咔唑与N-烷基咔唑光物理行为的差异

已知甲基、乙基咔唑等咔唑的衍生物与对位苯二甲酸二甲酯(DMTP)和邻位苯二甲酸二甲酯(DMP)可以形成激基复合物^[1],但是咔唑与DMTP或DMP相互作用时观察不到激基复合物的荧光。     

苯二甲酸二甲酯对咔唑荧光的淬灭

用邻苯二甲酸二甲酯(DMTP)可猝灭咔唑的荧光,由此相反,在DMTP-乙基咔唑体系中,末观察到激基复合物荧光.本文对此解释为激基复合物的形成能力不仅依赖于电子给予体的电离势和电子接受体的电子亲和力,而且还取决于附着于电子给予体和电子接受体的生色团上侧基间的相互作用.     

磺化竹红菌素对蛋白质荧光猝灭机理的研究

本文详细研究了磺化竹红菌素对多种蛋白质在溶液状态下的荧光猝灭过程。结果表明,磺化竹红菌素对多种蛋白质荧光猝灭服从Stern-Volmer曲线,实验观察了温度、粘度、pH值和盐酸胍对荧光猝灭过程的影响。由于磺化竹红菌素是一两性分子,对于不同蛋白具有不同猝灭过程;磺化竹红菌素对蛋白质的荧光猝灭常数K_q在10¹³mol/L·s^-1左右,这说明,磺化竹红菌素是一种比其它蛋白质荧光猝灭剂更加有效的荧光猝灭剂。     

盐酸异丙肾上腺素与牛血清白蛋白相互作用

采用荧光猝灭法和毛细管区带电泳法研究了盐酸异丙肾上腺素（IH）与牛血清白蛋白（BSA）的相互作用。荧光猝灭法研究表明:IH对BSA有较强的荧光猝灭作用,根据Stern-Volmer方程得到猝灭速率常数（K_q）为2.53×10¹³ L·mol^-1·s^-1,该荧光猝灭属于静态猝灭。采用位点结合模型公式计算得结合常数为1.72×10⁴ L·mol^-1,结合位点数n为1;毛细管区带电泳法研究表明:IH与BSA的结合常数为4.07×10⁴ L·mol^-1,结合位点数n为1。     

两种卟啉化合物在Ag溶胶表面的紫外-可见吸收光谱和表面增强拉曼散射光谱研究

表面增强拉曼散射(SERS)自1974年被Fleischmann等^[1]发现以来,日益受到人们的重视.通过SERS谱图分析,可以获得物质结构及其与基体作用的信息.由于SERS可使拉曼信号增强10⁵~10⁶倍^[2],并且在某些情况下银胶还能使表面吸附质的荧光猝灭^[3,4], SERS常用来检测一些普通拉曼光谱难以检测的样品和考察界面络合物的形成.     

3,4,9,10-四甲基苝荧光性质的研究

苝及其衍生物的分子结构, 荧光性质及激发态的动力学过程一直是十分活跃的研究课题^[1], 因为苝具有很高的荧光量子产率和光稳定性, 因而苝及其衍生物经常作为激光染料, 荧光探针分子或显示用液晶等^[2,3,4]。     

基于杯[4]芳烃的银离子荧光探针的合成及性能

合成了25,27-二羟基-26,28-二{3-[N-(2-萘基)-2-硫代乙酰胺]丙氧基}-5,11,17,23-四叔丁基杯[4]芳烃(2), 并利用荧光光谱考察了其在乙醇-水混合溶液中对Ag⁺的光谱选择性. 结果表明, 含有S₂O₂结合位点的探针分子2对Ag⁺具有良好的选择性. 通过荧光光谱连续滴定测得探针分子2-Ag⁺体系的猝灭常数为3.39×10³ L/mol, 探针分子对Ag⁺的检出限可达2.34×10^-7 mol/L. 在实际的Ag⁺检测中, 探针分子2具有一定的应用前景.     

4-(4-羧基苯氧基)间苯二甲酸构筑的过渡金属配位聚合物: 合成、 晶体结构、 荧光传感与光催化

采用水热法合成了4个配位聚合物[Zn(Hcpoia)(2,2'-bpy)·H₂O]_n(1)和[M(Hcpoia)(phen)]_n·nH₂O[M=Zn(2), Mn(3), Co(4); H₃cpoia=4-(4-羧基苯氧基)间苯二甲酸; 2,2'-bpy=2,2'-联吡啶; phen=1,10-邻菲罗啉], 利用X射线单晶衍射分析确定了配合物的晶体结构. 配合物1为一维链状结构, 中心Zn ²⁺离子的配位环境为[ZnO₄N₂]扭曲的八面体构型, 配体Hcpoia ^2-以μ₁∶η ¹η ⁰和μ₁∶η ¹η ¹配位模式桥连相邻的Zn ²⁺离子. 配合物2和4的结构与配合物1类似, 是由配体Hcpoia ^2-以μ₁∶η ¹η ⁰和μ₁∶η ¹η ¹配位模式联接[MO₄N₂]结构单元而形成的一维链状结构. 配合物1, 2和4中均存在分子间氢键(O—H…O), 氢键的存在使一维链连接形成二维超分子结构. 配合物3为二维网状结构, Mn ²⁺离子的配位环境为[MnO₄N₂]扭曲的八面体构型, 配体Hcpoia ^2-以μ₂∶η ¹η ¹配位模式桥连相邻Mn ²⁺离子形成[Mn₂COO₂]结构单元, 该结构单元被Hcpoia ^2-连接形成二维结构. 在4个配合物中, 2,2'-bpy和phen配体均以端基的形式与金属离子螯合配位. 研究了水溶液中抗生素分子和Fe ³⁺离子对配合物1与荧光强度的影响, 实验结果表明, 甲硝唑、 Fe ³⁺离子对配合物1有荧光猝灭作用, 并进一步考察了甲硝唑浓度和Fe ³⁺离子浓度对配合物1荧光强度的影响. 基于荧光猝灭机理, 配合物1可以用作荧光传感器检测水溶液中的甲硝唑和Fe ³⁺离子. 研究了配合物4对罗丹明B(RhB)的催化降解性能, 发现在氙灯照射和H₂O₂存在条件下, 配合物4对RhB具有较好的光催化降解作用.     

水溶性荧光共轭聚合物在检测出血热病毒中的应用

利用出血热病毒抗体-L133/抗原-EHF对水溶性荧光共轭聚合物聚(5-甲氧基-2-(3-磺酰化)丙氧基-1,4-对苯撑乙烯), (简写为MPS-PPV)荧光的增强/猝灭作用、抗原-EHF与抗体-L133之间的特异性相互作用及作用前后荧光强度的变化, 建立了一种基于水溶性荧光共轭聚合物荧光猝灭可逆的高灵敏、均相免疫测定新方法, 实现了出血热病毒抗 原-EHF的快速、灵敏检测, 检测抗原-EHF的线性范围是4.8×10^－9～5.0×10^－8 mol/L, 检出限为1.7×10^－9 mol/L. 实验表明, 生物分子对聚合物的荧光增强或猝灭不仅是静电作用, 而且还表现为聚合物形态构造的变化.     

高选择性检测Hg2+的喹啉酮衍生物荧光探针的合成及应用

设计合成了一种以喹啉酮为荧光团,具有新型结构的荧光探针（E）-N-（4-甲基-2-氧代-1,2-二氢喹啉-7-基）-3-（3-苯基-[1,2,4]三唑[3,4-b][1,3,4]噻二唑-6-基）丙烯酰胺（MNT）.研究结果表明,MNT可通过不饱和酰胺键异构化后与Hg²⁺配位,从而产生显著的荧光猝灭.1,2,4-三唑[3,4-b]-1,3,4-噻二唑缺电子的特征有助于提高猝灭效果的同时,能提供与Hg²⁺配位的杂原子.MNT探针对Hg²⁺具有高选择性、较高的量子产率和较强的抗干扰性,检测限为6.35×10^-8 mol/L,响应时间25 s.进一步研究发现,MNT在pH=4~13范围内均能特异性检测Hg²⁺.基于核磁滴定实验结果推测了该探针荧光检测Hg²⁺的机理,并由Job’s曲线确定了MNT与Hg²⁺之间的配位比为2：1.MNT在实际水样中的应用结果表明其可作为检测Hg²⁺的荧光探针.     

Inverse phase transfer catalysis: kinetics of the pyridine-1-oxide-catalyzed two-phase reactions of methyl-, methoxy-, iodo-, and nitro-benzoyl chlorides and benzoate ions

The substitution reactions of XC₆H₄COCl [X=2-, 3-, or 4-CH₃; 2-, 3-, or 4-CH₃O; 2-, or 4-I; or 2-, 3-, or 4-NO₂] and YC₆H₄COONa [Y=2-, 3-, or 4-CH₃; 2-, 3-, or 4-CH₃O; 2-I; 4-NO₂; or H] in a two-phase H₂O/CH₂Cl₂ medium using pyridine-1-oxide (PNO) as an inverse phase transfer catalyst were investigated. In general, the kinetics of the reaction follows a pseudo-first-order rate law, with the observed rate constant being a linear function of the concentration of PNO in the water phase. In contrast to other analogous reactions, the hydrolysis reaction of 2-, 3-, or 4-NO₂C₆H₄COCl in H₂O/CH₂Cl₂ medium is catalyzed considerably by PNO and reaches an equilibrium. In the PNO-catalyzed reaction of XC₆H₄COCl and XC₆H₄COONa in H₂O/CH₂Cl₂ medium, the order of reactivities of XC₆H₄COCl toward reaction with PNO in CH₂Cl₂ is 2-IC₆H₄COCl>4-IC₆H₄COCl>(C₆H₅COCl,3-CH₃OC₆H₄COCl)>3-CH₃C₆H₄COCl>(2-CH₃C₆H₄COCl,4-CH₃C₆H₄COCl)>4-CH₃OC₆H₄COCl>2-CH₃OC₆H₄COCl. Combined with the results of other analogous reactions, good Hammett correlations with positive reaction constant were obtained for the meta- and para-substituents, which supports that the XC₆H₄COCl–PNO reaction in CH₂Cl₂ is a nucleophilic substitution reaction.     

Reaction of diazonium salts with transition metals : X. Formylation of arenediazonium salts with carbon monoxide and silyl hydrides under palladium catalysis

Arenediazonium tetrafluoroborates (ArN₂BF₄ where Ar = X-C₆H₄; X = H, 2-Me, 3-Me, 4-Me, 4-MeO, 4-MeCO, 4-EtOCO, 2-Ph, 2-Cl, 3-Cl, 4-Cl, 4-Br, 4-I, 3-NO₂ and 4-NO₂) were easily converted to aromatic aldehydes (ArCHO) in good yields through the palladium-catalyzed reaction with CO and Et₃SiH or polymethylhydrosiloxane (PMHS) at room temperature.     

有机胺存在下三苯基氯化锡与邻苯二甲酸反应合成离子型有机锡羧酸酯及产物杀菌活性

在有机胺的存在下,三苯基氯化锡与邻苯二甲酸反应,得到了五配位阴离子型有机锡羧酸酯化合物,通过IR、¹H NMR、元素分析等技术手段对反应产物结构进行了表征,确定了反应产物的结构。 同时测定了反应产物对10种病菌的杀菌活性,结果表明,产物对芦笋茎枯、花生褐斑、水稻曲病菌和黄瓜黑星病菌的杀死率均为100%,对其它病菌具有中等强度的杀死率。     

Unexpected structural analogy between early and late 3d transition metal alkoxide carboxylates: Synthesis and single crystal X-ray study of Ni6(OH)2(OR)6(OCOR)2, R = C2H4NMe2, R = H, CH3

Modification of the liquid Ni(OR^N)₂, R^N = C₂H₄NMe₂, with stoichiometric or sub-stoichiometric amounts of carboxylic acids, HCOOH or CH₃COOH, results in formation of crystalline heteroleptic complexes Ni₆(OH)₂(OR^N)₆(OCOR)₂, R = H (1), CH₃ (3) with the core structure closely analogous to that observed earlier for hexanuclear titanium (IV) alkoxide carboxylates and derived from hexagonal packing of the donor atoms.     

Relation between sers intensity and electronic structures for a series of compounds C6H5(CH2)n COOH (n = 0, 1, 2)

In this paper, the SERS spectra of a series of compounds C₆H₅(CH₂)_nCOOH (n = 0, 1, 2) adsorbed on colloidal silver are recorded and compared with each other. The relation between the SERS intensities and the electronic structures of the compounds are discussed. The results support the molecular enhancement mechanism on SERS, especially the charge transfer idea.     

Dinuclear molybdenum complexes derived from diphenols: electrochemical interactions and reduced species

The new diphenolato complexes [{Mo(NO){HB(dmpz)₃}Cl}₂Q] where dmpz = 3,5-dimethylpyrazolyl and Q = OC₆H₄(C₆H₄O (n = 1 or 2), OC₆H₄CR=CRC₆H₄O (R = H or Et), and OC₆H₄CH=CHC₆H₄CH=CHC₆H₄O have been prepared and their electrochemical properties (cyclic and differential pulse voltammetry) compared with previously reported analogues where Q = OC₆H₄O, OC₆H₄EC₆H₄O (E = SO₂, CO and S), OC₆H₄ (CO)C₆H₄ C₆H₄(CO)C₆H₄O and 1,5- and 2,7-O₂C₁₀H₆. The electrochemical interaction between the redox centres in the new complexes is very weak, in contrast to that in the 1,4-benzenediolato and naphthalendiolato species. The EPR spectra of the reduced mixed-valence species [{Mo(NO){HB(dmpz)₃}Cl}₂Q]⁻ where Q = 1,3- and 1,4-OC₆H₄O and OC₆H₄SC₆H₄O shows that they are valence-trapped at room temperature, whereas those of the dianions [{Mo(NO){HB(dmpz)₃}Cl}₂Q]²⁻ where Q = 1,4-OC₆H₄O, OC₆H₄EC₆H₄O (E = CO or S) and OC₆H₄CH=CHC₆H₄CH=CHC₆H₄O shows that the unpaired spins on each molybdenum centre are strongly correlated (J, the spin exchange integral A_Mo, the metal-hyperfine coupling constant). The electrochemical properties and the comproportionation constants for the reaction [{Mo(NO){HB(dmpz)₃} Cl}₂Q] + [{Mo(NO){HB(dmpz)₃}Cl}O]₂]²⁻2[{Mo(NO) {HB(dmpz)₃}Cl}₂Q]⁻ where Q = diphenolato bridge, are compared with related compounds containing benzenediamido and dianilido bridges.     

C_6H_2(OH)_3CH_3氧化成羟基苯甲酸反应路径的DFT研究

运用密度泛函(DFT)理论,采用Materials Studio 8.0,用GGA/BP方法研究了C_6H_2(OH)_3CH_3氧化成羟基苯甲酸的反应路径。结果表明,甲基上的氢原子被氧化成羟基以及羟基被氧化为醛基及醛基被氧化成羧基均为放热过程。分子C_6H_2(OH)_3CH_3中甲基氧化成羧基的主路径为三个氢原子氧化反应路径,其路径为C_6H_2(OH)_3CH_3+3O→C6H2(OH)3C(OH)3→C6H2(OH)3COOH+H2O,该路径受限于羟基直接被氧化成羧基过程,需克服130 k J/mol的反应势垒,反应速率常数对数ln(k)为-22.96 s-1;醛基、羟基优先被氧化成羧基的顺序为:-CHO-C(OH)3-HC(OH)2-H2C(OH);提高反应温度、氧气浓度均有利于羟基苯甲酸的生成,适当的催化剂有利于促进整个反应的进行。     

含双蒽基团酰胺受体分子的合成及阴离子识别研究

合成了一种新型的带有双蒽基团的酰胺阴离子受体B.用荧光光谱、紫外-可见吸收光谱以及核磁共振氢谱研究了B与Cl^-,Br^-,I^-及对硝基酚氧阴离子的相互作用.结果表明,B与Cl^-,Br^-,I^-等阴离子无识别作用,而与对硝基酚氧阴离子有较好的选择性识别能力,其络合比为1∶1.利用荧光发射强度和吸光度的变化分别计算出主体B与客体相互作用的络合常数KS分别为(1.24±0.07)×10⁵和(1.27±0.18)×10⁵,并对主体分子B与客体之间的相互作用进行了讨论.     

π-Olefin-Iridium-Komplexe : XXI. Synthese und Kristallstrukturen heterobinuclearer Komplexe mit wannenförmiger, synfacial gebundener η: η-Benzolbrücke

CpIr(η⁴-C₆H₆) (2) has been obtained in high yield by a four-step synthesis. Thermal reaction of 2 with CpCO(C₂H₄)₂ and photochemical reaction of 2 with CpRh(C₂H₄)₂ or CpRh(C₂H₄)₂ give the compounds μ-(η³: η³-C₆H₆)CoIrCp₂ (3), μ-(η³: η³-C₆H₆)RhIrCp₂ (4), and μ-(η³: η³-C₆H₆)(RhCp)(IrCp) (5), respectively. The X-ray crystallography data of 3 and 4 reveal a boat-shaped conformation of the synfacially bridging benzene ligand with a rather long Co---Ir bond distance in 3 and a relatively short Rh---Ir bond length in 4 which are caused by almost constant folding angles of the benzene unit. The dynamic behaviour of the benzene bridge was investigated by NMR spectrometry.     

Retention behavior of arsenobetaine, arsenocholine, trimethylarsine oxide and tetramethylarsonium iodide on a styrene-divinylbenzene column with benzenesulfonates as ion-pairing reagents

The pH-dependent retention behavior of arsenobetaine, arsenocholine, trimethylarsine oxide, tetramethylarsonium iodide (cationic arsenic compounds), arsenite, arsenate, methylarsonic acid, and dimethylarsinic acid (anionic arsenic compounds) was studied on a Hamilton PRP-1 reversed-phase column (250×4.1 mm I.D.) with 10 mM aqueous solutions of benzensulfonic acids (X-C₆H₄SO₃⁻; X=H, 4-HO, 3-CO₂H; 4-HO-3-HO₂C-C₆H₃SO₃⁻) as ion-pairing reagents in the pH range 2–5 using flame atomic absorption spectrometry as the arsenic-specific detector. The dependencies of the k′-values of the ‘cationic’ arsenic compounds was rationalized on the basis of the protonation/deprotonation behavior of the arsenic compounds and of the four benzenesulfonates. The results provided evidence for the formation of a cationic species from trimethylarsine oxide below pH 3. Benzenesulfonate is the most hydrophobic ion-pairing reagent causing strong retention of the cationic arsenic compounds and consequently impeding their rapid separation. With the less hydrophobic, substituted benzenesulfonates the cationic arsenic compounds had retention times not exceeding 6 min. At a flow-rate of 1.5 cm³ min⁻¹ 10 mM aqueous 3-carboxy-4-hydroxybenzenesulfonate solution adjusted to pH 3.5 allowed the separation of arsenate, methylarsonic acid, arsenobetaine, trimethylarsine oxide, the tetramethylarsonium ion, and arsenocholine within 3 min. Dimethylarsinic acid coelutes with arsenobetaine at pH 3.5, but can be separated from arsenobetaine with the same mobile phase at pH 2.5. At pH 2.5 the signals for trimethylarsine oxide, the tetramethylarsonium ion, and arsenocholine are too broad to be useful for quantification. Arsenite and methylarsonic acid cannot be separated under these conditions.