Sensitive Spectrofluorimetric Method for Determination of Fluoroquinolones through Charge-Transfer Complex Formation

A sensitive spectrofluorimetric method was developed for determination of ciprofloxacin (CPFX), levofloxacin (LEV), gatifloxacin (GAT) and moxifloxacin (MOX) in pure, commercial formulations, human urine and plasma. The method is based on charge-transfer (CT) complex with chloranilic acid. Fluorescence intensity of the complexes was measured at emission wavelength ranging from 445-492 nm with excitation wavelengths from 285-330 nm. At optimum experimental conditions, a linear calibration plot was obtained in the concentration range of 20-1000 ng·mL-1, 60-320 ng·mL-1, 20-800 ng·mL-1 and 20 -00 ng·mL-1 for CPFX, LEV, MOX and GAT, respectively with good correlation coefficient in the range of 0.9929-1.0 in methanolic medium. The limit of detection and limit of quantification were found to be 5 ng·mL-1 and 18 ng·mL-1 for CPFX, 12 ng·mL-1 and 40 ng·mL-1 for LEV, 8 ng·mL-1 and 19 ng·mL-1 for MOX, 6 ng·mL-1 and 19 ng·mL-1 for GAT, respectively. The method was found free of interferences from excipients used as additive in pharmaceutical preparations, some common cations and compounds present in urine and plasma as well as co-administered analgesic, vitamins and other drugs. The method was successfully applied for quantification of selected fluoroquinolones in commercial formulations and also in spiked human urine and plasma samples with percent recoveries of 100.0 ± 1.56 and 100.2 ± 1.29 respectively.

Intramolecular Charge Transfer Dual Fluorescence pH Sensing using p-Dibutylaminobenzoic Acid-β-cyclodextrin Inclusion Complex

The intramolecular charge transfer dual fluorescence of p-dibutylaminobenzoic acid-b-cyclodextrin inclusion complex showed a substantially higher sensitivity toward aqueous solution pH variation when compared with that of p-dibutylaminobenzoic acid alone, which established a new principle for direct CT fluorescence sensing in aqueous solution by using the CT fluorophore-cyclodextrin inclusion complex.

Synthesis and Characterization of Charge-transfer Complexes of Aminoethylphosphono-and Dimethylaminoethylphosphono-heteropolytungstic Acids of Keggin Type Structure

Two charge-transfer complexes of 2a and 2b of Keggin type were synthesized and characterized by elemental analysis, IR spectra, UV spectra, XRD, TG-DSC; and were compared with Hquin-PW12. The primary structure of the heteropolyanions had not been changed after the formation of the charge transfer complexes.

Charge transfer complex enabled photoreduction of ether phosphonium salts for the selective oxyalkylation of enamides

A charge transfer complex(CTC)-enabled photoreduction of ether phosphonium salts for the generation of oxyalkyl radicals was described.The photoreduction provides a convenient method to achieve selective oxyalkylation of enamides with broad substrate scope.The method features operational simplicity,mild and inherent green conditions.

Anisotropic electrical conductivity, phase transition and thermal hysteresis of a charge-transfer salt dibutylammonium bis-7,7,8,8-tetracyanoquinodimethane DBA(TCNQ)_2

This paper reports that a charge-transfer salt dibutylammonium bis-7,7,8,8-tetraeyanoquinodimethane [DBA （TCNQ）2] has been prepared. The temperature dependences of the DC electrical conductivity of the DBA （TCNQ）2 single crystal measured along the crystallographic a, b, and c axes are reported. The crystal shows semicondueting behaviour and the room-temperature conductivities are highly anisotropic （σa = 3.63× 10^-4S/cm, σb = 2.84× 10^-6S/cm, and （σe = 1.82 × 10^-5S/cm）. Particularly, a sharp semiconductor to semiconductor transition has been observed around 270 K on the resistivity curves measured under cooling and heating. In addition, thermal hysteresis phenomena on conductivity and differential scanning calorimetry curves are also reported.

Fabrication of Semiconductor Polymer Membranes Combined with a Colored Charge Transfer Complexes Used in the Manufacture of Solar Cells as a Source of Alternative Energy

The main task of this article was to prepared of new pigment model in situ solar cells accordance to charge-transfer complexes of rhodamine C(RhC) donor as dye laser gain media with iodine(σ-acceptor) and chloranilic acid, CLA(π-acceptor). The synthesis stoichiometry of these complexes were of 1∶2(donor∶acceptor) with general formulas [(RhC)]I·I3 and [(RhC)(CLA)2]. The discussed data of elemental analysis, conductivity measurements, FT-IR, UV-Vis spectroscopy and photometric titration data visualized the stoichiometry, formula and complexity of the complexes. The physicochemical and spectroscopic analyses obtained suggested that the electron transfer occurred through nitrogen atom in a tertiary amine —N(C2H5)2 of RhC donor with acceptor. The synthesized solid complexes were under go to thermogravimetric analyses to investigate their thermal stability and decomposition steps. The molar conductance measurements revealed that RhC complexes have an electrolytic statement. The thermal stability of rhodamine C complexes was enhanced in comparable with RhC itself. The polymer membranes of poly-methyl methacrylate)(PMMA) combined with the RhC charge(transfer complexes in chloroform solvent have been prepared and characterized by(infrared & electronic) spectroscopy and scanning electron microscopy(SEM) morphological examination. The photo-stability properties of the RhC complexes have been investigated.

REACTIVITY RATIOS FOR COPOLYMERIZATION WITH THE PARTICIPATION OF A CHARGE-TRANSFER COMPLEX

The complexation between styrene (St) and N-phenylmaleimide (PMI) was investigated by H-1-NMR spectroscopy, and the existence of a complex was proved. The equilibrium constant of St/PMI in chloroform at 50 degrees C was determined to be 0.27. New elementary propagation reactions were proposed. On the basis of the propagation elementary reactions for copolymerization with the participation of a charge-transfer complex (CTC), a method for measuring the reactivity ratios is presented. Four reactivity ratios and relative reactivities of free monomer and CTC were obtained. They are r(12) = 0.034, r(21) = 0.012, r(1C) = 0.0030, r(2C) = 0.0034, and k(1C)/k(12) = 11.34, k(2C)/k(21) = 3.42.

Estimation of Metformin Drug for the Diabetes Patients by Simple,Quick and Cheap Techniques within the Formation of Colored Charge Transfer Complexes

Metformin(Met)is a drug developed for the treatment of patients with typeⅡ diabetes.Recently,Met estimation in pharmaceutical formulations and human fluids has gained a growing interest.To extend requisite data that can be used to assessment of Met quantitatively based on charge-transfer(CT)complexation,the present study describes the synthesis and characterization of CT complexes that formed between drug Met and the organicπ-acceptors picric acid(PA),chloranilic acid(CLA),chloranil(CHL),7,7',8,8'-tetracyanoquinodimethane(TCNQ),and dichlorodicyanobenzoquinone(DDQ).The properties of the formed CT complexes were investigated by elemental,spectral(UV-visible,IR,and Raman spectroscopies),thermal(TG)and morphological(SEM)studies.IR results indicated that the complexation of Met with either PA or CLA acceptors occurs through proton transfer interaction,whereas its complexation with CHL,TCNQ,or DDQ acceptors occurs through n→π*interaction.

Theoretical Studies on the Structure and Spectrum of Imidazole-Chloranil Charge Transfer Complex

分子的建筑群的紫外力的吸收系列由咪唑(Im ) 形成了， chloranil (CA ) 在氯仿被测量。imidazole-chloranil (Im-CA ) 的 stoichiometry 建筑群被使用 Benesi Hildebrand 的方程和工作的连续变化方法作为 1:1 决定。密度功能理论(DFT ) 和 MP2 计算被执行学习结构和 Im-CA 建筑群的有约束力的精力。计算定位了四符合构造(作为 S1 表示了 S4 ) 为 Im-CA，建筑群，连接的二边(Im )-to-face(CA) 和二个边(Im )-to-edge(CA) 连接了。edge-to-face 反对前者比 edge-to-edge 更稳定，这被发现。这些反对前者的结合的特征与自然人口被调查分析(NPA ) ，电子密度的拓扑的分析，和天赋结合轨道(NBO ) 分析。而 edge-to-edge 反对前者是氢契约建筑群， edge-to-face 反对前者是费用转移(CT ) 建筑群，这被揭示。为 Im-CA 建筑群( S1 )的最稳定的符合构造，咪唑 n ( N15 )的费用转移相互作用与 chloranil π 轨道的孤独的对*( C1 = O7 )轨道的戏在 Im-CA 绑定的一个关键角色，并且绑定被 O7 进一步加强... H20 氢债券。建筑群(S1 ) 的电子刺激精力与时间依赖者 DFT (TDDFT ) 被计算，并且建筑群的观察紫外可见的光谱基于计算结果被分析。

Spectroscopic Analysis and Study of Charge Transport Properties for Pinacyanol Chloride-Organic Acceptor Complex as Potential Optoelectronics Material

Organic photoconductor, pinacyanol chloride, has been studied with infrared spectroscopy because of its thermal activation energy (Ea) and band gap (Eg = 2Ea) lying in the infrared range. Particularly, pinacyanol chloride and its charge transfer (CT) complexes with chloranil, DDQ, TCNQ and TCNE as organic acceptors are studied in details. The CT complexes are having neither two absorption edges like ternary complex having one donor and two acceptors nor binary type with Lorentzian or Gaussian envelopes. The forbidden gap is direct band gap except chloranil complex due to increase in molecular distance and CT interaction. There is imperfect nesting and partial screening determining the mid-IR envelope, which is qualitatively different from the envelopes in binary systems. There is inverted parabola in some range below this envelope. It is explained how infrared absorption is related with the applications of such organic photoconductors in optoelectronic devices.

Doping-induced charge transfer in conductive polymers

Molecular doping has become a widely used method to modulate the electric performance of organic semiconductors(OSC).Highly effective charge transfer during molecular doping is desired to achieve ideal electrical conductivity.Two types of charge transfer mechanisms are widely accepted in molecular doping process:integer charge transfer(ICT)and charge transfer complex(CTC).In this review,fundamental principles of two mechanisms are revisited and the characterization methods are depicted.The key points for the formation of two mechanisms are highlighted from aspects of molecular structure and process engineering.Then,the strategies to improve the proportion of ICT are discussed.Finally,the challenges and perspectives for future developments in the molecular doping of polymer semiconductors are provided.

Controlled Growth Interface of Charge Transfer Salts of Nickel- 7,7,8,8-Tetracyanoquinodimethane on Surface of Graphdiyne

Here we report an in situ assembly growth method that controls the growth of NiTCNQ on the surface of graphdiyne(GDY).The catalytic system of donor–acceptor–donor(GDY/TCNQ/Ni)structure with multiple charge transfer(CT)was achieved by controlling the growth of NiTCNQ on the surface of GDY.Significantly,a controlled double layer interface of GDY/TCNQ/Ni was formed.This system implemented simultaneously the two elements we expected(1)an incomplete CT,and(2)the infinite distribution of active sites originating from highly asymmetric surface charge distribution.The high conductivity and typical semiconductor characteristics of the catalyst endows it with high catalytic activity.We found that an electrolytic cell consisting of the CT salt as a catalyst provided a 1.40 V ultra-small cell voltage up to 10 mA cm−2 and the outer GDY film effectively prevented the corrosion of the catalyst.Our study is the first to introduce CT complexes to a novel catalytic material platform for high selectivity of catalysts,and undoubtedly demonstrates the high selectivity,stability,and activity of such catalytic systems,which provides a new space for the development of novel conceptual catalysts.

Gaussian wave formalism model for propagation of charged-particle beam through a first-order optical systems

An elliptical Gaussian wave formalism model of a charged-particle beam is proposed by analogy with an elliptical Gaussian light beam. In the paraxial approximation, the charged-particle beam can be described as a whole by a complex radius of curvature in the real space domains. Therefore, the propagation and transform of charged-particle beam passing through a first-order optical system is represented by the ABCD-like law. As an example of the application of this model, the relation between the beam waist and the minimum beam spot at a fixed target is discussed. The result, well matches that from conventional phase space model, and proves that the Gaussian wave formalism model is highly effective and reasonable.

配体-金属电子转移强化类芬顿技术的破络特性与机制

为有效分解近中性废水中典型难降解强络合物Ni-EDTA,构建配体-金属电子转移强化类芬顿技术(LFGR),基于Ni(Ⅱ)去除效能等系统分析其在近中性条件下对Ni-EDTA的破络特性,重点探究Fe(Ⅲ)与H2O2投加量、pH值、浊度、常见有机酸与常规无机盐对LFGR破络特性的影响。结合H2O2消耗观测、自由基淬灭实验、自由基信号检测与降解产物分析等科学识别LFGR体系中主要活性氧物种,并进一步剖析Ni-EDTA的破络过程与主导机制。定量比较分析LFGR与其他UV活化氧化技术去除多种重金属EDTA络合物(M-EDTA)的特性,并进一步阐明LFGR的运行成本优势。对于络合物浓度为1.0 mmol/L的近中性模拟废水,LFGR的优化反应条件为:Fe(Ⅲ)投加量为0.1 mmol/L,H2O2投加量为50 mmol/L,UV光照时间为20 min。该条件下,EDTA可完全转化,且经碱沉淀后Ni(Ⅱ)去除率可高达99.40%;LFGR对水中常见有机酸与常规无机盐呈现出良好的抗干扰性;H_(2)O_(2)主要通过与配体-金属电子转移产生的Fe(Ⅱ)发生类芬顿反应消耗;LFGR的主要作用过程是Fe(Ⅲ)置换Ni(Ⅱ)并激发配体-金属电子转移反应从而促进EDTA光解,UV进一步驱动Fe(Ⅲ)还原并加快Fe物种循环,进而强化类芬顿技术活性氧自由基(主要为·OH和·O_(2)^(-))的催化作用。LFGR可在近中性条件下实现多种M-EDTA的良好破络效果,水处理费用合计为4.21元/t,具有良好技术经济性。

亚硫酸氢钠协同催化对苯醌加氢性能

利用亚硫酸氢钠与对苯醌加成反应形成的水溶性α-羟基亚硫酸钠衍生物可抑制醌氢醌的生成特点,考察了亚硫酸氢钠用量对醌氢醌的抑制效果,确定了对苯醌加氢反应的最优条件,并对亚硫酸氢钠的抑制机理进行了研究。实验结果表明,最佳的反应条件为氢气压力1.0 MPa、反应温度90℃、亚硫酸氢钠添加量为对苯醌量的25%(x)。添加亚硫酸氢钠可抑制对苯醌和对苯二酚的相互作用,在水相中,亚硫酸氢钠与对苯醌发生加成反应,阻断了对苯醌与对苯二酚之间氢键的形成,同时将对苯醌以水溶性α-羟基磺酸钠衍生物的形式存储,加氢时再调用,能有效抑制醌氢醌的形成,促进加氢反应进行。

Engineering intermolecular charge transfer in chiral organometallic crystals by rational doping for high-contrast CPL switches

The development of circularly polarized luminescence(CPL)switches is of great importance but challenging.Herein,a charge donor/acceptor pair comprising two chiral gold(I)-isocyanide complexes was designed to construct light-harvesting system via intermolecular charge-transfer(CT)interactions.By doping nonemissive S-Au I into blue-emitting S-AuCN,(S-Au CN)_(1-x)(S-AuI)_(x)(0≤x≤3.4%)with tunable emission from blue to red was achieved.This large red-shifted emission was realized based on the remarkable change of the electronic properties between the S-Au CN dimer and red-emitting(S-A CN)-(S-AuI)CT pair,and the resulting energy-transfer(En T)process between them.Importantly,the En T process can be switched off/on by external stimuli of grinding and CH_(2)Cl_(2)fuming,giving rise to high-contrast(blue versus red)CPL switching properties.This study opens a novel avenue for developing CPL switches by constructing light-harvesting CT-doped systems based on chiral organometallic complexes.

Luminescent Properties of A Novel Terbium Complex Tb(o-BBA)_3(phen)

A novel rare earth complex of terbium ion with 2-benzoylbenzoic acid and 1, 10-phenathroline （Tb（o-BBA）3 （phen）, o-BBA-2-benzoylbenzoic acid, phen = 1, 10-phenathroline） was used as an electroluminescent material for the first time. The Tb complex was blended with poly（N-vinylcarbazole） （PVK） in different weight ratios and spinn to coated into films （noted as PVK ：Tb films）. The photoluminescence （PL） properties of films were investigated and the optimum weight ratio between PVK and Tb（o-BBA）3（phen） was found to be 3：1. Monolayer devices with the structure ITO/PVK： Tb/AI were fabricated and emitted green light, which was characteristic of Tb^3＋ emission. The results show that mecha- nisms for PL and EL are different. The PL is considered to be caused because of energy transfer and direct excitation to the Tb（o-BBA）3（phen） molecule, while EL is mainly on charging trapping.

Spectrophotometric study of the charge transfer complexes of 4′-nitrobenzo-15-crown-5 and benzo-15-crown-5 with iodine in nonaqueous solvents

The formation of charge transfer complex between iodine with 4＇-nitrobenzo-15-crown-5（NB15C5） and benzo-15-crown-5 （B15C5） is investigated spectrophotometrically in chloroform and dichloromethane（DCM） solutions at 25℃.The pseudo-first-order rate constants for the transformation process were evaluated from the absorbance-time data and found to vary in the order of DCM CHCl_3.The values of the formation constant,K_f,for each complex are evaluated from Benesi-Hilebrand equation. Stability of the resulting complex in two solvents was also found to vary in the order of DCM CHCl_3.

Building up 1-D, 2-D, and 3-D Polyiodide Frameworks by Finely Tuning the Size of Aryls on Ar-S-TTF in the Charge-Transfer （CT） Complexes of Ar-S-TTFs and Iodine

The arylthio-substituted tetrathiafuivalenes （Ar-S-TTFs） are electron donors having three reversible states, neutral, cation radical, and dica- tion. The charge-transfer （CT） between Ar-S-TTFs （TTF1--TTF3） and iodine （12） is reported herein. TTF1--TTF3 show the CT with 12 in the CH2C12 solution, but they are not completely converted into cation radical state. In CT complexes of TTF1--TTF3 with 12, the charged states of Ar-S-TTFs are distinct from those in solution. TTF1 is at cation radical state, and TTF2--TTF3 are oxidized to dication. The iodine components in complexes show various structures including 1-D chain of V-shaped （Is）-, and 2-D and 3-D iodine networks composed of 12 and （13）^- .

Bright Red Luminescence from Novel Europium Complex Sensitized by Dibenzamide

A novel europium complex, bi(dibenzamide) benzoate europium(Ⅲ) (Eu-DBA-B), was synthesized. The composition and photoluminescence properties of Eu-DBA-B were investigated. The results show that the europium complex is an electroneutral complex, and it emits very strong red luminescence from (()~5D_1→()~7F_j) (j=0, 1, 2, 3, 4) transitions.