萘异硫氰酸酯修饰的水杨醛衍生物作为氟离子荧光探针的研究

以萘异硫氰酸酯分别化学修饰水杨醛、4-(二乙氨基)水杨醛,合成了两种荧光分子(分子1和2),利用核磁共振和高分辨质谱技术对其结构进行了表征和确证.采用荧光光谱技术对这两种分子与常见阴离子的结合进行研究,结果表明,分子1和分子2均可选择性识别F–,可作为检测F–的荧光探针.探针1(分子1)对F–表现出荧光增强型响应,当F...     

水杨醛乙酰腙席夫碱作为Al3+荧光探针分子的理论研究

用密度泛函理论和含时密度泛函理论研究了实验上合成的一种基于水杨醛席夫碱的Al~(3+)荧光探针的性质.通过优化探针分子及其与Al~(3+)形成的配合物可能存在的异构体的几何结构,并模拟各异构体的电子吸收光谱,找到了最可能存在的异构体.最后模拟了它们的荧光光谱,进一步验证了前面推测的异构体的正确性,加深了人们对这一探测过程的认识.     

一种基于苯并噻二唑衍生物的F~-荧光探针分子的理论研究

用密度泛函理论研究了最近实验上合成的一种基于苯并噻二唑衍生物的F~-荧光探针(1)的性质.通过对相关化学反应热力学参数的计算,提出了1对F~-具有高选择性的可能原因;同时用含时密度泛函理论对电子吸收光谱和荧光发射光谱进行了理论计算,解释了实验光谱.     

用于监控过氧化氮的近红外荧光探针的光物理性质及PET机理

含有机硒的七甲川菁染料是基于光诱导电子转移(PET)的近红外(IR)荧光探针, 能在生理条件下高灵敏、高选择性地监控过氧化氮. 本文应用含时密度泛函理论(TD-DFT)计算方法研究其光物理性质和PET机理.结果表明, 在激发态, 荧光母体发生最高占有分子轨道(HOMO)到最低非占有分子轨道(LUMO)的电子跃迁, 识别基团上的HOMO轨道能级提高到荧光母体的单电子占据的HOMO轨道能级之上, 并向其转移一个电子, 使激发态电子回落过程受阻而导致荧光部分淬灭. 硒被氧化后, 识别基团上的HOMO轨道能级降低, PET过程被阻断, 荧光发射恢复. 研究进一步证明, PET效应来自于识别基团上苯胺N原子的p电子, 它的电子转移能力受到其对位苯硒基的氧化-还原状态的影响, 产生了荧光信号的“开-关”作用.     

理论预测Al3+与一种萘酚衍生物荧光探针分子形成配合物的结构

用量子化学方法研究了实验上合成的一种基于萘酚的Al~(3+)荧光探针分子L的性质.筛选出了L与Al~(3+)可能形成的配合物的几何结构,并通过电子吸收光谱和荧光光谱进行了验证.在该配合物中,L与Al~(3+)的络合比为2∶2;Al~(3+)采用六配位的结构;与萘环相连的氧原子形成氧桥,将两个Al~(3+)连接起来.最后研究了L与Al~(3+)生成不同配比化合物的反应焓变和吉布斯自由能变.结果表明,L与Al~(3+)的络合比为2∶2时反应焓变和吉布斯自由能变最负,反应最可能发生.这一工作加深了人们对这一识别过程的理解.     

氟硼二吡咯类pH荧光探针PET光谱特性的理论计算

氟硼二吡咯(BODIPY)类pH荧光探针分子是基于光诱导电子转移(PET)的荧光探针分子, 识别基团氮原子上引入不同取代基可呈现不同的光学灵敏度. 本文应用密度泛函理论(DFT)及含时密度泛函理论(TD-DFT)方法对六种含不同取代基的探针分子进行了几何构型优化及激发态计算, 探讨了不同取代基对PET效应影响. 计算结果表明: 基态时这些探针分子的最高占有分子轨道(HOMO)和最低未占有分子轨道(LUMO)都在荧光母体BODIPY的π, π^*轨道, 而识别基团上氮原子孤对电子所在的轨道为HOMO-1轨道. 但是在激发态, 当氮原子上有两个取代基时, HOMO-1→LUMO跃迁的激发能都小于荧光团的HOMO→LUMO跃迁, 这将有可能产生PET效应并导致荧光熄灭, 而当氮原子上有一个取代基时不会出现这种现象. 通过激发态结构优化可以发现, 无论识别基团氮原子上有一个还是两个取代基, N原子的轨道对称性都发生变化, 由sp³→sp², 孤对电子占据在p轨道上, 其轨道能级升高至荧光团的HOMO和LUMO轨道之间, 将导致不同程度的PET效应, 与实验结果一致.     

1,8-萘酰亚胺类衍生物的结构及紫外-可见吸收光谱

用密度泛函方法(DFT)优化了一系列1,8-萘酰亚胺衍生物, 用含时密度泛函(TDDFT)和导体极化连续模型(CPCM)计算了它们在气相、环己烷和二氯甲烷溶剂条件下的紫外可见吸收光谱. 计算结果表明, 优化的几何结构和X射线晶体结构数据吻合较好. 萘环4和5位胺基上取代基团(氢基、甲基、苯基和萘基)的变化使得它与萘酰亚胺部分的连接键长(N—C)变长、电荷转移增强、带隙降低. 溶剂化显色效应和前线轨道电子云一致表明此类物质的最大吸收峰对应π-π*跃迁. 异构体A中的分子内电荷转移增大和带隙的降低是它的紫外吸收光谱最大吸收峰比异构体B的发生红移的主要原因.     

新型香豆素类氟离子荧光探针的合成及细胞成像研究

设计合成了一类基于分子内电荷转移（Intramolecular Charge Transfer,ICT）的香豆素类F^-荧光探针CS1,CS2和CS3,经¹H NMR,¹³C NMR,IR和HRMS表征了相应探针的结构,并解析了探针CS3的晶体结构.通过核磁和质谱实验验证了探针与F^-的作用机理是氟化物脱硅基.光谱分析实验结果显示,CS1,CS2和CS3均具有较好的选择性和灵敏度,且均能成功实现人乳腺癌细胞（MCF^-7）中F^-的检测.     

基于1,8-萘酰亚胺与罗丹明B间荧光共振能量转移的高选择性Hg2+比率荧光探针

以罗丹明B与1,8-萘二甲酰亚胺反应合成了1个高选择性Hg²⁺比率荧光探针(RN). 在甲醇/乙腈/4-羟基哌嗪乙磺酸缓冲溶液(pH=7.2, 体积比8:1:1)中, RN对Hg²⁺具有比色和比率荧光双重响应. 加入Hg²⁺后, RN的紫外-可见光谱在约556 nm处产生强吸收, 溶液由浅绿色变为橙色, 其它金属离子对RN的紫外-可见光谱几乎无影响. 无Hg²⁺存在时, RN的荧光光谱在540 nm处出现萘二甲酰亚胺荧光团的特征峰; 加入Hg²⁺后, 540 nm处的发射带逐渐消失, 同时在580 nm附近产生强荧光, 荧光颜色从绿色变为橙色. 这归因于从萘酰亚胺到开环罗丹明B的荧光共振能量转移(FRET), 探针RN对Hg²⁺的比率荧光响应具有高选择性, 不受其它共存金属离子的干扰.     

基于喹啉衍生物的汞离子选择性荧光传感分子的合成与应用

合成一种新型开-关(ON-OFF)型汞离子荧光传感分子triquinolin-8-yl benzene-1,3,5-tri-carboxylate（TQBTC）。 采用FT-IR、元素分析、¹H NMR测试技术对其结构进行了表征。 在对其荧光性质的研究中发现,TQBTC的乙腈-水溶液在253.0 nm波长辐射激发下于616.0 nm处发射强荧光,且对汞离子络合有较好的选择性。 TQBTC与Hg(Ⅱ)可形成1∶3型络合物,同时使荧光线性猝灭,TQBTC可作为Hg(Ⅱ)的荧光传感分子。 建立了一种测定Hg(Ⅱ)的灵敏分析方法。 Hg(Ⅱ)浓度在0~30 μmol/L的范围内与TQBTC的荧光猝灭呈线性关系,方法检出限为0.838 μmol/L。 方法应用于实际样品中Hg(Ⅱ)的检测,获得满意结果。     

含三(2-吡啶甲基)胺识别体的荧光化学敏感器核磁共振谱分析

采用二维核磁共振谱技术对新型丹磺酰胺和1,8-萘酰亚胺荧光化学敏感器的结构进行了测定。应用'H—'HCOSY、HSQC、HMBC等二维相关核磁谱对化合物的C和H进行了正确的归属。     

A Novel Fluorescent Probe for Determination of pH and Viscosity Based on a Highly Water-Soluble 1,8-Naphthalimide Rotor

A novel highly water-soluble 1,8-naphthalimide with pH and viscosity-sensing fluorescence was synthesized and investigated. The synthesized compound was designed as a molecular device in which a molecular rotor and molecular “off-on” switcher were integrated. In order to obtain a TICT driven molecular motion at C-4 position of the 1,8-naphthalimide fluorophore, a 4-methylpiperazinyl fragment was introduced. The molecular motion was confirmed after photophysical investigation in solvents with different viscosity; furthermore, the fluorescence-sensing properties of the examined compound were investigated in 100% aqueous medium and it was found that it could be used as an efficient fluorescent probe for pH. Due to the non-emissive deexcitation nature of the TICT fluorophore, the novel system showed low yellow–green emission, which represented “power-on”/“rotor-on” state. The protonation of the methylpiperazine amine destabilized the TICT process, which was accompanied by fluorescence enhancement indicating a “power-on”/“rotor-off” state of the system. The results obtained clearly illustrated the great potential of the synthesized compound to serve as pH- and viscosity-sensing material in aqueous solution.     

The Design of a Highly Selective Fluorescent Chemosensor for Cu(II) within Wide pH Region and a Molecular Switch Controlled by pH

A new calix[4]arene-based fluorescent compound with two thio-ether groups as ionophore and one 3-alkoxy-2-naphthoic acid moiety as fluorophore has been designed, which exhibited highly selective binding of Cu ²⁺ over alkali, alkaline earth and some transition metal ions, including Co ²⁺, Ni ²⁺, Zn ²⁺, Mn ²⁺, Cd ²⁺, Pb ²⁺, Hg ²⁺, Ag ⁺, Cu ⁺, in CH ₃OH–H ₂O (2:1) within wide pH region. Moreover, the change of pH induces the consecutive quenching/revival of the fluorescence, with a concomitant distinct difference of the fluorescence quantum yield. In consequence, this system could be considered as a molecular switch.     

A Novel Fluorescent Aminoacid Designed for Fluorometric Detection of Cu(II)

IntroductionIthasbeenwellknownthatα aminoacidcouldeffi cientlychelateCu(II) .1 3Applicationsbasedonthisnovelbindingcharacterhavebeenreported ,forinstance ,thechiraldiscriminationofD andL aminoacidsinaCu(II) cyclodextrincomplex4 ,5andtherecoveryofpyrenefluores cencebyaminoacidfromapyrene Cu (II) cyclodextrincomposite .6 ItwasthusenvisagedthatarationaldesignwouldleadtoanaminoacidderivativethatcouldworkasanovelligandforefficientdetectionofCu(II) .Acombina tionoftheaminoacidwithafluoropho…     

Vinyl monomers bearing chromophore moieties and their polymers. V. Synthesis and fluorescence behavior of a vinyloxy monomer bearing electron-accepting chromophore moiety,N-(2-(vinyloxy)ethyl)-1,8-naphthalimide,and its polymer

A vinyloxy monomer bearing electron-accepting chromophore, N-(2-(vinyloxy)ethyl)-1,8-naphthalimide (VOENI), was synthesized by reaction of potassium 1,8-naphthalimide with 2-chloroethyl vinyl ether. VOENI can be homopolymerized by cationic initiation and copolymerized with maleic anhydride (MAn) under radical initiation. The fluorescence behaviors of VOENI and its polymers were investigated. It has been found that the fluorescence intensity of the VOENI monomer is much lower than that of its polymers at the same chromophore concentration. This means that a “structural self-quenching effect” (SSQE) has been also observed in the vinyloxy monomer consisting of an electron-accepting chromophore, which has opposite electronic structure in comparison with acrylates bearing electron-donating chromophores as we have reported previously. The SSQE is attributed to the charge-transfer interaction between the electron-accepting chromophore and the electron-donating double bond in the same molecule. The fluorescence quenching of 1,8-naphthalic anhydride and P(VOENI-co-MAn) by ethyl vinyl ether (EVE), dihydrofuran, triethylamine (TEA), etc. evidences that the electron-rich vinyloxy group does act as an important role in the SSQE of VOENI. C₆₀ can also quench the fluorescence of the polymers, and an upward deviation from the linearity of the Stern–Volmer plot was observed showing that C₆₀ acted as a powerful electron donor to quench the fluorescence of the copolymer. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1111–1116, 1998     

双核Pt(II)配合物的光谱结构和激发态性质的密度泛函理论研究

采用基于第一性原理的密度泛函理论对单核和双核三联吡啶Pt(II)配合物[Pt(trpy)C≡CH]^＋ (1)和[Pt(trpy)C≡ (2)的基态和激发态以及光谱性质进行了系统研究. 结果揭示了双体配合物中Pt—Pt间距离在激发态时明显短于基态时的距离, 而且双体聚合后最低能吸收和发射波长相对单体配合物发生了明显红移, 这种激发的本质被指认为是来自于[d_σ*(d_δ*π*)]的MMLCT (metal-to-metal-to-ligand charge transfer)电荷转移跃迁. 另外, 对研究的配合物, 用VWN (Vosko-Wilk-Nusair)泛函优化得到的几何和用SAOP(轨道势的统计平均)计算的光谱能量和实验值符合得很好, 能够准确反映实验现象.     

TD-DFT Studies on Electronic and Spectral Properties of Platinum(II) Complexes with Phenol and Pyridine Groups

The molecular structures of the ground and the lowest triplet states for a series of Pt(II) complexes PtLCl(1)[L=6-(2-hydroxyphenyl)-2,2′-bipyridine], Pt(pp)₂[pp=2-(2-hydroxyphenyl)pyridine](2), PtbpyCl₂(bpy=2,2′- bipyridine)(3), and the free tridentate L ligand(4) were optimized by the density functional theory B3LYP and UB3LYP methods, respectively. On the basis of optimized geometries, the spectral properties were investigated with time-dependent density functional theory(TD-DFT). In comparison with those of complexes 2 and 3, the more rigid structure of complex 1 together with its low rate of the radiationless decay via nonemissive d-d state leads to higher photoluminescence quantum efficiency. And the phosphorescence quantum efficiency of complex 1 can be easily controlled by modifying auxiliary ligands. The introduction of fluorine ligand into complexes can effectively increase the radiation transition rate and decrease the radiationless d-d transition rate, and as a result, a novel complex PtLF(5) might be a good phosphorescent material suitable for organic electronic devices.     

Novel Fluorescent Chemosensor for Detection of F− Anions Based on a Single Functionalized Pillar[5]arene Iron(III) Complex

Novel fluorescent chemosensor with good selectivity for F^? anion was designed and synthesized. The sensor has a bearing on a single functionalized pillar[5]arene and Fe³⁺ metal complex (PN‐Fe), which showed prominent fluorescent response for F^? anion over other common anions (Cl^?, Br^?, I^?, AcO^?, HSO4^?, H₂PO₄^?, ClO₄^?, CN^? and SCN^?). These results were evaluated by fluorescent method. The detection limit of PN‐Fe to F^? was calculated to be 2.50×10^?7 mol/L. Moreover, the sensor PN‐Fe³⁺ might serve as a recyclable component in sensing materials.     

The influence of the cyclopeptide sequence on its coordination abilities towards Cu(II)

The binding abilities of three novel cyclohexapeptides with three histidyl residues are presented. The analysis of the potentiometric and spectroscopic results, together with the theoretical calculations, allow the characterization of the coordination abilities of c(GlyHisArgHisHisGly), c(GlyHisArgHisGlyHis), c(GlyHisArgGlyHisHis) towards copper(II) ions and the impact of the peptide sequence on the efficiency in Cu(II) binding, and the type of formed complexes is also presented.