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.

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.

Highly efficient H-bonding charge-transfer complex for microsupercapacitors under extreme conditions of low temperatures

Owing to sluggish ionic mobility at low temperatures, supercapacitors, as well as other energy-storage devices, always suffer from severe capacity decay and even failure under extreme low-temperature circumstances. Solar-thermal-enabled self-heating promises an attractive approach to overcome this issue.Here, we report a unique H-bonding charge-transfer complex with a high photothermal conversion efficiency of 79.5% at 405 nm based on chloranilic acid and albendazole. Integrated with a microsupercapacitor, the chloranilic acid-albendazole complex(CAC) film prompts an apparent temperature increase of 22.7 °C under 1 sun illumination at-32.6 °C, effectively elevating the working temperature of devices.As a result, the rate capability of the microsupercapacitor has been significantly improved with a 17-fold increase in capacitance at a current density of 60 μA cm^(-2), leading to outstanding low-temperature performances. Importantly, the integrated device is capable of working at a low temperature of-30 °C in the open air, which demonstrates the potential of CAC in practical applications for low-temperature ultracapacitive energy-storage devices.

SPECTROPHOTOMETRIC STUDY OF DDQ CHARGE-TRANSFER COMPLEXES WITH 1,10-PHENANTHROLINE AND ITS DERIVATIVES

1,10-phenanthroline and its derivatives can form charge-transfer complexes with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone(DDQ).The absorption spectra and conditions of complex formation,such as the reaction time,the quantity of DDQ, and the solvents, have been studied.After the HMO calculation of phenanthrolines,the molar absorptivities were found to depend on the substituents on the phenanthroline rings.

Study on Alternating LB Films of Charge-Transfer Complex of Octadecyl-TCNQ and Copper Phthalocyanine Derivative

Infrared spectra of alternating LB films of octadecyl-TCNQ/CuPc are studied. Charge-transfer complexes are formed in LB films and conductance increases about three orders than that of pure CuPc LB films.

Cation-Anion Redox Active Organic Complex for High Performance Aqueous Zinc Ion Battery

Organic redox compounds are attractive cathode materials in aqueous zinc-ion batteries owing to their low cost,environmental friendliness,multiple-electron-transfer reactions,and resource sustainability.However,the realized energy density is constrained by the limited capacity and low voltage.Herein,copper-tetracyanoquinodimethane(CuTCNQ),an organic charge-transfer complex is evaluated as a zinc-ion battery cathode owing to the good electron acceptation ability in the cyano groups that improves the voltage output.Through electrochemical activation,electrolyte optimization,and adoption of graphene-based separator,CuTCNQ-based aqueous zinc-ion batteries deliver much improved rate performance and cycling stability with anti-self-discharge properties.The structural evolution of CuTCNQ during discharge/charge are investigated by ex situ Fourier transform infra-red(FT-IR)spectra,ex situ X-ray photoelectron spectroscopy(XPS),and in situ ultraviolet visible spectroscopy(UV-vis),revealing reversible redox reactions in both cuprous cations(Cu^(+))and organic anions(TCNQ^(x-1)),thus delivering a high voltage output of 1.0 V and excellent discharge capacity of 158 mAh g^(-1).The remarkable electrochemical performance in Zn//CuTCNQ is ascribed to the strong inductive effect of cyano groups in CuTCNQ that elevated the voltage output and the graphene-modified separator that inhibited CuTCNQ dissolution and shuttle effect in aqueous electrolytes.

Photoluminescent nickel(Ⅱ)carbene complexes with ligand-to-ligand charge-transfer excited states

While nickel(II)complexes have been widely used as catalysts for carbon-carbon coupling reactions,the exploration of their photophysical and photochemical properties is still in the infancy.Here,a series of square-planar Ni(II)complexes[(diNHC)NiX2]bearing chelating benzimidazole-based bis(N-heterocyclic carbene)ligands and varying anionic coligands(1,X=Cl;2,X=Br;3,X=I)are synthesized and structurally characterized.In solid state,both 1 and 2 exhibit orange-red photoluminescence under ambient conditions.The photophysical and electrochemical measurements along with density functional theory(DFT)calculations reveal that the low-energy emissions can be attributed to singlet excited states with ligand-to-ligand charge-transfer(LLCT)character.This work suggests that strong-field N-heterocyclic carbene ligands play a crucial role to achieve the luminescence of Ni(II)complexes.

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.

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

UV-Vis absorption spectra of the molecular complex formed by imidazole （Ira） and chloranil （CA） were measured in chloroform. The stoichiometry of the imidazole-chloranil （hn-CA） complex was determined as 1：1 by applying Benesi-Hildebrand＇s equation and Job＇s continuous variation method. Density function theory （DFT） and MP2 calculations were performed to study the structures and the binding energies of the Im-CA complex. The calculations located four conformations （denoted as S1-S4） for the Ira-CA complex, two edge（Im）-to-face（CA） linked and two edge（Im）-to-edge（CA） linked. It was found that the edge-to-face conformers are more stable than the edge-to-edge ones. The bonding characteristics of these conformers were investigated with natural population analysis （NPA）, topological analysis of electron density, and natural bond orbital （NBO） analysis. It was revealed that the edge-to-face conformers are charge-transfer （CT） complexes whereas the edge-to-edge conformers are the hydrogen bond complexes. For the most stable conformation of the Ira-CA complex （S1）, the charge transfer interaction of the imidazole n（N15） lone pair orbital with the chloranil π＊ （C1=O7） orbital plays a crucial role in the Ira-CA binding, and the binding is further strengthened by the O7… H2O hydrogen bond. The electronic excitation energies of the complex （S1） were calculated with time-dependent DFT （TDDFT）, and the observed UV-Visible spectrum of the complex was analyzed based on the computed results.

Density Functional Theory Study on the First Hyperpolarizabilities of Mono-and Bimetal Ir(Ⅰ)/Rh(Ⅰ)2,2'-Bidipyrrins Complexes

Metal complexes with excellent nonlinear optical（NLO） properties have attracted considerable attention. The geometry structure, electronic spectra and NLO properties of 2,2？-bidipyrrins（L） and mono-and bimetal Ir（I）/Rh（I）–L complexes have been investigated by density functional theory method. Our calculations revealed that L with planar configuration shows the largest first hyperpolarizability value, which is 2.2 to 5.5 times larger than that of others. It is attributed to the single direction of intramolecular charge transfer. When metal ions were embedded in ligands, the first hyperpolarizability values of mono-and bimetal Ir/Rh（I）–L complexes were smaller than that of L, and that of bimetal Ir/Rh（I）–L complexes were smaller than the corresponding monometallic Ir/Rh（I）–L. This is caused by the intramolecular charge transfer from multiple directions as well as the amount of charge transfer. On the other hand, on increasing the number of metal ions, the charge transfer in the opposite direction cancels each other more obviously. Our work would provide some theoretical reference for the second-order NLO responses of mono-and bimetal complexes.

A Band Theory Perspective on Molecular Orbitals in Complex Oxides

In view of the growing interest in molecular orbitals (MOs) encountered in certain complex oxides, we review some of their properties from the band theory perspective and provide detailed examples based on real materials. Our discussion includes some technical aspects of identifying MOs in electronic structure calculations and considers cases when MOs can be both orthogonal and non-orthogonal. We also describe orthonormalization of MOs, a procedure converting them into Wannier functions, and discuss the problem of Wannier functions possibly being rather spatially extended and how using MO, rather than atomic orbital, based effective Hamiltonians might be a better choice in describing certain strongly correlated systems as well as systems with strong electron-phonon coupling. Furthermore, we address the problem of strongly correlated MOs and how it can be treated in band theory calculations.

Photochemical graft of γ-cyclodextrin's interior leading to in-situ charge-transfer complexes with unusual regioselectivity and its application in 3D photo-printing

Photoirradiation of anthraquinone(AQ)derivatives withγ-cyclodextrin(γ-CD)in aqueous solution led to aγ-CD derivative with a 9,10-dihydroxylanthracene grafting unprecedentedly at the 5′-position of one glucoside ofγ-CD in high efficiency.Meanwhile,another AQ enters into the remaining space of the 9,10-dihydroxylanthracene-occupiedγ-CD cavity to in-situ form a selfincluded quinhydrone charge transfer(CT)complex.The structure of the supramolecular CT complex was unambiguously demonstrated by 1 D and 2 D NMR(^(1)H NMR,^(13)C NMR,DEPT,^(1)H-^(1)H COSY,HSQC,HMBC,TOCSY,and ROESY)spectroscopies,which revealed a highly stereoselective stacking of the quinhydrone pairs in theγ-CD cavity.The supramolecular CT complex showed an unusually high binding affinity and improved oxidation resistance.Polyacrylamides bearingγ-CD or anthraquinone were respectively synthesized by co-polymerization of acrylamide with the corresponding monomer.Photoirradiation of aqueous mixtures containing these two types of polymers led to gelation,which was applied to 3 D photo-printing of soft materials.

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）^- .

Fast ethylamine gas sensing based on intermolecular charge-transfer complexation

We have investigated the fast ethylamine gas sensing of 2-chloro-3,5-dinitrobenzotrifluoride（CDBF） loaded poly（acrylonitrile） nanofiber based on an intermolecular charge-transfer complexation.Reversible response and recovery were achieved using alternating gas exposure.This system shows a fast ethylamine gas sensing within 0.4 s.

附着态半导体光催化剂光解可溶性染料的研究

以３００Ｗ中压汞灯和日光为光源，研究了将ＴｉＯ２等半导体粉末附着在海砂和玻璃表面对直接耐晒大红４ＢＳ（下简称４ＢＳ）、活性黑ＫＮ－Ｂ（下简称ＫＮ－Ｂ）和亚甲基蓝（下简称ＭＢ）水溶液的催化光解。结果表明：几种染料均显著光解；光解为一级动力学反应；附着复合的ＴｉＯ２－Ｆｅ２Ｏ３、ＴｉＯ２－ＷＯ３比附着单一的ＴｉＯ２光催化效果好；附着态ＴｉＯ２重复使用１５次（每次８ｈ）后催化能力降低１７．９％。

基于CPCM的复转矩系数法在复杂电力系统SSR问题研究中的应用

基于电力系统元件复频域端口导纳矩阵模型,采用分散消元的复转矩系数法,可方便地生成全系统复频域网络方程,有效降低计算复杂度;经适当处理后,可准确计及其他发电机组的轴系动态过程和其他转速控制元件的作用及其对被研究发电机组电气阻尼特性的影响。对某典型火电基地经串补输电系统的次同步谐振(subsynchronous resonance,SSR)特性及静止无功补偿器对SSR问题的抑制进行分析,并结合时域仿真验证分析结果的有效性。研究认为,在进行多机系统SSR问题复转矩系数分析时,需计及系统其它发电机组轴系动态和转速偏差对待研究机组阻尼特性的影响。同时,该方法可以根据网络结构的变化快速修改网络方程,以适应任意网络结构的次同步谐振分析,为研究复杂电力系统的SSR特性及抑制措施提供了有效手段。

新型有机电双稳态材料的设计和性质

随着微电子器件尺度的不断缩小,可作为非硅存储器的有机电双稳材料已成为分子电子学研究的一大热点[1,2].与传统的无机材料相比,有机材料具有作用体积小,容易获得,制作工艺简单等优点.

苯-卤素(X_2,X=F,Cl,Br,I)相互作用本质的对称性匹配微扰理论研究

在MP2水平下对被定义为"电荷转移复合物(CTC)"的苯(C6H6)-卤素分子X2(X=F,Cl,Br,I)相互作用体系进行了量子化学研究.在优化所得C6H6-X2(X=F,Cl,Br,I)复合物的平衡几何结构中,卤素分子X2接近垂直指向苯环上碳-碳双键的中心.自然键轨道(NBO)分析结果表明,苯-卤素体系中电荷转移的数量很少.对称性匹配微扰理论(Symmetry-adapted perturbation theory,SAPT)能量分解结果显示,在4个复合物体系中,静电作用的贡献相对较小(只占总吸引作用的20%左右),对于C6H6-F2体系,色散作用是其主要吸引作用,对于C6H6-Cl2,C6H6-Br2和C6H6-I2体系,诱导作用则是其主要的吸引作用,从F到I,色散作用逐渐减弱,诱导作用逐渐增强,表明在电子相关水平上将苯-卤素体系称为"电荷转移复合物"的说法并不确切.

EQCM监测高氯酸溶液中金电极上苯二酚电荷转移配合物的沉积

用电化学石英晶体微天平(EQCM)研究了高氯酸溶液中电位环扫过程中邻(间、对)苯二酚/醌电荷转移配合物(CTC)的生成和电沉积。结果发现,邻(对)苯二酚可产生CTC并在电极上沉积,而间苯二酚仅发生电聚合反应。以邻苯二酚为例考察了高氯酸和邻苯二酚浓度及电位扫描速度的影响。红外光谱证实了邻苯二酚/醌CTC的生成。结果发现,添加肝素钠对邻苯二酚/醌CTC的沉积有显著影响,肝素钠质量浓度分别低/高于0.05 g/L时,能增强/减弱沉积现象。EQCM技术可作为一种快速、简便、灵敏的工具可望用于CTC制备过程中的实时监测和筛选。

三乙胺与2-氯-5-甲氧基对苯醌光电子转移反应的CIDNP研究

用化学诱导动态核极化 (CIDNP)方法研究了三乙胺与 2 氯 5 甲氧基对苯醌在C6 D6 ,CD3CN溶剂中的反应机理 ,实验结果表明反应过程中首先形成基态电荷转移络合物 (CTC) ,在CD3CN中 ,光照电荷分离形成离子自由基对 ,使三乙胺亚甲基产生发射极化信号 .同时用UV