一种新型苯并咪唑-酰腙衍生物用于比色和荧光识别F~-和AcO~-

合成出了1个新的苯并咪唑-酰腙衍生物,N'-(2-羟基-1-萘基)亚甲基-2-[2-(4-甲基苯磺酰基甲基)-1H-苯并咪唑-1-基]乙酰肼(L),并利用IR,~1H NMR,~(13)C NMR,HRMS和元素分析对其结构进行了表征.利用裸眼、紫外-可见与荧光光谱研究了L对阴离子的识别性能.研究结果表明,向化合物L的CH_3CN溶液中加入F~-,Ac O~-和H _2PO_4~-后,溶液由无色变为亮黄色.在紫外灯下(λ=365 nm),加入F~-和AcO~-后,L的溶液发射出黄色荧光.表明化合物L可作为裸眼识别F~-,AcO~-和H_2PO_4~-的探针.紫外和荧光光谱实验结果显示,探针L可高选择性和高灵敏性识别F~-和AcO~-.探针L与F~-和AcO~-的结合常数(K_a)分别为4.25×10~3和2.96×10~4 L·mol~(-1),检出限(DL)分别为3.63×10~(-7)和8.51×10~(-8) mol·L~(-1).Job曲线和密度泛函理论(DFT)计算证明,探针L与F~-/AcO~-是1∶1配位.通过~1H NMR滴定确定了探针L与F~-/Ac O~-的络合机理.实验结果表明,化合物L可作为检测F~-和AcO~-的比色和荧光探针.     

基于席夫碱的氟离子比色探针的合成及识别性能研究

设计合成了新型的席夫碱探针2-羟基-1-萘甲醛缩-2-吡啶甲酰腙(L),通过红外、质谱、核磁氢谱和碳谱,对其结构予以了表征。利用紫外-可见吸收光谱研究了探针分子L对不同阴离子(F~-,Cl~-,Br~-,I~-,NO_3~-,CH_3COO~-,HSO_4~-,H_2PO_4~-,ClO_4~-)的识别性能,结果显示在乙腈体系中探针L对F~-具有单一选择性识别作用,可以实现对氟离子的裸眼识别。由Benesi-Hildebrand方程(采用紫外滴定光谱计算)显示,探针L与F~-以1:2的化学计量比稳定结合,二者的结合比为1.37×10~9(mol/L)~(-2),检测限为0.319μmol/L。采用~1H-NM R滴定实验研究了探针分子与氟离子的结合机理,结果表明探针L与氟离子先形成氢键然后发生去质子化过程,分子内电荷转移(ICT)是导致探针分子L和F~-作用后紫外-可见吸收光谱红移及颜色变深的主要原因。     

一种新型比色荧光增强型探针识别氟离子

以2-苯基-1,2,3-三唑基-4-甲醛和1,3-二氨基硫脲为原料,通过缩合反应合成了一种新型的席夫碱化合物M1。在M1的DMSO溶液中加入F-时,溶液的颜色由无色变为黄色,同时荧光增强,而加入其它阴离子如Cl~-,CN~-,Br~-,I~-,H2_PO_4~-,HSO_4~-,Ac O~-,NO_3~-等时,M1的溶液颜色和荧光均未发生变化,通过Job's plot和1H NM R滴定等方法研究了M1选择性识别F-的机理。结果表明席夫碱化合物M1作为荧光探针可选择性的比色识别F~-,并且对F~-的检测限为0.26μmol/L。     

一种咪唑并吩嗪内酰胺反应型识别氰离子的荧光探针

设计合成了一种新型咪唑并吩嗪内酰胺荧光传感器分子(S1),通过核磁共振氢谱、碳谱和高分辨质谱等手段对其结构进行了表征,并测定了S1在二甲基亚砜(DMSO)溶液中的荧光光谱,其最大荧光发射波长为524 nm.S1的DMSO溶液具有亮黄色荧光.当在S1的DMSO溶液中分别加入F~-,Cl~-,Br~-,I~-,AcO~-,H_2PO_4~-,HSO_4~-,ClO_4~-和SCN~-等阴离子后,发现只有CN~-的加入使S1的荧光光谱出现明显的下降并发生红移.其溶液荧光颜色由黄色变为橘红色,说明S1对CN~-具有良好的专一选择性.抗干扰实验结果表明,这一识别过程不受其它阴离子干扰.通过计算得到,S1对CN-的荧光光谱最低检测限为9.96×10~(-7)mol/L,这一数值低于世界卫生组织所规定的饮用水中氰离子含量.机理研究表明,S1是一种反应型识别CN~-的荧光传感器.此外,将S1负载于固态硅胶之上,制备成固体CN~-识别材料,并成功用于对固体NaCN的识别和对CN~-水溶液的检测.     

D-π-A型偶氮苯酚探针对氟离子的比色识别

设计合成系列D-π-A偶氮苯酚探针,利用紫外-可见光谱对F~-、Cl~-、Br~-、I~-、HSO_4~-、H_2PO_4~-、NO_3~-和AcO~-阴离子进行识别,考察探针电子结构和空间位阻对F~-识别能力的影响。结果表明,在乙腈中P1～P4对F~-能选择性地识别,检测限达到0.10～0.63μmol·L~(-1)(1.90～11.97 ppm),探针分子与F~-形成的络合物共轭程度增大有利于对F~-识别,识别基团邻位取代基团空间位阻对F~-识别并不产生明显的影响。~1H NMR滴定表明识别机理为探针分子酚羟基与F~-通过氢键结合形成1∶1络合物。     

基于氟引发串联释放的氟硼二吡咯类荧光探针的合成及其识别性能

以4-羟基氟硼二吡咯为荧光团,叔丁基二苯基硅基(TBDPS)作活泼羟基的保护基,设计合成了一种新颖的基于氟离子切断硅氧键,引发释放的氟硼二吡咯类氟离子荧光探针R.光谱实验研究表明,该荧光探针和氟离子作用后,紫外吸收光谱在605 nm处出现新的吸收峰,含R的溶液由橙黄色变成蓝色;荧光发射光谱中在514 nm处最大发射峰出现下降,荧光颜色由绿色变成荧光淬灭.此外,将荧光探针R应用于试纸条件下也能实现对氟离子的裸眼检测.     

基于黄酮醇的高选择性半胱氨酸荧光探针的合成及性能研究

报道了一种基于4’-二乙氨基黄酮醇、以丙烯酸酯为半胱氨酸(Cys)反应基团的荧光增强型探针A1,对Cys的检测响应快速(5 min内),能有效识别区分另外两种含巯基生物分子高半胱氨酸(Hcy)和谷胱甘肽(GSH)。探针溶液荧光强度与加入的Cys浓度呈线性相关,拟合方程为y=6.894x+0.8409(R~2=0.9973),检测限为1×10~(-7)mol/L。加入Cys后,探针溶液由浅色变为亮黄色,在自然光条件下实现对Cys的比色检测。检测机理推测为Cys对A1中的丙烯酰基进行了共轭加成并使酯键断裂,使荧光母体得到释放从而产生增强的荧光信号。探针A1可用于活细胞内对Cys的荧光成像分析。     

用作pH传感器的偶氮水杨醛吖嗪的合成及其阴离子识别研究

本文设计合成了一种对硝基偶氮水杨醛吖嗪pH传感器S1。通过紫外可见分光光度法研究了传感器S1与八种不同阴离子的识别性能。通过向10%HEPES缓冲液(DMSO/HEPES=9∶1,V/V,pH=5.63)的S1中分别加入F~-、Cl~-、Br~-、I~-、AcO~-、SO_4~(2-)、NO_3~-、H_2PO_4~-等阴离子后,发现F~-、AcO~-、H_2PO_4~-的加入使得S1在584、614、622nm处的吸收峰增强,溶液颜色由淡黄色转变为蓝色,同时其它离子的加入无上述现象。Job曲线测定了S1与F~-、AcO~-、H_2PO_4~-的化学计量比均为1∶1,及最低检测限分别为0.39,2.60和12.5μM。通过布朗斯特酸碱反应及密度泛函理论计算说明S1与F~-、AcO~-、H_2PO_4~-之间可能是脱质子化作用。由此可见传感器S1在溶液体系中是一种颜色可调的可视化传感器。     

用于检测过硼酸根离子的新型比值式荧光探针

设计合成了一种基于过硼酸根(BO!3)催化酯键水解机理的新型比值式荧光探针。此探针在pH=7.4的生理环境下,在BO!3的存在时,其荧光发射光谱由419 nm红移至552 nm。利用这一特性,采用此荧光探针对BO!3进行定量检测,检测的线性响应范围为0.1~4.0 mmol/L,检出限为7.8μmol/L。且对常见阴离子及氧化性试剂有较好的选择性。通过对响应前后分子的能级计算,解释了分子内电荷转移机理(ICT)导致的光谱红移现象。     

荧光增强型水合肼香豆素荧光探针的合成与应用

基于水合肼诱导乙酰基脱保护生成亚胺香豆素的原理,设计合成了一种荧光增强型检测水合肼的探针。相对于其他测试物(Cl~-,ClO_4~-,AcO~-,CO_3~(2-),H_2PO_4~-,K~+,Mg~(2+),Ca~(2+),Fe~(2+),Fe~(3+),Cys,GSH,NH_2OH,尿素,苯胺,硫脲,氨水,乙二胺),目标探针表现出对N2H4较高的选择性和专一性,探针溶液在500 nm处呈现显著的荧光恢复(25倍),探针溶液的荧光恢复与加入的水合肼浓度成正向关系,拟合方程为y=17.4309+4.5968x(R=0.9992),检出限2.7×10~(-8)mol/L。细胞荧光成像实验证明了合成的目标探针具有检测生物体系内水合肼的能力。     

A highly selective colorimetric and ratiometric two-photon fluorescent probe for fluoride ion detection

A naphthalimide-based highly selective colorimetric and ratiometric fluorescent probe for the fluoride ion displayed both one- and two-photon ratiometric changes. Upon reaction with the F(-) (TBA(+) and Na(+) salts) anion in CH(3)CN as well as in aqueous buffer solution, probe 1 shows dramatic color changes from colorless to jade-green and remarkable ratiometric fluorescence enhancements signals. These properties are mechanistically ascribed to a fluoride-triggered Si-O bond cleavage that resulted in a green fluorescent 4-amino-1,8-naphthalimide.     

Novel fluorogenic probe for fluoride ion based on the fluoride-induced cleavage of tert-butyldimethylsilyl ether

A highly sensitive and selective fluorogenic probe for fluoride ion, 4-methylumbelliferyl tert-butyldimethylsilyl ether (4-MUTBS), was designed and synthesized. 4-MUTBS was a weakly fluorescent compound and was synthesized via the one-step reaction of 4-MU with tert-butyldimethylsilyl chloride. Upon incubation with fluoride ion in acetone-water solution (7:3, v/v), the Si-O bond of 4-MUTBS was cleaved and highly fluorescent 4-methylumbelliferone (4-MU) was released, hence leading to the fluorescence increase of the reaction solution. The fluorescence increase is linearly with fluoride concentration in the range 50-8000 nmol l(-1) with a detection limit of 19 nmol l(-1) (3sigma). Because of the high affinity of silicon toward fluoride ion, the proposed probe shows excellent selectivity toward fluoride ion over other anions. The method has been successfully applied to the fluoride determination in toothpaste and tap water samples.     

Rh(Ⅱ)催化吲哚衍生物[3+3]环化机理及产物性质分析

采用密度泛函理论研究了双铑催化3-重氮吲哚啉-2-亚胺与2H-吖丙因[3+3]内环化反应过程. 该过程主要包含铑金属卡宾体形成、 C―N键活化裂解和吲哚啉[3+3]内环化反应. 研究结果表明, 双铑催化剂发生偶联作用, 促进C-N偶联及2H-吖丙因C―N键裂解; 反应控速步骤为吲哚[3+3]环化反应过程, 铑催化剂在[3+3]环化前脱出. 对产物吡嗪并吲哚类化合物光电性质的分析表明产物具有较低空穴重组能, 吸收与荧光发射光谱存在较大斯托克斯位移. 因此该产物可作为潜在的空穴传输材料和荧光发射材料.     

An ESIPT-Based Ratiometric Fluorescent Probe for Highly Sensitive and Rapid Detection of Sulfite in Living Cells

The novel ratiometric fluorescent probe HPQRB with an ESIPT effect based on Michael addition for highly sensitive and fast detection of sulfite in living HepG2 cells is reported. HPQRB can be easily synthesized by a two-step condensation reaction. HPQRB has a large emission shift (Δλ=116 nm), which is beneficial for fluorescence imaging research, and its sulfite-responsive site is based on a rhodamine-like structure with the emission peak at 566 nm, which decreases with increasing sulfite concentration. and its HPQ structure always has an ESIPT effect throughout the reaction process, keeping the emission peak at 450 nm as a self-reference. In particular, HPQRB has high selectivity for sulfite and responds quickly (within 30 s) with a low detection limit (44 nM). Furthermore, HPQRB has been successfully used for fluorescence imaging of sulfite in HepG2 cells, demonstrating the superior ability to detect sulfite under physiological conditions.     

Structure and C-S bond cleavage in aryl 1-methyl-1-arylethyl sulfide radical cations

Steady state and laser flash photolysis (LFP) of a series of p-X-cumyl phenyl sulfides (4-X-C(6)H(4)C(CH(3))(2)SC(6)H(5): 1, X = Br; 2, X = H; 3, X = CH(3); 4, X = OCH(3)) and p-X-cumyl p-methoxyphenyl sulfides (4-X-C(6)H(4)C(CH(3))(2)SC(6)H(4)OCH(3): 5, X = H; 6, X = CH(3); 7, X = OCH(3)) has been carried out in the presence of N-methoxy phenanthridinium hexafluorophosphate (MeOP(+)PF(6)(-)) under nitrogen in MeCN. Steady state photolysis showed the formation of products deriving from the C-S bond cleavage in the radical cations 1(+?)-7(+?) (2-aryl-2-propanols and diaryl disulfides). Formation of 1(+?)-7(+?) was also demonstrated by LFP experiments evidencing the absorption bands of the radical cations 1(+?)-3(+?) (λ(max) = 530 nm) and 5(+?)-7(+?) (λ(max) = 570 nm) mainly localized in the arylsulfenyl group and radical cation 4(+?) (λ(max) = 410, 700 nm) probably mainly localized in the cumyl ring. The radical cations decayed by first-order kinetics with a process attributable to the C-S bond cleavage. On the basis of DFT calculations it has been suggested that the conformations most suitable for C-S bond cleavage in 1(+?)-4(+?) and 7(+?) are characterized by having the C-S bond almost collinear with the π system of the cumyl ring and by a significant charge and spin delocalization from the ArS ring to the cumyl ring. Such a delocalization is probably at the origin of the observation that the rates of C-S bond cleavage result in very little sensitivity to changes in the C-S bond dissociation free energy (BDFE). A quite large reorganization energy value (λ = 43.7 kcal mol(-1)) has been calculated for the C-S bond scission reaction in the radical cation. This value is much larger than that (λ = 12 kcal mol(-1)) found for the C-C bond cleavage in bicumyl radical cations, a reaction that also leads to cumyl carbocations.     

Model studies of DNA C5' radicals. Selective generation and reactivity of 2'-deoxyadenosin-5'-yl radical

The reaction of hydrated electrons (e(aq)(-)) with 8-bromo-2'-deoxyadenosine has been investigated by radiolytic methods coupled with product studies and addressed computationally by means of DFT-B3LYP calculations. Pulse radiolysis revealed that this reaction was complete in approximately 0.3 mus, and, at this time, no significant absorption was detected. The spectrum of a transient developed in 20 mus has an absorbance in the range 300-500 nm (epsilon(max) congruent with 9600 M(-1) cm(-1) at 360 nm), and it was assigned to aromatic aminyl radical 3. Computed vertical transitions (TD-UB3LYP/6-311+G) are in good agreement with the experimental observations. Radical 3 is obtained by the following reaction sequence: one-electron reductive cleavage of the C-Br bond that gives the C8 radical, a fast radical translocation from the C8 to C5' position, and an intramolecular attack of the C5' radical at the C8,N7 double bond of the adenine moiety. The rate constant for the cyclization is 1.6 x 10(5) s(-1). On the basis of the theoretical findings, the cyclization step is highly stereospecific. The rate constants for the reactions of C5' and aminyl 3 radicals with different oxidants were determined by pulse radiolysis methods. The respective rate constants for the reaction of 2'-deoxyadenosin-5'-yl radical with dioxygen, Fe(CN)(6)(3)(-), and MV(2+) in water at ambient temperature are 1.9 x 10(9), 4.2 x 10(9), and 2.2 x 10(8) M(-1) s(-1). The value for the reaction of aminyl radical 3 with Fe(CN)(6)(3-) is 8.3 x 10(8) M(-1) s(-1), whereas the reaction with dioxygen is reversible. Tailored experiments allowed the reaction mechanism to be defined in some detail. A synthetically useful radical cascade process has also been developed that allows in a one-pot procedure the conversion of 8-bromo-2'-deoxyadenosine to 5',8-cyclo-2'-deoxyadenosine in a diastereoisomeric ratio (5'R):(5'S) = 6:1 and in high yield, by reaction with hydrated electrons in the presence of K(4)Fe(CN)(6).     

黄豆黄素与黄豆黄苷吸收光谱和荧光光谱的比较研究

研究了黄豆黄素和黄豆黄苷在不同pH条件下的吸收光谱和荧光光谱, 从分子结构的角度解释了二者呈现不同光谱特征的原因. 黄豆黄素分子基本无荧光. 在弱碱性时, 黄豆黄素分子发生7-OH质子的电离, 导致吸收光谱中320 nm的吸收峰红移至348 nm. 采用pH-光度法测得7-OH质子的电离常数pK_a1=7.08±0.04. 黄豆黄素一价阴离子呈现较强荧光, 最大激发和发射波长λ_ex/λ_em分别为334 nm/464 nm, 荧光量子产率为0.049. 在碱性溶液中, 黄豆黄素4'-OH质子电离, 导致吸收光谱中254 nm的吸收峰红移至260 nm, 电离常数pK_a2=9.96±0.01. 黄豆黄苷分子基本无荧光. 在碱性条件下, 黄豆黄苷分子的4'-OH质子发生电离, 导致吸收光谱中256 nm的吸收峰红移至 280 nm, 电离常数pK_a=9.81±0.03. 黄豆黄苷阴离子基本无荧光, 但在热碱性条件下发生γ-吡喃酮环裂解反应而产生较强荧光, λ_ex/λ_em为288 nm/388 nm, 裂解产物的荧光量子产率为0.056. 虽然, 黄豆黄苷与黄豆黄素是苷与苷元的关系, 但黄豆黄苷不能在热碱性条件下通过糖苷水解转变为黄豆黄素, 二者的荧光增强机理存在本质不同.     

新型吡啶-杯[4]芳烃荧光探针的合成及其对Fe3+的检测性能

合成了一种新型的高选择性检测Fe3+的上沿功能化吡啶-杯[4]芳烃荧光探针,其结构经1H NMR, 13C NMR和HR-MS表征。离子检测实验结果表明,该吡啶-杯[4]芳烃探针的最大吸收峰出现在295 nm处,并在371 nm处显示出一个强的荧光发射带。与其他金属离子相比,新型探针对Fe3+表现出高选择性和强抗干扰能力的荧光淬灭响应。通过荧光滴定法和Job曲线图研究了探针与Fe3+的结合性。结果表明,探针与Fe3+形成2:1的配合物,缔合常数为3.26×107 M-1,检出限为7.9×10-7 M。     

荧光探针法研究核壳结构有机硅-丙烯酸酯乳液的聚合行为

以芘为荧光探针,探讨了有机硅-丙烯酸酯核壳乳液聚合过程中,芘的第一振动峰(373 nm处)与第三振动峰(384 nm处)荧光强度的比值I1/I3与乳化剂、有机硅单体(D4)和引发剂(KPS)用量之间的关系,并结合聚合过程中探针芘的I1/I3峰值与单体转化率及乳胶粒形态演变之间的关系,研究了核壳结构有机硅-丙烯酸酯乳液的聚合行为.研究结果表明,探针芘的I1/I3峰值随乳化剂用量,D4用量,KPS用量不同发生相应的变化,随单体转化率的增加而增大.当乳化剂用量、D4用量、KPS与总单体的质量比依次为2 g、8 g、0.7%时,得到的乳液具有优良的综合性能.聚合反应过程中,当种子乳胶粒转变为核壳乳胶粒时,芘的I1/I3峰值仍呈现出明显的转变,说明有机硅-丙烯酸酯核壳乳液具有互穿聚合物网络结构.因此,荧光探针可用于研究有机硅-丙烯酸酯核壳乳液聚合反应进程.     

以喹啉酮为核心高选择快速检测谷胱甘肽的荧光探针

为了选择性检测小分子生物硫醇,以具有优良荧光性能的喹啉酮为荧光团,依据依布硒啉中Se—N键易与硫醇分子反应的性质,将喹啉酮组块(E)-3-(5-巯基-1,3,4-恶二唑-2-基)-N-(4-甲基-2-氧代-1,2-二氢喹啉-7-基)丙烯酰胺(MQ5)与依布硒啉2-(4-溴苯基)苯并[d][1,2]硒唑-3(2H)-酮(SQ6)对接,设计合成了一种新型荧光探针(E)-N-(4-甲基-2-氧代-1,2-二氢喹啉-7-基)-3-(5-((4-(3-氧代苯并[d][1,2]硒烯唑-2 (3H)-基)苯基)硫基)-1,3,4-噁二唑-2-基)丙烯酰胺(MNQ)。 通过傅里叶变换红外光谱(FT-IR)、核磁共振波谱仪(NMR)和高分辨质谱(HRMS)和荧光光谱等测试手段对其进行了结构表征,探究了其荧光性能。 结果表明,MNQ对谷胱甘肽(GSH)有明显的荧光猝灭,在其他氨基酸等干扰时,探针具有良好的抗干扰能力,可作为识别检测GSH的荧光猝灭型探针。 检测限为2.99×10^-8 mol/L,响应时间在35 s可完成,有望作为检测谷胱甘肽的荧光探针。