A Highly Selective and Sensitive Fluorescent Chemosensor for Detection of Al3+ in Totally Aqueous Media

A fluorescent chemosensor ( 1 ) based on 2‐hydroxy‐1‐naphthaldehyde Schiff‐base was developed for the detection of Al³⁺ in 100% aqueous solution. Upon addition of Al³⁺, a significant fluorescence enhancement was observed, which was not affected by other metal ions including Na⁺, K⁺, Ca²⁺, Mg²⁺, Mn²⁺, Co²⁺, Ni²⁺, Cu²⁺, Cr³⁺, Ag⁺, Pb²⁺, Zn²⁺, Cd²⁺, Hg²⁺, Fe²⁺ and Fe³⁺ under weak acid conditions. Moreover, the specific response to Al³⁺ was visible under natural light. The binding mode between 1 and Al³⁺ was clarified by ESI‐MS and ¹H NMR.     

A New Fluorescent Chemosensor for Cu2+ Based on 1,2,3,4,5,6,7,8,9,10‐Decahydroacridine‐1,8‐dione Fluorophore

A new chemosensor for Cu²⁺ was synthesized based on 1,2,3,4,5,6,7,8,9,10‐decahydroacridine‐1,8‐dione dyes, which exhibited an obvious fluorescent selectivity to the sensing of Cu²⁺ ions over other cations, such as Na⁺, K⁺, Ca²⁺, Cd²⁺, Co²⁺, Hg²⁺, Mg²⁺, Mn²⁺, Ni²⁺, Zn²⁺, Ag⁺ and Pb²⁺. Moreover, it presented a fluorescent switch function when EDTA was added to the compound‐Cu²⁺ complex in examined systems.     

A Fluorescent Probe for Al3+ Based on Calix[4]arene Containing Salicylaldehyde-Derived Schiff Base

Two novel fluorescent probes L1 and L2 for recognizing Al³⁺ have been prepared by cooperating salicylaldehyde-derived Schiff base groups onto the upper rim of the calix[4]arene. Of these probes, L2 is the most effective at recognizing Al³⁺, displaying a highly selective fluorescence “on” response with an emission wavelength at 478 nm and a Stokes shift of 88 nm. Additionally, probe L2 can form a 1 : 1 coordination complex with Al³⁺ with a binding constant of 2.6×10¹⁰ M⁻¹. Furthermore, its fluorescence intensity exhibits a good linear relationship with Al³⁺ concentration within the range of 2.0×10⁻⁵ M to 1.4×10⁻⁴ M, and the probe has a low detection limit of 4.36×10⁻⁷ M.     

Metal‐Mediated Production of Isocyanates,R3ENCO from Dinitrogen,Carbon Dioxide,and R3ECl

A highly efficient and versatile chemical cycle has been developed for the production of isocyanates through the molecular fixation of N₂, CO₂ and R₃ECl (E=C, Si, and Ge). Key steps include a ‘one‐pot’ photolytic N? N bond cleavage of a Group 6 dinuclear dinitrogen complex with in situ trapping by R₃ECl to provide a metal terminal imido complex that can engage in simultaneous nitrene‐group transfer and oxygen‐atom transfer to generate an intermediate metal terminal oxo complex with release of the isocyanate product. Reaction of the oxo complex with additional equivalents of R₃ECl regenerates a metal dichloride that is the precursor for dinuclear dinitrogen starting material.     

1,8-萘酰亚胺为发色团的Zn2+荧光探针的合成及性能研究

合成了以1,8-萘酰亚胺为发色团,以联吡啶为离子受体的Zn²⁺荧光探针,并进行了表征及离子识别性能的研究。研究表明该化合物对Zn²⁺具有良好的识别性能,同时相对于Ca²⁺, Cd²⁺, Co²⁺, Cu²⁺, Hg²⁺, Fe³⁺, Mn²⁺, Ni²⁺, Pb²⁺等金属离子具有良好的选择性。     

Metal‐Mediated Production of Isocyanates,R3ENCO from Dinitrogen,Carbon Dioxide,and R3ECl

A highly efficient and versatile chemical cycle has been developed for the production of isocyanates through the molecular fixation of N₂, CO₂ and R₃ECl (E=C, Si, and Ge). Key steps include a ‘one‐pot’ photolytic N N bond cleavage of a Group 6 dinuclear dinitrogen complex with in situ trapping by R₃ECl to provide a metal terminal imido complex that can engage in simultaneous nitrene‐group transfer and oxygen‐atom transfer to generate an intermediate metal terminal oxo complex with release of the isocyanate product. Reaction of the oxo complex with additional equivalents of R₃ECl regenerates a metal dichloride that is the precursor for dinuclear dinitrogen starting material.     

A Highly Selective and Turn‐on Fluorescent Probe for Fe3+ Ion Based on Perylene Tetracarboxylic Diimide

We have demonstrated a turn‐on fluorescent sensor 6 for detection of Fe³⁺ based on photo‐induced electron transfer (PET) mechanism. The probe comprises a perylene tetracarboxylic diimide (PDI) fluorophore and two bis((1,2,3‐triazol‐4‐yl)methyl)amine (DTA) moieties as the metal ion receptors. It exhibits high selectivity toward Fe³⁺ over various other metal ions in CH₃CN/H₂O (1:1, V/V). The binding stoichiometry for 6 ‐Fe³⁺ complexes has been determined to be 1:2 by a Job plot of fluorescence. The association constant between 6 and Fe³⁺ was estimated to be 1.04×10¹⁰ (mol/L)^?2 by Benesi‐Hildebrand equation.     

基于杯[4]芳烃的对N-乙酰基-天冬氨酸盐对映选择性识别的荧光传感器

合成了携带有丹磺酰基荧光团和（1R,2R）- 或（1S,2S）-1,2-二苯基乙二胺键合单元的双臂杯[4]芳烃手性阴离子受体（1和2）。通过荧光光谱检测了受体对手性氨基酸阴离子的键和能力。非线型曲线拟合的结果表明受体（1或2）与N-乙酰基-L或D－天冬氨酸盐通过多重氢键的相互作用形成了1：1的络合物。并且展现了对N-乙酰基天冬氨酸盐对映体良好的对映选择性的荧光识别（受体1： K_ass(D)/ K_ass(L)=6.74;受体2： K_ass(L)/ K_{ass (D)}=6.48）。明显不同的荧光响应说明受体1和2能被用作为对N-乙酰基天冬氨酸盐的荧光化学传感器。     

基于四丹磺酰胺杯[4]芳烃的汞离子荧光化学传感器

我们方便地合成了上沿修饰四丹磺酰胺基团的杯[4]芳烃衍生物1,发现该化合物在含50％水的乙腈中显示出对汞离子高选择性和灵敏性的识别作用,竞争实验表明多数金属离子对其检测干扰较小。机理研究结果表明荧光萃灭源于由丹磺酰胺基团到汞离子的光致电子转移过程。另外,通过研究1和1-Hg2+的荧光衰减实验,以及对比双丹磺酰胺杯[4]芳烃2和单丹磺酰胺杯[4]芳烃3对汞离子的识别作用,发现化合物1的四丹磺酰胺基团具有很好的预组织和协同作用。化合物1对汞离子的检测限为3.41×10-6 mol·L-1,这可以使1成为一个潜在的汞离子荧光化学传感器。     

A New Fluorescent Chemosensor for Metal Ions Based upon 1,8‐Naphthalimide and 8‐Hydroxyquinoline

A new fluorescent chemosensor based upon 1,8‐naphthalimide and 8‐hydroxyquinoline was synthesized, and its fluorescent properties in the presence of different metal cations (Hg²⁺, Ag⁺, Zn²⁺, Fe²⁺, Cd²⁺, Pb²⁺, Ca²⁺, Cu²⁺, Mg²⁺, and Ba²⁺) were investigated. It displayed fluorescence quenching with some heavy and transition metal (HTM) ions, and the quenching strongly depended on the nature of HTM ions.     

A Logic Fluorescent Chemosensor Based on Eu3+ Functionalized Cd-MOFs for Sensing Fe3+ and Cu2+ Synchronously

One of the most critical and yet unsolved issues is the effective monitoring of multiple heavy metal ions in complex systems through their specific function in fluorescence detection. In this work, luminescence-active cadmium base metal-organic frameworks (Cd-MOFs) based on the planar and rigid π-conjugated structure ligand benzo-(1,2;3,4;5,6)-tris (thiophene-2’-carboxylic acid) (H₃BTTC) was chosen. A series of sensing experiments demonstrated that the Cd-MOFs exhibits selective and sensitive response for Fe³⁺ and Eu³⁺ through fluorescence “turn off” and “antenna effect” respectively. In addition, the encapsulation of Eu³⁺ inside the Cd-MOFs (Eu³⁺@Cd-MOFs) led to an excellent probe with dual emission. To this end, a programmable fluorescence platform was developed to detect Fe³⁺ and Cu²⁺, in which the emission peaks of both the ligand and Eu³⁺ are completely quenched by Fe³⁺. The ratiometric detection of Cu²⁺ leads to a decrease in Eu³⁺ emission, while the ligand emission remains stable. To demonstrate the strategy, the fluorescence (Output) of Cd-MOFs, Eu³⁺@Cd-MOFs, and the analytes (Eu³⁺, Fe³⁺, and Cu²⁺, input) achieved elementary Boolean logic operations (OR, NOR, AND) and they constitute a logic fluorescent chemosensor to analyze Fe³⁺ and Cu²⁺ synchronously.     

A Fluorescent Probe for Hg2+ Based on Gold(I) Complex with An Aggregation‐Induced Emission Feature

A gold(I) complex that exhibited aggregation‐induced emission in acetonitrile‐water mixtures was designed. It showed high selectivity and sensitivity for Hg²⁺ in acetonitrile‐H₂O (1:1, V:V) solution. Dynamic light scattering measurements were conducted to verify that the addition of Hg²⁺ changed the particle size and induced fluorescence quenching.     

2-羟基萘甲醛苯甲酰腙衍生物对Al~(3+)的裸眼识别和荧光传感

设计合成了化合物4-羟基苯甲酰-(2-羟基萘甲醛)腙(L)探针,经金属离子识别研究发现探针L对Al~(3+)具有良好的荧光增强识别效果且不受其它金属离子的干扰,且识别过程中溶液的颜色发生了明显变化,可以实现Al~(3+)的可视法检测,核磁滴定、job-plot、基质辅助激光解吸电离飞行时间质谱(MALDI-TOF)等实验结果显示,探针L与Al~(3+)以摩尔比2∶1的方式进行配位。通过对紫外滴定数据的非线性拟合分析,探针L与Al~(3+)的结合常数为1.3×10~4L/mol,最低检测限为3.71×10~(-6)L/mol。因此,该腙类衍生物作为Al~(3+)的荧光及比色探针,识别体系线性范围较宽,检测限低,在痕量Al~(3+)的检测方面具有潜在的应用价值。     

基于2，3-萘-18-冠-6单元的共轭高分子对金属离子的荧光传感器

能发射蓝绿色荧光的共轭高分子由单体1,4-二溴-2,3-萘-18-冠-6(M-2)与1,4-二乙烯基-2,5-二丁氧基苯(M-3)通过Pd催化的Heck偶联反应合成制得。通过荧光和紫外-可见光谱探讨了高分子对金属离子的响应性质,其中Hg²⁺能使高分子荧光淬灭、吸收增强,但As^Ⅲ、Pb²⁺和K⁺对高分子的荧光光谱改变很小。结果表明以2,3-萘-18-冠-6作为荧光团和识别位点的共轭高分子可作为有效识别Hg²⁺的荧光化学传感器。     

A CdII‐Based Metal‐Organic Framework with pcu Topology as Turn‐On Fluorescent Sensor for Al3+

A new metal‐organic framework (MOF) {[Cd₂(bbib)₂(ndc)₂]?2DMF}_n ( JXUST‐1 ) (bbib=1,3‐bis(benzimidazolyl)benzene, H₂ndc=1,4‐naphthalenedicarboxylic acid, DMF=N,N‐dimethylformamide) has been solvothermally synthesized and characterized by single‐crystal X‐ray diffraction, PXRD, TGA, IR and elemental analysis. JXUST‐1 exhibits a three‐dimensional 6‐connected pcu topology with a Schläfli symbol {4¹².6³} constructed by [Cd₂(CO₂)₃] secondary building units. Fluorescence studies show that this MOF can sensitively and selectively recognize Al³⁺ via a fluorescence enhancement effect, and the detection limit is 0.048 ppm. Furthermore, JXUST‐1 displays relatively good thermal and chemical stabilities as well as reusability. All these results suggest JXUST‐1 to be a highly selective and recyclable luminescent sensing material for the detection of Al³⁺.     

A Highly Selective and Sensitive Fluorescent Probe Recognition for Co2+ in Aqueous Media Based on 8‐Hydroxyquinolin‐2‐carbaldehyde‐2‐pyridylformylhydrazone Derivative

A new (8‐hydroxyquinolin‐2‐yl)methylene picolinohydrazide derivative ( L ) has been successfully synthesized and characterized. The probe L displays high selectivity to Co²⁺ in CH₃CN/HEPES (1:1, Ｖ/Ｖ, 10 mmol·L^?1, pH=7.4) with a fluorescence "ON‐OFF" response. The Co²⁺ ion recognition event possesses some distinct features including rapid response, high selectivity and sensitivity, good anti‐interference ability and being applicable within a wide pH range. Based on job's plot and ESI‐MS studies, the 1:1 binding mode was proposed. The binding constant of L and Co²⁺ is 1.63×10⁸ L·mol^?1 and the detection limit is 1.15 µmol·L^?1. Natural water samples experiments revealed that probe L can be potentially applied to the detection of Co²⁺ in real environment.     

基于杯[4]芳烃和S-联萘酚的荧光传感器的合成及其对N-Boc保护谷氨酸阴离子的对应选择性识别性能研究

合成了一种基于杯[4]芳烃和S-联萘酚单元的新型手性大环受体4,并用荧光光谱和核磁氢谱研究了该受体与阴离子的键合性质。非线性曲线拟合结果表明受体4与N-Boc保护L-和D-谷氨酸阴离子都能通过多重氢键形成1:1的络合物,而且对N-Boc保护谷氨酸阴离子对映体显示了较好的对应选择性识别性能（Kass(L) / Kass(D) = 4.65）。不同的荧光响应表明受体4可以用作N-Boc保护谷氨酸阴离子的对应选择性的荧光化学传感器。     

A Novel Dual Channel Fluorescent Probe for Ca2+ and Zn2+ Based on a Coumarin Schiff Base

A novel coumarin Schiff base fluorescent probe ethyl 7‐hydroxycoumarin‐3‐carboxylate‐8‐formaldehyde benzoyl hydrazone ( EBH ) has been designed and synthesized which shows solvent dependent dual sensing, viz., recognition of Ca²⁺ in DMF‐H₂O (9∶1, V /V ) solution based on C = N isomerization, photoinduced electron transfer (PET ) inhibition and chelation‐enhanced fluorescence (CHEF ) mechanism as well as detection of Zn²⁺ in H₂O‐CH₃OH (9∶1, V /V ) solution by excited‐state intramolecular proton transfer (ESIPT ) and CHEF processes. The structure of the probe EBH has been confirmed by single‐crystal X‐ray diffraction analysis. Meanwhile, the probe was also used to image intracellular Zn²⁺ ions in MCF ‐7 cells with a good performance.     

Characterization and Activity of MnO/γ‐Al2O3 for Hydrogenation of Methyl Benzoate to Benzaldehyde

The activities of a MnO/γ‐Al₂O₃ catalyst for the selective reduction of methyl benzoate to benzaldehyde have been studied in a continuous flow reactor. Characterization of the catalyst has been conducted by XRD, XPS, NH₃‐TPD and TPD‐IR. XRD and XPS results revealed that the steady state catalyst is mainly MnO₂/γ‐AlO₃ before reduction and MnO/γ‐Al₂O₃ after reduction. Monolayer dispersion capacity obtained by XPS method is about w (Mn)11.3% TPD‐IR results revealed that there are only L acidic centers on the catalytic surface. NH₃‐TPD determinations have verified that the catalyst with a certain number of moderate strength acidic sites is advantageous to hydrogenation of methyl benzoate to benzaldehyde.