Thermochemical Study on Coordination Complex of Samarium with Salicylic Acid and 8-Hydroxyquinoline

The coordination complex Sm（C7H5O2）2·（C9H6NO）, synthesized from the reaction of samarium chloride sixhydrate with salicylic acid and 8-hydroxyquinoline, was characterized with IR, elemental analysis, molar conductance, and thermogravimatric analysis. The standard molar enthalpies of solution of [ SmCl3·6H2O （s） ], [ 2C7H6O3 （s） ], [ C9H7NO （ s ） ] and [ Sm （C7H5O3） 2·（ C9H6NO ） （ s ） ] in the calorimetric solvent were determined with the solution-reaction isoperibol calorimeter at 298.15 K to be △sHm^- [ SmCl3·6H2O （s）, 298.15 K ] = - 103.98 ± 0.04 kJ·mol^-1, △sHm^- [2 C7H6O3 （s）, 298.15 K] = 16.35±0.14 kJ·mol^-1,△sHm^-[C9H7NO （s）, 298.15 K] = -6.11±0.08 kJ·mol^-1 and △sHm^-[Sm（C7H5O3）2·（C9H6NO） （s）, 298.15 K] = - 130.08 ± 0.04 kJ·mol^-1, respectively. The enthalpy was determined to be △rHm^- = 89.59 ±0.18 kJ·mol^-1 for the reaction SmCl3·6H2O（s） ＋ 2C7H6O3（s） ＋ C9H7NO（s） = Sm （C7H5O3） 2·（C9H6NO） （ s ） ＋ 3HCl （g） ＋ 6H2O （ l ）. According to the above results and the data given in literature and through Hess＇ law, the standard molar enthalpy of formation of Sin（ C7H5O3 ）2·（C9H7NO）（s） was estimated to be △rHm^- [ Sm （C7H5O3）2·（C9H6NO） （s）, 298.15 K] = - 2055.9 ± 3.03 kJ·mol^-1.

Crystal Structure and Characterization of a Binuclear Cd(Ⅱ) Quaternary Coordination Complex [Cd_2(phen)_2Q_2(BP)]_n(phen=1,10-Phenanthroline,BP = Biphenyl-4,4'-dicarboxylic acid,Q=8-Hydroxyquinoline Anion)

The structure of a binuclear cadmium（Ⅱ） quaternary complex, [Cd2（phen）2- Q2（BP）]n 1 （phen = 1,10-phenanthroline, BP = biphenyl-4,4′-dicarboxylic acid, Q = 8-hydroxy- quinoline-anion）, has been determined by X-ray crystallography and characterized by elemental analysis, IR spectrum and thermogravimetric analysis. It crystallizes in the monoclinic system, space group P21/n with a = 13.1906（18）, b = 10.9623（15）, c = 16.947（2）A, β = 111.3430（10）°, V = 2282.5（5）A^3, Z = 4, Mr = 556.85, Dc = 1.620 g/cm^3, F（000） = 1116,μ= 0.994 mm^-1 and S = 1.056. In the structure, 1D chains are connected via biphenyl-4,4′-dicarboxylic acid, 8-hydroxy quinoline anion and binuclear cadmium atoms into an infinite 1-D molecular chain architecture. Via aryl ring π-π stacking interactions a supramolecular structure is formed in 1.

Synergistic extraction of praseodymium with 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester and 8-Hydroxyquinoline

The synergistic extraction of Pr^3＋ from hydrochloric medium using mixture of 2-ethylhexyl phosphonic acid mono- 2-ethylhexyl ester （P507, HL） and 8-Hydroxyquinoline （HQ） in heptane was investigated. The effect of equilibrium of aqueous acidity on extraction of Pr^3＋ was discussed. The effect of extractant concentraction, different diluents, equilibrium time and acetate ion concentration oil extraction reaction were also studied. With a method of double-logarithmic slope, composition of the extracted species on 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester and 8-Hydroxyquinoline was derived. The result shows that the synergistic extraction system not only overcomes emulsification of 8-Hydroxyquinoline, but also shows perfect capacity of synergistic extraction. The largest synergistic enhancement factor can be calculated to be 5.49 at pH 3.6 for Pr^3＋.

Bipolar resistive switching based on bis(8-hydroxyquinoline) cadmium complex:Mechanism and non-volatile memory application

Stable and persistent bipolar resistive switching was observed in an organic diode with the structure of indium-tin oxide （ITO）/bis（8-hydroxyquinoline） cadmium （Cdq2）/Al. Aggregate formation and electric field driven trapping and detrapping of charge carriers in the aggregate states that lie in the energy gap of the highest occupied molecular orbital （HOMO） and the lowest unoccupied molecular orbital （LUMO） of the organic molecule were proposed as the mechanism of the observed bipolar resistive switching, and this was solidly supported by the results of AFM investigations. Repeatedly set, read, and reset measurements demonstrated that the device is potentially applicable in non-volatile memories.

Synthesis and Structural Characterization of [Co(Q)_2(H_2O)_2](Q=8-Hydroxyquinoline Ion)

The single crystal of bi（8-hydroxyquinoline） bihydrated cobalt （Ⅱ） complex, [ Co（Q）2 （H2O2 ] （Q = 8-hydroxyquinoline ion）, has been synthesized by general method and structurally characterized by single crystal X-ray diffraction. Crystal data： C18H16CoN2O4, monoclinic, C2/c, α = 1.336 2（4） nm, b = 0.941 2（3） nm, c = 1.354 3（4） nm, β= 109.672（4）°, Z = 4. In the complex, Co（ Ⅱ ） ion is six-coordinated, forming a distorted octahedron. H-bonding and π-π stacking interaction play a significant role to form and stabilize the three-dimensional structure.

A Hydrogen Bond Stabilized 3D Network Built from Pyrazine-2,3,5,6-tetracarboxylic Acid and 8-Hydroxyquinoline

8-Hydroxyquinoline salt of pyrazine-2,3,5,6-tetracarboxylic acid [HQ]2[H2pztc]· 2H2O （1） was prepared and characterized by single-crystal X-ray diffraction, NMR, IR, TGA, elemental analysis and fluorescent measurements. Compound 1 crystallizes in orthorhombic, space group Pbcn with a = 9.953（3）, b = 15.966（3）, c = 16.081（5） A, V = 2555.5（13） A3, Z = 4, μ = 0.122 mm^-1, Dc = 1.514 Mg/m3, T= 296（2） K, C26H22N4O12, Mr = 582.48, F（000） = 1208, S = 1.006, R = 0.0448 and wR = 0.1149. Compound 1 has a three-dimensional （3D） network, in which pyra- zine-2,3,5,6-tetracarboxylic acids build up two-dimensional （2D） sheets and 8-hydroxyquinoline cations and water molecules act as pillars to connect the 2D sheets into an extended 3D network through strong intermolecular hydrogen bonding and π…π stacking interactions. Especially, a very short O-H…O hydrogen bond （O…O 2.470（2） A） between two neighboring [H2pztc] anions was observed.

Thickness Dependent Behavior of Photoluminescence of Tris(8-hydroxyquinoline)Aluminum Film

通过原位测量对八-羟基喹啉铝薄膜(Alq_3)光致发光的厚度依赖性质进行了研究.在 Alq_3向玻璃衬底沉积的初始阶段,Alq_3光致发光谱峰发生了显著红移,此后谱峰随着 Alq_3厚度的增加红移变缓并趋于饱和.Alq_3薄膜厚度从2nm 逐渐变化到500nm 时,Alq_3谱峰位总红移约为12nm.这种 Alq_3薄膜沉积的初始阶段 Alq_3谱峰的显著红移可归因于二维激子向三维激子态的转变.同时,由于激子同衬底的相互作用所引起的非辐射衰变,在 Alq_3沉积的初始阶段 Alq_3光致发光谱峰的强度呈现不同的变化,随后该谱峰的强度随 Alq_3薄膜厚度的增加而快速增加,并在薄膜厚度较大时,趋向于饱和.

Corrosion Inhibition Synergism between Lanthanum(Ⅲ) Ion and 8-Hydroxyquinoline for Zinc in Hydrochloric Acid

The effects of La 3+ ion and chelate reagent 8 hydroxyquinoline on the corrosion rate of zinc in hydrochloric acid were investigated by using weight loss method and electrochemical method. It is found that in a specific concentration range of La 3+ ion and 8 hydroxyquinoline, the obvious corrosion inhibition synergism is obtained. The mechanism of corrosion inhibition synergism was discussed on basis of adsorption theory.

TD-DFT Study on the Electronic Spectrum Properties of 2,7′-(Ethylene)-bis-8-hydroxyquinoline and Its Derivatives

The structures of 2,7＇-（ethylene）-bis-8-hydroxyquinoline and its derivatives were optimized at the ground states using ab initio HF and B3LYP methods. At the same time, the molecular structures of the first singlet excited state for 2,7＇-（ethylene）-bis-8-hydroxyqulnoline and its derivatives were optimized by CIS/6-31G（d）. The absorption and emission spectra based on the above structures were obtained by the time-dependent density functional theory （TD-DFT） by the B3LYP method with the 6-31G（d） basis set. The calculated results of luminescence originate from the electronic transition from the hydroxphenol ring of 8-hydroxyquinoline A to the pyridine ring of 8-hydroxyquinoline B. Their luminescence wave bands can be tuned by different substituents on the ligand of 8-hydroxyquinoline.

Thermochemical Study on Coordination Complex of Neodymium Trichloroacetic Acid with 8-Hydroxyquinoline

Two coordinate reactions, NdCl 3·6H 2O(s) +3CCl 3COOH(s)( or TCA) =Nd(TCA) 3·3H 2O(s) +3HCl(g) +3H 2O(l) and Nd(TCA) 3·3H 2O(s) +2C 9H 7NO(s)= Nd(TCA)(C 9H 6NO) 2 (s) +2CCl 3COOH(s) +3H 2O(l), were studied by the classical solution calorimetry at 298.15K. The molar dissolution enthalpies of the reactants and the products in certain solvent (the first reaction in 1 mol·L -1 HCl, the second in a mixed solution consisting of absolute ethyl alcohol, dimethyl sulfoxide and 4 mol·L -1 HCl ) were measured by using an isoperibol calorimeter at 298.15K . From the results and other auxiliary quantities, the standard molar formation enthalpies of [Nd(TCA) 3·3H 2O,s,298.15K] and [Nd(TCA) (C 9H 6NO) 2 ,s, 298.15K] are determined as Δ fH m °[Nd(TCA) 3·3H 2O,s,298.15K]= -3053.3 kJ·mol -1 and Δ fH m° [Nd(TCA) (C 9H 6NO) 2 ,s, 298.15K] = -1355.6 kJ·mol -1 .

Spectrofluorimetric Determination of Magnesium (Ⅱ) with 7-(8-Hydroxy-3, 6-Disulfonaphthylazo)-8-Hydroxyquinoline-5-Sulfonic Acid

A new fluorescent reagent, 7 (8 hydroxy 3, 6 disulfonaphthylazo) 8 hydroxyquinoline 5 sulfonic acid (HDNHQ) for the determination of magnesium has been developed. It reacted with magnesium to form a 1∶1 fluorescent complex with λ ex / λ em =356/495 nm immediately at room temperature in ammonia ammonium chloride buffer (pH 10.7). A linear relationship was obtained in the magnesium concentration range of 0 160 ng·mL -1 with the detection limit of 0.04 ng·mL -1 . The proposed method was simple, rapid and sensitive. It has been successfully applied to the determination of trace magnesium in blood serum with recoveries of 103.75% and 98.16%, respectively.

Theoretical Studies on the Ground State and Excited State of 2,7′- （Ethylene）-bis-8-hydroxyquinoline

2,7'-( 乙烯)-bis-8-hydroxyquinoline 与 DFT/B3LYP 和 ab initio HF 方法被优化，因此电离潜力和电子亲密关系能是坚定的。吸收光谱被 ZINDO 和 TD-DFT 计算。CIS 方法被用来计算混合物的 S1 激动的状态，以后，排放光谱被计算。当溶剂效果被考虑时，计算结果与已知的试验性的数据显示出令人鼓舞的同意。分析在精力和吸收系列之间的关系的结果显示搬运电子的能力与 8-hydroxyquinoline 相比被加强并且吸收和排放系列是转移红的。tris 的 intramolecular 重组精力(2,7'-( 乙烯)-bis-8-hydroxyquinoline)-aluminum 暗示它搬运性质的电子比 tris (8-hydroxyquinoline ) 更坏铝。预言的最大的排放波长与 tris (8-hydroxyquinoline ) 相比是转移红的铝。

Metal Complexes with 8-Hydroxyquinoline: Synthesis and <i>In Vitro</i>Antimicrobial Activity

In this paper, three complexes with 8-hydroxyquinoline (8-HQ) were synthesized, their spectral analysis was performed and the antimicrobial effect was examined in vitro. The stoichiometric ratio of the complex was determined conductometrically and spectrophotometrically. FTIR and UV/VIS spectroscopy were used for structural characterization. Antimicrobial activity was examined by diffusion technique on selected gram-positive and gram-negative bacteria, and C. albicans. Square planar and octahedral geometry complexes were synthesized by mixing in a molar ratio of 1:2 (M:L). Based on the spectral data, it is concluded that both oxygen and nitrogen atoms from 8-HQ are involved in the formation of the complex. The antimicrobial activity of the complexes is high, with zones of inhibition in the range of 15 - 28 mm. 8-HQ was shown to have a significantly higher ability to inhibit the growth of the tested microorganisms.

Organic Electroluminescent Thin Film Using 8-hydroxyquinoline Zinc as Emitting Layer

Organic electroluminescent thin film using Znq 2 (Znq 2) as the emitting layer material with structure of glass/ITO/Znq 2/Al (cell)was fabricated. The V I curve, V B curve and electroluminescent spectra of the cell were measured. Meanwhile the fluorescent spectra, excited spectra and absorption spectra of Znq 2 with powder and film states were also measured.

Mitigating phytotoxicity of tetracycline by metal-free 8-hydroxyquinoline functionalized carbon nitride photocatalyst

Photooxidative removal of pharmaceuticals and organic dyes is an effective way to eliminate growing micropollutants. However, photooxidation often results in byproducts as secondary hazardous substances such as phytotoxins. Herein, we found that photooxidation of common antibiotic tetracycline hydrochloride(TCH) over a metal-free 8-hydroxyquinoline(8-HQ) functionalized carbon nitride(CN) photocatalyst significantly reduces the TCH phytotoxic effect. The phytotoxicity test of photocatalytic treated TCH-solution evaluated towards seed growth of Cicer arietinum plant model endowed natural root and shoot growth.This study highlights the conceptual insights in designing of metal-free photocatalyst for environmental remediation.

Evaluating the Efficiency of Cadmium Removal by Alginate Hydrogels from Water Using 5,7-Dibromo-8-hydroxyquinoline as a Complexing Reagent

Cadmium toxicity in wastewater is a rising concern due to industries like batteries,metallurgy,electroplating,plastic stabilizers,and pigments.The quantitative detection of Cd^(2+)and its remediation from wastewater samples are of major concern from an environmental point of view.In the present work,an effective spectrophotometric method has been reported using 5,7-dibromo-8-hydroxyquinoline(DBHQ)as a complexing agent for Cd^(2+).This method has advantages like using recyclable,less toxic solvents and easy sample preparation.The limit of detection,limit of quantification,and sensitivity of the proposed method were found to be 33.30,36.70 mg L^(−1),and 2×10^(−3),respectively.The DBHQ method was validated using atomic absorption spectroscopy,and the recovery percentage was more than 98%.These results indicate that DBHQ can be effectively used for monitoring Cd^(2+)in aqueous systems.The method developed was further employed for monitoring Cd^(2+)adsorption on calcium alginate(AL)hydrogels.Batch adsorption studies were done to optimize parameters of Cd^(2+)removal using AL hydrogels,and the data obtained were used for kinetic and thermodynamic studies.Kinetic studies indicated that the pseudo-first-order model showed better fitting,and thermodynamic studies showed Freundlich-like adsorption.The maximum adsorption capacity of Cd^(2+)on AL hydrogels was found to be 56.45 mg g^(−1).The validation studies of DBHQ were performed using statistical analysis methods like t-tests and one-way variance.

Studies on synergistic solvent extraction of rare earth elements from nitrate medium by mixtures of 8-hydroxyquinoline with Cyanex 301 or Cyanex 302

Synergistic solvent extraction of rare earth elements （REEs） from nitrate medium was investigated with mixtures of 8-hydroxyquinoline （HQ） and acidic organophosphorus extractants, bis（2,4,4-trimethylpentyl） dithiophosphinic acid （Cyanex 301） and bis（2,4,4-trimethylpentyl） monothiophosphinic acid （Cyanex 302）. The extraction behavior of Cyanex 301/Cyanex 302 and their binary mixtures with HQ towards several lanthanoids （La, Nd, Sm, Tb, Ho, Tm） and yttrium （Y） was investigated. The separation ability of REEs was studied according to the various extraction effects. The extraction mechanisms for yttrium were studied with the methods of slope analysis and constant moles in the synergistic systems. The extracted compounds, the equilibrium constants, and thermodynamic functions were also determined.

Determination of Some Trace Metals in Environmental Samples by Flame AAS Following Solid Phase Extraction with Amberlite XAD-2000 Resin after Complexing with 8-Hydroxyquinoline

A procedure for preconcentration of Mn（Ⅱ）, Fe（Ⅱ）, Co（H）, Cu（Ⅱ）, Cd（Ⅱ）, Zn（Ⅱ）, Pb（Ⅱ） and Ni（Ⅱ） based on retention of their complexes with 8-hydroxyquinoline （HQ） on Amberlite XAD-2000 resin in a column was proposed for the analysis of environmental samples by flame AAS. Various parameters such as pH, eluent type, volume, concentration, flow rate and volume of sample solution, and matrix interference effect on the retention of the metal ions were investigated. The optimum pHs for the retention of metal complexes in question were about 6 except for Mn^2＋ for whose value is 8. The loading capacity of the adsorbent for these metals and their recoveries from the resin under the optimum conditions were in the range 6.82-9.26 mg·g^-1 and 95%-101%, respectively. The enrichment factor was calculated as 100 and the limit of detection was in the range 0.3-2.2 μg·L^-1 （n=20, blank＋ 3s）. The proposed enrichment method was applied to tap water, stream water and vegetable samples. The validation of the procedure was carried out by analysis of certified reference material and standard addition. The analytes were determined with a relative standard deviation lower than 6% in all samples.

Electronic property and molecule design for luminescent metal complexes of tris(8-hydroxyquinoline) gallium

By means of ab initio HF and DFT B3LYP methods, the structure of Gaq3 (q = 8-hydroxyquinoline) was optimized. The frontier molecular orbital characteristics and energy levels of Gaq3 have been analyzed systematically in order to study the electronic transition mechanism in Gaq3. Three derivatives of Gaq3 and their polymers were designed and the possibilities that they were employed as luminescent materials were discussed. The regularities and characteristic of energy bands of Gaq3 and its derivatives were also investigated. The results show that the electronic π-π* transitions in Gaq3 are localized on the quinolate ligands. The emission of Gaq3 is due to the electron transitions from a phenoxide donor to a pyridyl acceptor. Two possible electron transfer pathways are presented, one by carbon atoms, and the other via metal cation Ga3+. The derivatives of Gaq3 may possess high luminescence efficiency.