射流式单重态氧发生器研究

单重态氧O2 (a1Δg)是迄今唯一能用纯化学反应高效产生的具有长寿命的亚稳激发态分子 .为了考察提出的用两个O2 (1Δ)能量汇集反应生成氧第二单重激发态O2 (b1Σ+ g)以实现近可见短波长化学激光方案的现实性 ,设计和实验了一个氯流量为 3～ 10mmol/s的射流式单重态氧发生器 (JSOG) .考察了三种具有不同孔径和孔数目的喷头、氯气流量和脱水冷阱温度等对JSOG出口的O2 (1Δ)浓度、O2 (1Δ)分压、氯利用率及水蒸气含量的影响 .发现用聚氯乙烯管作冷阱时 ,最佳冷阱介质温度为 - 140～ - 15 0℃ ,对此提出了O2 (1Δ)表面脱活与脱水互相竞争的解释 .在最佳条件下 ,可将O2 (1Δ)气中水分压降低至 4Pa ,这一结果是首次报导     

Synthesis and Characterization of New Fluorene-Based Singlet Oxygen Sensitizers

The synthesis, photophysical characterization, and determination of singlet oxygen quantum yields (Φ_Δ) for a class of fluorene derivatives with potential application in two-photon photodynamic therapy (PDT) is reported. It has been demonstrated that these compounds possess the ability to generate singlet oxygen (¹O₂) upon excitation. A photochemical method, using 1,3-diphenylisobenzofuran (DPBF) as ¹O₂ chemical quencher, was employed to determine the singlet oxygen quantum yields (Φ_Δ) of the fluorene-based photosensitizers in ethanol. Φ_Δ values ranged from 0.35 to 0.75. These derivatives may have potential application as two-photon photosensitizers when pumped via two-photon excitation in the near-IR spectral region.     

钯酞菁配合物的荧光光谱与单线态氧的生成速率

分别测定了四-α-(2,2,4-三甲基-3-戊氧基)酞菁钯(锌)和四-α-(2,4-二叔丁基苯氧基)酞菁钯(锌)配合物的紫外-可见电子吸收光谱,荧光发射光谱和单线态氧生成速率,结果表明虽然酞菁钯的中心金属离子为开壳层电子结构,但其生成单线态氧(1O₂)的能力与中心金属为闭壳层结构的相应取代酞菁锌相近,这可能是与其荧光发射很弱,系间串跃很强相关。     

亚磷酸三苯酯臭氧化合物分解产生单重态氧的研究

现在世界上功率最大的短波长化学激光、氧碘化学激光是以亚稳态的O2 (a1△)作为储能分子,通过近共振碰撞传能给碘原子,使碘原子激发而发射激光,因此,O2 (a1△)的发生是其主要关键技术.目前使用的方法是H2 O2 的碱溶(BHP)与Cl2 气反应[1] .它具有化学效率高的优点,但此方法产生的O2 (a1△)中含有水份,而水对碘原子具有强的猝灭作用;另外,BHP不能长期保存;氯气还有毒性.196 1年Thompson发现,在- 78℃时亚磷酸三苯酯(TPP)与O3加成为亚磷酸三苯酯臭氧化合物(TPPO3) [2 ] ,并在高于- 35℃分解产生O2 (a1△) .　(C6 H5O) 3P +O3-78℃(…     

光敏化反应生成单线态氧的电子耦合计算及其分子轨道重叠描述

三重态融合反应又称三重态-三重态湮灭反应,近年来被广泛应用于光催化、太阳能电池和生物成像等前沿领域. 在光敏化生成单线态氧的反应中,三重态激发的光敏剂分子通过三重态融合反应将激发态能量传递给基态氧分子³O₂,生成单重态的激发氧分子即单线态氧. 本文以6-aza-2-thiothymine为光敏剂,通过量子化学计算得到该反应的非绝热耦合强度,然后通过分子间运动下的积分转换,得到反应的透热电子耦合强度. 最后使用光敏剂分子和O₂的前线分子轨道计算轨道重叠强度,对量子化学计算得到的电子耦合值进行拟合,验证三重态融合反应的分子轨道重叠描述. 结果表明,分子轨道重叠可以较好地描述不同间距下光敏剂-O₂三线态融合反应的电子耦合强度分布,为预测三重态融合反应电子耦合提供了一种简便而有效的新方法.     

The Effect of Temperature and Excitation on the Single- and Two-Photon Excited Emission Spectrum of Curium in a Glass Matrix

Single and two-photon excited emission has been observed from a curiumdoped borosilicate glass matrix at both room and liquid nitrogen temperatures. The emission spectrum was measured using several different excitation energies and intensities. In addition to the expected line narrowing, variations in the ratios of emission intensities between states, and between crystal field levels within the each state were observed with cooling. Slight variations in the emission spectrum also arose as a function of the excitation intensity. These variations in the Cm ion's emission spectrum as a function of experimental parameters are presented and discussed.     

关于PDT光敏剂敏化效应光谱及其量子产率的研究

从实验的角度研究了HA光敏剂激发态的敏化特性,建立了单态氧量子产率在近红外区的荧光光谱测量系统,测定了HA光敏剂的单态氧量子产率为0．78。结果表明,该类光敏剂具有较强的敏化效应,是一类有前途的光动力治疗(PDT)候选光敏剂。     

Electronic Energy Transfer from Sinclet Molecular Oxygen to Carotenoids

Abstract

Aerated benzene solutions containing anthracene together with one of the carotenoids, β-carotene, β-apo-8′-carotenal, ethyl β-apo-8′-carotenate and canthaxanthin were subjected to laser photolysis. Under these conditions oxygen quenching of triplet anthracene produces the excited singlet state of molecular oxygen O₂? (¹δ_g) which in turn transfers energy to the carotenoid thereby yielding its triplet state, the absorption of which was monitored thereby confirming electronic energy transfer as the mechanism of quenching of O₂ ?(¹δ_g) by these carotenoids and enabling the bimolecular quenching constansts which vary from 1.2 – 1.45 × 10¹⁰ 1 mol^?1s^?1 to be measured.     

青蒿素光化学合成中二氢青蒿酸与单线态氧反应的动力学研究

青蒿素是一种优异的抗疟药,广泛用于临床医学. 但由于青蒿素天然来源的限制,青蒿素的化学合成一直受到高度关注. 二氢青蒿酸是合成青蒿素的关键前体. 二氢青蒿酸与单线态氧反应形成过氧化物是青蒿素光化学制备中的关键步骤,制约着青蒿素化学合成的产率. 然而关于二氢青蒿酸与单线态氧反应的重要动力学信息并未有报道. 本文通过光敏化法产生单线态氧,研究二氢青蒿酸与单线态氧之间的反应速率常数. 通过直接检测单线态氧在1270 nm处的发光衰减动力学,得出单线态氧与二氢青蒿酸在不同溶剂中的反应速率常数分别为：在CCl₄中为1.81×10⁵ (mol/L)^-1·s^-1,在CH₃CN中为5.69×10⁵ (mol/L)^-1·s^-1,DMSO中为3.27×10⁶ (mol/L)^-1·s^-1. 发现在三种溶剂中二氢青蒿酸与单线态氧的反应速率常数随着溶剂极性的增加而增加. 这些结果为优化青蒿素光化学合成的实验条件提供了基础知识,有助于提高青蒿素的合成效率.     

硫代碱基与单态氧反应速率常数的时间分辨光谱测定

硫代碱基作为一类免疫抑制性药物被广泛关注,由于硫原子的取代,硫代碱基可以吸收UVA波段紫外光,并通过系间窜越至激发三重态敏化氧气生成广泛应用于光动力学治疗的活性氧物质单态氧(~1O_2).然而,硫代碱基容易与自身敏化产生的~1O_2氧化发生反应,导致光毒性.在已有关于硫代碱基与~1O_2反应机理的研究基础上,本文采用瞬态光谱方法直接测得~1O_2在1270 nm处磷光信号的衰减动力学,得到硫代碱基与单态氧反应的速率常数.通过比较6-硫代鸟嘌呤、4-硫代尿嘧啶、2,4-二硫代尿嘧啶分别在水、乙腈以及二者混合溶剂中与~1O_2的反应,发现硫代碱基与单态氧反应速率常数受溶剂的极性影响.随着溶剂极性增大,反应速率常数则减小.此外,通过对比研究,发现硫代嘧啶类碱基与~1O_2的反应速率小于硫代嘌呤类碱基,说明在光动力学治疗中以硫代嘧啶类药物作为光敏剂是较为合适的选择.     

瞬态磷光发射光谱研究阿替洛尔与单线态氧反应的动力学

药物活性化合物阿替洛尔是一种β受体阻滞剂,若将其排放到地表水资源中会对人类健康和生态系统产生不利的影响. 受光驱动的直接光降解以及间接光降解法可以有效去除环境中的阿替洛尔. 在间接光降解方法中,¹O₂是降解阿替洛尔这类污染物的重要活性物种. 然而,关于阿替洛尔与¹O₂反应动力学的信息还比较缺乏,二者间的反应速率常数仍存在争议. 本文通过直接观察¹O₂在1270 nm处衰减动力学来研究阿替洛尔与¹O₂在不同溶剂中的反应速率常数：在重水中为7.0×10⁵ (mol/L)^-1·s^-1,在乙腈中为8.0×10⁶ (mol/L)^-1·s^-1,在乙醇中为8.4×10⁵ (mol/L)^-1·s^-1. 在极性强、给氢能力弱的溶剂中阿替洛尔与¹O₂的反应速率常数更大. 这些结果对光降解阿替洛尔等β受体阻滞剂提供相关动力学信息.     

Pentacene Nanorods as Effective Photosensitizer for Photodynamic Therapy of Tumor via Singlet Fission

Singlet fission (SF), whereby a singlet exciton is converted into a pair of triplet excitons, can improve the efficiency of solar cells. Pentacene has been extensively studied as the most promising SF compound, owing to its 200% yield of triplet states. However, the easy degradation of pentacene in the presence of light and air owing to photooxidation cannot be explained by the classical ¹O₂ generation mechanism. To address this issue, in the present study, pentacene nanorods (Pc NRs) are prepared as a novel photosensitizer (PS); self-carried Pc NRs exhibited higher ¹O₂ generation capacity. Thus, a novel ¹O₂ generation mechanism is proposed based on the SF effect. The initial photon absorption occurs to access single-exciton states, S1–S3. Excited-state Pc pairs accelerate the SF effect in pentacene NRs, leading to a non-adiabatic transition to the dark D state. Dark D state is a singlet state by two triplets coupled overall, and it can transfer its energy to ³O₂ for generating ¹O₂. Using Pc NRs as PSs, photodynamic therapy (PDT) inhibits tumor growth in 4T1 tumor-bearing mice upon 405-nm-wavelength and 650-nm-wavelength laser irradiations. This study paves the way to discover novel PSs that are not considered with classical ¹O₂ generation mechanisms.     

皂化残液化学需氧量的快速测定方法研究

以Na2CO3粉末处理皂化残液沉淀Ca2 可以消除CaSO4对光度法测定结果的干扰,催化剂NiSO4-CuSO4配比为80:20,通过正交设计法得到消化最佳实验条件为:消化温度175℃、浓硫酸用量30mL、催化剂用量0.2g、消化时间15min.本法测定的CODcr值与标准回流法所得结果一致,且本法比标准回流法省时.     

Singlet Oxygen Generating Properties of Different Sizes of Charged Graphene Quantum Dot Nanoconjugates with a Positively Charged Phthalocyanine

Various sizes of graphene quantum dots (GQDs) denoted as GQD₂, GQD₆ and GQD₁₀ (increasing in size) were non-covalently attached to 2,9,16,23-tetrakis[4-(N-methylpyridyloxy)]-phthalocyanine (ZnTPPcQ) to form GQDs-ZnTPPcQ nanoconjugates. X-ray photoelectron spectroscopy (XPS) showed that increasing sizes of GQDs decreases the atomic concentrations of oxygen, which leads to blue shift in spectra of the GQDs. Relative to Pcs alone (0.03), the presence of GQDs improved the singlet oxygen quantum yields with the following values: GQD₂-ZnTPPcQ (0.17), GQD₆-ZnTPPcQ (0.27) and GQD₁₀-ZnTPPcQ (0.11). GQD₂-ZnTPPcQ nanoconjugate system had the most ZnTPPcQ loading, but did not generate the most singlet oxygen species due to aggregation. This study shows that, the quantity of oxygen, size and quality of GQDs as well as amount of Pc loading are amongst the vital properties to consider when constructing GQD-nanoconjugate systems with optimal singlet oxygen quantum yields.     

光敏剂对肿瘤细胞损伤效应与孵育时间关系的拉曼光谱分析

利用拉曼光谱研究光敏剂与HepG2肝癌细胞不同孵育时间的光动力损伤效应。结果表明孵育时间与光动力损伤效应成正相关性,但孵育时间超过一定值,延长孵育时间并不能提高光动力损伤效应。     

新型光敏剂二氢卟吩e_6-C_(15)单甲酯荧光光谱特性及其体内分析应用

研究了二氢卟吩e_6-C_(15)单甲酯在不同溶剂体系中的荧光光谱特性,据此建立了检测血浆中二氢卟吩e_6-C_(15)单甲酯的荧光分析法。首先,通过比较分析二氢卟吩e_6-C_(15)单甲酯在甲醇、乙醇、丙酮、乙腈、磷酸盐缓冲液和水六种不同溶剂体系中的荧光光谱特征,考察了溶剂体系对二氢卟吩e_6-C_(15)单甲酯荧光光谱特性的影响,结果发现甲醇和乙腈是比较理想的溶剂体系,而磷酸盐缓冲液优于水溶液。通过进一步考察有机溶剂含量和溶液pH对二氢卟吩e_6-C_(15)单甲酯发射波长和荧光强度的影响,结果表明pH 7.2磷酸盐缓冲液-乙腈(3:7)混合溶液中二氢卟吩e_6-C_(15)单甲酯荧光强度大、性质稳定。采用pH 7.2磷酸盐缓冲液-乙腈(3:7)混合溶液沉淀SD大鼠血浆蛋白,选择498.00和664.05 nm作为激发波长和发射波长,建立的SD大鼠血浆样品中二氢卟吩e_6-C_(15)单甲酯荧光分析法专属性好,灵敏度高,线性范围为0.50~50.00μg·mL~(-1)(R~2≥0.999),批内和批间精密度RSD均小于10%,提取回收率大于90%。该方法简便、快速、可靠,成功地应用于二氢卟吩e_6-C_(15)单甲酯在SD大鼠体内的药代动力学研究。     

氧弹分解ICP-AES法测定煤中砷的应用研究

应用电感耦合等离子体原子发射光谱法,对煤样在氧弹燃烧后获得的试液进行砷的分析测定。系统地研究了基体元素对被测元素分析线的光谱干扰,选择了氧弹分解ICP-AES法测定的最佳条件。方法检出限为0.013μg·mL-1,相对标准偏差<6％。经国家一级标准物质分析验证,结果与推荐值相符。     

水体中溶解氧的静态注射化学发光法测定

建立了静态注射化学发光碘与鲁米诺体系测定水体中的溶解氧,线性方程为y=4.32×10^6＋1.29×10^7x,相关系数0.9951,与滴定分析方法相比无显著性差异,方法简单、快速,适于环境监测部门的质量监控。     

Metal-enhanced Singlet Oxygen Generation: A Consequence of Plasmon Enhanced Triplet Yields

In this Rapid Communication, we report the first observation of Metal-Enhanced singlet oxygen generation (ME¹O₂). Rose Bengal in close proximity to Silver Island Films (SiFs) can generate more singlet oxygen, a three-fold increase observed, as compared to an identical glass control sample but containing no silver. The enhanced absorption of the photo-sensitizer, due to coupling to silver surface plasmons, facilitates enhanced singlet oxygen generation. The singlet oxygen yield can potentially be adjusted by modifying the choice of MEF (Metal-Enhanced Fluorescence) & MEP (Metal Enhance Phosphorescence) parameters, such as distance dependence for plasmon coupling and wavelength emission of the coupling fluorophore. This is a most helpful observation in understanding the interactions between plasmons and lumophores, and this approach may well be of significance for singlet oxygen based clinical therapy.     

The Influence of Human Serum Albumin on The Photogeneration of Singlet Oxygen by meso-Tetra(4-Sulfonatophenyl)Porphyrin. An Infrared Phosphorescence Study

meso-Tetra(4-sulfonatophenyl)porphyrin (TPPS₄) is a water soluble photosensitizer, which is currently clinically tested as a PDT drug. In our contribution, we present IR spectral- and time-resolved phosphorescence data reflecting the influence of human serum albumin (HSA) on singlet oxygen photogeneration by TPPS₄. IR emission of TPPS₄ was studied in samples containing various concentrations of HSA in phosphate buffer. The observed changes in spectral and temporal behaviour of TPPS₄ and singlet oxygen phosphorescence caused by the addition of HSA are equivalent to the effect of nitrogen purging of HSA-free solutions of TPPS₄. The main feature induced by addition of HSA appears to be the occurrence of a long-lived (tens of microseconds) photosensitizer phosphorescence at 900 nm besides ordinary short-lived (≈2 μs) one at 820 nm. It is accompanied by presence of a long-lived component of singlet oxygen emission with lifetime roughly corresponding to that of the long photosensitizer phosphorescence component. Moreover, the quantum yield of singlet oxygen phosphorescence decreases with increasing HSA concentration, while total quantum yield of TPPS₄ phosphorescence rises. These facts are explained by a shielding effect of HSA on bound molecules of TPPS₄ against quenching by oxygen which is analogous to oxygen removal by nitrogen purging.