荧光法研究对羧基苯偶氮基杯[8]芳烃与诺氟沙星的作用

合成了一种超分子探针对羧基苯偶氮基杯[8]芳烃(简称CPAC).利用荧光光谱法研究了溶液状态下该探针与诺氟沙星(简称NFLX)的相互作用.实验表明,两者之间存在较强烈的相互作用,CPAC与NFLX形成外式包结物,静态猝灭NFLX的荧光,CPAC的杯腔体与NFLX的喹啉环间的疏水作用是主要作用方式.测定了该反应的结合常数(K=6.38×105 L·mol-1)和结合比(n=1).实验发现,小牛胸腺DNA能夺取CPAC-NFLX体系中的CPAC,使NFLX游离,说明超分子化合物CPAC可用于诺氟沙星药物的储存和定点释控.     

杯[4]芳烃纳米粒子的制备及其光谱性质研究

用再沉淀法制备了一种新型的有机纳米微粒子—杯[4]芳烃纳米粒子(CN),通过透射电镜观察其平均尺寸约为40 nm, 与杯[4]芳烃分子相比具有较好的荧光性能。在弱酸性条件下,适量的Fe3+能使其荧光发生明显猝灭,荧光猝灭值与Fe3+的浓度在一定范围内呈良好线性关系,据此建立了一种测定Fe3+的荧光新方法。在最优化条件下,测得Fe3+的线性范围和检出限分别为1.0×10-6～2.4×10-5 mol·L-1和3.1×10-7 mol·L-1。将其应用于水样中三价铁离子的定量分析,回收率和相对标准偏差都令人满意。     

杯[8]芳烃-硝酸稀土配合物的红外光谱及荧光性能

合成了以对叔丁基杯[8]芳烃(LH₈)、硝酸根及DMF为配体,单一稀土RE³⁺(Sm³⁺、Eu³⁺、Tb³⁺、Dy³⁺)及混合稀土Tb³⁺:Ln³⁺(Ln=La³⁺,Gd³⁺,Y³⁺)为中心的7种稀土配合物,对其进行了元素分析、摩尔电导、热谱、红外光谱及荧光性能研究.荧光光谱的测试表明所有Tb³⁺及其共掺杂配合物具有较强的特征荧光发射,荧光惰性离子La³⁺、Gd³⁺、Y³⁺对Tb³⁺的荧光有增强作用,其中Y³⁺的荧光增强作用最大,Gd³⁺次之,La³⁺最小.     

荧光光谱法研究对-二甲氨甲基-杯[8]芳烃与DNA相互作用

首次采用阿霉素作荧光探针研究了水溶性对-二甲氨甲基-杯[8]芳烃(简称杯[8]胺或CX8)与小牛胸腺DNA相互作用,并考察了溶液的pH值、离子强度及解链DNA对DNA和杯[8]胺相互作用的影响。实验发现,DNA能猝灭阿霉素的荧光,向该体系中加入杯[8]胺时荧光又逐渐增强,这说明杯[8]胺能与DNA的磷氧负离子强烈作用。通过Scatchard图等进一步分析发现,杯[8]胺对DNA-阿霉素的影响表现为混合模式,一方面,在中性或酸性的条件下,杯[8]胺能中和DNA上的磷氧负离子,导致DNA收缩,从而影响DNA的构象,使嵌入的阿霉素从DNA中部分游离出来,荧光增强;另一方面,杯[8]胺与阿霉素也存在静电位点竞争。     

几种外向式杯[4]芳烃偶氮衍生物新试剂的合成及其吸收光谱性质

本文合成，提纯并初步鉴定了十种外向式杯「４」芳烃偶氮衍生物类新试剂，试验了其吸收光谱性质，测定了其酸碱离解常数。     

荧光法研究对-二甲氨甲基-杯[8]芳烃与二苯胺磺酸钠包结作用

用荧光法研究了水溶性对-二甲氨甲基-杯[8]芳烃与二苯胺磺酸钠的相互作用。发现当对-二甲氨甲基-杯[8]芳烃加入到二苯胺磺酸钠溶液时,二苯胺磺酸钠的荧光峰发生了明显的蓝移,荧光增强,可能的作用机理是二苯胺磺酸钠中的磺酸根与对-二甲氨甲基-杯[8]芳烃中带正电的氮原子之间有较强的静电作用,二苯胺磺酸钠进入了对-二甲氨甲基-杯[8]芳烃的疏水空腔。同时研究了几种有机溶剂对包结物的荧光强度的影响,初步探讨了其作用机理。     

对叔丁基杯[8]芳烃稀土配合物的合成、表征及荧光研究

合成了以RE3 (Sm3 ,Eu3 ,Tb3 ,Dy3 )及Tb3 掺杂Ln3 (La3 ,Gd3 ,Y3 )为中心,以对叔丁基杯[8]芳烃(LH8)及DMF,DMSO为配体的两个系列14种同核与掺杂稀土固体配合物,对其进行了元素分析、摩尔电导、热谱、红外光谱、紫外光谱、核磁共振氢谱的测定及荧光性能研究.荧光光谱的测试表明,所有Tb3 及其掺杂配合物具有较强的特征荧光,第二配体DMF对Tb3 及其掺杂配合物的荧光增强作用比DMSO更明显,掺杂荧光惰性离子对Tb3 的荧光增强作用顺序为La3 ＜Gd3 ＜Y3 .     

荧光光谱法研究儿茶素与对磺化杯[n]芳烃的相互作用

采用荧光光谱法在室温下研究了酸性(pH=2.00)、中性(pH=7.00)及碱性(pH=9.00)条件下对磺酸基杯[4]芳烃(SCX4)、对磺酸基杯[6]芳烃(SCX6)及对磺酸基杯[8]芳烃(SCX8)与儿茶素的包合作用.固定儿茶素浓度,逐渐改变对磺化杯[n]芳烃的浓度,儿茶素的荧光强度有规律地降低,表明主-客体包合物的形成.同时用最小二乘法进行非线性拟合计算出包合常数,初步验证了对磺化杯[n]芳烃与儿茶素1:1的包合模式,并且室温条件下,SCX8在pH=9.00的磷酸缓冲体系中对儿茶素的包合能力最强,包合常数为2.769×104L·mol-1.     

电荷转移金属[60]富勒烯盐的光电性质

用物理喷束淀积技术制备了过渡金属[60]富勒烯盐C60Ni薄膜，研究了Al/C60Ni/ITO光电池的光伏效应和正反向电学特性并与Al/C60/ITO膜进行了比较。用界面偶极电场解释了Al/C60Ni界面光伏效应和整流应的增强，表明在该样品中发生的从Ni原子到C60的电子转移使Al/C60Ni界面偶极电场增强。     

螺双杯[4]芳烃-冠-3醚在溶液中构象的研究

研究了螺双杯[4]芳烃-冠-3醚在溶液状态下的¹H、¹³C、¹H-¹³C HMQC、¹H-¹³C HMBC、¹H-¹H TOCSY等核磁共振谱,对其¹H、¹³C谱进行了归属,确定了室温该化合物在溶液状态下的稳定构象为锥式,并利用2D NOESY近似求出杯芳烃区的各种氢的距离,以此为约束进行了模拟淬火计算,证实了2D NOESY谱中多种羟基存在方式,并利用二维交换矩阵计算得出几种羟基的交换速率及其与溶剂中痕量水的交换速率.     

Studies on the adsorption of arsenic on calix[6]arene

p‐tert‐butyl calix[6]arene (PTC6) was synthesized and characterized by solid‐ and liquid‐state NMR and LC‐MS techniques. The adsorption of arsenite and arsenate on calix[6]arene under different pH conditions and adsorbate doses was studied. The maximum adsorption of arsenic species on calix[6]arene was observed around neutral pH and the adsorption density of As (III) was higher than that of As (V). The adsorption of neutral H₃AsO₃ and negatively charged H₂AsO molecules on calix[6]arene was attributed to the condensation reaction between hydroxyl groups of PTC6 and arsenic species. The complexation of arsenite with phenolic oxygen was confirmed by solid‐state ¹³C NMR CP‐MAS. Exo attack mechanism was proposed to describe the interaction of arsenous and arsenic acid molecules with PTC6. The specific interaction between calix[6]arene and arsenic species was further substantiated by zeta‐potential (ζ‐potential) measurements and free energy of adsorption. The free energy of adsorption ( ) estimated from Stern–Grahame equation was found to be 25 kJ/mole for As (III) and 19 kJ/mole for As (V). Copyright © 2010 John Wiley & Sons, Ltd.     

Investigation of the inclusion behavior between p-sulfoniccalix[8]arene and norfloxacin by fluorescence spectroscopy

The host-guest complexation between p-sulfoniccalix[8]arene (SC₈A) and norfloxacin (NFLX) in aqueous solution was investigated by fluorescence spectroscopy. Strong fluorescence intensity of the NFLX aqueous solution alone and obvious fluorescence quenching of NFLX solution in the presence of SC₈A were observed. The fluorescence lifetimes of NFLX and SC₈A-NFLX inclusion complex were determined and the effect of temperature on SC₈A-NFLX inclusion complex was studied. The static quenching of the inclusion was obtained, that is the SC₈A can form a nonfluorescent ground-state inclusion complex with NFLX. As the results show, the combined ratio (n) was 1:1 and association constant K was 1.17×10⁵ L/mol. Based on the experimental results, the mechanism of the inclusion complex was explored. The space matching, electrostatic force and hydrogen bond play important effects in the inclusion process. Subsequently, the addition of bovine serum albumin (BSA) solution led to the recovery of fluorescence intensity. It is indicated that BSA can liberate the NFLX into the solution by destructing the SC₈A-NFLX inclusion complex. Hence SC₈A may be used for controlled-release drug delivery in the pharmaceutical industry.     

Quenching of Pyrene Fluorescence by Calix[4]arene and Calix[4]resorcinarenes

Interactions involving calixarene and its derivatives are of major importance due to their widespread applications as unique hosts. Fluorescence from a common probe pyrene is used to study interactions involving calix[4]resorcinarene [1a] and its tetra-morpholine derivative [1b] in 1 M aqueous NaOH. These compounds efficiently quench the pyrene fluorescence. A comparison with the fluorescence quenching behavior of N-methylmorpholine clearly indicates the presence of long-range interactions involving 1a and 1b; the interactions are specific to the calixarene molecular framework. This is not the case for a tetra-nitro-substituted calix[4]arene [2b], an electron/charge acceptor quencher, as p-nitrophenol also shows similar interactions with pyrene. Effectiveness of cesium as the quencher of pyrene fluorescence is reduced in the presence of electron/charge donating 1b; fluorescence enhancement is observed upon addition of cesium as the concentration of 1b is increased in the solution. The role of calixarene framework in interactions involving such compounds is established.     

Electrochemical synthesis of Ag nanoparticles supported on glassy carbon electrode by means of p-isopropyl calix[6]arene matrix and its application for electrocatalytic reduction of H2O2

The silver nanoparticles were prepared on the glassy carbon (GC) electrode, modified with p-iso propyl calix[6]arene, by preconcentration of silver ions in open circuit potential and followed by electrochemical reduction of silver ions. The stepwise fabrication process of Ag nanoparticles was characterized by scanning electron microscopy and electrochemical impedance spectroscopy. The prepared Ag nanoparticles were deposited with an average size of 70 nm and a homogeneous distribution on the surface of electrode. The observed results indicated that the presence of calixarene layer on the electrode surface can control the particle size and prevent the agglomeratione and electrochemical deposition is a promising technique for preparation of nanoparticles due to its easy-to-use procedure and low cost of implementation. Cyclic voltammetry experiments showed that Ag nanoparticles had a good catalytic ability for the reduction of hydrogen peroxide (H₂O₂). The effects of p-isopropyl calix[6]arene concentration, applied potential for reduction of Ag⁺, number of calixarene layers and pH value on the electrocatalytic ability of Ag nanoparticles were investigated. The present modified electrode exhibited a linear range from 5.0 × 10⁻⁵ to 6.5 × 10⁻³ M and a detection limit 2.7 × 10⁻⁵ M of H₂O₂ (S/N = 3) using amperometric method.     

Spectrofluorimetric study on the inclusion behavior of p-sulfonated calix arene with cetyltrimethylammonium bromide and analytical application

The characteristics of host-guest complexation between p-sulfonated calix [G. Arena, S. Gentile, F. G. Gulino, D. Sciotto, C. Sgarlata, Tetrahedron Lett. 45 (2004) 7091] arene (SC6A) and cationic surfactant cetyltrimethylammonium bromide (CTAB) were studied by fluorescence spectrometry. A 1:1 stoichiometry for the complexation was established and the complex constant was also calculated by a deduced equation. It was found the fluorescence of the complex could be remarkably quenched by an appropriate amount of ceftriaxone sodium (CTRX). Based on the results, a novel spectrofluorimetric method for determination of CTRX was developed with a linear range of 9.2×10⁻⁷-8.5×10⁻⁵ mol L⁻¹ and a detection of 3.5×10⁻⁷ mol L⁻¹. The proposed method was used to determine CTRX in their commercial preparations with satisfactory results. Moreover, the probable interaction mechanisms of the systems were also discussed.     

New pyrazolino and pyrrolidino[60]fullerenes: the introduction of the hydrazone moiety for the formation of metal complexes

The [3 + 2] cycloaddition reaction of C₆₀ with pyridine‐derived hydrazones (acting as dipolar reagents) was successfully conducted resulting in fullerene derivatives 5a , 5b . The compounds were characterized by means of NMR, UV–Vis spectroscopy, and X‐ray crystallography. The electrochemical behavior was also investigated. The fulleropyrazoline 5a exhibits anodically shifted reduction potentials of about 100 mV when compared with those for C₆₀, whereas 5b exhibits cathodic shifts relative to pristine C₆₀. The complexation reaction of 5b with metallic ions (Zn²⁺, Cd²⁺, and Fe²⁺) was achieved. Job and Benesi–Hildebrand analysis confirmed the formation of complexes with a molar ratio of 1:1 and binding constants between 2.26 × 10⁵ and 1.59 × 10⁵ M^?1. Electrochemistry of these complexes showed a marked influence of the metal ion on the reduction potentials. Copyright © 2016 John Wiley & Sons, Ltd.