Molecular Recognition of Pyromellitic Imide-azacyclophane to Organic Pollutant

Anion can be identified by pyromellitic imide-azacyclophane which is one of the host compounds.This article investigated the interaction between the host and organic pollution compounds.The host and other eight compounds were optimized by DFT（density functional theory） B3LYP/6-31G level and the energy of compounds was corrected using Boys-Bemardi method.On the basis of B3LYP/6-31G optimized geometries,the RDG function and sign（λ2（r））ρ（r） function values of space points were calculated,and color RDG isosurface map was drawn.3He chemical shift was calculated by the B3LYP/6-31G method.The results showed that the eight organic pollution molecules with the host one shaped stable configurations by hydrogen bonds,respectively.The stabilization energy of complexes 4 and 7 showed repulsion（steric effects） of cyclophane cage observably affecting the stability of the complexes.The location,intensity and the type of interaction in complex 1 were analyzed through color-filled RDG isosurface map.Aromaticity calculations showed that the weak interaction reduced the transverse induction ring current in the host rings,and deteriorated the aromaticity of compounds.

Hartree-Fock and Density Functional Theory Studies on the Molecular Recognition of the Cyclodextrin

This study involves initial Hartree-Fock and Density Functional theory calculations onthe molecular recognition of the cyclodextrins. The α-cyclodextrin-acetophenone complexationsystem was investigated with PM3, HF/3-21G* and B3LYP/3-21G* methods. The results indicatedthat the inclusion orientation in which the acetyl group of the acetophenone points towards thesecondary hydroxyls of the a-cyclodextrin was preferable in energy. The steric effect wassupposed as the physical reason of such a behavior Hence, the simple rule the anti-parallelarrangement of the dipoles of the host and guest molecules in the cyclodextrin complexqtion is notgenerally applicable.

Study on Molecular Recognition of Crown Ethers to Aniline and Monosaccharides

Theoretical study on coordinates between crown ethers and aniline as well as monosaccharides is performed by AM1, MNDO and PM3 methods. It is indicated that crown ethers possess ability to recognize polar guests especially ionic guests and monosaccharides. Electronic spectra of coordinates are computed by the INDO/SCI method. The reason of the blue-shift for UV absorption of complexes relative to that of hosts is discussed and electronic transition is theoretic- cally assigned.

Study on Mimetic Peroxidase and Molecular Recognition of Phenols With Inclusion Complex of Ironporphyrin Immobilized by β-CD Polymer

β-Cyclodextrin (β-CD) and its cross-linked polymer (β-CDP) were known as the mimetic models. Metalloporphyrin had been widely used in the enzymatic method of analysis and molecular recognition. In present work, it was investigation that supramolecular recognition for halogenated phenols, three crosols, three nitrophenols and three aminophenols, served respectively as the substrate of the mimetic receptor, iron-5, 10, 15, 20-tetrakis (sulforphenyl)-21H, 23H-porphine (FeTPPS) or FeTPPS-β-CDP. Supramolecular complex, FeTPPS-β-CDP with function of mult i-recognition and induced-fit, was a advanced kind of mimetic peroxidase; Methyl phenol or polyphenol was the substitute of chlorophenic acid, while aminophenols and other phenols were suggested not to be utilized to enzymatic assay of H2O2. Being a mimetic enzyme mimicking the space structure of overall proteinase, beaimed by immobilized mimetic enzyme with a large number of β-CD interior cavities, chlorophenol was identified optimal substrate in the system tested.

Molecular Recognition Based on Hydrogen-bonding in the Coliposomes of Phosphatidylcholine and Amphiphiles Using Nucleobases

A functional amphiphile, N^6 -myristoyl-9-[ 8-（ 1-trimethylamino） octyl ] adenine bromide （MTOAB）, was used to form coliposomes of phosphatidyleholine（PC）, PC/thymine, and PC/TOTB using sonication . The morphologies of the coliposomes were characterized using TEM （transmission electron microscopy）. The UV-Vis spectroscopic behavior of PC/MTOAB/thymine （molar ratio = 5： 1： 1 ） and PC/MTOAB/TOTB （molar ratio = 5： 1： 1 ） of coliposomal solutions showed that as a result of base pairing, absorption intensity showed a decrease at 263 nm with increase of time. The decrease of absorption intensity is ascribed to the hypochromic effect, which is because of the formation of hydrogen bonds between adenine and thymine in the coliposomes. The same effect was also observed for the mixture of aqueous PC/MTOAB liposomes and PC/TOTB liposomes after fusion, whereas the nocomplementary coliposomcs formed from PC/MTOAB and PC/TOTB did not show these spectroscopic changes. The molecular recognition through hydrogen interactions between adenine and thymine is very slow because of the possible occurrence of molecular lateral diffusion and exchange of amphiphile before recognition progresses in coliposomes. These results provide useful information for the design of supramolecular devices such as vesicles and liposomes,which can be used to mimic primitive recognition processes observed in biological systems.

INTELLIGENT METATAL COMPLEXES CONTAINING N-GLYCOSIDES FORMED FROM TRIS (2-AMINOETHYL) AMINE AND ALDOSES, HAVING MOLECULAR RECOGNITION ABILITY

Assembly of carbohydrates on nickel (Ⅱ) center by utilizing N-glycosidicbond formation with a branched amine: tris(2-aminoethyl)amine (tren), an unprecedentedchiral inversion around the metal center (Co or Mn) induced by an interaction betweensugars and sulfate anions, peroxo-bridged dinuclear cobalt (Ⅲ) complex containing N-glycoside ligands from tren and D-glucose and its reversible dioxygen binding property,and novel trimanganese complexes with a linear Mn_3 (Ⅱ, Ⅲ, Ⅱ) assemblage bridged bycarbohydrates are described.

Synthesis and Characterization of Cerium Tetraphenylporphyrin Nitrate and Molecular Recognition for NO

Cerium （III） tetraphenylporphyrin nitrate Ce（TPP）NO3 was synthesized by using meso- tetraphenylporphyrin （TPP） and Ce（NO3）.6H20 in mixture solution of CHC13 and C2HsOH （V：V=1：1）. The complex was characterized by UV-Vis, FT-IR, conventional fluorescence, MALDI-TOF-MS, and ^1H NMR spectral techniques. The structure of complex was proposed viaSpectral analyses, in which tetraphenylporphyrin was coordinated to a cerium ion in a tetradentate fashion, while one nitrate was coordinated to the same cerium ion. After bubbling NO to the solution of Ce（TPP）NO3 in CH2Cl2, spectral analyses suggested that Ce（TPP）NO3 could interact with NO to form a novel complex of Ce（TPP）（NO）NO3, and NO was coordinated to the center cerium ion. When nitrogen was poured into the Ce（TPP）（NO）（NO3） solution, the complex could be reduced to Ce（TPP）NO3.

Molecular recognition of cyclophanes in water

Molecular recognition in water,the biological solvent,always receives significant research focus in supramolecular chemistry.The mechanisms of molecular recognition in water is key to comprehending biological processes at the molecular level.Over the past five decades,supramolecular chemists have developed a vast array of synthetic receptors with highly diverse structures and recognition properties.Among them,cyclophanes represent an important family of macrocyclic receptors that have been extensively explored.The aromatic moieties in cyclophanes not only facilitate chemical modifications to impart water solubility but also enable forming hydrophobic cavities for guest inclusion in aqueous environments.Pioneered by Koga et al.,who reported the first inclusion complex of cyclophanes in water and solid state,numerous water-soluble cyclophanes,including derivatives of blue box,calixarenes,resorcinarenes,pillararenes,octopusarenes,biphenarenes,coronarenes,and naphthotubes,etc.,have been synthesized and subjected to investigation of the recognition capabilities in aqueous solutions.This review provides an overview of cyclophane receptors designed to bind organic guests in water.We categorize them into two classes based on the modifications made to their hydrophobic cavities:those with“exo-functionalized hydrophobic cavities”and those with“endo-functionalized hydrophobic cavities”.We introduce their distinctive features and discuss strategies to enhance recognition affinity and selectivity.This review aims to inspire the development of novel synthetic receptors with intriguing properties and foster practical applications of cyclophanes.

Amide naphthotubes:Biomimetic macrocycles for selective molecular recognition

Selective molecular recognition in water is routine for bioreceptors,but remains challenging for synthetic hosts.This is principally because noncovalent interactions are usually less efficient in aqueous environments.By mimicking the cavity feature of bioreceptors,Prof.Wei Jiang proposed and clarified the concept of“endo-functionalized cavity”.Through situating polar binding sites into a deep hydrophobic cavity,we designed and synthesized several macrocyclic hosts,among which amide naphthotubes are the most representative.The hosts can selectively recognize various polar molecules including organic micropollutants,drug molecules,and chiral molecules in water by employing the hydrophobic effect and shielded hydrogen bonding.In addition,these biomimetic hosts have been applied in spectroscopic analysis,adsorptive separation and self-assembly.In this review,we provide an overview of recent advances on amide naphthotubes with special emphasis on the efforts of Jiang's group.We are convinced that these biomimetic macrocycles will make further contributions to supramolecular chemistry and beyond.

Photoswitchable Molecular Recognition Enabled by Dithienylethene-Mediated Structural Changes of Dynamic Covalent Hydrazone Bonds

Light-induced recognition,assemblies,and materials are intensive areas of research due to their high spatiotemporal resolution.Herein,we demonstrated photoswitchable molecular recognition via dithienylethene-triggeredreversible structural regulation of dynamic covalent hydrazone bonds.By combining dithienylethenes and cyclic hemiacetals,the photochemical open-ring and closed-ring forms enabled turningoff and on the creation of awide range of hydrazones when desired.Light-induced bidirectional switching between hydrazones and their cyclization structures promoted by a neighboring carboxyl group was further achieved.By taking advantage of reversible structural changes totoggleon andoff the binding pocket,photoswitchable recognitionofmetal ionswas realized.Finally,the construction of an acylhydrazone polymer offered a facile way for light-mediated selective extraction/release.The strategies and results reported here should find applications in many contexts,such asdynamicassemblies,molecular switches,and smart materials.

Hematoma-like dynamic hydrogelation through natural glycopeptide molecular recognition for infected bone fracture repair

Infected bone fractures remain a major clinical challenge for orthopedic surgeons.From a tissue regeneration perspective,biomaterial scaffolds with antibacterial and osteoinductive activities are highly desired,while advanced materials capable of mimicking the pathological microenvironment during the healing process of infected tissues remain an area deserving more research.Hematoma,the gel-like blood coagulum,plays an essential role in bone fracture repair because of its ability to serve as a dynamic and temporary scaffold with cytokines for both pathogen elimination and tissue healing.In light of this,we designed a dynamic hydrogel with hematoma-like antimicrobial or reparative performance for infected bone fracture repair in this study.The proposed dynamic hydrogel network was based on the reversible recognition of a natural glycopeptide antibiotic vancomycin(Van)and its target dipeptide D-Ala-D-Ala(AA),which could serve as a hematoma-like scaffold for obliterating bacteria in the fracture region and promoting bone repair by introducing an endogenous osteogenic peptide(OGP).In vivo experiments demonstrated that the hydrogel could rapidly eradicate bacteria,improve bone regeneration and restore the local inflammatory microenvironment.Together,findings from this study imply that the use of hematoma-like dynamic hydrogel could lead to a biomimetic revolution in surgical strategies against susceptible bone fractures.

A Stable Luminescent Covalent Organic Framework Nanosheet for Sensitive Molecular Recognition

Despite rapid advances in fluorescence detectors over the past decade,the development of a highly stable,sensitive,and selective fluorescence platform for molecular recognition remains a considerable challenge.Here we report a stable carbazole-based sp2 carbon fluorescence covalent organic framework(COF)nanosheet,termed a JUC-557 nanosheet.Owing to the synergistic effect of aggregation-induced emission-and aggregation-caused quenching-based chromophores,the architecture of the JUC-577 shows high absolute quantum yields(up to 23.0%)in the solid state and when dispersed in various solvents as well as excellent sensing performance toward specific analytes,such as iodine(Ka:2.10×10^(5)M−1 and LOD:302 ppb),2,4,6-trinitrotoluene(Ka:4.38×10^(5)M−1 and LOD:129 ppb),and especially nitrobenzene(Ka:6.18×10^(6)M−1 and LOD:5 ppb)that is superior to that of fluorescence detection materials reported so far.Furthermore,the JUC-557 nanosheet preserves strong luminescence and sensitive recognition,even under harsh conditions,and allows trace detection of various analytes via a handheld UV lamp.These findings pave the way for developing stable ultrathin COF nanomaterials for highly sensitive and selective molecular detection.

Molecular recognition and homochirality preservation of guanine tetrads in the presence of melamine

Molecular recognition between nucleobases plays a crucial role in all kinds of biological processes.However,real-space investigation of the recognition capability of nucleobases in the presence of interfering compounds remains unexplored.Herein,based on the combination of scanning tunneling microscopy imaging and density functional theory modeling,we report the impact of the presence of melamine(M)on the formation and chirality of guanine(G)-tetrads on Au(111).Although M can interact with G by double hydrogen bonding,the Hoogsteen base pairing of G is not compromised,forming identical individual G-tetrads as would have happened without the presence of M.G-tetrads coexist with M on the surface not only in separate domains,but also within the mixture network of G-tetrads and M-dimers.Although the adsorption orientation of G-tetrads in the mixture network diversifies into two distinct angles,all G-tetrads in the network keep the same chirality,emphasizing the high preference of homochirality in such biochemical systems.

New Promises of Advanced Molecular Recognition:Bioassays,Single Cell Analysis,Cancer Therapy,and Beyond

The development of biomimetic affinity materials holds great value for scientific research and practical applications.Starting from boronic acid chemistry,we developed a series of boronate affinity materials(BAMs)with desired binding properties in aspects of binding pH,affinity and selectivity.Based on BAMs,molecularly imprinted polymers(MIPs)and aptamers capable of targeting vital biomolecules were rationally designed and prepared.Using these affinity reagents as potent tools and combining with advanced analytical techniques particularly liquid chromatography,mass spectrometry and spectrometry allowed for the construction of promising analytical methods to provide new qualitative and quantitative solutions to challenging applications including targeted proteomics analysis,single cell analysis and disease diagnostics.In addition,the targeting capability of these affinity reagents particularly nanoscale MIPs opened a unique access to develop innovative nanotherapeutics for cancer treatment.

Molecular recognition: monomer of the yeast transcriptional activator GCN4 recognizes its dimer DNA binding target sites specifically

It is widely believed that dimerization is a requirement for the yeast transcriptional activator GCN4 to recognize its specific DNA target sites. We used the basic region (226-252) of the yeast transcriptional activator GCN4, as both a monomeric peptide and a disulfide-linked dimer to investigate the interaction of the peptides with the DNA target sites AP-1 and CRE. CD and ITC experiments indicate that although the monomeric peptide GCN4-M has a weaker affinity with the DNA relative to the disulfide-linked dimer peptide GCN4-D, it recognizes AP-1 and CRE target sites specifically.

Molecular Recognition of Bridged Bis(β-cyclodextrin)s Linked by Phenylenediseleno Tether on the Primary or Secondary Side with Fluorescent Dyes

A Novel β-cyclodextrin dimer,2,2′-o-phenylenediseleno-bridgedbis（β-cyclodextrin）（2）,has been synthesized by reaction ofmono-[2-O-（p-tolylsulfonyl）]-β-cyclodextrin and poly（o-phenylenediselenide）.The complexation stability constants（Ks）and Gibbs free energy changes（-ΔG°）of dimer 2 with fourfluorescence dyes,that is,ammonium 8-anilino-1-naphthalene-sulfonate（ANS）,sodium 6-（p-toluidino）-2-naphthalenesul-fonate（TNS）,Acridine Red（AR）and Rhodamine B（RhB）have been determined in aqueous phosphate buffer solution(pH=7.2,0.1 mol·L-1at 25℃ by means of fluorescence spec-

Synthesis of O6-Corona[3]arene[3]pyridazines and Their Molecular Recognition Property in Organic and Aqueous Media

O6-Corona[3]arene[3]pyridazines were synthesized from the one-pot macrocyclic condensation reaction of 3,6-dichlorotetrazine with 1,4-dihydroquinone derivatives followed by the inverse electron demand Diels-Alder reaction of the tetrazine rings with a cyclopentanone-derived enamine. Conversion of six ester groups within macrocycle into all sodium acetate moieties afforded a water soluble O6-corona[3]arene[3]pyridazine. The coronary macrocycle host formed complexes selectively with organic ammoniums and dinitrile guests in a 1 ： 1 stoichiometric ratio in organic solvents with association constants ranging from （2.96± 0.10）× 10^1 to （2.53±0.33）× 10^5 L·mol^-1. Water soluble O6-corona[3]arene[3]pyridazine was also able to complex strongly with organic ammoniums in water to give an association constant up to （2.67 ± 0.21） × 10^4 L·mol^-1. The pseudo-rotaxane and inclusion structures of the host-guest complexes were revealed by the X-ray crystallography.

Direct Synthesis of Monodisperse Hollow Molecularly Imprinted Polymers Based on Unfunctionalized SiO2 for the Recognition of Bisphenol A

A novel and effective approach was developed to synthesize monodisperse hollow molecularly imprinted polymers （MHMIPs） with unfunctionalized SiO2 spheres in a mixture of toluene and CH3CN. The factors that affected the synthesis of MHMIPs were systematically investigated. It was determined that a suitable ratio of toluene to CH3CN and the use of a functional monomer that can generate double H-bonding interactions were the critical factors to obtain MHMIPs with high uniformity and rnonodispersion. The obtained MHMIPs exhibited a fast adsorption rate and high adsorption capacity （270 μmol/g） for bisphenol A. As the shell thickness increased from 90 nm to 130 nm, the binding capacity of the imprinted shells decreased gradually. The relative selectivity coefficients of MHMIPs for tetra-brornobisphenol A （TBBPA）, phenol and p-tert-butylphenol （PTBP） were calculated as 1.53, 1.83 and 1.90, respectively. These findings indicate that MHMIPs have good adsorption performances and suggest applications in the selective removal or sensitive analysis of bisphenol A.

Interaction and Interfacial Molecular Recognition of Calix[4]arene Derivatives Bearing Nucleobases for Complementary Nucleoside

The p tert butyl calixarene derivatives 1a with uracils and 1b with adenines at the lower rim were synthesized. The Interaction between 1a and 1b in CDCl 3 solution was demonstrated by 1H NMR spectra. The interfacial molecular recognitions of 1a and 1b for the complementary nucleosides in aqueous subphases were investigated by Langmuir Blodgett technique.

Study on the Molecular Recognition of α,α,α,β-ZnT（o-BocThr）APP toward Imidazole Derivatives and Amino Acid Esters

Molecular Recognition of α,α,α,β-ZnT（o-BocThr）APP （1） toward a series of imidazole derivatives and amino acid esters was investigated. Association constants were determined in chloroform by means of UV-Vis titration method. The association constants of 1 with imidazole derivatives are larger than those of 1 with amino acid esters. 1H NMR spectra were investigated to describe the binding mode of the recognition system, showing that all the protons of the guests were shifted to upfield. The circular dichroism spectra of 1-L-/D-ValOMe showed a split cotton effect in Soret region, while those of 1-L-/D-PheOMe showed no split cotton effect. Molecular modeling was performed to understand chiral recognition on a molecular level. Quantum chemical calculation was carried out based on the stable conformations of these recognition systems, which gave a reasonable explanation for the behavior of molecular recognition. The results indicated that the conformation of 1-D-ValOMe was more stable than that of 1-L-ValOMe.