检索结果-南通市图书馆

1-Imino Nitroxide Pyrene, a Burst-type H^(+) fluorescent switch

Chinese Chemical Letters 2005年第8期16卷 1125-1128页

作者： Jun LI Hong Mei WANG Hui Min MA De Qing ZHANG Shao Xiang XIONG Center for Molecular Sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100080

1-Imino nitroxide pyrene 1 has been characterized as a H^＋ fluorescent switch. The effects of various interfering species, solvents and the irradiation of ultraviolet light on the fluorescence intensity of 1 are also investigated. 1 fluoresces weakly in the 85% ethanol media containing no more than 4.5x10-5 mol/L of H^＋（HCI）, but can produce a burst increase of about 4 times in the fluorescence intensity when the concentration of H＋ is increased to or over 4.9×10^-5mol/L. The extremely sharp response of 1 to H＋ occurs only within such a narrow concentration range. Moreover, the decrease of H^＋ concentration through adding sodium hydroxide causes the fluorescence quenching, suggesting that 1 may serve as a fluorescent switch for monitoring the concentration change of H＋ around the point of 4.5×10^-5 mol/L.

关键词： fluorescent switch l-imino nitroxide pyrene H^+

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

fluorescent switch Behavior of 1, 2-Bis(4-pyridyl) Ethylene Controlled by pH in Aqueous Solution

引用

Chemical Research in Chinese Universities 2008年第6期24卷 712-716页

作者： ZOU Wen-sheng SHEN Qian-jin WANG Yu JIN Wei-jun School of Chemistry and Chemical Engineering Shanxi University Taiyuan 030006 P. R. China College of Chemistry Beijing Normal University Beijing 100875 P. R. China

With the decrease of pH value from 8.45 to -1.0, the UV-Vis absorption and fluorescent spectra of 1,2-bis（4-pyridyl） ethylene（BPE） took on the same changing trend at four different successive pH stages： 8.45--7.20, 7.20--5.62, 5.62--2.60, and 2.60--1.0, namely, no change, decrease, increase, and decrease again. Among these, in a range of 7.20--5.62, the fluorescence wavelength blueshifted from 418 to 359 nm, but the UV-Vis absorption wavelength, in contrast, redshifted from 285 to 298 nm. The fluorescence intensity of BPE had a drop even to quench upon a decline in the pH value from 2.60 to -1.0 probably owing to its cation-re interaction to reduce the π electron cloud density of BPE. Two dissociation constants, pKa1（4.30±0.01） and PKa2（5.65±0.04）, were obtained based on fluorescence data. The changes of fluorescence spectra indicate that BPE has ＂oft-on-off＂ switch behavior. The fluorescent spectra of BPE were nearly independent on the presence of α- and β-cyclodextrins.

关键词： 1,2-Bis(4-pyridyl) ethylene fluorescent switch pH fluorescence probe Cation-π interaction

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Conjugated Polyelectrolyte-Ag＋ fluorescent switch for Biothiol Sensing

引用

Chemical Research in Chinese Universities 2013年第5期29卷 845-849页

作者： XIAO Yi LI Sha HUANG Hong-mei ZHANG Ye XUE Zun-zun TANG Xue-yan HE Xiao-xiao WANG Ke-min Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research Ministry of Education College of Chemistry and Chemical Engineering Hunan Normal University Changsha 410081 P. R. China State Key Laboratory of Chemo/Biosensing and Chemometrics College of Chemistry and Chemical Engineering College of Biology Hunan University Changsha 410082 P. R. China

A new ＂off-on＂ switch for sensitive and selective fluorescence detection of biothiols[glutathione（GSH）, cysteine（Cys） and homocysteine（Hcy）] was developed based on an anionic conjugated polyelectrolyte（CPE）, pyridyl-functionalized poly（phenylene ethynylene）（Pl）. The fluorescence of P1 can be significantly quenched by Ag＋ due to complexation-mediated interpolymer aggregation. Furthermore, biothiols can efficiently recover the fluorescence intensity of P1 as a result of the stronger binding between thiol group and Ag＋, which dissociates PI from the P1/Ag＋ complex and disrupts interpolymer aggregation. Under optimum conditions, a good linear relation- ship in a range of 100--4200 nmol/L is obtained for GSH with a detection limit of 80 nmol/L（S/N=3）. As a result of specific interaction between the thiol group and Ag＋, the proposed method shows a high selectivity for biothiols. In addition, the CPE-based fluorescence ＂off-on＂ switch has been used to quantitatively detect total biothiols in cell lysates.

关键词： fluorescent switch Biothiol Silver(I) Conjugated polyelectrolyte

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Fabricating UCNPs-AuNPs fluorescent Probe for Sensitive Sensing Thiamphenicol

引用

Chemical Research in Chinese Universities 2022年第6期38卷 1453-1460页

作者： YI Jiaqi LI Xiaoshuang CUI Di HAN Lixia JIANG Wei ZHANG Renguo NIU Na CHEN Ligang Key Laboratory of Forest Plant Ecology College of ChemistryChemical Engineering and Resource UtilizationNortheast Forestry UniversityHarbin150040P.R.China

A novel fluorescent probe has been constructed based on fluorescence resonance energy transfer(FRET)between upconversion nanomaterials(UCNPs)NaYF4:Yb,Er and gold nanoparticles(AuNPs).The fluorescent“off-on”switching was formed for the detection of thiamphenicol(TAP)in egg *** fluorescence of UCNPs can be quenched to a certain degree by *** adding TAP,the AuNPs generated aggregation and the fluorescence of UCNPs was *** synthesized amination UCNPs and AuNPs were characterized by Fourier transform infrared spectroscopy(FTIR),UV-Vis,X-ray diffraction(XRD),energy dispersive spectrometer(EDS),and transmission electron microscope(TEM)techniques for observation and *** a model target,the detection of TAP has two linear ranges in the buffer solution within 0.01–0.1µmol/L and 0.1–1µmol/L using this fluorescent *** detection limit was obtained to be 0.003µmol/L(S/N=3),which is favorable for trace *** recovery of TAP from 98.2%to 105.3%was obtained,and the relative standard deviation(RSD)was from 2.5%to 4.3%.Furthermore,the method established in this study based on the UCNPs auto-low background fluorescence has high selectivity and strong ability to eliminate interference,which is beneficial to analyzing complex samples.

关键词： Upconversion nanomaterial fluorescent switch Thiam-phenicol Fluorescence resonance energy transfer Egg analysis

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

A Highly Selective fluorescent Chemosensor for Cu2＋

引用

Chemical Research in Chinese Universities 2015年第3期31卷 347-351页

作者： GUAN Jie ZHANG Peng WEI Taibao LIN Qi YAO Hong ZHANG Youming Key Laboratory of Eco-environment-related Polymer Materials Ministry of Education Key Laboratory of Polymer Materials of Gansu Province College of Chemistry and Chemical EngineeringNorthwest Normal University Lanzhou 730070 P.R.China

A new Zn2＋ probe L2-Zn（L2=naphthofuran carbonylhydrazone derivant） was synthesized as a fluores- cence chemosensor for Cu2＋, by which Cuz＋ ion could be detected with high selectivity and sensitivity in a wide pH range via a displacement ＂turn-off＂ signaling strategy. Whereas the coordination between Zn2＋ and L2 resulted in a considerable enhancement of typical luminescence of a naphthalofuran group in complex L2-Zn, the addition of Cu2＋ ion led to a dramatic decrease in the emission intensity of probe L2-Zn at about 503 nm（excitation at 423 nm）. The competitive fluorescent experiments showed that other metal ions, such as Hgz＋, Fe3＋, Ag＋, Ca2＋, Co2＋, Ni2＋, Cd2＋, Pb2＋, Zn2＋, Cr3＋ and Mg2＋ could not impact tile detection of Cu2＋. The detection limit of the novel probe L2-Zn for Cu2~ ion was as low as 2.3× 10 7 mol/L, which is far lower than the guideline value of 1.6× 10-5 mol/L of the United States Environmental Protection Agency.

关键词： Znic complex fluorescent switch Copper ion Turn-off signal

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Visualized thermoresponsive helix-helix switch of polyphenylacetylene with a wide-range tunable transition temperature

引用

Science China Chemistry 2023年第3期66卷 887-895页

作者： Sheng Wang Siyu Xie Hongxu Du Hua Zeng Jie Zhang Xinhua Wan Beijing National Laboratory for Molecular Sciences Key Laboratory of Polymer Chemistry and Physics of Ministry of EducationCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China

Polymers with tunable helicity and naked-eye structural change under external stimuli are valuable for fabricating smart materials. Herein, we report a novel thermoresponsive color and fluorescent polyphenylacetylene switch with a tunable critical temperature. It relies on the temperature and solvent sensitivity of intramolecular n→π* interactions between the vicinal carbonyl groups of ester substituents located at 3,5-positions, which are indispensable for forming the cis-cisoid helical conformation of polyene backbones. In a properly chosen solvent, a compressed cis-cisoid helix is stabilized by n→π* interactions at low temperatures and yields a colorless solution. Increasing temperature causes the conformational transition toward an extended cis-transoid helix due to the disruption of n→π* interactions and produces a yellow solution. Reducing the hydrogen bond donating ability or polarity of solvents increases the switching temperature. By introducing a fluorogenic pendant, this conformational transition can also be read out by fluorescence quenching. This work may open a new window for developing intelligent materials through precisely tuning conformational transitions.

关键词： polyphenylacetylene thermoresponsive conformation transition fluorescent switch n→π*interaction

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：