Synthesis and Properties of New Thiacalixarene Derivatives with Palladium Ion

Three new thiacalix[4]arene derivatives, 5,11,17,23-tetra-tert-butyl-25,27-di(2-hydroxyethoxy)-26,28-dihydroxythiacalix-{}[4]arene (2), 5,11,17,23-tetra-tert-25, 26,27,28-tetrakis[(methylcarboxyl)methoxy]thiacalix[4]arene (3),5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrakis(2-hydroxy-1-propanoxy)thiacalix[4]arene (4), were synthesized for the first time. The coordination properties of thiacalix[4]arene(1) and its derivatives (2 and 4) were investigated by detecting the interactions betweenthese compounds and two palladium complexes, cis-[Pd(en)(H₂O)₂]²⁺ and cis-[Pd(dtco-3-OH)(H₂O)₂]²⁺, by means of electrospray ionization mass spectrometry (ESI-MS) technique.     

Unprecedented cyclisations of calix[4]arenes under the Mitsunobu protocol. Part 3: Thiacalix[4]crowns versus dimers

Intermolecular couplings versus intramolecular ring closures were observed in the reaction of p-tert-butylthiacalix[4]arene and diethylene glycols affording dimers 2 and/or the inherently chiral 1,2-thiacalix[4]crown-3 derivatives 5 under the Mitsunobu protocol. The enantiomeric separation of 5a was achieved by chiral HPLC. The reaction of thiacalix[4]monocrowns 1 with diethylene glycols failed to give crowned thiacalix-tubes 7, instead biscrowns 8 were formed. Partially alkylated double thiacalix[4]arenes 10, 11 were obtained via the base promoted alkylations of a thiacalixarene dimer 2a containing diethyleneoxy linkers.     

Sulfur‐linked Phenolates as Ligands for the Syntheses of Low‐Nuclearity Iron(III) Complexes

Exploiting thiacalix 4 arene and sulfur‐bridged bisphenolates as ligands for bioinorganic studies involving iron(III) requires the prior development of synthetic routes (varying substituents and reaction conditions) to construct complexes with low nuclearities and accessible coordination sites, which was in the focus of this investigation. Treating p‐tert‐butylthiacalix 4 arene (H₄TC) and 1, 4‐dimethyl‐p‐tert‐butylthiacalix 4 arene (Me₂H₂TC) with Fe[N(SiMe₃)₂]₃ yielded in the formation of the iron(III) complexes [(Me₃SiTC)₂Fe₂] ( 1 ) and [(Me₂TC)₃Fe₂] ( 3 ), respectively. While 1 is a sandwich compound, in 3 one [Me₂TC]^2– unit is bridging two [Me₂TCFe]⁺ moieties. Employing thiobisphenolates as ligands it turned out, that in dependence on the residues R and the preparation method it is possible to selectively access sandwich, anionic or neutral complexes, which were shown to contain central high‐spin iron(III) atoms. The syntheses, structures, and electronic properties of three iron(III) bisphenolate complexes, [^ClL₂Fe]NEt₃H ( 4 ), [^MeLFeCl₂]NEt₃H ( 5 ), and [^tBuLFeCl(thf)] ( 7 ) are discussed.     

Structure and conformational equilibrium of thiacalix[4]arene by density functional theory

Density functional theory calculations for the structure and conformational equilibrium of thiacalix[4]arene are reported. The conformational equilibrium of thiacalix[4]arene, a heterocalixarene in which the phenol groups are bridged by sulphur atoms is compared to the conformational equilibrium of calix[4]arene. Thiacalix[4]arene conformational energies relative to the cone conformer (ΔE's) are reduced in comparison with calix[4]arene. This conformational change is in qualitative agreement with recent NMR spectroscopy measurements of the conformational equilibrium for a tetraethylether of thiacalix[4]arene in a CDCl₃ solution which indicates an enhanced chemical exchange of thiacalixarene conformers in comparison with similar methylene bridged structures. Density functional theory results for the structure of thiacalix[4]arene are in good agreement with recent X-ray diffraction measurements. The electrostatic potentials in the cone conformers of thiacalix[4]arene and calix[4]arene suggest that their complexation or recognition abilities can be significantly different. Dipole moments of the four thiacalix[4]arene conformers are in the order: cone>1,2-alternate>partial-cone>1,3-alternate.     

Chemoselective ring closure of thiacalix[4]arene-1,3-bis(N-ω-hydroxyalkylamides) via the Mitsunobu reaction

Chemoselective intramolecular ring closure on the phenolic OH groups of p-tert-butylthiacalix[4]arene-1,3-bis(N-ω-hydroxyalkylamides) attained under Mitsunobu conditions affords inherently chiral macrocycles capped by carboxamide bridges. Oxazoline or oxazine cyclization products derived from self-condensation of the hydroxyalkylamide moieties were not isolated. In one case the detection of enantiomers was achieved by chiral HPLC.     

Catechol-Containing Schiff Bases on Thiacalixarene: Synthesis,Copper (II) Recognition,and Formation of Organic-Inorganic Copper-Based Materials

For the first time, a series of catechol-containing Schiff bases, tetrasubstituted at the lower rim thiacalix[4]arene derivatives in three stereoisomeric forms, cone, partial cone, and 1,3-alternate, were synthesized. The structure of the obtained compounds was proved by modern physical methods, such as NMR, IR spectroscopy, and HRMS. Selective recognition (K_b difference by three orders of magnitude) of copper (II) cation in the series of d-metal cations (Cu²⁺, Ni²⁺, Co²⁺, Zn²⁺) was shown by UV-vis spectroscopy. Copper (II) ions are coordinated at the nitrogen atom of the imine group and the nearest oxygen atom of the catechol fragment in the thiacalixarene derivatives. High thermal stable organic-inorganic copper-based materials were obtained on the base of 1,3-alternate + Cu (II) complexes.     

Functionalized thiacalix- and calix[4]arene-based Ag ionophores: synthesis and comparative NMR study

Thiacalix[4]arene ionophores comprised of cyclic or linear O,S,N ligating and/or π-coordinate groups on the lower rim were synthesized and their Ag⁺ binding was studied by ¹H NMR methods in comparison with the respective known and novel calix[4]arene counterparts. Calix[4](O,S,N)crowns were found stronger binders than the π-coordinate molecules and thiacalixarene ionophores were generally superior to calixarenes. This study helped to develop silver ion-selective electrodes working in the subnanomolar region.     

The Synthesis of Sodium and Potassium Complexes of Two Calix[4]arene Derivatives

Two compounds (1 and 2) which have calix[4]arene units and their Na⁺ and K⁺-complexes were prepared. All the complexes have a metal-ligand ratio of 1 : 1. The newly prepared compounds were characterized on the basis of their ¹H NMR, IR, UV-visible as well as elemental analysis.     

Chlorination of Calix[4]arene Derivatives

New convenient method for synthesis of p-chlorinated calix[4]arenes is reported. The sulfuryl chloride was used for chlorination of unsubstituted at the lower rim calix[4]arenes. The products of this reaction were very suitable for further O-alkylation.     

A Hexacoordinated P-Bridged Calixarene Derivative -- Phosphorylation of p-tert -Butylthiacalix[4]arene

p-tert -Butylthiacalix[4]arene ( 1 ) reacts with phosphorus pentachloride under participation of the sulfur atoms to a hexacoordinated phosphorus derivative ( 2 ) of the thiacalixarene. Hydrolysis of 2 leads to the twofold 1,2-bridged thiacalixarene bis(chlorophosphate) 3 .     

杯[4]芳烃对单糖及嘧啶衍生物的分子识别和分子开关

用AM1和INDO/SCI方法对八羟基杯[4]芳烃与单糖及嘧啶衍生物形成的超分子体系进行理论研究,结果表明,主体通过CH-π相互作用对单糖类进行分子识别,尤其对赤藓糖识别效果更好;主体与嘧啶没有明显的π-π堆砌作用,但能识别含吸电子基团的嘧啶衍生物,据此可设计酸碱调控的分子开关.讨论了配合物的UV谱带与主体相比发生红移的原因.     

Synthesis and Characterization of Thiacalix[4] arene Derivatives with Polymerisable Groups

Introduction Calixarenes are versatile host molecules for molecular recognition and supram olecular assembly be-cause its functional groups can be readily introduced in-to the phenolic OH or the para position to realize a wide variety of functions[1-5].     

含苯并噻唑基的硫桥杯芳烃衍生物的合成及结构

在碳酸钾存在下, 对叔丁基硫桥杯芳烃(1)分别与端基二溴代烷和碘甲烷反应, 生成硫桥杯芳烃衍生物2 和3, 它们分别与过量的2-巯基苯并噻唑在碳酸钾存在下反应, 生成含苯并噻唑基的硫桥杯芳烃衍生物5a～5d. 通过 1H NMR, 13C NMR, IR, MS和元素分析等手段对产物进行了表征. 同时, 采用X射线衍射分析确定了硫桥杯芳烃5b的晶体结构.     

Syntheses and Metal-ion Binding Properties of Calix[4]arene Derivatives Containing Soft Donor Atoms: Highly Selective Extraction Reagents for Ag+

A series of calix[4]arene derivatives containing N or S atoms atthe lower rim were synthesized by etherification of OH groups and their metal-ion extraction abilities were studied. The extraction selectivity for Ag⁺ over other ions with these novel receptors was outstanding. Among these ligands, calix[4]arene podand, which possessed two linear ligands, has shown better binding ability with Ag⁺ than calix[4]crowns.     

Scrupulous recognition of biologically important acids by fluorescent “turn off-on” mechanism of thaicalix reduced silver nanoparticles

Water dispersible silver nanoparticles(AgNps) were prepared using thiacalix[4]arene tetrahydrazide(TCTH) as a reducing and stabilizing agent.TCTH-AgNps were characterized by surface plasmon resonance(SPR),transmission electron microscopy(TEM) and energy dispersive X-ray(EDX).Relatively uniform 20 nm spherical particles of TCTH-AgNps were efficiently formed over a pH range of 5-9 and from 10-40 ℃.The interaction behavior of TCTH-AgNps with different amino acids was investigated using spectrophotometry and spectrofluorimetry.Among the amino acids tested,only tryptophan and histidine showed fluorescence quenching and fluorescence enhancement,respectively.The linear detection range by Stern-Volmer plot was 5 nmol/L to 0.48 μmol/L for tryptophan and 4 nmol/L to 0.54 μmol/L for histidine.TCTH-AgNps were able to effectively reduce the levels of gram-positive bacteria,gram-negative bacteria,and fungi.These properties argue for the potential use of TCTH-AgNps as detectors of histidine and tryptophan and as antibiotics.     

Host-Guest Complexation of Oxaliplatin and Para-Sulfonatocalix[n]Arenes for Potential Use in Cancer Therapy

P-sulfonatocalix[n]arenes have demonstrated a great potential for encapsulation of therapeutic drugs via host-guest complexation to improve solubility, stability, and bioavailability of encapsulated drugs. In this work, guest-host complexes of a third-generation anticancer drug (oxaliplatin) and p-4-sulfocalix[n]arenes (n = 4 and 6; p-SC4 and p-SC6, respectively) were prepared and investigated, using ¹H NMR, UV, Job’s plot analysis, and DFT calculations, for use as cancer therapeutics. The peak amplitude of the prepared host-guest complexes was linearly proportional to the concentration of oxaliplatin in the range of 1.0 × 10⁻⁵ M⁻¹ to 2.1 × 10⁻⁴ M⁻¹. The reaction stoichiometry between either p-SC4 or p-SC6 and oxaliplatin in the formed complexes was 1:1. The stability constants for the complexes were 5.07 × 10⁴ M⁻¹ and 6.3 × 10⁴ M⁻¹. These correspond to complexation free energy of −6.39 and −6.52 kcal/mol for p-SC4 and p-SC6, respectively. Complexation between oxaliplatin and p-SC4 or p-SC6 was found to involve hydrogen bonds. Both complexes exhibited enhanced biological and high cytotoxic activities against HT-29 colorectal cells and MCF-7 breast adenocarcinoma compared to free oxaliplatin, which warrants further investigation for cancer therapy.     

The Role of Triazole and Glucose Moieties in Alkali Metal Cation Complexation by Lower-Rim Tertiary-Amide Calix[4]arene Derivatives

The binding of alkali metal cations with two tertiary-amide lower-rim calix[4]arenes was studied in methanol, N,N-dimethylformamide, and acetonitrile in order to explore the role of triazole and glucose functionalities in the coordination reactions. The standard thermodynamic complexation parameters were determined microcalorimetrically and spectrophotometrically. On the basis of receptor dissolution enthalpies and the literature data, the enthalpies for transfer of reactants and products between the solvents were calculated. The solvent inclusion within a calixarene hydrophobic basket was explored by means of ¹H NMR spectroscopy. Classical molecular dynamics of the calixarene ligands and their complexes were carried out as well. The affinity of receptors for cations in methanol and N,N-dimethylformamide was quite similar, irrespective of whether they contained glucose subunits or not. This indicated that sugar moieties did not participate or influence the cation binding. All studied reactions were enthalpically controlled. The peak affinity of receptors for sodium cation was noticed in all complexation media. The complex stabilities were the highest in acetonitrile, followed by methanol and N,N-dimethylformamide. The solubilities of receptors were greatly affected by the presence of sugar subunits. The medium effect on the affinities of calixarene derivatives towards cations was thoroughly discussed regarding the structural properties and solvation abilities of the investigated solvents.     

Synthesis and Properties of Double Calix[4]arene Derivatives Linked by Schiff-base in the Lower Rim

Calixarenesareregardedasthethirdgenerationofh0stmoleculesbecauseoftheirinclusionabilitytocati0ns,anionsandneutralmoleculesI'2.Duringthepastdecademosteff0rtshavebeentakenonthefunctionalizati0n0fcalixareness0thattheycanbeappliedn0tonlyastheionoph0resintheextractionprocess','andassensitivematerialsforionelectrodes"',butalsoastheenZymemimicscatalyzingthecleavageofphosphatediesters"'.Inordertoenablethemtoincludeandrecognizelargerchemicalspecies,manyappr0acheshavebeenusedtoc0nstructoIigo-calixarene…     

Synthesis of (thia)Calixarene-based exTTF Derivatives and Their Electron Transfers Towards p-Chloranil and C60

Two novel (thia)calixarene-based exTTF derivatives(3a and 3b) were prepared by Mitsunobu reactions in toluene using diethyl azodicarboxylate(DEAD) and triphenylphosphine(PPh₃) system. The cyclic voltammograms of compounds 3a and 3b were provided, and two electron-irreversible waves with redox potentials were observed. Meanwhile, the intermolecular electron transfer(ET) properties of both compounds 3a and 3b towards p-chloranil(Q) and C₆₀ were investigated via UV-Vis and fluorescent spectroscopies, respectively. The results indicated that the introduced nonoxidable metal ions(Al³⁺, Pb²⁺, Sc³⁺) might promote the intermolecular ET from compounds 3a and 3b towards Q ensembles, whereas the effects of Sc³⁺ were the most impressive. Furthermore, the effects of the same metal ions(Al³⁺, Pb²⁺, Sc³⁺) added for compound 3b were greater than those for compound 3a. Additionally, the photoinduced intermolecular ET from compounds 3a and 3b towards C₆₀ was observed.     

基于甲氧基柱[5]芳烃的聚丙烯酸酯有机膜对对硝基苯衍生物的吸附行为

柱芳烃是一类有别于冠醚、杯芳烃、葫芦脲等的柱状大环分子,具有独特的富电子空腔和口腔的可修饰性。 它们可以包结多种有机污染物,对有机污染物的吸附和脱除具有广泛的应用前景。 本文通过核磁共振和紫外滴定的方法首先研究了对硝基苯衍生物与甲氧基柱[5]芳烃(MeP5A)的包结行为,测定了包结常数。 在此基础上,将MeP5A物理混合到聚丙烯酸酯(PA)乳液中,首先制备了甲氧基柱[5]芳烃/聚丙烯酸酯(MeP5A/PA)共混乳液,然后通过静电纺丝技术,得到了MeP5A/PA纳米纤维膜。 采用红外光谱、扫描电子显微镜对MeP5A/PA纳米纤维膜的结构和形貌进行了表征。 将MeP5A/PA纳米纤维膜用于4种对硝基苯衍生物的吸附实验。 结果表明,对硝基苯乙腈显示出与MeP5A最强的包结作用,其K_a=(6.0±0.3)×10² L/mol,PA膜中引入MeP5A,增大了吸附量,但并未改变纤维状形貌。 MeP5A/PA纳米纤维膜的最佳吸附平衡时间为2 h,且MeP5A/PA纳米纤维膜中MeP5A的含量越高,吸附量越大。 但当吸附溶液中MeP5A浓度达到4 mmol/L时(对应的膜中含有的MeP5A物质的量为1.4×10^-2 mmol),其吸附基本达到平衡,继续增加MeP5A物质的量,其吸附量变化不大。