A novel calix[4]arene fluorescent receptor for selective recognition of acetate anion

A novel bridged fluorescent calix[4]arene with 1,8-diaminoanthracene and glycine at the upper rim has been prepared, which exhibited selective recognition towards AcO⁻ over other anions such as F⁻, Cl⁻, Br⁻, , , I⁻ and by fluorescence spectroscopy and ¹H NMR method.     

高选择性氟离子受体的合成与识别性能研究

设计合成了一种新型腙类阴离子受体1。利用紫外-可见吸收光谱,荧光光谱考察了其与Ac O-,H2PO4-,Cl-,Br-,I-和F-几种阴离子之间的作用。当加入F-时,导致紫外光谱的可见光区明显变化(大约115nm红移),同时伴随着浅黄色变为蓝紫色的"裸眼"颜色变化。而加入其他离子后溶液颜色几乎没有发生颜色。据此建立了裸眼比色法检测F-的方法。     

Amide-based tripodal receptors for selective anion recognition

The binding properties of ethylester derivative of p-tetraphenyl tetrahomodioxacalix[4]arenes (1) towards alkali, alkaline-earth, transition and heavy metal cations using UV-absorption spectrophotometry and ¹H-NMR spectroscopy are reported.     

A selective artemisinin-sensor using metalloporphyrin as a recognition element entrapped in the Au-nanoparticles-chitosan modified electrodes

An amperometric artemisinin (ARN) sensor based on the supramolecular recognition of glycosylated metalloporphyrin, which is included in the Au-nanoparticles-chitosan film coated on the glass carbon electrodes, was developed. For the improvement of the selectivity of artemisinin detection, 5,10,15,20-tetrakis[2-(2,3,4,6-tetraacetyl-β-d-glucopyranosyl)-1-O-phenyl]porphyrin (T(o-glu)PPH) metal complex [FeT(o-glu)PPCl] was synthesized and employed as a ARN-sensitive and -selective material in the amperometric sensors. The proposed [FeT(o-glu)PPCl]/Au-nanoparticles modified electrodes showed excellent selectivity and sensitivity toward ARN with respect to a number of interferents and exhibited stable current response, which can be attributed to the coordination of ARN with the [FeT(o-glu)PPCl] in the electrodes. The calibration graph obtained with the proposed sensor was linear over the range of 1.8 × 10⁻⁷-1.7 × 10⁻⁹ mol l⁻¹, with a detection limit of 1.7 × 10⁻⁹ mol l⁻¹ for ARN. Significant advantages of the proposed procedure over the conventional reductive electrochemical methods are the selective detection and the relatively low applied potential requirement of the ARN-sensor. The prepared sensor is applied for the determination of ARN in plant samples and the results agreed with the values obtained by the pharmacopoeia method.     

A novel calix[4]arene-based neutral semicarbazone receptor for anion recognition

A series of novel calix[4]arene-based neutral semicarbazone and thiosemicarbazone receptors have been synthesized and characterized. The molecular receptor 4a recognizes in preference to other anions (Cl⁻, Br⁻, I⁻, , and ) through a 1:1 binding-stoichiometry.     

Combined study of anion recognition by a carbazole-based neutral tripodal receptor in a competitive environment

Anion recognition studies have been carried out on a series of neutral synthetic receptors in which carbazole-2-carboxamide has been used as building block. Different ligands which include one to three carbazole units in their structure have been prepared. Binding experiments have been performed under competitive conditions in DMSO and DMSO-water solutions. The tripodal receptor offered a better host-guest association due to the synergistic effect of a well arranged set of hydrogen bonds. A selective response towards the biologically important pyrophosphate anion has been achieved. This selectivity is enhanced when studies are carried out with an increasing water content, which gets as high as 20% (v/v) in NMR experiments. The significance of this result lies in the use of a neutral receptor which exclusively interacts with the anionic guest through hydrogen bonding. The influence of multiple equilibria in the studied system has been analysed. Several techniques ((1)H NMR, (31)P NMR, mass spectrometry, diffusion-NMR, ITC, absorption and emission spectroscopy) have been employed to get a better understanding of the different processes taking place in solution for the evaluated receptors.     

Synthesis and anion recognition of a novel oleanolic acid-based cyclic dimer

A novel cyclic dimer based on oleanolic acid was synthesized using click chemistry and it showed remarkable selectivity and affinity to bind fluoride ion through C-H?F hydrogen bond interactions which involved the delocalization of proton in methylene.     

Carboxylate anion selective receptor with glycoluril molecular scaffold

Glycoluril based tweezer-type receptor has been designed and synthesized. Anion binding studies carried out using ¹H NMR and UV-vis revealed that this compound displays good affinities for Y-shaped anions such as acetate and benzoate, while binding spherical-shaped anions and tetrahedral-shaped anions only weakly.     

A novel neutral receptor for selective recognition of H2PO 4 −

A new urea-based receptor was designed to selectively recognize H₂PO₄⁻ among other anions (such as F^-, Cl^-, Br^-, I^-, OH^-, AcO^-) in organic solvent (DMSO) through intermolecular hydrogen bonding. Addition of anions to the receptor caused changes in UV–vis spectrum which provided the first indication of its anion binding ability. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Naked eye detection of anions by alkynyl-ruthenium exo-receptors: selective recognition of fluoride anion

Alkynyl-ruthenium complexes bearing terminal hydrogen-bonding receptors act as efficient anion sensors exhibiting large guest-induced colour changes and show unexpectedly high selectivity to fluoride ions.     

A hyodeoxycholic acid-based molecular tweezer: a highly selective fluoride anion receptor

A new molecular tweezer receptor Hc1 based on hyodeoxycholic acid has been synthesized and its binding properties were accessed by ¹H NMR and isothermal titration calorimetry experiments. Molecular tweezer Hc1 shows a high selectivity toward F⁻ over Cl⁻, Br⁻, I⁻, and H₂PO₄⁻.     

Halide anion capture and recognition by a tetrahedral tetraammonium receptor in water: a molecular dynamics investigation

We report molecular dynamics potential of mean force (PMF) simulations on the capture of halide anions X(-) (F(-), Cl(-), Br(-)) by a tetrahedral receptor L(4+) built from four quaternary ammonium sites connected by six (CH(2))(n) chains, leading to the formation of inclusion complexes X(-) subset L(4+). Simulations performed with a reaction field correction of the electrostatics and with PME-Ewald summation gave very similar energy profiles. In aqueous solution, an energy barrier of 12-17 kcal mol(-1) was found for the three anions, mainly due to their dehydration when they enter through the largest triangular face of L(4+). In the inclusion complexes, the anion is anchored near the center of the cavity due to the electrostatic field of the four positively charged ammonium sites, shielded from the surrounding water molecules. It was predicted that L(4+) is selective for Cl(-) over Br(-) which both form stable inclusion complexes, while the F(-) complex should dissociate. The comparison of PMFs in aqueous solution and in the gas phase and the energy component analysis demonstrates the importance of solvent on the nature of these complexes and on the complexation energy profiles. The Cl(-)/Br(-) selectivity obtained from the dissociation pathways in water was in good agreement with the results of free energy perturbation simulations based on the "alchemical route" of a thermodynamic cycle, and consistent with experimental observations.     

Bromide selective fluorescent anion receptor with glycoluril molecular scaffold

Glycoluril based fluorescent anion receptor has been designed and synthesized. Anion binding studies carried out using fluorescence spectroscopy and ¹H NMR revealed that this compound displays good affinities for bromide ion.     

一种双腙受体的合成及阴离子识别性能研究

设计合成了一种含双腙类阴离子受体1(5-甲基双水杨醛-2,4-二硝基苯腙)。用紫外-可见吸收光谱、荧光光谱考察了其与AcO-,H2PO4-,F-,Cl-,Br-和I-阴离子的作用。当加入AcO-、F-和H2PO4-时,受体分子1的吸收光谱发生明显的红移,与此同时溶液颜色由浅粉色变为紫色,而加入其他阴离子则无变化。通过在DMSO-d6核磁滴定实验进一步研究受体1和F-相互作用的本质。     

Steric and electronic factors influencing recognition by a simple, charge neutral norbornene based anion receptor

Based on (1)H NMR studies, subtle electronic factors rather than pre-organisation dictate the binding stoichiometry of the new, norbornene based, anion hosts 1 and 2 with acetate, however, the binding of dihydrogenphosphate appears to be based solely on steric constraints.     

Triphenylamine-based receptor for selective recognition of dicarboxylates

A new triphenylamine-based receptor 1 has been designed and synthesized for the recognition of aliphatic dicarboxylates of various chain lengths. This receptor has been designed to utilize an amide-urea conjugate for binding dicarboxylates. The receptor 1 is found to bind the dicarboxylates with moderate binding strength under a semi rigid, propeller shaped, fluorescent triphenylamine spacer. The binding behavior was studied in CH₃CN using ¹H NMR, fluorescence and UV-vis spectroscopic methods. The conformational behavior of 1 and its complexation modes have been investigated using classical and quantum mechanical theoretical methods. The receptor is found to be selective for long chain suberate.     

Novel anion receptors for selective recognition of dimethyl phosphinate and carboxylate

We have designed and synthesized new anion receptors 1 and 2, which have amide NH, pyrrole NH and vinyl CH as hydrogen bond donors. These receptors are selective for dimethyl phosphinate and carboxylates. Due to electron withdrawing effect of the cyano group which is trans to the vinyl hydrogen with respect to carbon-carbon double bond, receptor 1 has higher binding constants for phosphinate and carboxylate than those of receptor 2. Modeling studies shows that cyano group polarized all three hydrogens through planar π-electron network. In addition, receptor 1 gave orange colored 1,4-addition product for cyanide.     

硫脲衍生物受体的阴离子识别研究

设计、合成了双支链结构的萘基硫脲衍生物。利用吸收光谱和1^HNMR表征了该化合物与不同链长的二羧酸盐阴离子的相互作用。实验结果表明,阴离子与主体化合物间通过多重氢键形成配合物、导致萘基硫脲衍生物光谱发生变化。测定了配合物的稳定性,发现衍生物对二羧酸盐阴离子的选择性取决于二羧酸阴离子链的长短。并根据实验结果提出了可能的配合物结合方式。     

Synthesis,crystal structure,and photoluminescence of a zinc metalloporphyrin

A zinc metalloporphyrin, ZnTCPP(acetone) (1) (TCPP = meso-tetra(4-carboxyphenyl)porphyrin), has been prepared via a solvothermal reaction and structurally characterized by single-crystal X-ray diffraction. Compound 1 features an isolated structure with a planar macrocycle and an embedded zinc ion binded to four pyrrole nitrogen atoms and one acetone oxygen atom. Photoluminescent investigation reveals that compound 1 displays an intensive emission in the red region.