Zinc-specific fluorescent response of tris(isoquinolylmethyl)amines (isoTQAs)

Isoquinoline-based tetradentate ligands with C(3)-symmetry, tris(1- or 3-isoquinolylmethyl)amine (1- or 3-isoTQA), have been prepared and their zinc-induced fluorescence enhancement was investigated. Upon excitation at 324 nm, 1-isoTQA shows very weak fluorescence (? = ～0.003) in DMF/H(2)O (1/1) solution. In the presence of zinc ion, 1-isoTQA exhibits fluorescence increase (? = 0.041) at 359 and 470 nm. This fluorescence enhancement at 470 nm is specific for zinc. However, 3-isoTQA exhibited a smaller fluorescence enhancement upon zinc complexation (? = 0.017, λ(em) = 360 and 464 nm) compared with 1-isoTQA. Crystal structures of zinc complexes of isoTQAs demonstrate the diminished steric crowding and shorter Zn-N(aromatic) distances compared with isoTQENs (N,N,N',N'-tetrakis(isoquinolylmethyl)ethylenediamines) leads to a higher fluorescent response toward zinc relative to cadmium.     

Isoquinoline-based TQEN family as TPEN-derived fluorescent zinc sensors

The hexadentate nitrogen ligands 1-isoTQEN ( N,N,N',N'-tetrakis(1-isoquinolylmethyl)ethylenediamine) and 3-isoTQEN ( N,N,N',N'-tetrakis(3-isoquinolylmethyl)ethylenediamine) have been prepared. The structures of these ligands are based on that of TPEN ( N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine). The introduction of a benzene ring into TPEN affords fluorescence ability upon zinc-ion binding. Compared to the quinoline isomer TQEN, isoquinoline derivatives 1-isoTQEN and 3-isoTQEN exhibit a lower-energy shift in the excitation and emission wavelengths and an enhanced fluorescence intensity, probably because of the energy-transfer mechanism between adjacent isoquinoline rings. Importantly, an increase in the Zn (2+)/Cd (2+) discriminating ability and a reduction in the background fluorescence induced by pH were also achieved for isoquinoline derivatives. The zinc-ion-induced fluorescence of these isoTQENs was not quenched by an addition of TPEN, which demonstrates the significantly high zinc-ion binding ability of these isoTQEN ligands.     

Tetrakis(2-quinolinylmethyl)ethylenediamine (TQEN) as a new fluorescent sensor for zinc

A new fluorescent sensor for zinc that binds 1 equivalent of zinc ion, N,N,N',N'-tetrakis(2-quinolylmethyl)ethylenediamine (TQEN), has been prepared and characterized. Zinc-bound TQEN exhibits fluorescence around 383 nm upon excitation at 317 nm, while free TQEN emits very weak fluorescence. UV-Vis and 1H NMR spectral changes also detected the binding of TQEN with zinc ion. The crystal structure of zinc complex with TQEN was determined by X-ray crystallography and compared with that of the TPEN-Zn complex (TPEN =N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine). The binding affinity of TQEN with zinc ion is very high (Kd < 1 microM in aqueous dmf solution). Competition experiments reveal that the zinc-binding affinity of TQEN is lower than the parent, strong metal ion chelator TPEN, and comparable to EGTA (EGTA = ethylene glycol-bis(2-aminomethyl)-N,N,N',N'-tetraacetic acid).     

Specific spectrofluorimetric determination of chloroquine in blood plasma

Chloroquine (? 150 ng ml^?1 is separated from its dealkylated metabolites by reacting the latter with ethylchloroformate followed by extraction of unchanged chloroquine into dilute acid. The aqueous extract is made alkaline and its fluorescence intensity (λ(ex) = 335 nm, λ(em) = 390 nm) is measured.     

Methoxyquinoline-diethylenetriamine conjugate as a fluorescent zinc sensor

A 6-methoxyquinoline conjugated diethylenetriamine derivative, N,N'-bis(6-methoxy-2-quinolylmethyl)diethylenetriamine (6-MeOBQDIEN) has been synthesized and its fluorescent response toward zinc ion was investigated. In the presence of zinc ion, 6-MeOBQDIEN exhibits fluorescence (λ(ex) = 329 nm, λ(em) = 418 nm, φ = 0.039). The fluorescent intensity of the zinc complex of the compound is two times higher than the parent BQDIEN (φ = 0.021) under the same conditions. The crystal structure of 6-MeOBQDIEN-Zn complex shows that all five nitrogen atoms participate to the metal coordination in a distorted square-pyramidal geometry (τ = 0.145) with the aliphatic nitrogen in an apical position. Fluorescent microscopic analysis using 6-MeOBQDIEN reveals the zinc ion concentration change in living cells.     

Methoxy-substituted TQEN family of fluorescent zinc sensors

Two methoxy-substituted TQEN (N,N,N',N'-tetrakis(2-quinolylmethyl)ethylenediamine) derivatives, T(MQ)EN (N,N,N',N'-tetrakis(6-methoxy-2-quinolylmethyl)ethylenediamine) and T(TMQ)EN (N,N,N',N'-tetrakis(5,6,7-trimethoxy-2-quinolylmethyl)ethylenediamine), have been prepared, and their fluorescence properties with respect to Zn2+ coordination were investigated. Introduction of a methoxy substituent at 6-position of the quinoline ring enhances the fluorescence intensity by 10-fold, and the three methoxy substituents in the 5,6,7-positions afford significant enhancement of the long-wavelength component of the fluorescence of zinc complex. The substituents did not alter the binding affinity of these compounds toward zinc ion significantly. T(MQ)EN was proved to be effective in detection of zinc ion in cells by fluorescent microscopy.     

[MeCl4]-型配阴离子-亚甲蓝离子缔合物的溶剂萃取和荧光法测定痕量亚甲蓝

研究了离子缔合物溶剂萃取的适宜条件、有机相中荧光和共振荧光光谱特征, 讨论了离子缔合物的组成和结构, 考察了有关的分析化学性质. 建立了测定痕量亚甲蓝的高灵敏度的方法, 其检出限分别为0.2和0.6 ng/mL(荧光法)以及1.1和2.8 ng/mL(共振荧光法), 荧光法具有更高的灵敏度, 更宜于痕量亚甲蓝的测定. 将该方法用于人血清和尿样中痕量亚甲蓝的测定, 结果较好.     

Water-soluble mitochondria-specific ytterbium complex with impressive NIR emission

A water-soluble porphyrinato ytterbium complex linked with rhodamine B (Yb-2) showed mitochondria-specific subcellular localization and strong two-photon-induced NIR emissions (λ(em) = 650 nm, porphyrinate ligand π → π* transition; λ(em) = 1060 nm, Yb(III) (5)F(5/2) → (5)F(7/2) transitions; σ(2) = 375 GM in DMSO) with an impressive Yb(III) NIR emission quantum yield (1% at λ(ex) = 340 nm; 2.5% at λ(ex) = 430 nm) in aqueous solution.     

含有双发色团的化合物分子内能量传递的研究

合成了一系列含有萘环和蒽环的不同链长的二元化合物, 简写为N-Mn-A(n=2,4,6,8,10)。在有机溶剂中做了上述系列化合物的荧光光谱。激发波长为λex=280nm时, 发现荧光光谱中有两个发射峰, λem1=370nm, λem2=450nm。前者为萘的荧光峰, 后者为蒽的荧光峰。实验证明, 只有萘吸收280nm的光, 而蒽无吸收。所以在激发萘的条件下, 能量由处于激发态的萘环传向了外于基态的蒽环。在不同的有机溶剂中, 分别做了该系列化合物的荧光光谱随浓度的变化。实验结果指出, 两个荧光峰强度的比值不随浓度的变化而变化, 表明其能量传递为分子内的能量传递。另外在1%的糖淀粉水溶液中, N-Mn-A的浓度为1.0×10^-^5mol.dm^-^3,通过荧光光谱发现没有发生能量传递。表明处于伸展状态的N-Mn-A化合物分子不能发生能量传递。     

新型荧光试剂1-(8-喹啉)-3-(3,5-二溴-2-吡啶)-三氮烯的合成及其应用

将具有荧光特性的杂环8-氨基喹啉和吡啶类试剂结合,并引入三氮烯结构,合成了新型荧光试剂1-(8-喹啉)-3-(3,5-二溴-2-吡啶)-三氮烯(QBPyT)。其结构经元素分析、红外光谱、核磁共振波谱证实。研究结果表明,在pH 9.5硼酸-氢氧化钠缓冲溶液的介质存在下,该试剂在λex/λem=248nm/496nm处产生强荧光,并且能与铅(Ⅱ)形成配合物从而使荧光增强。据此建立了三氮烯测定铅(Ⅱ)的新型荧光分析法。铅的浓度在5.0×10-7～1.2×10-5 mol.L范围内与其荧光强度呈线性关系,检出限(3S/N)为9.5×10-8 mol.L。将其应用于水样中铅(Ⅱ)的测定,测得回收率在92.6%～94.0%之间,测定值的相对标准偏差(n=5)小于3.5%。     

Nickel(II)-induced excimer formation of a naphthalene-based fluorescent probe for living cell imaging

Ni(2+)-induced intramolecular excimer formation of a naphthalene-based novel fluorescent probe, 1-[(naphthalen-3-yl)methylthio]-2-[(naphthalen-6-yl)methylthio]ethane (L), has been investigated for the first time and nicely demonstrated by excitation spectra, a fluorescence lifetime experiment, and (1)H NMR titration. The addition of Ni(2+) to a solution of L (DMSO:water = 1:1, v/v; λ(em) = 345 nm, λ(ex) = 280 nm) quenched its monomer emission, with subsequent enhancement of the excimer intensity (at 430 nm) with an isoemissive point at 381 nm. The fluorescence lifetime of free L (0.3912 ns) is much lower than that of the nickel(2+) complex (1.1329 ns). L could detect Ni(2+) as low as 1 × 10(-6) M with a fairly strong binding constant, 2.0 × 10(4) M(-1). Ni(2+)-contaminated living cells of plant origin could be imaged using a fluorescence microscope.     

Environment-sensitive fluorophores with benzothiadiazole and benzoselenadiazole structures as candidate components of a fluorescent polymeric thermometer

An environment-sensitive fluorophore can change its maximum emission wavelength (λ(em)), fluorescence quantum yield (Φ(f)), and fluorescence lifetime in response to the surrounding environment. We have developed two new intramolecular charge-transfer-type environment-sensitive fluorophores, DBThD-IA and DBSeD-IA, in which the oxygen atom of a well-established 2,1,3-benzoxadiazole environment-sensitive fluorophore, DBD-IA, has been replaced by a sulfur and selenium atom, respectively. DBThD-IA is highly fluorescent in n-hexane (Φ(f) =0.81, λ(em) =537?nm) with excitation at 449?nm, but is almost nonfluorescent in water (Φ(f) =0.037, λ(em) =616?nm), similarly to DBD-IA (Φ(f) =0.91, λ(em) =520?nm in n-hexane; Φ(f) =0.027, λ(em) =616?nm in water). A similar variation in fluorescence properties was also observed for DBSeD-IA (Φ(f) =0.24, λ(em) =591?nm in n-hexane; Φ(f) =0.0046, λ(em) =672?nm in water). An intensive study of the solvent effects on the fluorescence properties of these fluorophores revealed that both the polarity of the environment and hydrogen bonding with solvent molecules accelerate the nonradiative relaxation of the excited fluorophores. Time-resolved optoacoustic and phosphorescence measurements clarified that both intersystem crossing and internal conversion are involved in the nonradiative relaxation processes of DBThD-IA and DBSeD-IA. In addition, DBThD-IA exhibits a 10-fold higher photostability in aqueous solution than the original fluorophore DBD-IA, which allowed us to create a new robust molecular nanogel thermometer for intracellular thermometry.     

荧光衍生中性糖的高效液相色谱分析

在HypersilODS2色谱柱上,利用新型荧光试剂1,2-苯并-3,4-二氢咔唑-9-乙基肼基甲酸酯(BCEC)作柱前衍生化试剂,采用梯度洗脱对5种中性糖荧光衍生物进行了优化分离.65℃下在乙腈溶剂中以冰乙酸作催化剂,衍生反应6.5h后获得稳定的荧光产物,衍生反应完全.激发和发射波长分别为λex=333nm,λem=390nm.线性回归系数均在0.999以上,检测限为24.3～62.1fmol.     

新型含吲哚基噻唑烷硫酮化合物的合成及其光学性质

以吲哚-2-甲酸为起始原料,经酰氯化后在三乙胺作用下与2-噻唑硫酮经缩合反应合成了一种新的含吲哚基噻唑烷硫酮化合物(3),其结构和光学性质经UV-Vis, FL, ¹H NMR, IR和X-射线单晶衍射表征。结果表明：3的最大吸收波长位于315 nm;在312 nm波长激发下,3在正己烷中的最大发射波长位于401 nm,荧光量子产率为0.16;在305 nm波长激发下,3的固体荧光最大发射波长位于476 nm。     

Synthesis, Structure, and Photoluminescence Property of a Novel One-dimensional Inorganic-organic Hybrid Gallophosphate JGP-2

A novel one-dimensional inorganic-organic hybrid gallophosphate compound, Ga(2,2′-bipy)(HPO4)· (H2PO4)(denoted JGP-2) was synthesized hydrothermally with 2,2′-bipyridine as a ligand and characterized by X-ray powder diffraction (XRD), elemental analysis, inductively coupled plasma(ICP), TGA analysis, solid-state 31P NMR, and luminescence spectra and structurally determined by single-crystal X-ray diffraction analysis. JGP-2 crystallized in the triclinic system, space group Pī(No.2), with a=0.7818(1) nm, b=0...     

脂肪胺荧光衍生物的高效液相色谱分离及质谱鉴定

采用新型荧光衍生试剂2-(9-吖啶酮)-乙酸(AAA)进行柱前衍生并经荧光检测对脂肪胺进行了高效液相色谱(HPLC)分离和在线质谱定性.衍生物荧光激发和发射波长为λex=404nm,λem=440nm.30℃下在乙腈溶剂中用N-乙基-N′-[(3-二甲氨基)丙基]碳二亚胺盐酸盐(EDC)做催化剂,衍生反应20min后获得稳定的荧光产物.在HypersilBDSC18(4.6mm×100mm,5μm)色谱柱上,采用梯度洗脱对12种脂肪胺衍生物进行了优化分离.采用大气压化学电离源(APCISource)正离子模式进行在线柱后质谱定性,实现了各种脂肪胺衍生物的快速、准确测定.该方法具有良好的重现性,多数脂肪胺的线性回归系数大于0.9996,检测限为12.09~25.52fmol.     

新型荧光衍生试剂用于脂肪胺的反相高效液相色谱-荧光检测分析

利用新型荧光试剂4-(1H-菲并[9,10-d]咪唑-2-)苯甲酸(PIBA)进行柱前衍生并经荧光检测对脂肪胺进行了高效液相色谱(HPLC)分离和在线质谱定性。激发和发射波长分别为ex=261nm,em=443nm。80℃下在吡啶溶剂中用N-乙基-N’-[(3-二甲氨基)丙基]碳二亚胺盐酸盐(EDC)做催化剂,衍生反应10min后获得稳定的荧光产物。在EclipseXDB-C8色谱柱(4.6150mm,5mm)上,梯度洗脱对12种游离脂肪胺衍生物进行了优化分离。采用大气压化学电离源(APCI)正离子模式,实现了各种脂肪胺衍生物的测定。多数脂肪胺的线性回归系数大于0.9999,检测限为10.5～53.4fmol。     

铜-硫堇同步荧光光谱行为研究及其应用

研究了Cu2+对硫堇(TH)荧光光谱的影响,发现Cu2+对TH的荧光有猝灭作用。为了消除瑞利散射的干扰,进一步考察了Cu2+对TH同步荧光(Δλ=4～12 nm)的猝灭情况,并确定λex为626 nm,λem为635 nm(Δλ=9 nm)为工作波长。在同步荧光猝灭度(ΔF)与Cu2+质量浓度(ρCu2+)之间呈良好的线性关系,并据此建立了测定Cu2+的新方法。Cu2+的线性范围0.0133～0.975μg/mL,检出限为0.004μg/mL,加标回收率为97.4%～104.2%。该方法可用于自来水和矿泉水中痕量铜的测定。     

EASC荧光标记和LC-APCI-MS检测环境水样中游离脂肪胺

采用新型荧光标记试剂10-乙基吖啶酮-2-磺酰氯(EASC)作为柱前衍生试剂, 在Hypersil BDS C18反相色谱柱上(4.6 mm×200 mm, 10 μm i.d.), 采用梯度洗脱在20 min内实现了12种EASC-脂肪胺衍生物的快速基线分离. 最佳检测波长为λex/λem=270 nm/430 nm. EASC与常用的Dansyl-Cl相比具有更强的光致发光特性(紫外和荧光): 紫外吸收强度之比为3.2∶1, 相对荧光强度之比为30.0∶1~105.4∶1, 荧光量子效率之比为43.0∶1. 通过荧光检测及离子阱大气压化学电离源的正离子模式获得了胺类组分的准确定量和相应的柱后质谱鉴定. 质谱灵敏度之比为1.6∶1~6.2∶1. 建立的方法对环境水样中脂肪胺类化合物的测定具有快速、准确和重现性良好等优点, 回归系数大于0.9995, 检出限为4.0~12.7 fmol.     

Application of 10‐ethyl‐acridine‐3‐sulfonyl chloride for HPLC determination of aliphatic amines in environmental water using fluorescence and APCI‐MS

A simple, sensitive method for the determination of aliphatic amines based on a sulfonylation reaction using 10‐ethyl‐acridine‐3‐sulfonyl chloride (EASC) as pre‐column labeling reagent with fluorescence detection and APCI‐MS identification has been developed. The labeled derivatives exhibited high stability and were enough to be efficiently analyzed by HPLC with an excitation maximum at λ_ex 270 nm and an emission maximum at λ_em 430 nm. Identification of derivatives was carried out by online post‐column MS in positive‐ion mode. Comparing with the widely used 5‐dimethylaminonaphthalene‐1‐sulfonylchloride (Dansyl‐Cl), EASC‐amine derivatives not only exhibited high fluorescence but also exhibited excellent MS ionizable potential. Detection limits obtained from 0.10 pmol injection, at a S/N of 3, were 4.0–12.7 fmol. The mean intra‐ and inter‐assay precision for all aliphatic amine levels were <3.84 and 3.21%, respectively. Excellent linear responses were observed with coefficients of >0.9995.