Synthesis,characterization and dc electrical conductivity of some oligmer mixed metal complexes

The synthesis of the oligomer metal complexes was systematically carried out in three steps starting from condensing terephthaldehyde with 2,5-diamino-3,4-dicyanothiophene in DMF. Dithienylenephenylene (TBT) produced was complexed with copper acetate to give di-TBT copper complex [Cu(TBT)₂]. This was complexed once more with a metal salt to give the 12-ring tri-metal oligomer M[Cu(TBT)₂]₂, where M is Co, Ni, or Cu.The presence of different transition metal ions allowed the comparison of the chemical and physical properties of the mixed metal complexes. The 12-ring mixed metal complexes were characterized through a comparative study of FTIR, electronic spectra and thermal analyses (TGA and DSC) in addition to the elemental analyses and metal content. A comparative study of the dc electrical conductivity in its intrinsic and 5% I₂-doped states with temperature variation in the range 300–500 K allowed tracing the action of the three different transition metals on the dc electrical conductivity of the mixed metal complexes.     

Preparation and characterization of high salts polymer electrolyte based on poly（lithium acrylate）

1　INTRODUCTIONWorldwide research and efforts are currentlyunderway to fabricate all solid state, rechargeableLi and Li ion batteries utilizing Li+ conductivepolymer electrolytes[1]. Solid polymer electrolytespossesses many advantages including high ionicconductivity, high specific surface energy, solventfree, wide electrochemical stability windows, lightand easy processability[2]. Apart from polyethy lene oxide ( PEO )[3], poly ( vinyl alcohol )(PAV)[4], …     

Synthesis,characterization and electrical conductivity of polyesters,polyamides and doped polymers

The synthesis and characterization of polyamides and polyesters containing azomethyne linkages are reported here. The electrical conductivity of the polymers is measured and the results explained with simple Pariser-Parr-Pople calculations. The polymers are doped with Ag and the electrical conductivity of each polymer is found to register a significant increase. Attempts are made to explain this increase.     

Synthesis and characterization of completely soluble and highly thermally stable PANI-DBSA salts

This paper presents synthesis and characterization of soluble polyaniline-dodecylbenzenesulfonic acid (PANI-DBSA) via inverse polymerization. A mixture of chloroform and 2-butanol was used as dispersion medium for the first time. This polymerization pathway leads to the formation of PANI-DBSA salts which are completely soluble in a number of common organic solvents (such as DMSO, DMF, chloroform and in a mixture of toluene) and 2-propanol (so far highest number of solvents for solubility of PANI). The influence of synthesis parameters such as concentration of aniline, benzoyl peroxide and dodecylbenzenesulfonic acid (DBSA) on the yield and other properties of the resulting PANI-DBSA salts was studied. Further characterization of the synthesized materials was done with the help of viscosity measurements, UV–Vis spectroscopy, cyclic voltammetry, XRD and SEM. TGA was used to analyze the thermal properties of synthesized polymer. The synthesized salts were found to be highly stable.     

Synthesis, characterization, and thermostability of bis（2,2,6,6-tetramethyl-3,5-heptanedionato）barium（II）

The metal-organic chemical vapor deposition (MOCVD) technique is a promising process for high-temperature superconductor YBa2 Cu3O7-δ(YBCO) preparation. In this technique, it is a challenge to obtain barium precursors with high volatility. In addition, the purity, evaporation characteristics, and thermostability of adopted precursors in whole process will decide the quality and reproducible results of YBCO film. In the present report, bis(2,2,6,6-tetramethyl-3,5-heptanedionato)barium(Ⅱ) (Ba(TMHD)2) was synthesized, and its structure was identified by FTIR, 1 H NMR, 13C NMR, and ESI-MS spectroscopy. Subsequently, the thermal properties and the kinetics of decomposition were systematically investigated by nonisothermal thermogravimetric analysis methods. Based on the average apparent activation energy evaluated by the Ozawa, Kissinger, and Friedman methods, the volatilization process was discussed, and all results show that Ba(TMHD)2 is unstable and highly sensitive to the change of temperature during the whole evaporation process. Therefore, it is very important to choose suitable volatilization technology and conditions for avoiding Ba(TMHD)2 break-down (or thermal aging) during MOCVD process. Subsequently, the possible conversion function is estimated through the Coats-Redfern method to characterize the evaporation patterns and follows a phase boundary reaction mechanism by the contracting surface equation with average activation energy of 118.7 kJ .mol-1.     

Synthesis and characterization of graft copolymers of melamine: Thermal stability, electrical conductivity, and optical properties

In this study, novel three Schiff bases of melamine were synthesized via condensation reaction of melamine with salicylaldehyde, 3-hydroxybenzaldehyde, and 4-hydroxybenzaldehyde namely N,N′,N′′,-tris[(2-hydroxyphenyl)methylene]-1,3,5-triazine-2,4,6-triamine (2-HPMTT), N,N′,N′′-tris[(3-hydroxyphenyl)methylene]-1,3,5-triazine-2,4,6-triamine (3-HPMTT), N,N′,N′′-tris[(4-hydroxyphenyl)methylene]-1,3,5-triazine-2,4,6-triamine (4-HPMTT), respectively. Then, oligo/polyphenol derivatives of these Schiff bases were obtained by grafting melamine onto oligosalicylaldehyde (OSA), oligo-3-hydroxybenzaldehyde, and oligo-4-hydroxybenzaldehyde that have generate names of poly-N,N′,N′′-tris[(2-hydroxyphenyl)methylene]-1,3,5-triazine-2,4,6-triamine (P-2-HPMTT), poly-N, N′,N′′-tris[(3-hydroxyphenyl)methylene]-1,3,5-triazine-2,4,6-triamine (P-3-HPMTT), and oligo-N,N′,N′′-tris[(4-hydroxyphenyl)methylene]-1,3,5-triazine-2,4,6-triamine (O-4-HPMTT), respectively. The structures of the synthesized compounds were confirmed by FT-IR, UV–vis, ¹H NMR, and ¹³C NMR techniques. The characterization was made by TG-DTA, DSC, size exclusion chromatography (SEC), and solubility tests. Electrical conductivities of the synthesized materials were measured by four-point probe technique using a Keithley 2400 electrometer showing that the synthesized oligo/polyphenols have higher electrical conductivities than the monomeric Schiff bases. Also considerable increases in the conductivities were observed when they were doped with iodine as a doping agent. The order of increase rates of the conductivities were found as follows: 2-HPMTT > P-2-HPMTT > P-3-HPMTT > 3-HPMTT > 4-HPMTT > P-4-HPMTT. Additionally, the optical band gaps (E_g) were calculated by using the absorption spectra and found to be 2.78, 2.17, 3.58, 3.30, 4.03, and 2.82 eV for 2-HPMTT, P-2-HPMTT, 3-HPMTT, P-3-HPMTT, 4-HPMTT, and O-4-HPMTT, respectively.     

Synthesis,characterization,and thermostability of bis(2,2,6,6-tetramethyl-3,5-heptanedionato)copper(Ⅱ)

Owing to the adaptability to large scale processing,excellent composition control and film uniformity,the metal-organic chemical vapor deposition(MOCVD)technique is a promising process for high-temperature superconductor YBa2Cu3O7-δ(YBCO)preparation.In this technique,the evaporation characteristics and thermostability of adopted precursors in whole process will decide the quality and reproducible results of YBCO film.In the present report,bis(2,2,6,6-tetramethyl-3,5-heptanedionato)copper(Ⅱ)(Cu(TMHD)2)was synthesized by the interaction of copper acetate hydrate with TMHD in methanol solution,and its structure was identified by FTIR,1H NMR,and EI-MS spectroscopy.Subsequently,thermal property and the kinetics of decomposition were systematically investigated by nonisothermal thermogravimetric analysis methods(TGA)at different heating rates in streams of N2,and the average apparent activation energy of evaporation process was evaluated by the Ozawa,Kissinger,and Friedman methods.The possible conversion function was estimated through the Coats-Redfern method to characterize the evaporation patterns and followed a phase boundary reaction mechanism by the contracting area equation with average activation energy of 85.1 kJ·mol-1.     

Synthesis,characterization, thermal stability,conductivity and band gap of oligo-4-[(2-hydroxybenzylidene)amino]benzoic acid

In this study, the oxidative polycondensation reaction conditions of 4-[(2-hydroxybenzylidene)amino]benzoic acid (4-HBAB) by using oxidants such as air O₂, H₂O₂ and NaOCl were studied in an aqueous alkaline medium between 40 and 90 °C. The structures of the synthesized monomer and oligomer were confirmed by FT-IR, UV–vis, NMR and elemental analysis. The characterization was made by TG-DTA, size exclusion chromatography (SEC) and solubility tests. At the optimum reaction conditions, the yield of oligo-4-[(2-hydroxybenzylidene)amino]benzoic acid (O-4-HBAB) was found to be 68% (for air O₂ oxidant), 70% (for air H₂O₂ oxidant) 53% (for NaOCl oxidant). According to the SEC analysis, the number-average molecular weight (M_n), weight-average molecular weight (M_w) and polydispersity index (PDI) values of O-4-HBAB were found to be 932, 1469 g mol⁻¹ and 1.576, using H₂O₂, and 1895, 2560 g mol⁻¹ and 1.354, using air O₂ and 2320, 3015 g mol⁻¹ and 1.300, using NaOCl, respectively. According to TG analysis, the weight losses of 4-HBAB and O-4-HBAB were found to be 96.86% and 73.10% at 1000 °C, respectively. O-4-HBAB was shown higher stability against thermal decomposition. Also, electrical conductivity of the O-4-HBAB was measured, showing that the polymer is a typical semiconductor. Electrochemical HOMO, LUMO and energy gaps (E_g) of 4-HBAB and O-4-HBAB were found to be −6.28, −6.36; −2.39, −2.64; 3.89 and 3.72 eV, respectively. According to UV–vis measurements, optical band gap (E_g) of 4-HBAB and O-4-HBAB were found to be 3.23 and 3.09 eV, respectively.     

Synthesis,characterization, mesomorphic and electrical properties of tetrakis(alkylthio)-substituted lutetium(III) bisphthalocyanines

The synthesis of new lutetium(III) bisphthalocyanines substituted with alkylthio groups (1–5) is described. These compounds (Pc₂Lu) are soluble in most common organic solvents and have been fully characterized (elemental analysis, FT-IR, UV–Vis spectroscopy, mass spectrometry). The thermal stabilities of the Pc compounds were determined by thermogravimetric analysis (TGA). The mesogenic properties of these new materials forming columnar-hexagonal (Col_h) mesophases were studied by differential scanning calorimetry (DSC), optical microscopy and X-ray diffraction. The compounds 2–5 exhibit a double clearing point. DC electrical properties of these compounds in different phases were determined by measuring I–V characteristics and dark current of their thin films on interdigital electrodes. The measurements were carried out in ambient air, in vacuum and in high purity nitrogen (N₂) flow in the temperature range between 300 and 420 K. Dark current measurements obtained in the crystal, liquid crystal (LC) and isotropic liquid phases were in agreement with the phase transitions of these compounds obtained by DSC and optical microscopy results. The relation between the phase transition and conductivity of the Pc₂Lu derivatives were investigated. Also, the influence of the nature of the substituted group (alkylthia and alkoxy) upon the DC electrical properties of the Pc₂Lu derivatives was investigated. The DC conductivities and the thermal activation energies depending on alkyl chain lengths of these compounds were found to be in the range of 10^?8 to 10^?5 S/cm and 0.12–0.38 eV in solid phase.     

Investigations in the field of synthetic metals. VI. Synthesis and properties of dibenzotetrathiafulvalene halides

Direct oxidation of dibenzotetrathiafulvalene (DBTTF) by halogens in acetonitrile and nitrobenzene yielded DBTTF₂I₃, DBTTF·I₃, DBTTF·Cl_x (x = 0.7 ? 1), DBTTF·Br_x (x = 0.8 ? 1), and DBTTF·Br_1.2 complexes. Ir-, u.v.-, and e.p.r.-spectra of these compounds have been studied. X-ray data for the complex DBTTF·I₃ are discussed. Conductivities of the above mentioned complexes lie in the range 10^?2 – 10^?4 ohm^?1 cm^?1.     

Synthesis,characterization and electrical conductivity of a novel conjugated Schiff base macrocycle containing 1,3,4-oxadiazole ring

A new conjugated Schiff base macrocycle containing 1,3,4-oxadiazole ring was prepared by elimination of a tosyl group from a sulfonamide under basic conditions. This synthetic method will provide access to a wide variety of novel conjugated Schiff base macrocycles. The reaction mechanism was examined. The macrocycle has a highly conjugated ring structure and high thermal stability and was doped with iodine to form a stable conducting complex with a conductivity of 10⁻² S/cm. It can be used as semiconductive material.     

Synthesis,characterization, and NLO properties of novel chromophores based on dipicolinate

Three novel chromophores, trans-dimethyl 4-(4′-methoxystyryl)pyridine-2,6-dicarboxylate (5), trans-dimethyl 4-(4′-nitrostyryl)pyridine-2,6-dicarboxylate (6), trans-dimethyl 4-(2-(1H-benzo[d]imidazol-2-yl)vinyl)pyridine-2,6-dicarboxylate (7) were synthesized and characterized. Their absorption, photoluminescence as well as two-photon absorption properties were studied. These compounds have strong linear absorption bands around 322–340 nm. From femtoscond nonlinear transmission measurements, compounds 5 and 7 have effective two-photon cross sections (σ) at 800 nm.     

Synthesis and characterization of polyaniline–Fe3O4 nanocomposite: Electrical conductivity,magnetic, electrochemical studies

Fe₃O₄ nanoparticles were prepared by hydrolysis reaction of urea in ethylene glycol as solvent at 160 °C. The prepared Fe₃O₄ nanoparticles were incorporated into polyaniline (PANI) matrix during in situ chemical oxidative polymerization of aniline with different molar ratios of aniline:Fe₃O₄ (19:1, 16:1, 12:1, 9:1) using (NH₄)₂S₂O₈ as oxidant in aqueous solution of sodium dodecylbenzene sulphonic acid under N₂ atmosphere. Room temperature conductivities of the synthesized PANI, PANI/Fe₃O₄ (19:1) and PANI/Fe₃O₄ (9:1) are 3.2 × 10^?4, 1.8 × 10^?5 and 1.0 × 10^?5 S/cm, respectively, indicating decrease of conductivity with increase of Fe₃O₄ in PANI. Saturation magnetizations of Fe₃O₄, PANI/Fe₃O₄ (19:1), and PANI/Fe₃O₄ (9:1) are 27.5, 5.5 and 6.3 emu/g, respectively, indicating an increase of ferromagnetic interaction with more incorporation of Fe₃O₄ in PANI matrix, whereas PANI is diamagnetic. Electrochemical studies shows that Zn-PANI/Fe₃O₄ (9:1) battery had delivered maximum discharge capacity (78.6 mAh/g) as compared to Zn-PANI battery (50.1 mAh/g) at constant current of 0.5 mA cm^?2. At constant resistance of 1000 Ω, discharge capacities of Zn-PANI/Fe₃O₄ and Zn-PANI battery are 73.37 and 50.8 mAh/g, respectively.     

Synthesis,characterization and optical properties of novel well-defined di(1-ethynylpyrene)s

Three di(ethynylpyrenes) were synthesized and characterized: (Z)-1,1′-(buta-1,3-diene-1,3-diyl)dipyrene (DEPS), (E)-1,1′-(buta-1,3-diene-1,3-diyl)dipyrene (DEPA) and 1,1′-(but-3-ene-1,3-diyl)dipyrene (DEPH). The optical properties of these oligomers were studied by absorption and fluorescence spectroscopies and the results were compared to those previously obtained for the related polymer trans-poly(1-ethynylpyrene) (trans-PEP). Intramolecular interactions occur between adjacent pendant pyrene units (associated pyrenes) in DEPS and DEPH, giving rise to static excimer emissions resulting from the stacking of aromatic rings. Excitation spectra jointly with life time fluorescence decays proved that such interactions take place in the ground state.     

羧酸铑(II)轴向配合物的合成、表征及催化性能

以羧酸铑(II)为母体,吡啶-2-基(吡啶-4-基)甲酮(24ma)为轴向配体,合成了4种新型羧酸铑(Ⅱ)轴向配合物,且成功培养出化合物单晶。使用1H NMR、13C NMR、MS、IR和X-单晶射线衍射对其结构进行表征,讨论了取代基和轴向配体对分子结构的影响,并初步测试了它们对美罗培南类化合物合成反应的催化性能。结果表明,与母体分子羧酸铑(II)相比,所选定的羧酸铑(Ⅱ)轴向配合物因在反应体系中溶解度较差、配体不易解离等原因,导致催化合成美罗培南类化合物的产率不高。     

Li_(1 2x)Zn_(1-x_PO_4的合成及其锂离子的导电性

以Li2 CO3,ZnO和NH4 H2 PO4 为原料 ,采用传统固相合成法和柠檬酸盐溶胶凝胶法制备了组成为Li1 2xZn1-xPO4 (x =0～ 0 .5 )的固体粉末和烧结体。对合成材料作了DTA ,TG ,XRD和SEM等分析 ,并用交流阻抗技术测定了样品的导电性。实验结果表明 ,与传统的固相合成方法相比 ,溶胶凝胶法可以使样品合成温度降低约 40 0℃ ,并且具有较高的导电率。     

Synthesis and characterization of new electroluminescent poly(p-phenylene) derivative

A new electroluminescent poly(p-phenylene) (PPP)-type polymer (CHALC-PPP) incorporating chalcone-type groups as side-chains has been synthesized via a chemical modification of a precursor acyl-functionalized polymer. The chemical structure of the polymer was characterized by ¹H NMR, ¹³C NMR, and FT-IR spectroscopic analysis. CHALC-PPP contains a substitution ratio of 40% of vinylaryl groups. It is fully soluble in common organic solvents and has a number–average molecular weight of 3750 g/mol. CHALC-PPP thin solid film absorbs in UV and emits in the green region with a maximum at 512 nm. From the cyclic voltammetry analysis, the HOMO and LUMO energies levels values are ?5.67 and ?2.70 eV, respectively. A multilayer diode device with the configuration ITO/PEDOT:PSS/CHALC-PPP/BCP/Al emitting a green light has been fabricated.     

Synthesis and characterization of a partial-conjugated hyperbranched poly(p-phenylene vinylene) (HPPV)

A novel partial-conjugated HPPV has been designed and easily synthesized from A₂ + B₃ monomers, employing distrylbenzene, an oligomer of poly(p-phenylene vinylene) with high fluorescence quantum yield, as one of starting materials. HPPV was characterized by FT-IR, H-NMR, GPC and elemental analysis. Its properties, such as thermal, electrochemical and photoluminescent, etc., have been investigated systematically. HPPV exhibits good solubility and processability, a high glass transition temperature (T_g) and high fluorescence quantum yield in chloroform solution (much higher than fully conjugated hyperbranched and linear PPV).     

铱配合物(Ir(ppy)2(SFO))的合成及结构表征

在乙二醇单乙醚介质中,将二聚体Ir2(μ-Cl2)(ppy)4和辅助配体2-噻吩甲酰三氟丙酮(SFO)在碱性条件下,加热回流反应,一步生成了铱配合物Ir(ppy)2(SFO),产率85.2%。采用核磁共振(¹H-NMR、¹³C-NMR)和质谱等分析表明产物为目标配合物。