Synthesis of Schiff Base Bearing Phenolic Hydroxy Group and Its Anion Recognition

A new anion receptor bearing phenolic hydroxy group based on 3,5- ditertbutylsalicylaldehyde-p-nitrophenylhydrazone （1） was designed and synthesized. Upon addition of AcO- and F-, the receptor exhibited visible color changes from deep yellow to purple. However, no obvious color changes were observed on addition of the other anions tested （H2PO4-, Cl-, Br-, I-）. The binding properties of the receptor with anions such as AcO and F- were investigated by UV-Vis and fluorescent titrations. The result indicated that the receptor 1 had a higher affinity to AcO- and F- and a 1：1 host-guest complex was formed through H-bond interactions between 1 and anions.

Synthesis and Anion Recognition of a Novel Heterocyclic Organotin Complex

A novel heterocyclic hexacoordinate organotin(Ⅳ) complex, bis(O-vanillin)-semi ethylenediamino dibenzyltin (VEDBT) was synthesized by the reaction of dibenzyltin dichloride with bis(O-vanillin)-semiethyenediamine, its structure has been characterized by spectral methods. The electrodes using VEDBT as a neutral carrier show high selectivity for salicylate anions.

Research on Inorganic Anion Recognition of Calix[4]pyrroles and Dipyrrylmethanes by Capillary Zone Electrophoresis

Capillary electrophoresis （CE） can separate charged and neutral substances with high speed and efficiency. In this paper, utilizing meso-octamethylcalix[4]pyrrole, meso-tetraspirocyclohexylcalJx[4]pyrrole, bimethyl bi（2-pyrryl）- methane and 1,1-bi（2-pyrryl）cyclohexane as additives in capillary zone electrophoresis （CZE） electrolyte, their recognition ability to inorganic anions was discussed. The dipyrrylmethanes have better recognition ability than others. Their effects on separation of seven normal inorganic anions by CZE were studied.

Study on the Anion Recognition Properties of Synthesized Receptors （Ⅲ）： Convenient Synthesis and Anion Recognition Property of Bisthiosemicarbazone Derivative

A new series of bisthiosemicarbazone derivative receptors （1, 2 and 3） have been synthesized by simple steps in good yields. Their anion recognition properties were studied by UV-Vis and ^1H NMR spectroscopy. The result showed that the receptors 1, 2 and 3 all had a better selectivity to F^-, CH3COO^- and H2PO4^-, but no evident binding with Cl^-, Br^-, I^-, NO3^- and HSO4^-. Upon addition of the three anions to the receptors in DMSO, the solution acquired a color change from colorless to dark yellow that can be observed by the naked-eyes, thus the receptors can act as fluoride ion sensors even in the presence of other halide ions. The data showed that it was regular that the three receptors had different binding ability with the three anions. For the same anion, the association constants followed the trend： receptor 1〉3〉2. The UV-Vis data indicates that a 1 ： 1 stoichiometry complex is formed through hydrogen bonding interactions between compound 1, 2 or 3 and anions.

New Host Molecules with Imidazoliums as Functional Arms:Syntheses and Anion Recognition

The bridged tri imidazoliums 3·3X --5·3X - (X -=PF - 6, Br -, I -) and bis imidazoliums 6·2PF - 6 were synthesized by N quaternization of imidazole derivative 1 in acetonitrile under reflux. UV spectroscopic titration experiments showed that the halide salts and hexafluorophosphate salts of these imidazoliums exhibited good recognition toward anions in water and in acetonitrile, respectively.

The Synthesis of a Fluorescent Chemosensor Containing Two Thiourea Groups and Its Recognition Behavior for Dicarboxylate Anions

A novel anion receptor2 bearing anthracene flurophore and thiourea was synthesized and identified by1H NMR, MS, IR and elemental analysis. The interaction between receptor2 and various α, ω-dicarboxylate anions was studied by fluorescence spectrum. The obtained fluorescence data indicate that 1∶1 stoichiometry complex is formed between receptor2 with diferent dicarboxylate anions through a hydrogen-bonging interaction. The selectivity of2 for recognition of different dicarboxylates deponds on chain length of the anionic species. Key words anion receptor - fluorescence - synthesis - anion recognition CLC number O 626 Foundation item: Supported by the National Science Foundation of china (20372054)Biography: WANG Fa-jun (1976-), male, Master Candidate, research direction: supramolecular chemistry.

Design,Synthesis and Recognition Properties of a New Acetate Ion Receptor Based on Shiff-base Derivative

A simple colorimetric acetate ion receptor based on 3-methoxysalicylaldehyde-4＇-nitrophenyl-hydrazone was synthesized in an ethanol solution through one step,and characterized by 1H NMR and elemental analyses.Its anion-binding ability was examined by UV-Vis absorption spectroscopy in DMSO（dimethyl sulfoxide）.The result shows that the compound has a high affinity for and a high selectivity toward acetate ions,and also an advantage of ＇naked-eye＇ recognition of color changing from yellow to purple.

New Subsidiary Interaction Mode of Counteranions with the Periphery Cavity of Calix[4]pyrroles Binding with the Anion Subunits

The solution binding properties of calix[4]pyrroles with anion （as tetraalkylammonium salts） were investigated using UV-Vis spectroscopic techniques. The obvious red-shift of absorption maximum band of calix[4]pyrrole in EtOH in the presence of the tetramethylammonium （TMA^＋） salts or tetraethylammonium （TEA^＋） salts were observed, due to the charge-transfer interactions between the electron-rich pyrrole rings of calix[4]pyrroles and TMA^＋ or TEA^＋ cation subunit. The results indicated that calix[4]pyrrole receptors, which link the anionic species through multiple hydrogen bonding interactions, can use the periphery cavity for selectively binding cation subunits by cation-π charge-transfer interaction. The subsidiary interaction mode helps to further stabilize the calix[4]pyrrole-anion complex.

Synthesis and Crystal Structure of 1,2-Bis-(p-nitrophenylsulfonamido)-4,5-dinitrobenzene

The title compound, 1,2-bis-（p-nitro-phenylsulfonamido）-4,5-dinitrobenzene, was synthesized and characterized by elemental analysis, IR and 1H NMR. A pale yellow prism crystal of C23H26N8O13S2 （Mr = 686.64） was obtained in DMF solution and determined by single-crystal X-ray diffraction method. It crystallizes in triclinic system, space group P1 with a = 10.346（4）, b = 12.210（5）, c = 12.976（5）A , α = 108.220（8）, β = 99.482（4）, γ = 95.490（4）°, V = 1516.7（10） A^3, Z = 2, Dc = 1.504 g/cm^3, F（000） = 712, μ = 0.254, Mr = 686.64, the final R = 0.0561 and wR = 0.1487. One sulfonamido group of the title compound is deprotoned and forms N（3）=C（13）. The crystal involves N,N-dimethylamine from the decomposition of DMF and the proton is transferred to N,N- dimethylamine. It is a strong proof for the characterization of deprotoned recognition compound by X-ray single-crystal structure.

Synthesis and Crystal Structure of 1-(N,N-Di-(p-toluenesulfonyl))-amino-2-(N'-p-toluenesulfonyl)-amino-3,5-dinitrobenzene

The title compound, 1-（N,N-di-（p-toluenesulfonyl））-amino-2-（N＇-p-toluenesulfonyl）- amino-3,5-dinitrobenzene, was synthesized and structurally determined by single-crystal X-ray diffraction method. It crystallizes in orthorhombic, space group Pna21 with a = 13.723（2）, b = 25.354（4）, c = 8.6565（12） A, V= 3011.9（8） A^3, Z = 4, Mr = 660.68, F（000） = 1368, Dc = 1.457 g/cm^3, μ = 0.309, the final R = 0.0609 and wR = 0.1042. The H atom of N2-H group, which is the unique recognition site to anion, is enveloped by two oxygen atoms and one benzene from two and one p-toluenesulfonyl moieties, respectively.

Synthesis of Novel Anionic Receptors with (Thio) urea and Amide Binding Sites and the Recognition Properties for Anions

Two new neutral receptors (1 and 2) containing (thio)urea and amide groups were synthesized by simple steps in good yields. The binding properties for anions of 1 and 2 were characterized by UV-vis and fluorescence spectra. Receptor 1 had an excellent selectivity for AcO - in comparison with other anions. The association constants of 1·AcO - and 2·p-NO_2PhOPO 2- _3 were higher than those of other anions (Cl -,Br -,I -,H_2PO -_4 and p-NO_2PhO -). In particular,an obvious color change was observed from light yellow to golden yellow upon addition of AcO - to the solution of 1 in DMSO. The results of non-linear curve fitting by UV-vis and fluorescence spectral data indicate that a 1∶1 stoichiometry complex is formed between compound 1 or 2 and anions through a hydrogen bonding interaction.

Ultracycles consisting of macrocycles

Presented here is a one-pot strategy starting from rationally designed macrocyclic precursors for the diverse construction of sophisticated ultracycles.The type and amount of the base were found to significantly influence the macrocyclization outcome.The use of 4.0 equiv.CsF resulted in ultracycles of both types A and B while the presence of CsF larger than 6.0 equiv.produced only type B ultracycles.Existence of anion template increased the total yields and affected the distribution of the ultracycles.The ultracycles can accommodate large organic dicarboxylates anions via multiple anion-πand hydrogen bonds,and show selectivity to the size-matched heptanedioate(C7^(2−)).Based on all possible species and relevant equilibrium constants as well as material and charge balances,a numerical iterative algorithm was developed and applied to fit the association constants of B2H with dicarboxylates from glutarate(C5^(2−))to octanedioate(C8^(2−)),which gave association constants up to 10^(3) L/mol.

Thiourea Based Tweezer Anion Receptors for Selective Sensing of Fluoride Ions

Three 3,3＇-di（4-substituted-phenyl）-1,1＇-isophthaloylbis（thiourea） compounds were designed as novel neutral anion receptors, and synthesized by simple steps in good yields. The single crystal structure of receptor 1 shows that a solvent molecule was captured by the host molecule through intermolecular hydrogen bonding. Moreover, it was self-assembled as a supramolecular system for the presence of abundant inter- and intramolecular hydrogen bonding and π-π interactions between phenyl groups. Their application as anion receptors has been examined by UV-Vis and ^1H NMR spectroscopy, showing that they had a higher selectivity for fluoride than other halides. The host and guest formed a 1 ： 1 stoichiometry complex through hydrogen bonding interactions in the first step, then following a process of deprotonation in presence of an excess of F^- in the solvent of DMF.

Synthesis of Bis-benzimidazolium Cyclic Receptors and Their Anion Binding Properties

A series of cyclic receptors 1--5 based on bis-benzimidazolium group were designed and synthesized. Their anion recognition properties were investigated by UV-vis, fluorescent spectroscopy, 1H NMR and MALDI-TOF mass spectrometry. The UV-vis and fluorescent spectroscopic studies showed that the receptors 1--5 had different binding abilities for various anions such as fluoride, chloride, bromide, iodide and acetate. The high selectivity of the receptors for fluoride and acetate anions is attributed to their basicity. Job plot and MALDI-TOF mass spec- trometry demonstrated that the receptors form 1 ： 1 complex with fluoride. DFT calculation and 1H NMR studies indicated that the receptors bind anions through （C--H）＋…X- hydrogen bond.

Recent advances in click-derived macrocycles for ions recognition

The Cu（I）-catalyzed azide-alkyne 1,3-dipolar cycloaddition（CuAAC） reaction, popularly known as the ＂click reaction＂, have been widely used in chemosensor field. This reaction gives a mild and efficient coupling reaction between the binding site and the reporter. In addition, the formation 1,4-disubstituted1,2,3-triazole linker shows a high binding affinity toward both anions and metal ions. Recently researches revealed this reaction is also an efficient tool to form rigid or shape-persistent, preorganized macrocyclic species. This review summarized the recent advances in click derived macrocyclic receptors for recognition of anion, metal ion and ions pair.

Novel N,N＇-Diacylhydrazine-Based Colorimetric Receptors for Selective Sensing of Fluoride and Acetate Anions

Three novel and simple N,N＇-diacylhydrazine-based colorimetric receptors have been prepared. The binding properties of the receptors to anions such as F^-, Cl^-, Br^-, AcO^-, HSO4^- and HEPO4^- in acetonitrile solution were examined by UV-Vis spectroscopy methods, which show high sensitivity and selectivity to F^- and AcO^- over other anions. The results indicated that a 1 ： 1 stoichiometry complex was formed between the receptors and the anions, while ^1H NMR titrations confirmed hydrogen binding interaction between the receptors and the anions.

Preparation and fluorescent recognition properties for fluoride of a nanostructured covalently bonded europium hybrid material

A novel covalently bonded Eu3＋-based silica hybrid material was designed and its spectrophotometric anion sensing property was studied. The fluorescent receptor （europium complex） was covalently grafted to the silica matrix via a sol-gel approach. FTIR, UV-vis spectra, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, X-ray diffraction （XRD） and photoluminescent spectra were characterized, and the results revealed that the hybrid material with nanosphere structure displayed excellent photophysical property. In addition, the selective anion sensing property of the hybrid material was studied by UV-vis and fluorescence spectra. The results showed that the hybrid material exhibited a smart response with fluoride anions.

Two Multi-armed Neutral Receptors for α,ω-Dicarboxylate Anions

Two new multi-armed neutral receptors 1 and 2 containing thiourea and amide groups were synthesized by simple steps in good yields. Receptors 1 and 2 have a better selectivity and higher association constants for malonate anion than other anions examined by the present work. In particular, distinct color changes were observed upon addition of dicarboxylate anions to the solution of 1 in DMSO. The UV-Vis and fluorescence spectra data indicate that a 1 ： 2 stoichiometry complex was formed between compound 1 or 2 and dicarboxylate anions of shorter carbon chain, and a 1 ： 1 stoichiometry complex was formed between compound 1 or 2 and dicarboxylate anions of longer carbon chain through hydrogen bonding interactions.

Amide-based Fluorescent Macrocyclic Anion Receptors

Two fluorescent anion receptors (1 and 2) based on amide macrocycle were synthesized and corresponding fluorescence quenching induced by anion complexation was observed in different degree. Receptors form 1∶1 complexes with anions by hydrogen bonding interactions. Receptor 1 bound anions in the order of F->Cl->24HPO->CH3COO->>Br-, I- and receptor 2 showed high selectivity to F- over other anions.

Synthesis of a Phenylhydrazone-based Colorimetric Anion Sensor with Complementary IMP/INH Logic Functions

A dinitrophenyl hydrazone colorimetric anion sensor （receptor 1） was synthesized and its recognition properties towards various anions were investigated by naked eye observation and spectroscopic methods, namely UV-vis and 1H NMR titrations in DMSO. The addition of AcO？, F？ and H2PO4？ to receptor 1 resulted in marked red shift of the charge-transfer absorbance band （Δλ=91 nm, 407 nm to 498 nm） concomitant with a ＇naked-eye＇ detectable colour change from yellow to pink. However, both the colour and spectral changes were reversible by the addition of cations （MII） of 3d5-10 as well as CdII, HgII, MgII and CaII. Subsequently, complementary IMP/INH logic functions based on colour and spectral switching （ON/OFF） were affirmed. The sensor can, thus be utilized as a colorimetric molecular switch modulated by F？/MII.