amino ester) copolymers

Ethyl 3-(4-(hydroxymethyl)piperidin-1-yl)propanoate (EHMPP) was prepared in quantitative yield under mild conditions via Michael addition reaction of 4-piperidinemethanol with ethyl acrylate. EHMPP underwent condensation polymerization in the presence of a lipase catalyst (CALB) to form poly[3-(4-(methylene)piperidin-1-yl)propanoate] (poly(MPP) or PMPP). Ring-opening and condensation copolymerization of EHMPP with ω-pentadecalactone (PDL) led to the synthesis of novel poly(PDL-co-MPP) copolymers, whose compositions were readily controlled by varying the monomer feed ratio. NMR analyses, including statistical analysis on repeating unit sequence distribution, indicate that the copolymers are totally random polymers. TGA analysis revealed that the degradation temperature of PMPP is approximately 160 °C lower than that of PPDL and that all poly(PDL-co-MPP) copolymers degrade in two well defined weight loss steps attributable to thermal degradation of MPP and PDL unit fractions in the polymers. The crystallinity of the polymers was studied by DSC analysis. Although PMPP and the copolymers rich in MPP units do not easily crystallize upon cooling from melt, the homopolymer and all copolymers obtained via precipitation from solution are semi-crystalline materials. WAXS analysis showed that the copolymers rich in PDL (≥51 mol%) crystallize in PPDL lattice and those with ≤21 mol% PDL content develop PMPP-type crystals while in the copolymer with 36 mol% PDL, PMPP-type and PPDL-type crystals co-exist. PMPP and poly(PDL-co-MPP) represent a new type of biodegradable poly(β–amino esters) that are potentially useful biomaterials for specific biomedical applications (e.g., gene delivery).     

Chitosan–Oligo(silsesquioxane) Blend Membranes: Preparation, Morphology, and Diffusion Permeability

Preparation of the blend chitosan (CHI) membranes containing polyhedral oligomeric silsesquioxane (POSS) derivatives was investigated. POSS derivatives such as (3-aminopropyl)isobutyl-POSS (amino-POSS), [2-(3,4-epoxycyclohexyl)ethyl]isobutyl-POSS (epoxy-POSS), and octa(tetramethylammonium)-POSS were used. The blend CHI–amino-POSS membranes were predicted to be the most porous due to having the weakest interactions between the components in the blends. The CHI–epoxy-POSS blend membranes were assumed to be more dense owing to chemical binding of the chitosan amino groups with the epoxy groups of POSS. Studies of membrane morphology and diffusion permeability support these predictions.     

Synthesis and properties of polyimides based on isomeric (4, 4′-methylenediphenoxyl) bis (phthalic anhydride)s (BPFDAs)

Isomeric (4, 4′-methylenediphenoxyl) bis (phthalic anhydride)s (BPFDAs)were synthesized and their structures were determined via IR spectra and ¹H NMR. Polyimides were then prepared from isomeric BPFDAs and aromatic diamines in N, N-Dimethylacetamide (DMAc) via the conventional two-step method. Polyimides based on 3, 3′-BPFDA are soluble in common organic solvents at room temperature, while polyimides based on 4, 4′-BPFDA were only partially soluble in high-boiling-point solvent even upon heating. The 5% weight-loss temperatures (T _5% ) of these polyimides were in the range of 430–500 °C in air. Dynamic mechanical thermal analysis (DMTA) indicated that the glass-transition temperatures of polyimides from 3, 3′-BPFDA are around 10–20 °C higher than those of polyimides from 4, 4′-BPFDA. The wide-angle X-ray diffraction showed that all polyimides are amorphous.     

Crystallization and morphology of poly(ethylene succinate) and poly(β-hydroxybutyrate) blends

Summary The melting and crystallization behavior of poly(β-hydroxybutyrate) (PHB) and poly(ethylene succinate) blends has been studied by differential scanning calorimetry and optical microscopy. The results indicate that PHB and PES are miscible in the melt. Consequently the blend exhibits a depression of the melting temperature of both PHB and PES. In addition, a depression of the equilibrium melting temperature of PHB is observed. The Flory-Huggins interaction parameter (χ₁₂ ), obtained from melting point depression data, is composition dependent, and its value is always negative. Isothermal crystallization in the miscible blend system PES/PHB is examined by polarized optical microscope. The presence of the PES component gives a wide variety of morphologies. The spherulites exhibit a banded structure and the band spacing decreases with increase PES content. Received: 29 June 1998/Revised version: 31 August 1998/Accepted: 10 September 1998     

Influence of Al-substitution on structures,resistivity and magnetic properties of LaxSr(2−x)Fe(1+y)Mo(1−y)O6 (x=3y,y=0.05, 0.1, 0.15, 0.2)

Two series of single-phased La_xSr_(2−x)Fe_(1+y)Mo_(1−y)O₆ and La_xSr_(2−x)Fe_(1+0.5y)Al_0.5yMo_(1−y)O₆ (x=3y, y=0.05, 0.1, 0.15 and 0.2) double perovskites were prepared by solid-state reaction. The effects of Al-substitution on the structures, resistivity and magnetic properties of La_xSr_(2−x)Fe_(1+y)Mo_(1−y)O₆ were investigated. Although Al-replacement exhibits a negligible influence of on the B-site ordering degree, it results in the suppression of magnetisation caused by non-magnetic Al³⁺ ions. Reduction of grain sizes leads to increased resistivity, thus an optimised magnetoresistance (MR) behaviour is observed. The greatest MR extent improvement can be obtained when y is 0.15 and the MR% of the Al-doped ceramics reaches −10.5% (10 K, 1 T), which is 2 times greater than that of the undoped ceramics (−4.6%, 10 K, 1 T). Interestingly, the Curie temperature (Tc) of both Al-doped and undoped samples maintained relatively constant values of approximately 420 K and 405 K, respectively, which were different results from the data obtained for similar electron-doping systems in the literature.     

Binuclear rhodium(III) and iridium(III) monoselenocarboxylates: Synthesis,spectroscopy and structure of an ortho-metallated iridium complex featuring an IrCCC(μ-Se) chelate ring

Monoselenocarboxylate–bridged binuclear complexes of Rh^III and Ir^III, [(Cp1MCl)₂(μ-SeCOAr)₂] (1) (M = Rh or Ir; Cp1 = pentamethylcyclopentadienyl; Ar = Ph, C₆H₄Me–4), have been isolated either by the reaction between [Cp1₂M₂(μ-Cl)₂Cl₂] with KSeCOAr in acetonitrile or by treatment of [Cp1MCl(solvent)₂][PF₆] with KSeCOAr in acetone. The novel binuclear complexes, [Cp1IrCl(μ-SeCOAr)(κ²-SeCOC₆H₃R–)IrCp1] (2) (R = H or Me-4) with ortho-metallation at one of the iridium centres have been isolated following the use of excess AgPF₆. The single crystal structure of [Cp1IrCl(μ-SeCOC₆H₅)(κ²-SeCOC₆H₄–)IrCp1] (2a) exhibits two phenylcarboselenolate moieties situated in syn fashion with respect to the “Ir₂Se₂” plane, one of which leans towards the metal centre in order to undergo ortho-metallation after iridium–chlorine bond dissociation.