钯（II）-克林霉素-卤代荧光素体系的共振瑞丽散射光谱及其分析应用

在pH为5.0-5.4的乙酸-乙酸钠缓冲溶液中,克林霉素（Clin）与钯(Ⅱ)形成螯合阳离子,它能进一步与二碘荧光素（DIF）,赤藓红（Ery）,曙红Y（EY）等卤代荧光素类染料反应形成1：1：1的三元离子缔合物,此时将引起吸收光谱变化和荧光猝灭,同时还导致共振瑞利散射(RRS)的急剧增强并产生新的RRS光谱,钯(Ⅱ)-克林霉素与DIF,Ery和EY形成产物的最大散射波长分别位于285,287,32 1nm处,另外还有些较弱的散射峰存在。散射增强（ΔI）与克林霉素浓度在一定范围内成正比,可用于克林霉素的定量测定。对于DIF,Ery和EY体系的线性范围和检出限分别为0.025-2.1μg•mL-1和7.8 ng•mL-1,0.053-2.4μg•mL-1和16.0 ng•mL-1;以及0.038-2.4μg•mL-1和11.0 ng•mL-1。本文研究了适宜的反应条件,考察了共存物质的影响,表明方法有较好的选择性,基于三元离子缔合物的RRS光谱,发展了一种高灵敏、简便快速测定克林霉素的新方法。文中还对离子缔合物的组成,结构和反应机理,以及离子缔合物对吸收,荧光和RRS光谱的影响进行了讨论。     

Fading Spectrophotometric Method for the Determination of Polyvinylpyrrolidone with Eosin Y

在弱酸性HC1-NaAc缓冲介质中,曙红Y（EY）在可见光区有强烈的光吸收,其最大吸收波长(lmax)位于517 nm处,而聚乙烯吡咯烷酮(PVP)在250-700 nm之间无光吸收,当EY与PVP反应形成结合产物时,EY发生明显的褪色作用,最大褪色波长仍位于517 nm,并在545 nm处出现一个较小的吸收峰。其褪色程度（DA）与PVP浓度在0.40~3.20 µg mL-1范围成线性关系,此褪色反应的灵敏度高,摩尔吸光系数(ε)是6.4 × 106 L mol-1 cm-1,对PVP的检出限为0.12 µg mL-1。并研究了反应的影响因素,结果表明方法具有较好的选择性,据此发展了一种曙红Y褪色分光光度法测定PVP的新方法。方法简便快速,可用于啤酒中PVP的定量测定。     

Post‐Synthetic Polymerization of UiO‐66‐NH2 Nanoparticles and Polyurethane Oligomer toward Stand‐Alone Membranes for Dye Removal and Separation

Metal–organic frameworks (MOFs) are widely used as porous materials in the fields of adsorption and separation. However, their practical application is largely hindered by limitations to their processability. Herein, new UiO‐66‐Urea‐based flexible membranes with MOF loadings of 50 ( 1 ), 60 ( 2 ), and 70 wt % ( 3 ) were designed and prepared by post‐synthetic polymerization of UiO‐66‐NH₂ nanoparticles and a polyurethane oligomer under mild conditions. The adsorption behavior of membrane 3 towards four hydrophilic dyes, namely, eosin Y (EY), rhodamine B (RB), malachite green (MG), and methylene blue (MB), in aqueous solution was studied in detail. It exhibits strong adsorption of EY and RB but weak adsorption of MG and MB in aqueous solution. Owing to the selective adsorption of these hydrophilic dyes, membrane 3 can remove EY and RB from aqueous solution and completely separate EY/MB, RB/MG, and RB/MB mixtures in aqueous solution. In addition, the membrane is uniformly textured, easily handled, and can be reused for dye adsorption and separation.     

UV/TiO2 Photocatalytic Degradation of Xanthene Dyes

UV/titanium dioxide (TiO₂) degradation of two xanthene dyes, erythrosine B (Ery) and eosin Y (Eos), was studied in a photocatalytic reactor. Photocatalysis was able to degrade 98% of Ery and 73% of Eos and led to 65% of chemical oxygen demand removal. Experiments in buffered solutions at different initial pH values reveal the pH dependence of the process, with better results obtained under acidic conditions due to the electrostatic attraction caused by the opposite charges of TiO₂ (positive) and of anionic dyes (negative). Batch activity tests under methanogenic conditions showed the high toxicity exerted by the dyes even at low concentrations (~85% with initial concentration of 0.3 mmol L^?1), but the end products of photocatalytic treatment were much less toxic toward methanogenic bacteria, as detoxification of 85 ± 5% for Eos and 64 ± 7% for Ery were obtained. In contrast, the dyes had no inhibitory effect on the biogenic‐carbon biodegradation activity of aerobic biomass, obtained by respirometry. The results demonstrate that photocatalysis combining UV/TiO₂ as a pretreatment followed by an anaerobic biological process may be promising for the treatment of wastewaters produced by many industries.     

Directed cleavage of RNA within an imperfect complementary complex by oligonucleotide—bleomycin A5 conjugates

It was demonstarted for the first time that RNA can be subjected to site-specific oxidative cleavage induced by the glycopeptide antibiotic bleomycin A₅ (Blm) covalently linked to the 3"-terminus of an oligodeoxyribonucleotide through two, three, or four residues of hexaethylene glycol phosphate (p-heg) _n . The oligonucleotide conjugate with bleomycin forms an imperfect complementary complex with the RNA to be cleaved (5"-prCGGAGUUGGAAAACAAUGAAAAGGCCCCCA/Blm-(p-heg) _n -3"-pdGCCTCACCTTTTGTTA). The cleavage occurs at the only nucleotide residue (U) preceding a one-nucleotide bulge in the RNA chain, which is formed due to imperfect complementarity between the oligodeoxyribonucleotide and the RNA to be cleaved.     

Characterization and Mechanism Elucidation of Dye Adsorption Using Cuprous Selenide Nanoparticles from Aqueous Solutions

The removal of cationic dyes, methylene blue(MB) and rhodamine B(RB), and anionic dyes, methyl or-ange(MO) and eosin Y(EY), from aqueous solutions by adsorption using Cu₂Se nanoparticles(Cu₂SeNPs) was studied. The effects of the initial pH values, adsorbent doses, contact time, initial dye concentrations, salt concentrations, and operation temperatures on the adsorption capacities were investigated. The adsorption process was better fitted the Langmuir equation and pseudo-second-order kinetic model, and was spontaneous and endothermic as well. The adsorption mechanism was probably based on the electrostatic interactions and π-π interactions between Cu₂SeNPs and dyes. For an adsorbent of 0.4 g/L of Cu₂SeNPs, the adsorption capacities of 23.1(MB), 22.9(RB) and 23.9(EY) mg/g were achieved, respectively, with an initial dye concentration of 10 mg/g(pH=8 for MB and pH=4 for RB and EY) and a contact time of 120 min. The removal rate of MB was still 70.4% for Cu₂SeNPs being reused in the 5th cycle. Furthermore, the recycled Cu₂SeNPs produced from selenium nanoparticles adsorbing copper were also an effective adsorbent for the removal of dyes. Cu₂SeNPs showed great potential as a new adsorbent for dyes removal due to its good stability, functionalization and reusability.     

Ultrafast excited-state dynamics of eosin B: a potential probe of the hydrogen-bonding properties of the environment

The photophysics of two dyes from the xanthene family, eosin B (EB), and eosin Y (EY) has been investigated in various solvents by femtosecond transient absorption spectroscopy, first, to clarify the huge disparity of the EB fluorescence lifetimes reported in literature, and, second, to understand the mechanism responsible for the ultrafast excited-state deactivation of EB in water. The excited-state lifetime of EB was found to be much shorter in water and in other protic solvents, due to the occurrence of hydrogen-bond assisted nonradiative deactivation. This mechanism is associated with the hydrogen bonds between the solvent molecules and the nitro groups of EB, which become stronger upon optical excitation due to the charge-transfer character of the excited-state. This process is not operative with EY, where the nitro groups are replaced by bromine atoms. Therefore, the excited-state lifetime of EB in solution is directly related to the strength of the solvent as a hydrogen-bond donor, offering the possibility to build a corresponding scale based on the fluorescence quantum yield or lifetime of EB. This scale of hydrogen-bonding strength could be especially useful for studies of liquid interfaces by time-resolved surface second harmonic generation.     

Bis-ratiometric absorbance detection of Al(III) in the rhodamine B-functionalized bis-polydiacetylene film

A rhodamine B-functionalized bis-polydiacetylene (RB/bis-PDA) film sensor was prepared. Rhodamine B derivatives as the ion-recognition elements were embedded in the bis-polydiacetylene matrix through the hydrolysis/condensation process of organic silicon. The as-prepared blue-phase RB/bis-PDA film could transfer to yellow phase at high temperatures. Upon dipping the blue and yellow RB/bis-PDA films into various metal ion solutions, respectively, only Al³⁺ could induce remarkable changes in absorption and color signals. The UV–Vis absorption spectrum of the Al³⁺-containing film showed two separate absorption peaks at 556 nm and at another wavelength (617 or 470 nm), corresponding to ring opening of the spirolactam structure in rhodamine moiety and PDA (blue- or yellow-phase PDA), respectively. Utilizing the different intensity ratios of the two absorption signals (A₅₅₆/A₆₁₇ or A₅₅₆/A₄₇₀), the RB/bis-PDA system could be used as a bis-ratiometric absorbance sensor for Al³⁺. The reusable and free-standing films have great potential in environmental and biological sensing fields as they are more convenient to achieve real-time sensing than the conventional probes dissolved in aqueous or organic solvents.     

Reductive Decolourisation of Sulphonated Mono and Diazo Dyes in One- and Two-Stage Anaerobic Systems

This work assessed the application of one- and two-stage mesophilic anaerobic systems to colour removal of sulphonated mono and diazo dyes with ethanol as electron donor. The dyes Congo Red (CR), Reactive Black 5 (RB5) and Reactive Red 2 (RR2) were selected as model compounds and tested separately in seven different periods. The one-stage system (R₁) consisted of a single up-flow anaerobic sludge blanket (UASB) reactor, whereas the two-stage system (R₂) consisted of an acidogenic UASB reactor (R_A), a settler and a methanogenic UASB reactor (R_M). For CR and RB5, no remarkable difference was observed between the colour removal performance of both anaerobic systems R₁ and R₂. The experiments with RR2 revealed that R₂ was more efficient on colour removal than R₁, showing efficiencies almost 2-fold (period VI) and 2.5-fold (period VII) higher than those found by R₁. Additionally, R₂ showed a higher stability, giving a good prospect for application to textile wastewaters. Finally, the acidogenic reactor (R_A) had an important role in the overall decolourisation achieved by R₂ during the experiments with CR and RB5 (>78 %), whereas for RR2, a more recalcitrant dye, R_A was responsible for up to 38 % of the total colour removal.     

Kinetic and mechanistic studies of the oxidation of poly(o‐toluidine) doped with 5‐sulfosalicylic acid

Protonation of poly(o‐toluidine) base form (POT‐EB) with 5‐sulfosalicylic acid (SSA) was proved experimentally and computationally. Molecular mechanics (MM+) calculations showed that the potential energy (PE) of the optimum molecular geometric structure of SSA‐doped POT is 4.703 × 10³ kcal mol^?1 or at least three orders of magnitude higher than the PE of the molecular geometric structure of the same matrix. These calculations indicate that the optimization of this matrix is necessary for understanding the stability. Dark green coloration (λ ～800 nm) after addition of SSA into POT‐EB matrix (dark blue, λ ～600 nm) revealed that the SSA was working as a protonating agent to convert POT base form (POT‐EB) to salt form (SSA‐doped POT). The change of the dark green color of SSA‐doped POT to dark brown (λ ～500 nm) after addition of oxidant (K₂CrO₄) was due to the highest oxidized form of the matrix obtained (the quinoid one), which undergoes a hydrolysis reaction to produce p‐hydroquinone (H₂Q) by a mechanism similar to Schiff‐base hydrolysis. Kinetic parameters of the oxidation reaction were deduced employing a computer‐aided kinetic analysis of the absorbance (A) at ～800 nm against the hydrolysis time (t) data. The results obtained indicate that the rate controlling process may be governed by the Ginstling–Brounshetin equation for three‐dimensional diffusion (D4). The proposed mechanism for the oxidation of SSA‐doped POT matrix is also supported by MM+ calculations. Activation parameters for the rate of the oxidation process of acid‐doped POT matrix have been computed and discussed. © 2003 Wiley Periodicals, Inc. Int J Chem Kinet 35: 260–272, 2003     

Extending spectrum response of squaraine-sensitized solar cell by Förster resonance energy transfer

To extend the spectral response region of squaraine dye (SQ)-sensitized solar cell, eosin Y (EY) is encapsulated in the SQ-sensitized nanocrystalline thin film. EY is first adsorbed on nanocrystalline TiO₂ thin film (n-TiO₂), then a thin layer of EY contained ZnO (EY-ZnO) is electrodeposited, and SQ dye is finally sensitized to form two dye-sensitized nanocrystalline thin film with a structure of n-TiO₂/EY/EY-ZnO/SQ. There is a perfect spectral overlap between the emission of EY and the absorption of SQ; EY as an energy donor simultaneously transfers both electron and hole to the energy acceptor SQ according to the Förster resonance energy transfer (FRET) process. EY shifts the spectral response edge of SQ-sensitized solar cell toward blue from 550 to 450 nm through the FRET process in this new structure. Two dye-sensitized nanocrystalline thin film demonstrates a significant enhancement in light harvesting and photocurrent generation due to the FRET process. The thickness of the EY-ZnO thin layer and spectral overlap between emission of donor dye and absorption of acceptor dye are two important factors that affect the FRET process between EY and SQ in the structure of n-TiO₂/EY/EY-ZnO/SQ.     

Site-specific modification of the 5"-terminal fragment of PGY1/MDR1 gene mRNA by reactive conjugates of antisense oligonucleotides

The site-specific modification of the 5"-terminal fragment of PGY1/MDR1 mRNA by oligodeoxyribonucleotide conjugates bearing residues of bleomycin A₅ (Blm), cobalt(ii) tetracarboxyphthalocyanine (Phcn), 4-[N-(2-chloroethyl)-N-methylamino]benzylamine (RCl), or perfluoroarylazide (Az) was studied. Conjugates of oligonucleotides complementary to the RNA sequences 123—138 and 155—166 selectively modify RNA in the vicinity of these regions. The highest efficacy (up to 50%) was achieved in reactions with alkylating and perfluoroarylazide conjugates of oligonucleotides. Conjugates of perfluoroarylazide with 2"-O-modified oligonucleotides are much more efficient than analogous conjugates with oligodeoxyribonucleotides (extents of RNA modification are 40—50% and 20%, respectively).     

Photocatalytic degradation of triazine dyes over N-doped TiO2 in solar radiation

Photocatalytic degradation of the reactive triazine dyes Reactive Yellow 84 (RY 84), Reactive Red 120 (RR 120), and Reactive Blue 160 (RB 160) on anatase phase N-doped TiO₂ in the presence of natural sunlight has been carried out in this work. The effect of experimental parameters like initial pH and concentration of dye solution and dosage of the catalyst on photocatalytic degradation have also been investigated. Adsorption of dyes on N-doped TiO₂ was studied prior to photocatalytic studies. The studies show that the adsorption of dyes on N-doped TiO₂ was high at pH 3 and follows the Langmuir adsorption isotherm. The Langmuir monolayer adsorption capacity of dyes on N-doped TiO₂ was 39.5, 86.0, and 96.3 mg g^?1 for RY 84, RR 120, and RB 160, respectively. The photocatalytic degradation of the dyes follows pseudo first-order kinetics and the rate constant values are higher for N-doped TiO₂ when compared with that of undoped TiO₂. Moreover, the degradation of RY 84 on N-doped TiO₂ in sunlight was faster than the commercial Aeroxide^® P25. However, the P25 has shown higher photocatalytic activity for the other two dyes, RR 120 and RB 160. The COD of 50 mg l^?1 Reactive Yellow-84, RR 120 and RB 160 was reduced by 65.1, 73.1, and 69.6 %, respectively, upon irradiation of sunlight for 3 h in the presence of N-doped TiO₂. The photocatalyst shows low activity for the degradation of RY 84 dye, when its concentration was above 50 mg l^?1, due to the strong absorption of photons in the wavelength range 200–400 nm by the dye solution. LC–MS analysis shows the presence of some triazine compounds and formimidamide derivatives in the dye solutions after 3 h solar light irradiation in the presence of N-doped TiO₂.     

Resonance Rayleigh scattering method for the determination of polyvinylpyrrolidone using eosin Y as the probe

The intensities of resonance Rayleigh scattering (RRS) of poly (vinyl pyrrolidone) (PVP) and of eosin Y (EY) are weak in solutions of pH 2.9 to 3.4. If reacted with each other, the intensities of RRS are largely enhanced and new RRS bands appear at 276 nm and 320 nm. The intensity at 276 nm is linearly related to the concentration of PVP in the range from 0.10 to 1.6 μg mL^-1. The correlation coefficient is 0.9987, and the detection limit is 28.7 ng mL^-1. The binding mode between PVP and EY was studied by RRS, and by absorption and fluorescence spectroscopy. The optimum reaction conditions and some potential interferences were investigated. The method displays good selectivity and was applied to the determination of PVP in beer.     

卤代荧光素与西布曲明的荧光猝灭和褪色光谱及其分析应用

在弱酸性缓冲溶液中,乙基曙红(EE)、赤藓红(ET)和荧光桃红(PX)3种卤代荧光素与盐酸西布曲明(SH)形成离子缔合物,导致吸收光谱发生变化和荧光猝灭。研究了反应产物的吸收和荧光光谱特征,适宜的反应条件,据此建立了以卤代荧光素为光谱探针的灵敏、简便、快速测定SH的新方法。其中ET体系褪色反应灵敏度最高,对SH的线性范围为0.1～4.0μg/mL,检出限为0.06μg/mL;PX-SH体系的荧光猝灭法对SH的线性范围是0.2～4.6μg/mL(λex/λem=540nm/560nm),检出限为0.09μg/mL。讨论了离子缔合反应对荧光及吸收光谱的影响及卤代荧光素荧光猝灭和褪色的原因。     

钯(Ⅱ)-盐酸吗啉胍螯合物与卤代荧光素类染料相互作用的共振瑞利散射光谱及其分析应用

在pH值为4.2~4.4的HAc-NaAc介质中,盐酸吗啉胍(ABOB)与Pd(Ⅱ)反应形成螯合阳离子[Pd(ABOB)2]2+,它能进一步与曙红Y(EY)、赤藓红(Ery)和二溴荧光素(DBF)阴离子形成离子缔合物,此时将引起共振瑞利散射(RRS)的急剧增强并产生新的RRS光谱。 盐酸吗啉胍与Pd(Ⅱ)和3种染料反应后的产物具有相似的光谱特征,最大RRS波长位于315 nm附近。 在一定条件下散射增强(ΔI)与ABOB浓度成正比,EY、Ery和DBF这3个体系的线性范围分别为0.012×10-6~1.2×10-6 g/mL、0.23×10-6~2.3×10-6 g/mL和0.24×10-6~1.5×10-6 g/mL。 方法具有较高的灵敏度,对于ABOB的检出限依次为0.003 6×10-6、0.070×10-6和0.025×10-6 g/mL,其中以EY体系灵敏度最高,其次是DBF和Ery。 研究了适宜的反应条件和影响因素,表明本方法具有良好的选择性,并以EY体系为例考察了共存物质的影响。 据此建立以曙红Y作探针,用RRS技术快速、简便,高灵敏测定ABOB的新方法。 文中还对离子缔合物的形成和反应机理进行了讨论。     

Development of 166Ho bleomycin as a possible therapeutic complex

Due to interesting therapeutic properties of ¹⁶⁶Ho and the antineoblastic antibiotic, bleomycin (BLM), ¹⁶⁶Ho-bleomycin (¹⁶⁶Ho-BLM) was developed as a possible therapeutic compound. ¹⁶⁶Ho chloride was obtained by thermal neutron irradiation (1 × 10¹³ n cm^?2 s^?1) of natural Ho(NO₃)₃ samples (specific activity = 3–5 GBq mg^?1), dissolved in acidic media. At optimized conditions (room temperature, 12 h, 0.15–0.3 mg bleomycin for 74 MBq ¹⁶⁶HoCl₃) a radiochemical purity of 94–97% was obtained as shown by ITLC and HPLC (specific activity, 700–740 GBq mmol^?1). Biodistribution studies of ¹⁶⁶Ho chloride and ¹⁶⁶Ho-BLM were performed in wild-type rats. The accumulation of the radiolabeled compound in lungs, liver and spleen demonstrates a similar pattern to the other radiolabeled bleomycins.     

Assessing the Applicability of Singlet Oxygen Photosensitizers in Leaf Studies

Singlet oxygen (¹O₂) is of special interest in plant stress physiology. Studies focused on internal, chlorophyll‐mediated production are often complemented with the use of artificial ¹O₂ photosensitizers. Here, we report a comparative study on the effects of Rose Bengal (RB), Methylene Violet (MVI), Neutral Red (NR) and Indigo Carmine (IC). These were infiltrated into tobacco leaves at concentrations generating the same fluxes of ¹O₂ in solution. Following green light‐induced ¹O₂ production from these dyes, leaf photosynthesis was characterized by Photosystem (PS) II and PSI electron transport and oxidative damage was monitored as degradation of D1, a PSII core protein. Cellular localizations were identified on the basis of the dyes’ fluorescence using confocal laser scanning microscopy. We found that RB and NR were both localized in chloroplasts but the latter had very little effect, probably due to its pH‐dependent photosensitizing. Both RB and intracellular, nonplastid MVI decreased PSII electron transport, but the effect of RB was stronger than that of MVI and only RB was capable of damaging the D1 protein. Intercellularly localized IC had no significant effect. Our results also suggest caution when using RB as photosensitizer because it affects PSII electron transport.     

Electronic Characterization of Reaction Intermediates: The Fluorenylium,Phenalenylium, and Benz[f]indenylium Cations and Their Radicals

Three vibrationally resolved absorption systems commencing at 538, 518, and 392 nm were detected in a 6 K neon matrix after mass‐selected deposition of C₁₃H₉⁺ ions (m/z=165) produced from fluorene in a hot‐cathode discharge ion source. The benz[f]indenylium (BfI⁺: 538 nm), fluorenylium (FL9⁺: 518 nm), and phenalenylium (PHL⁺: 392 nm) cations are the absorbing molecules. Two electronic systems corresponding to neutral species are apparent at 490 and 546 nm after irradiation of the matrix with λ<260 nm photons and were assigned to the FL9 and BfI radicals, respectively. The strongest peak at 518 nm is the origin of the 2 ¹B₂←X̃ ¹A₁ absorption of FL9⁺, and the 490 nm band is the 2 ²A₂←X̃ ²B₁ origin of FL9. The electronic systems commencing at 538 nm and 546 nm were assigned to the 1 ¹A₁←X̃ ¹A₁ and 1 ²A₂←X̃ ²A₂ transitions of BfI⁺ and BfI. The 392 nm band is the 1 ¹E′←X̃ ¹A₁′ transition of PHL⁺. The electronic spectra of C₁₃H₉⁺/C₁₃H₉ were assigned on the basis of the vertical excitation energies calculated with SAC‐CI and MS‐CASPT2 methods.     

Electronic Characterization of Reaction Intermediates: The Fluorenylium,Phenalenylium, and Benz[f]indenylium Cations and Their Radicals

Three vibrationally resolved absorption systems commencing at 538, 518, and 392 nm were detected in a 6 K neon matrix after mass‐selected deposition of C₁₃H₉⁺ ions (m/z=165) produced from fluorene in a hot‐cathode discharge ion source. The benz[f]indenylium (BfI⁺: 538 nm), fluorenylium (FL9⁺: 518 nm), and phenalenylium (PHL⁺: 392 nm) cations are the absorbing molecules. Two electronic systems corresponding to neutral species are apparent at 490 and 546 nm after irradiation of the matrix with λ<260 nm photons and were assigned to the FL9 and BfI radicals, respectively. The strongest peak at 518 nm is the origin of the 2 ¹B₂←X? ¹A₁ absorption of FL9⁺, and the 490 nm band is the 2 ²A₂←X? ²B₁ origin of FL9. The electronic systems commencing at 538 nm and 546 nm were assigned to the 1 ¹A₁←X? ¹A₁ and 1 ²A₂←X? ²A₂ transitions of BfI⁺ and BfI. The 392 nm band is the 1 ¹E′←X? ¹A₁′ transition of PHL⁺. The electronic spectra of C₁₃H₉⁺/C₁₃H₉ were assigned on the basis of the vertical excitation energies calculated with SAC‐CI and MS‐CASPT2 methods.