STUDIES ON CALIXARENES I THE CNDO/2 CALCULATION OF EQUILIBRIUM MOLECULAR GEOMETRY OF CALIX[4]ARENE IN CONE CONFORMATION

The equilibrium molecular geometry of 25, 26, 27. 28-tetrahydroxycalix[4]arene in cone cowtrmation was calculated by a CNDO/2 method based on the standard geometrical models. The results are in good agreement with those obtained from X-ray analysis.

COVALENTLY ATTACHED MULTILAYER ULTRA-THIN FILMS FROM DIAZORESIN AND CALIXARENES

A kind of photosensitive ultra-thin film was fabricated from diazoresin (DR) and various calixarenes by using theself-assembly technique. Under UV irradiation both the ionic- and hydrogen bonds between the layers of the film will convert into covalent bonds. As a result, the stability of the film toward polar solvents increases dramatically.

Synthesis of calixarenes and their extraction performance for ester catechins

A series of extractants （tert-butylcalix[6]arene, tert-butylcalix[8]arene and octeacetate of tert-butylcalix[8]arene） were synthesized, and their structures were identified by IR and JH-NMR. The distribution behavior of ester catechins monomer in the aqueous and chloroform two-phase system containing one of calixarene was studied. The influences of different extractants, concentration of tert-butylcalix[8]arene and extraction temperature on the partition coefficients and the separation factors were investigated. The experiment results show that tert-butylcalix[8]arene is the best extractant that forms a more stable supramolecular compound with gallocatechin gallate （GCG） than with epigallocathechin gallate （EGCG） or epicatechin gallate （ECG）. When the concentration ofp-tert-butylcalix[8]arene is 3.79 mmol/L, the extraction temperature is 4 ℃, the partition coefficients ofKGCG, KECG, KEGCG are 0.987, 0.629, 0.449, the separation factors of al and a2 are 1.450 and 1.596, respectively. The important factors influencing the extraction properties of calixarene are discovered to be its cavity size and hydrogen bonding.

Bridging of Calixarenes with N,N′-Bis(Chloroacetyl)Propylenediamine

A new bridging reagent, N,N ′\|bis(chloroacetyl)propylenediamine was used to explore the relative activity and bridging pattern of p \|tert\|buty lcalix\arene, p \|tert\|buty lcalix\arene and butylcalix\arene. It was found that the bridging reaction is selectively, at least, preferably at 1,3\|position for p \|tert\|butylcalix\arene and p \|tert\|b utylcalix\arene, 1,5\|position for p \|tert \|butylcalix\arene. Taking the yield of bridged calixarene as a comparsion standard, the activity decreases with the increasing of the number of phenolic units in calixarene.

Azocalixarenes: a scaffold of universal excipients with high efficiency

Excipients are important components of pharmaceutical preparations that affect their quality, safety, and efficacy. Macrocyclic receptors are a family of supramolecular excipients with several advantages, including molecular-level protection, small sizes,fast kinetics of host-guest recognition, and modular construction. With the continuous advances in the medical field, personalized and precision medicine requires the development of excipients with low dosages, integrated modifying effects, universality,and controlled release. To meet these requirements, we have developed a new family of macrocyclic excipients based on calixarenes by integrating their covalent(broad chemical design space) and noncovalent(wide range of substrates) advantages.Accordingly, azocalixarenes(Azo CAs) were designed, showing high binding affinities to a broad spectrum of active pharmaceutical ingredients(APIs), selectivity to interferents, and responsiveness to hypoxic microenvironments. Due to their highly efficient and controllable recognition, Azo CAs serve as low-dose excipients for 30 APIs. Molecular encapsulation by Azo CAs results in the integrated modification of the physicochemical properties of APIs, including solubility, stability, bioavailability,and biocompatibility. Moreover, Azo CAs can be reduced by azoreductases overexpressed in hypoxic microenvironments,leading to the controlled release of APIs. Collectively, Azo CA excipients have broad application prospects for a series of diseases such as enteritis, arthritis, stroke, cancer, bacterial infection and kidney injury, with diverse therapeutic modalities,including chemotherapy, photodynamic therapy, photothermal therapy, immunotherapy, boron neutron capture therapy, radiotherapy, fluorescence imaging, and their combinations.

Controlled drug delivery systems based on calixarenes

In recent years, cancer has become the number two cause of death around the world, and scientists have exploited various treatment maps. Calixarenes, with diversified features, have been widely applied into drug delivery systems, which can respond to multi-stimuli and exhibit excellent performance. In this mini-review, we summarize the recent advances on controlled drug delivery systems based on calixarenes, in the form of inclusion complexes, amphiphilic self-assembly nanocarriers including micelles, hydrogels, vesicles and liposomes, and supramolecular nanovalves on mesoporous silica nanomaterials.

Calixarenes enabling well-adjusted organic-inorganic interface for inverted organic solar cells with 18.25%efficiency and multifold improved photostability under max power point tracking

Compared with organic solar cells(OSCs) adopting conventional architecture,inverted OSCs have offered generally better stability,where Zn O is the most widely used electron transporting layer(ETL) material.For ZnO-based inverted OSCs,a welltuned interface of organic(active layer)-inorganic(Zn O film) with matched surface energy(γS) is critical for both high performance and high stability.In this work,two typical calixarenes,C4A and Bu C4A,were employed as the tuning agents to adjust this organic-inorganic interface for ZnO-based inverted OSCs.As a result,with PM6:L8-BO as the active layer,significantly promoted power conversion efficiencies(PCEs) from 17.14%(for ZnO) to 18.25%(for ZnO/C4A) and 17.80%(for ZnO/Bu C4A) were achieved.Photodynamic studies indicate that the enhanced performance is due to the faster charge extraction process,the suppressed recombination and more ideal internal electric field in ZnO/calixarene-based devices.In addition,wellmatched interface energy and more ordered molecular aggregation in active layer effectively improved photostability and thermal stability for ZnO/calixarene-based devices.These results indicate that calixarenes could act as effective modifying agents of ZnO to improve inverted OSCs’ performance and stability simultaneously,and likely also stimulate calixarenes’ and other macromolecules’ broader studies in other organic electronic devices.

Extraction of copper with p-tert-butyl-calixarenes

The extraction of copper with calixarenes was researched by comparing the results from calix[4]-, calix[6]- and calix[8]-arenes. The extraction ability increased as the order: calix [4]? calix[8]? calix[6]-arenes, with the binding ratio being 1:1. The extraction mechanism was also discussed, and its equation Cu(NH3)42+ +H2L(0)→KexCu(NH3)4L(0) +2H+ and the extraction equilbrium constants (Kex) for calix[6]- and calix[8]-arenes were obtained respectively.

Transport of Ca^(2+) Ion through a Bubbling Pseudo-emulsion Liquid Membrane with Calixarenes and Calixcrowns as Carriers

Several new calixcrowns were synthesized and characterized. The transport of Ca 2+ ion was investigated through a bubbling pseudo emulsion liquid membrane with these calixcrowns, the parent calixarenes ( n =4, 6, 8) and the ester, acid derivatives of calixarene as mobile carriers. The effects of the initial concentrations of Ca 2+ ion in the source phase and the initial pH difference (ΔpH) between the receiving phase and the source phase were studied. The results suggest that there are two different transport mechanisms. The transports using calixarenes and their ester, acid derivatives as carriers represent a proton coupled co transport with a flow of protons in the opposite direction, while the transports using the calixcrowns as carriers exhibit the characteristics of an anion coupled co transport with a flow of anion in the same direction.

Organic supramolecular aggregates based on water-soluble cyclodextrins and calixarenes

Macrocycle-induced formation of pure organic supramolecular aggregates is a challenge that has attracted considerable attention from researchers in the fields of chemistry,biology,and materials science.In particular,aggregation induced by water-soluble cyclodextrins and calixarenes,which are two classic of macrocycles with a hydrophobic cavity and a hydrophilic external surface,has attracted interest because these host molecules can form aggregates with guest molecules via various noncovalent interactions,including hydrophobic interactions,van der Waals forces,hydrogen bonds,and electrostatic interactions.In this review,we focus mainly on some impressive recent progress,both by our group and other groups,on the construction of cyclodextrin-and calixarene-based organic supramolecular aggregates,control of their topological morphology,and their use for biological applications such as molecular recognition and bioimaging,photodynamic therapy,light-harvesting energy transfer,and targeted drug delivery.We also discuss shortcomings of the current reported results and future prospects for the development of multifunctional organic supramolecular aggregates for use in various fields.

Study on the Complexation Property of Calixarenes

Calixarenes are macrocyclomolecules consisting of phenol units bridged together bymethylene groups. Their structure may be expressed

Synthesis and inclusion properties of amphiphilic calixarenes

Study of host-guest interaction with the aid of proper model system is helpful to the understanding of complicated chemical reactions in biological processes on the molecular level. Cyclodextrins and crown ethers are two kinds of the most extensively studied host molecules and enzyme mimics. The cyclodextrins are very hydrophilic on their out rims but lipophilic on the inner remainder; the crown ethers are highly lipophilic on the outside and hydrophilic on the inside. In recent years, calixarene has been found a new kind of host compounds, which can form host-guest inclusion complexes with many kinds of

Upper Rim Diester-bridged Calixarenes and Oligocalix-arenes: the Effects of the Length of Bridged Reagents on Their Distribution

A series of monobridged calixarenes 3a-f, cyclic biscalix arenes 4a-f, diametrically bridged at the upper rim with saturated aliphatic diester chains, have been synthesized. The results at dilute conditions show that the percentage of yields of mono , bis and oligo calixarenes are related to the length of the chains. With the shortening of the chains, the percentage of monocalixarenes decreased. All the calixarene moieties are in a cone conformation according to the AB quartet pattern of the methylene protons between the phenolic rings in the 1H NMR spectra.

Studies on the Intramolecular Inclusion Complexes of Functionalized Calixarenes with CH_3X (X=CN, NO_2)

Two functionalized calixarenes in cone conformation L 2-3 have been synthesized and their intramolecular inclusion complexes (1∶1) with organic neutral molecules CH 3CN and CH 3NO 2 have been prepared and characterized, respectively. The X-ray crystallographic analysis shows that L 2 in L 2·CH 3CN·C 2H 5OH has C 4 symmestry and L 3 in L 3·CH 3NO 2 exhibits C 2 symmestry. The CH-π aromatic interactions between the CH group of the guest and the phenyl rings of the calix backbond have been proved to be able to stabilize the intramolecular inclusion complexes formed. The interaction is directional, but it is independent of the acidity of the guest. To gain information on CH-π interactions, suitable geometrical parameters have been calculated from the crystal data of intramolecular inclusion complexes. The results show that L 3·CH 3NO 2 with L 3 in C 2 symmestry can also be bound stably in the intramolecular inclusion complex, being consistent with the thermal analysis. The geometrical parameters and the results of the thermal analysis of L 1·CH 3CN and L 1·CH 3NO 2 were also given and discussed.

Natural Silicate as a Solid Support for the Calix[4]Thiophosphorus Derivative for Removal Mercury (II), as Picrate from Water

Currently a technique widely used for gold extraction is mercury by amalgamation technique, the tailing produced pollutes water of all kinds, so it is necessary to develop a form of selective mitigation, for which it is necessary to use complexing agents based on calixarene functionalized with mercury sequestering agents. These are immobilized by adding supports based on natural silica to form polymers and make them insoluble in all types of solvents, so that they can be used as an extractor and at the same time regenerate to their original properties for continuous reuse.

应用于纳米制造的新型电子束抗蚀剂Calixarene的工艺研究

为了满足电子束光刻(EBL)对高分辨率、性能优秀抗蚀剂的需求,研究了将Calixarene衍生物作为电子束抗蚀剂在胶液配制、电子束曝光及显影等工艺过程中的相关技术.其中电子束曝光实验在JEOL JBX-5000LS系统上进行.实验结果表明,在入射电子能量50 keV、束流50 pA的条件下,Calixarene可以方便地形成50 nm的单线、50nm等线宽与间距的图形结构.通过与常用电子束抗蚀剂的对比,总结了Calixarene在电子束光刻性能上的优缺点,并分析了其成因.作为一种新型的高分辨率电子束光刻抗蚀剂,Calixarene有望应用在纳米结构制造、纳米尺寸器件及电路的研制等领域.

Two novel fluorescent calix[4]arene derivatives with benzoazole units in 1,3-alternate conformation for selective recognition to Fe^(3+) and Cr^(3+)

Two novel fluorescent calix[4]arene derivatives la and lb with benzoxazole or benzothiazole units in 1,3-alternate conformation have been synthesized and characterized by IR, ^1H NMR, ^13C NMR and MS. Their complexation properties to different heavy and transition metal ions have been studied by UV-vis spectroscopy and fluorescence spectrometer. Compounds 1a and 1b show selective recognition to Fe^3＋ and Cr^3＋.

Synthesis and properties of novel calix[4]arene derivatives bearing fluorogenic coumarin units

Four novel calix[4]arene derivatives 5-8 bearing four fluorogenic coumarin units attached via imino group acting also as binding sites at the upper rim have been prepared and characterized by IR, IH NMR and MS. Compounds 5-8 adopt a cone conformation. Their complexation properties to different heavy and transition metal ions have been studied by UV-vis spectroscopy. Compounds 5, 6, 8 show selective recognition to Fe^3＋ and Cr^3＋.

Synthesis and Conformational Studies of Some Metacyclophane Compounds

Various [3.3.3]metacyclophane derivatives were synthesized from 6,15,24-tri-tert-butyl-9,18,27-trimethoxy [3.3.3] metacyclophane-2,11,20-trione 1 using simple chemical reactions. The conformations of the synthesized compounds were studied using mainly solution Proton Nuclear Magnetic Resonance (1H NMR) spectroscopic methods. Two of the synthesized compounds 5, 6, were found to have a partial cone conformation with the third, 4, having the cone conformation. Detailed variable temperature Proton Nuclear Magnetic Resonance studies further confirmed the partialcone conformation for the two products, 5, 6. During the variable temperature nuclear magnetic resonance spectroscopic studies, 6,15,24-tri-tert-butyl-9,18,27-trimethoxy[3.3.3]metacyclophane-2,11,20-triol was found to have a coalescence temperature of about 0?C.

RING-OPENING POLYMERIZATION OF TRIMETHYLENE CARBONATE CATALYZED BY NOVEL SINGLE COMPONENT RARE EARTH CALIXARENE COMPLEXES

In this paper,ring-opening polymerization of trimethylene carbonate(TMC)with rare earth(Nd,Y,La)ρ-tert- butylcalix[n]arene(n=4,6,and 8)complexes as catalysts has been studied.Poly(trimethylene carbonate)(PTMC)with M_v of 21,400 was produced by bulk polymerization under the conditions as follows:[TMC]_0/[Nd](molar ratio)=1000,80℃, 8 h.Mechanism study reveals that the polymerization proceeds via a coordination mechanism.