Highly Luminescent Host-Guest Systems Based on Zeolite L and Lanthanide Complexes

Supramolecular incorporation of lanthanide complex has been obtained by loading of organic ligand into Eu3+-exchanged zeolite L. This was achieved by a two-step procedure: (1) zeolite L was ion-exchanged with Eu(Ⅲ) ions; (2) organic ligand was then loaded into the channels of the Eu3+-exchanged zeolite by gas diffusion procedure. Loading of ligand into the channels of zeolite L was confirmed by element analysis. Luminescence spectroscopy has confirmed that lanthanide complex are formed in the nanochannels of zeolite L crystals. In addition to the sharp emissions of lanthanide ions, broad band ranged from 350～500 nm can also be observed. This study provides alternative method for fabricating full-color display materials.

Recent Advances in Pure-Organic Host-Guest Room-Temperature Phosphorescence Systems Toward Bioimaging

Organic room-temperature phosphorescence(RTP)materials have garnered considerable attention in the fields of biosensing,optoelectronic devices,and anticounterfeiting because of their substantial Stokes shifts,tunable emission wavelengths,and prolonged lifetimes.These materials offer remarkable advantages for biological imaging applications by effectively reducing environmental autofluorescence and enhancing imaging resolution.Recently,host-guest systems have been employed as efficient approaches to fabricate pure-organic RTP materials for bioimaging,providing benefits such as controllable preparation and flexible modulation.Consequently,an increasing number of corresponding studies are being reported;however,a comprehensive systematic review is still lacking.Therefore,we summarize recent advances in the development of pureorganic RTP materials using host-guest systems with regard to bioimaging,including rigid matrices and sensitization.The challenge and potential of RTP for biological imaging are also proposed to promote the biomedical applications of organic RTP materials with excellent optical properties.

A supramolecular self-assembly material based on cucurbituril and cationic TPE as ultra-sensitive probe of energetic pentazolate salts

The successful synthesis of the pentazolate anion(cyclo-N-5)has been a great breakthrough in the field of energetic materials.However,the detection methods for these energetic materials based on the pentazolate anion are quite rare.Herein,two fluorescent probes for cyclo-N-5anion were designed.Sensor 1(TPE2N)was synthesized with a tetraphenylethylene functionalized by two cationic groups which can generate strong electrostatic interactions with pentazolate anion and result in specific fluorescent changes.Sensor 2 was designed based on sensor 1 and supramolecular cucurbit[7]uril(CB[7]).The unique structural features of CB[7]provide sites for the interaction between the cations and N-5anion in its cavity,which would generate a platform for the detection and enhance the recognition performance.Isothermal titration calorimetry(ITC)experiment and fluorescence titration experiment indicate the binding molar ratio between sensor 1 with CB[7]is 1:2.Both sensors display typical aggregation-induced emission(AIE)features and good water-solubility.The sensors demonstrate excellent sensitivity to pentazole hydrazine salt with high enhancement constant(sensor 1:1.34×10^(6);sensor 2:3.78×10^(6))and low limit of detection(LOD:sensor 1=4.33μM;sensor 2=1.54μM).The formation of an AIE-based supramolecular sensor effectively improves the sensitivity to N-5anion.In addition,the probes also have good selectivity of N-5anion salts.The research would shed some light on the design of novel fluorescent sensors to detect pentazolate-based molecules and provides an example of supramolecular chemistry combined with fluorescent probes.

Formation and Properties of Organic Long Persistent Luminescence Crystals Containing Benzidine Derivatives by Melt Crystallization

Organic molecules that exhibit long persistent luminescence (LPL) are rapidly gaining attention for a variety of applications. In this study, organic molecules with simple structures were selected and organic long persistent luminescence (OLPL) crystals were prepared. The crystal structure of the prepared OLPL crystal was elucidated and the guideline for the design of OLPL crystal was clarified. LPL was observed in OLPL crystals prepared with TMB as the guest molecule and 1,2-bis(diphenylphosphino)ethane as the host molecule. XRD measurements of the OLPL crystals suggest that the guest molecule is a solid solution substituted in the stable crystal structure of the host molecule in a lattice-shrinking direction.

Host-guest supramolecular interaction behavior at the interface between anode and electrolyte for long life Zn anode

The hydrogen evolution reaction (HER) and dendrite growth associated with Zn anode have become the main bottlenecks for the further development of zinc ion batteries (ZIBs).In this work,the electrochemical activity of H_(3)O^(+) is inhibited by the supramolecular host–guest complex composed of H_(3)O^(+) as guest and 18-crown-6 as host.The even Zn plating is induced by the host–guest complex electrostatic shielding layer on Zn anode,as detected by in-situ optical microscopy.The lamellar Zn is plated which profits from the improved Zn plating behavior.Density functional theory (DFT) calculation presents the stable structure of complex.The less produced H_(2) content is monitored online by a mass spectrometer during Zn plating/stripping,which indicates HER can be hampered by the host–guest behavior.Thus,the ZIBs with long life and high Coulombic efficiency are achieved via introducing 18-crown-6.The proposed host–guest supramolecular interaction is expected to facilitate the furthermore development of Zn batteries.

Insight into the effects of electrochemical factors on host-guest interaction induced signature events in a biological nanopore

The signature events caused by host-guest interactions in the nanopore system can be used as a novel and characteristic signal in quantitative detection and analysis of various molecules.However,the effect of several electrochemical factors on the host-guest interactions in nanopore still remains unknown.Here,we systematically studied host-guest interactions,especially oscillation of DNA-azide adamantane@cucurbit[6]inα-Hemolysin nanopore under varying pH,concentration of electrolytes and counterions(Li+,Na+,K+).Our results indicate correlations between the change of pH and the duration of the oscillation signal.In addition,the asymmetric electrolyte concentration and the charge of the counterions affects the frequency of signature events in oscillation signals,and even the integrity of the protein nanopore.This study provides insight into the design of a future biosensing platform based on signature oscillation signals of the host-guest interaction within a nanopore.

Host-guest interaction of β-cyclodextrin with isomeric ursolic acid and oleanolic acid:physicochemical characterization and molecular modeling study

Ursolic acid(UA) and oleanolic acid(OA) are insoluble drugs. The objective of this study was to encapsulate them into β-cyclodextrin(β-CD) and compare the solubility and intermolecular force of β-CD with the two isomeric triterpenic acids. The host-guest interaction was explored in liquid and solid state by ultraviolet-visible absorption,1H NMR, phase solubility analysis, and differential scanning calorimetry, X-ray powder diffractometry, and molecular modeling studies. Both experimental and theoretical studies revealed that β-CD formed 1: 1 water soluble inclusion complexes and the complexation process was naturally favorable. In addition, the overall results suggested that ring E with a carboxyl group of the drug was encapsulated into the hydrophobic CD nanocavity. Therefore, a clear different inclusion behavior was observed, and UA exhibited better affinity to β-CD compared with OA in various media due to little steric interference, which was beneficial to form stable inclusion complex with β-CD and increase its water solubility effectively.

Synthesis and Characterization of the Host-Guest NanocompositeMaterial Zeolite Y-Iron Bipyridine

This paper reports the synthesis of host-guest nanocomposite material [Fe(bpy)(3)]Y2+ (where bpy=2,2'-bipyridine) using the flexible ligand method. X-ray diffraction analysis. adsorption technique, and cyclic voltammetry were used to characterize the material. The results show that [Fe(bpy)(3)](2+) has been entrapped in the supercage of zeolite, its electron transfer is realized by electron hopping of [Fe(bpy)(3)](2+) within the supercage of zeolite.

A Spectrophotometric Study on the Host-Guest Complexation of β-Cyclodextrin with 3-Indolyl Acetate in Dilute Aqueous Solution by Determining Solubility of Guest Substance

3-Indolyl acetate can be soluhilized in dilute aqueous solution of beta cy clodextrin. dueto the formation of host-guest complex through hydrophobic interaction between the indolyl groupand the inside cave of the cyclodextrin molecule. The thermodynamic pararneters of thecomplexing process can be estimated utilizing the spectrophotometric data.

Characteristic Studies of Arylated β-Cyclodextrins in Host-Guest Complexation with Small Molecules

The aryl moiety which was bonded as a functional group on the primary alcohol side ofβ-CD or the secondary alcohol side of β-CD or the secondary alcohol side of β-CD with anethylenediamino chain could show remarkable different molecular recognition abilities in thecomplexation with small molecular guests such as alkanes, cycloketones etc.

Structure Studies on Host-Guest Recognition Sensory Systems

Rhodamine B-ethylenediamine-beta-cyclodextrins (RhB-beta-CDen) and rhodamine B-beta-cyclodextrins (RhB-beta-CD) form inclusion complexes with many guest molecules, which can be used as nucleic acid probe. In this paper we determined the most stable conformations of RhB-beta-CDen and RhB-beta-CD by molecular mechanics and dynamics simulation. The interaction between RhB-beta-CDen and two guest molecules, 1-borneol and cyclohexanol, have been investigated both theoretically and experimentally. The results show that the interaction between borneol and RhB-beta-CDen is stronger than that between cyclohexanol and RhB-beta-CDen.

基于环糊精的抗肿瘤药物主客体递送系统研究进展

恶性肿瘤是威胁人类健康的重大疾病。开发安全高效的抗肿瘤药物及其递送系统是改善抗肿瘤药物疗效的重要保证。近年来,基于环糊精的抗肿瘤药物主客体递送系统受到了广泛关注。环糊精是通过淀粉酶解获得的环状低聚糖,具有外部亲水内部疏水的特殊结构,在基因治疗、免疫细胞治疗、免疫靶向治疗和化疗中均得到了广泛的应用。本综述主要总结了环糊精作为抗癌药物递送载体近10年的相关进展,同时对主客体递送系统在癌症治疗方面的机遇和挑战进行了展望和讨论。

内嵌金属富勒烯Ce_(2)@C_(100)与碳纳米环之间的相互作用

铈基金属富勒烯中内嵌的Ce^(3+)([Xe]4f^(1))上存在一个不成对的f电子,导致其具有顺磁性。将铈基金属富勒烯内嵌于大环分子内形成的复合结构,通过限域的方式实现了金属富勒烯的定向排布,因此研究复合物结构中的主客体相互作用可为金属富勒烯基器件的构建提供理论指导。基于密度泛函理论(DFT),使用全氟环对苯撑(PF[12]CPP,主体分子)和铈基金属富勒烯(Ce_(2)@D_(5)(450)-C_(100),客体分子)构建了主客体复合物结构,并对其进行了详尽的研究和分析。计算结果表明Ce_(2)@D_(5)(450)-C_(100)分子倾向于半躺在主体分子的空腔中,且自旋多重度为3时体系有着更好的稳定性。弱相互作用分析显示主客体之间通过π-π相互作用结合,且弱相互作用区域与主客体之间的界面距离有关。这些结果为基于金属富勒烯的主客体体系研究提供了理论支持。

Synthetic host-guest pairs as novel bioorthogonal tools for pre-targeting

Due to its simplicity, high efficiency, and chemo-selectivity, bioorthogonal chemistry has shown a great application potential in pre-targeting.Currently, four bioorthogonal pairs as targeting tools, including (strept)avidin/biotin, antibody/antigen, oligonucleotide hybridization and IEDDA tools, have been developed and applied in targeted delivery.Nevertheless, all of these tools still suffer from some limitations, such as difficult modification, biochemical fragility and larger molecular weight for biological association tools, as well as chemical instability for IEDDA tools.Synthetic host-guest pairs with relatively small molecular sizes not only possess strong chemical stability, but also have the features of fast conjugation rate, tunable binding affinity , easy modification, and high chemo-selectivity.Consequently, they can be used as a novel non-covalent bioorthogonal tool for pre-targeting.In order to further promote the development of host-guest pairs as novel bioorthogonal tools for pre-targeted delivery, we firstly calculate their conversion rate to make researcher aware of their unique advantages;next, we summarize the recent research progress in this area.The future perspectives and limitations of these unique tools will be discussed.This review will provide a systemic overview of the development of synthetic host-guest pairs as novel bioorthogonal tools for pre-targeting, and may serve as a “go for” resort for researchers who are interested in searching for new synthetic tools to improve pre-targeting.

Increase of chiral sensing ability in host-guest chemistry by magnetic anisotropy

Enantiomeric molecules generally play distinct functions in chemistry,biology,and pharmacology.Similar physical and chemical properties of chiral analytes lay difficulty in discrimination and quantification of the enantiomers.We report herein an efficient approach of increasing the chiral sensing ability ofβ-cyclodextrin(β-CD),a widely used host molecule,in the hostguest chemistry by magnetic anisotropy.A rigid and chiral lanthanide binding tag was attached to theβ-CD to amplify the changes of nuclear magnetic resonance(NMR)signals in the host-guest recognition process.The installation of the paramagnetic lanthanide ion inβ-CD greatly enhances the enantiomeric discrimination up to 30-fold in comparison with the diamagneticβ-CD reference.In addition,the magnitude of the paramagnetic effects is tunable according to the diverse range of paramagnetic strength of the lanthanide series.The reported method significantly increases the chiral sensing ability ofβ-CD,which can be applied to other host molecules.The transferred paramagnetic effects,pseudocontact shifts(PCSs)and paramagnetic relaxation enhancements(PREs),from the host to the guest molecules,are valuable structural restraints to determine the absolute stereochemistry of the chiral analytes.The strategy does not need modification of the analytes and is complementary to the reported analytical methods that rely on the functionalization of the chiral analytes.

Achieving highly efficient long-wavelength phosphorescence emission of large singlet-triplet energy gap materials by host-guest doping

High-efficiency long-wavelength phosphorescence emissions of large singlet-triplet energy gap(ΔE_(ST))materials are essential for applications in biology and display.However,few long-wavelength phosphorescence emissions of largeΔE_(ST)materials have been reported due to the weak spin-orbit coupling(SOC)and strong non-radiative transitions.Herein,we develop a strategy to achieve highly efficient long-wavelength room temperature phosphorescence(RTP)emission of largeΔE_(ST)materials,which display bright red RTP emission with above 400μs lifetime and 6.5%phosphorescent quantum efficiency.Our experiments and theoretical calculations reveal that the fishbone-like packing and the zig-zag interactions provide favorable conditions for suppressing the non-radiative transitions of triplet state excitons,and heavy atoms effectively promote the intersystem crossing(ISC)process for highly efficient long-wavelength phosphorescence emission.The universality of the method for highly efficient long-wavelength RTP emission of largeΔE_(ST)materials was further investigated in various guests.Moreover,these materials with largeΔE_(ST)manifest the advantages of large color contrast on the display and utilization potentiality in information encryption.This strategy paves the way for the high contrast display and development of information encryption with RTP emission.

Engineering singlet and triplet excitons of TADF emitters by different host-guest interactions

Understanding the host-guest interactions for thermally activated delayed fluorescence(TADF)emitters is critical because the interactions between the host matrices and TADF emitters enable precise control on the optoelectronic performance,whereas technologically manipulating the singlet and triplet excitons by using different kinds of host-guest interactions remains elusive.Here,we report a comprehensive picture that rationalizes host-guest interaction-modulated exciton recombination by using time-resolved spectroscopy.We found that the early-time relaxation is accelerated in polar polymer because dipole-dipole interaction facilitates the stabilization of the 1CT state.However,an opposite trend is observed in longer delay time,and faster decay in the less polar polymer is ascribed to theπ-πinteraction that plays the dominant role in the later stage of the excited state.Our findings highlight the technological engineering singlet and triplet excitons using different kinds of host-guest interactions based on their electronic characteristics.

Out-of-Equilibrium Assembly Based on Host-Guest Interactions

The field of supramolecular chemistry is rapidly progressing,transitioning from the creation of thermodynamically stable systems found in local or global minima on the free energy landscape to the development of out-of-equilibrium systems that rely on chemical reactions to establish and maintain their structures.Over the past decade,numerous artificial out-of-equilibrium systems have been devised in various domains of supramolecular chemistry,many of which have been extensively reviewed.However,one area that has received limited attention thus far is the use of out-of-equilibrium processes to regulate host-guest interactions.This minireview aims to address this gap by exploring the construction of out-ofequilibrium systems based on host-guest complexation,which likely employs similar strategies to those employed in analogous noncovalent interactions.The review begins with a summary of these shared strategies.Subsequently,it discusses representative publications that exemplify these strategies and classifies thembased onwhich component is being modulated-host,guest,or competitive molecules.Through this examination,our objective is to shed light on the design of out-of-equilibrium systems relying on host-guest interactions and provide valuable insights into the preparation strategies for various transient materials.

具有氢键假想孔道结构的[M(en)_3][GeF_6](M=Ni,Co)的合成与表征

描述了两个具有管状氢键假想孔道结构的化合物[N i(en)3][GeF6][JLG-1(N i)]和[Co(en)3].[GeF6][JLG-1(Co)].在这两个结构中,[GeF6]2-阴离子与手性金属配合物阳离子[M(en)3]2+(M=N i,Co)通过F…N之间复杂的弱氢键相互作用,在沿着63螺旋轴方向形成六方蜂窝状排布的管状氢键假想孔道.结构研究发现,配对的[GeF6]2阴离子和手性[M(en)3]2+阳离子同属于D3点群,这是JLG-1(N i)和JLG-1(Co)形成管状氢键假想孔道的关键.这一研究成果对设计合成氢键假想孔道体系具有一定的指导意义.

钴(Ⅲ)-胺配合物模板导向合成新型草酸盐化合物[Co(dien)_2][NaCo_2(C_2O_4)_4]·H_2O

以Co(dien)2.Cl3为模板剂,在水热条件下导向合成出新型草酸盐化合物[Co(dien)2].[NaCo2(C2O4)4].H2O,并通过X射线单晶结构分析、元素分析、ICP以及X射线粉末衍射分析对该化合物的结构进行了表征.结果表明,该化合物结构属于单斜晶系,C2/c空间群,晶胞参数a=1.3805(3)nm,b=1.3017(3)nm,c=1.5913(3)nm,β=104.41(3)°,V=2.7695(10)nm3,Z=4.在该化合物的结构中,Co2+先与草酸基团相互交替连接形成一个常见的链状结构基元[Co(C2O4)2]2nn-,这些链状结构基元进一步被分布于链间的Na+连接成三维开放骨架结构[NaCo2(C2O4)4]3nn-.金属配合物离子Co(dien)23+存在于孔道中起模板剂的作用.