Synthesis and electroluminescence properties of zinc(2,2′ bipyridine)8-hydroxyquinoline

New electroluminescent material, namely zinc(2,2′ bipyridine)8-hydroxyquinoline [Zn(Bpy)q] has been synthesized and characterized. A solution of Zn(Bpy)q showed absorption maxima at 382 nm and 342 nm in toluene solution attributed to π − π transition. The photoluminescence spectrum in toluene solution showed peak at 545 nm. The material was stable up to 350 °C. Organic light emitting diode (OLED) fabricated with the structure ITO/α-NPD/Zn(Bpy)q/Alq₃/LiF/Al exhibits a broad electroluminescence peak at 548 nm. The maximum current efficiency of OLED was 1.34 cd/A at 5 V and the maximum power efficiency 0.84 lm/W at 5 V.     

Synthesis and blue electroluminescent properties of zinc (II) [2-(2-hydroxyphenyl)benzoxazole]

This study reports on the properties of organic light-emitting diodes (OLEDs) with zinc (II) [2-(2-hydroxyphenyl)benzoxazole] as a hole-blocking layer. OLEDs devices are prepared in a conventional OLEDs structure (i.e., anode/HTL/EL/HBL/cathode and anode/HTL/HBL/EL/cathode). The luminescence efficiencies and the turn-on voltage are significantly affected by the existence of the hole-blocking layer. This is attributed to an excellent hole-blocking property, which is in turn due to the high HOMO energy level (6.5 eV). The device showed luminous efficiency 2.46 lm/W at 5 V. The maximum luminance of about 10,000 cd/m² is obtained, and the turn-on voltage (2.5 V) is affected by the existence of the hole-blocking layer.     

2-(2-羟基苯基)苯并咪唑锌的合成及其光谱性能研究

合成了一种纯蓝的发光材料2-(2-羟基苯基)苯并咪唑锌(Zn(pbm)2),用元素分析、核磁共振、红外光谱、紫外-可见光吸收光谱、循环伏安曲线、原子力显微镜以及光致发光光谱、热重等表征了材料的结构、光学带隙、能带结构、成膜性能、发光性能以及热稳定性.实验结果表明,配合物具有较好的热稳定性;在DMSO溶液中Zn(pbm)2的紫外吸收峰波长为299、334、357nm;光学带隙为3.03eV.利用真空热蒸镀法可以得到均匀致密的Zn(pbm)2薄膜,其粗糙度为7.05nm.在365nm紫外光的激发下,产生发光峰在445nm附近,半高宽(FWHM)为81nm的纯蓝光发射.     

8-羟基喹啉锌/碳微球复合材料的合成表征及发光性能

利用流变相反应法制备了碳微球(CMSs)负载8-羟基喹啉锌(Znq2)的复合材料.通过场发射扫描电子显微镜、X射线衍射仪、热重分析仪、X射线光电子能谱仪、傅里叶红外光谱仪和荧光分光光度计等对Znq2/CMSs复合材料结构和发光性能进行了表征和分析.结果表明:Znq2以非共价键形式负载于直径均匀的CMSs(300～400...     

新型含氟8-羟基喹啉锌配合物的合成及光学性能研究

设计合成了3种新型含单氟8-羟基喹啉衍生物配体:(E)-2-[2-(2-氟代苯基)乙烯基]-8-羟基喹啉(4a)、(E)-2-[2-(3-氟代苯基)乙烯基]-8-羟基喹啉(4b)、(E)-2-[2-(4-氟代苯基)乙烯基]-8-羟基喹啉(4c)及其相应的锌配合物(5a)、(5b)、(5c),利用1 H-NMR、IR、MS、元素分析确认了其结构。测定了它们在DMF溶液中的荧光性质;荧光光谱显示化合物4a、4b、4c在DMF溶液中的λmax分别是505nm、487nm、513nm;5a、5b、5c的λmax分别是559nm、598nm、588nm,荧光光谱显示氟基位置的改变可以调控8-羟基喹啉锌配合物的发光性质。     

Two polymeric metal complexes based on polycarbazole containing complexes of 8-hydroxyquinoline with Zn(II) and Ni(II) in the backbone: Synthesis,characterization and photovoltaic applications

Two novel polymeric metal complexes PZn(Q)₂–C and PNi(Q)₂–C based on polycarbazole containing complexes of 8-hydroxyquinoline with Zn(II) and Ni(II) were synthesized and applied in dye-sensitized solar cells (DSSCs) as photosensitizers. They possess moderate thermal stability and good open-circuit voltages, and the power conversion efficiency of them reached to 1.11% and 0.45%, respectively, under simulated AM 1.5 G solar irradiation (100 mW cm⁻²), which shows a new strategy to design photosensitizers for DSSCs.     

Synthesis and electrophosphorescent properties of iridium complexes based on 2-fluorenylquinoline derivatives

A series of cyclometalated iridium complexes with 2-fluorenylquinoline derivative ligands were synthesized and their photophysical and electroluminescent properties examined using multilayered, organic light-emitting diodes fabricated with the complexes as dopant materials. In the device containing the complex 3 dopant, the maximum luminance was 20,200 cd/m² at 14 V, the luminous and power efficiencies were 14.1 cd/A and 11.0 lm/W, respectively, and the CIE coordinates were (0.65, 0.35) which were close to saturated red emission.     

Fabrication and electrogenerated chemiluminescence properties of uniform octahedral 8-hydroxyquinoline zinc (Znq2)

Well-defined octahedral Znq₂ has been synthesized via a facile solvothermal route. Field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) images show that the as-prepared product has an octahedral structure with an edge length of 2 μm. The reaction parameters, such as solvent, reaction time and temperature, play an important part in the morphology of the final product. A possible formation mechanism for octahedral Znq₂ is proposed. The as-prepared octahedral Znq₂ exhibits excellent electrogenerated chemiluminescence (ECL) behaviour.     

Synthesis and optoelectronic properties of oxadiazole-functionalized iridium complexes in the poly(vinylcarbazole)-hosted devices

A class of oxadiazole-functionalized iridium complexes was used as phosphor emitters in poly (vinylcarbazole)-hosted devices. Efficient green electrophosphorescences were achieved in the devices with a maximum luminance efficiency of 9.3 cd/A at 10.6 mA/cm² and brightness of 3882 cd/m² at 92.1 mA/cm². More importantly, the iridium complexes-doped devices exhibited a low turn-on voltage of 7.0 V and an applied voltage of 9.2 V at 500 cd/m². The good optoelectronic properties of the complexes were attributed to the enhanced electron-injection and transport properties resulting from the effect of oxadiazole ligands in the complexes.     

2-[(8-羟基喹啉)-2-基]-5-(2-噻吩基)[60]富勒烯吡咯烷的合成、光学及电化学性能

通过1,3-偶极环加成反应合成出2-[(8-羟基喹啉)-2-基]-5-(2-噻吩基)[60]富勒烯吡咯烷,利用UV-Vis、FT-IR、RAMAN、MALDI-TOF MS、1 HNMR、13C NMR等手段对产物的结构进行了表征,并研究了产物的光学及电化学性能。结果表明,相对于C60来说,该产物的紫外吸收波长及荧光发射波长均发生红移,各对氧化还原峰的半峰电位发生明显的负移,更有利于应用于光电转化领域。     

Synthesis and electroluminescent property of tris{2-(naphtha [3,4]imidazol-2-yl) pyridinato} Aluminum

An emission material, tris{2-(naphtha [3,4]imidazol-2-yl) pyridinato} Aluminum (AlNIP) used for organic light emitting devices, has been synthesized. The decomposition temperature was observed at 510 °C and no melting transition (T_m) of AlNIP was observed up to 400 °C. The emission spectrum of organic emitting device using AlNIP as emitted layer exhibits a broad maximum at 536 nm. The color of the emitted light is in the orange region in the CIE coordinate of x = 0.41 y = 0.53.     

Studies on copper(II)- and zinc(II)-mixed ligand complexes of humic acid

Interactions between humic acid (HA), extracted from Brazilian peat soil, and cations of copper(II) and zinc(II) have been examined by infrared spectroscopy, and electrochemical and thermogravimetric analyses. Spectral studies revealed that the interaction with metals occurred mainly at the carboxylic acid groups of HA. The stability constants of HA complexes formed with Cu(2+) and Zn(2+) were found, by square wave voltammetry and application of the Lingane model, to be 8.93 x 10(10) and 2.92 x 10(2), respectively. Thermal analysis indicated that the stability of HA was increased by the presence of divalent cations of copper and zinc.     

Growth and characterization of tris(8-hydroxyquinoline)-aluminum molecular films

Various tris(8-hydroxyquinoline)-aluminum (Alq3) molecular solid films were grown on top of indium-tin-oxide (ITO) glass substrates using physical vapor deposition. The effect of changing the growth conditions on the properties of the films was studied. From scanning electron microscopy, an Alq3 planar layer over an ITO-substrate was observed at the initial period, and an Alq3 tubular structure (which becomes dominant at substrate temperature T_sub ≧ 90 °C) was found to nucleate from this layer. From X-ray diffraction, the Alq3 planar layer possesses an amorphous character while the Alq3 tubular layer has a triclinic α-phase structure. Based on an Arrhenius plot of the growth rate versus 1/T_sub, the growth behaviors in various T_sub-regions were discussed to be dominated by adhesion (for T_sub < 90 °C), steric effect (90 °C < T_sub < 150 °C), and re-evaporation (T_sub > 150 °C). Then, from optical transmission and photoluminescence spectra performed on the high crystalline Alq3 films, two signals associated with the optical-bandgap E_g absorption and the gap-state absorption were determined and discussed in terms of the optical properties of the constituent Alq3 molecules. Finally, from a fit of E_g(T) by an effective electron-phonon interaction model, the physical significance of these fitting parameters for the Alq3 molecular solid was investigated.     

Seaweeds for the remediation of wastewaters contaminated with zinc(II) ions

Eleven different species of marine macroalgae were screened at different pH conditions on the basis of zinc(II) biosorption potential. Among the seaweeds, a green alga, Ulva reticulata, exhibited a highest uptake of 36.1 mg/g at pH 5.5 and 100 mg/l initial zinc(II) concentration. Further experiments were conducted to evaluate the zinc(II) biosorption potential of U. reticulata. Sorption isotherm data obtained at different pH (5-6) and temperature (25-35 degrees C) conditions were fitted well with Sips model followed by Freundlich, Redlich-Peterson and Langmuir models. A maximum zinc(II) biosorption capacity of 135.5 mg/g was observed at optimum conditions of 5.5 (pH) and 30 degrees C (temperature), according to the Langmuir model. It was observed from the kinetic data that the zinc(II) biosorption process using U. reticulata follows pseudo-second-order kinetics. Various thermodynamic parameters, such as DeltaG degrees , DeltaH degrees and DeltaS degrees were calculated and they indicated that the present system was a spontaneous and an endothermic process. The influence of the co-ions (Na(+), K(+), Ca(2+) and Mg(2+)) along with zinc(II) present in the wastewater was also studied. Desorption of zinc(II) ions from the zinc(II)-loaded biomass were examined using 0.1 M CaCl(2) at different pH conditions in three sorption-desorption cycles. A fixed-bed column (2 cm i.d. and 35 cm height) was employed to evaluate the continuous biosorption performance of U. reticulata. The column experiments at different bed heights and flow rates revealed that the maximum zinc(II) uptake was obtained at the highest bed height (25 cm) and the lowest flow rate (5 ml/min). Column data were fitted well with Thomas, Yoon-Nelson and modified dose-response models. The column regeneration studies were carried out for three sorption-desorption cycles. A loss of sorption performance was observed during regeneration cycles indicated by a shortened breakthrough time and a decreased zinc(II) uptake.     

Synthesis and spectral properties of new tetrakis-2,3-{5,7-bis[(E)-2-(4-methylphenyl)vinyl]pyrazino}porphyrazine metal complexes

The new styryl substituted pyrazinoporphyrazine complex has been synthesised for the first time. The spectral properties of the ytterbium complex have been studied. The introduction of the styryl fragments in the cycle leads to bathochromatic shift of the Q-band. It can be explained by the stabilisation of LUMO.     

Synthesis and electroluminescent property of bis (2-(benzimidazol-2-yl) quinolinato) zinc

An emission material, (2-(benzimidazol-2-yl) quinolinato) zinc (ZnBIQ) used for organic light emitting devices, has been synthesized. The melting transition (T_m) of ZnBIQ is 436 °C and no glass transition temperature (T_g) was observed up to 430 °C. The emission spectrum of organic emitting device using ZnBIQ as emitted layer exhibits a broad maximum at 625 nm. The color of the emitted light is in the red region in the CIE coordinate of x=0.54, y=0.39.     

Use of 8-hydroxyquinoline-chitosan chelating resin in an automated on-line preconcentration system for determination of zinc(II) by F AAS

This study presents the development of an on-line preconcentration system for zinc(II) determination in aqueous samples. The analyte was trapped in a mini-column filled with a chelating resin based on a chitosan biopolymer modified with 8-hydroxyquinoline obtained by the diazotization reaction. Flow and chemical variables of the system, as well as the potential interference ions, were optimized through a multivariate procedure. The factors selected were sample pH, eluent concentration (HNO(3)), and sample and eluent flow rates. It was verified through a full factorial design that the sample pH and eluent flow rate factors were statistically significant at the 95% confidence level. A final optimization of the significant factors was carried out using a Doehlert matrix. The preconcentration system was linear between 2.5 and 75 microgL(-1), with a regression coefficient of 0.9995. The enrichment factor was 17.6. The limits of detection and quantification were 0.8 and 2.5 microgL(-1), respectively. The repeatability and the analytical frequency were, respectively, 2.7 (25.0 microgL(-1), n=8) and 18 samples per hour. Results for recovery tests using mineral water samples were between 85 and 93%. Certified reference materials were analyzed in order to check the accuracy of the proposed method.     

Synthesis and characterization of platinum(II) complexes with 2,2'-bipyridine derivative supporting ligands

The reaction of the [Pt(bpy-R)Cl2](bpy-R: R=H (2,2'-bipyridine); R=CH3 (4,4'-dimethyl-2,2'-biypridine (DM-bpy), 3,3'-5,5'-tertamethyl-2,2'-bipyridiyl (TM-bpy)) with 1,4-Bis(5'-2',2"-bipyridine)benzene (bpy-Ph-bpy) affords the following mono- and di-platinum complexes of [(bpy)Pt(bpy-Ph-bpy)][PF6]2 (1), [(bpy)Pt(bpy-Ph-bpy)Pt(bpy)])[PF6]4 (2), [(DM-bpy)Pt(bpy-Ph-bpy)])][PF6]2 (3), and [(TM-bpy)Pt(bpy-ph-bpy)[PF6]2 (4), respectively. These complexes were characterized by NMR, IR, UV/VIS, PL and cyclic voltammetry. The internal quantum yields of these platinum(II) complexes are very high (0.83-0.99) and these complexes emit light at deep blue regions (373-417 nm). The redox behavior of complexes 1 and 2 shows quasi-reversible process.     

Competitive adsorption of copper(II), cadmium(II), lead(II) and zinc(II) onto basic oxygen furnace slag

Polluted and contaminated water can often contain more than one heavy metal species. It is possible that the behavior of a particular metal species in a solution system will be affected by the presence of other metals. In this study, we have investigated the adsorption of Cd(II), Cu(II), Pb(II), and Zn(II) onto basic oxygen furnace slag (BOF slag) in single- and multi-element solution systems as a function of pH and concentration, in a background solution of 0.01M NaNO(3). In adsorption edge experiments, the pH was varied from 2.0 to 13.0 with total metal concentration 0.84mM in the single element system and 0.21mM each of Cd(II), Cu(II), Pb(II), and Zn(II) in the multi-element system. The value of pH(50) (the pH at which 50% adsorption occurs) was found to follow the sequence Zn>Cu>Pb>Cd in single-element systems, but Pb>Cu>Zn>Cd in the multi-element system. Adsorption isotherms at pH 6.0 in the multi-element systems showed that there is competition among various metals for adsorption sites on BOF slag. The adsorption and potentiometric titrations data for various slag-metal systems were modeled using an extended constant-capacitance surface complexation model that assumed an ion-exchange process below pH 6.5 and the formation of inner-sphere surface complexes at higher pH. Inner-sphere complexation was more dominant for the Cu(II), Pb(II) and Zn(II) systems.     

Efficacy of modified distillation sludge of rose (Rosa centifolia) petals for lead(II) and zinc(II) removal from aqueous solutions

Removal of lead(II) and zinc(II) from aqueous solutions was studied using chemically modified distillation sludge of rose (Rosa centifolia) petals by pretreatment with NaOH, Ca(OH)(2), Al(OH)(3), C(6)H(6), C(6)H(5)CHO and HgCl(2). The adsorption capacity of biomass was found to be significantly improved. NaOH pretreated biomass showed remarkable increase in sorption capacity. Maximum adsorption of both metal ions was observed at pH 5. When Freundlich and Langmuir isotherms were tested, the latter had a better fit with the experimental data. The overall adsorption process was best described by pseudo second order kinetics. The thermodynamic assessment of the metal ion-Rosa centifolia biomass system indicated the feasibility and spontaneous nature of the process and DeltaG degrees was evaluated as ranging from -26.9501 to -31.652 KJmol(-1) and -24.1905 to -29.8923KJmol(-1) for lead(II) and zinc(II) sorption, respectively, in the concentration range 10-640mgL(-1). Distribution coefficient (D) showed that the concentration of metal ions at the sorbent-water interface is higher than the concentration in the continuous aqueous phase. Maximum adsorption capacity of biomass tends to be in the order Pb(II) (87.74mgg(-1))>Zn(II) (73.8mgg(-1)) by NaOH pretreated biomass.