scholarly journals Solid-solid synthesis, characterization and thermal decomposition of a homodinuclear cobalt(II) complex

2015 ◽  
Vol 80 (11) ◽  
pp. 1391-1397 ◽  
Author(s):  
Di Li ◽  
Guo-Qing Zhong ◽  
Zhi-Xian Wu

The homodinuclear cobalt(II) complex [Co2(dipic)2(H2O)5]?2H2O was synthesized with pyridine-2,6-dicarboxylic acid (H2dipic) and cobalt(II) acetate as raw materials by room temperature solid-solid reaction. The complex was characterized by elemental analyses, single crystal X-ray diffraction, X-ray powder diffraction, Fourier transform infrared spectroscopy, UV spectra, and thermogravimetry and differential scanning calorimetry. Its crystal structure belongs to monoclinic system and space group P2(1)/c. There are two types of the Co(II) ions, and they are all six-coordination, one Co(II) is coordinated by four carboxyl O atoms and two pyridine N atoms from two dipic2- anions, and another Co(II) is coordinated by five O atoms from five H2O molecules and one bridged carboxyl O atom from the dipic2- anion. The possible pyrolysis reactions in the thermal decomposition processes of the complex, the experimental and calculated percentage mass loss are also given.

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Di Li ◽  
Guo-Qing Zhong

The antimony(III) complex [Sb(Hedta)]·2H2O was synthesized with ethylenediaminetetraacetic acid (H4edta) and antimonous oxide as main raw materials in aqueous solution. The composition and structure of the complex were characterized by elemental analysis, infrared spectra, single crystal X-ray diffraction, X-ray powder diffraction, thermogravimetry, and differential scanning calorimetry. The crystal structure of the antimony(III) complex belongs to orthorhombic system, space group Pna2(1), with cell parameters ofa=18.4823(18) Å,b=10.9408(12) Å,c=7.3671(5) Å,V=1489.7(2) Å3,Z=4, andDc=1.993 g cm−3. The Sb(III) ion is five-coordinated by two amido N atoms and three carboxyl O atoms from a single Hedta3−ligand, forming a distorted trigonal bipyramid geometry. The thermal decomposition processes of the complex include dehydration, oxidation, and pyrolysis of the ligand, and the last residue is Sb2O3at the temperature of 570°C.


2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Mei-Ling Wang ◽  
Guo-Qing Zhong ◽  
Ling Chen

Four complexes were synthesized in methanol solution using nickel acetate or nickel chloride, manganese acetate, manganese chloride, and biuret as raw materials. The complexes were characterized by elemental analyses, UV, FTIR, Raman spectra, X-ray powder diffraction, and thermogravimetric analysis. The compositions of the complexes were [Ni(bi)2(H2O)2](Ac)2·H2O (1), [Ni(bi)2Cl2] (2), [Mn(bi)2(Ac)2]·1.5H2O (3), and [Mn(bi)2Cl2] (4) (bi = NH2CONHCONH2), respectively. In the complexes, every metal ion was coordinated by oxygen atoms or chlorine ions and even both. The nickel and manganese ions were all hexacoordinated. The thermal decomposition processes of the complexes under air included the loss of water molecule, the pyrolysis of ligands, and the decomposition of inorganic salts, and the final residues were nickel oxide and manganese oxide, respectively.


2013 ◽  
Vol 787 ◽  
pp. 58-64 ◽  
Author(s):  
Xiang Feng Li ◽  
Zhao Zhang ◽  
Fang Liu ◽  
Shu Ping Zheng

The LiFePO4/C composites with different morphology are synthesized by a novel glucose assisted hydrothermal method at various glucose concentrations (from 0 to 0.25mol/L) and the insoluble lithium source Li2CO3, (NH4)2Fe (SO4)2·6H2O and (NH4)2HPO4(n (Li):n (Fe):n (P)=1:1:1) are used as raw materials. The structure, morphology, thermal performance and electrochemical properties of the synthesized composites are characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), thermogravimetry/differential scanning calorimetry (TG-DSC), galvanostatic charge/discharge tests and cyclic voltammetry (CV). The results show that the LiFePO4/C synthesized with 0.125mol/L glucose has the relatively small particles size (0.1~0.5μm) and the well spherical morphology. The optimal sample exhibits a high discharge capacity of 160.0mAh/g at the first cycle and exhibits a good reversibility and stability in CV tests.


Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2457 ◽  
Author(s):  
Haifeng Zhao ◽  
Jing Lv ◽  
Junshan Sang ◽  
Li Zhu ◽  
Peng Zheng ◽  
...  

In this work, a mixing-calcination method was developed to facilely construct MXene/CuO nanocomposite. CuO and MXene were first dispersed in ethanol with sufficient mixing. After solvent evaporation, the dried mixture was calcinated under argon to produce a MXene/CuO nanocomposite. As characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and X-ray photoelectron spectra (XPS), CuO nanoparticles (60–100 nm) were uniformly distributed on the surface and edge of MXene nanosheets. Furthermore, as evaluated by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA), the high-temperature decomposition (HTD) temperature decrease of ammonium perchlorate (AP) upon addition of 1 wt% CuO (hybridized with 1 wt% MXene) was comparable with that of 2 wt% CuO alone, suggesting an enhanced catalytic activity of CuO on thermal decomposition of AP upon hybridization with MXene nanosheets. This strategy could be further applied to construct other MXene/transition metal oxide (MXene/TMO) composites with improved performance for various applications.


2006 ◽  
Vol 514-516 ◽  
pp. 843-847 ◽  
Author(s):  
Cristina Borges Correia ◽  
João C. Bordado

Polyurethane adhesives provide excellent flexibility, impact resistance and durability. Polyurethanes are formed through the reaction of an isocyanate component with polyether or polyester polyols or other active hydrogen compounds. This paper refers to polyurethane adhesives made from polyester polyols with long aliphatic chains (up to 36 carbon atoms) and MDI (diphenylmethane-4,4’-diisocyanate). The polyester polyols have been made from dimer acids obtained from renewable sources and short chain diols. The polyols that were used presented different degrees of unsaturation. The influence of the different raw materials in the adhesives performance is studied. The polyurethanes were produced by reaction between quasi-stoichiometric quantities of polyol and MDI, at several temperatures. The reaction was carried under inert atmosphere and at temperatures below 100°C. Performance of the adhesives was tested by carrying adhesion, hardness and water absorption tests. Characterization of both the polyester polyols and polyurethane adhesives was carried by Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), Magnetic Nuclear Resonance (NMR), X-Ray Diffraction (WAXD), Scanning RMN Imaging of 1H of Stray- Field b (MRI) and Brookfield viscometry.


1998 ◽  
Vol 23 (0) ◽  
pp. 91-98 ◽  
Author(s):  
Ana Glauce ZAINA CHIARETTO ◽  
Marco Aurélio da Silva CARVALHO FILHO ◽  
Nedja Suely FERNANDES ◽  
Massao IONASHIRO

Solid state compounds of general formula ML2.nH2O [where M is Mg, Ca, Sr or Ba; L is cinnamate (C6H5 -CH=CH-COO-) and n = 2, 4, 0.8, 3 respectively], have been synthetized. Thermogravimetry (TG), derivative thermogravimetry (DTG), differential scanning calorimetry (DSC) and X-ray diffraction powder patterns have been used to characterize and to study the thermal stability and thermal decomposition of these compounds.


2019 ◽  
Vol 42 (1) ◽  
pp. 51-59 ◽  
Author(s):  
Asiyeh Mahmoudpour ◽  
Shohreh Nafisi ◽  
Ezzatollah Najafi ◽  
Behrouz Notash

Abstract A new mixed-ligand diorganotin(IV) complex, [μ-(4-dpe){Me2Sn(cup)2}2] (1), was synthesized by reacting dimethyltin(IV) dichloride with 1,2-di(4-pyridyl)ethylene (4-dpe) and ammonium N-Nitroso-N-phenylhydroxylamine (cup). The prepared complex was fully characterized by PXRD, 1H, 13C and 119Sn NMR, IR, and UV spectra and elemental analysis (CHN). The structural analysis of complex 1 by X-ray diffraction showed that this compound consists of centrosymmetric binuclear units that crystallize in the monoclinic system with the space group of P21/c. Thermal behavior of this complex was interrogated by thermogravimetric and differential thermal analysis (TGA and DTA) under air atmosphere. The study of thermal behavior and luminescence properties of prepared diorganotin(IV) complex exhibited that this complex can be used as a emitting layer in the preparation of optical devices. The prepared coordination compound was used in two different concentrations in the manufacture of two light-emitting diodes (OLEDs).


2013 ◽  
Vol 773 ◽  
pp. 709-713
Author(s):  
Bao Hua Rong ◽  
Yan Wen Lu ◽  
Qing Lin Chen ◽  
Kun Tang ◽  
Xue Wen Liu ◽  
...  

LiFePO4/C was successfully synthesized by one-step solid-state reaction using Fe2O3, LiH2PO4 and sucrose as raw materials. The effect of synthesis temperature and sintering atmosphere on the electrochemical performance were investigated. LiFePO4/C materials were characterized by differential scanning calorimetry and thermogravimetry, X-ray diffraction, scanning electron microscopy and XPS. The results show that the synthesis temperature between 750 °C and 800 °C were appropriate and the reductive ambience can enhance the electrochemical performance effectively especially at high rates. The precursor calcined at 750°C for 5h in a N2+5%H2 atmosphere exhibited the highest discharge capacity of 155 mAh/g at 0.1C and 141 mAh/g at 1C and showed the best cycle performance.


2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Chongwei An ◽  
Hequn Li ◽  
Baoyun Ye ◽  
Jingyu Wang

Spray drying method was used to prepare cocrystals of hexanitrohexaazaisowurtzitane (CL-20) and cyclotetramethylene tetranitramine (HMX). Raw materials and cocrystals were characterized using scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, Raman spectroscopy, and Fourier transform infrared spectroscopy. Impact and friction sensitivity of cocrystals were tested and analyzed. Results show that, after preparation by spray drying method, microparticles were spherical in shape and 0.5–5 µm in size. Particles formed aggregates of numerous tiny plate-like cocrystals, whereas CL-20/HMX cocrystals had thicknesses of below 100 nm. Cocrystals were formed by C–H⋯O bonding between –NO2 (CL-20) and –CH2– (HMX). Nanococrystal explosives exhibited drop height of 47.3 cm, and friction demonstrated explosion probability of 64%. Compared with raw HMX, cocrystals displayed significantly reduced mechanical sensitivity.


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