Synthesis of Thiourea‐Bridged Cluster Glycoside Calixarenes

Thiourea‐bridged peracetylated glycoside calixarenes have been smoothly synthesized by the addition reactions of tetraacetylglycosyl isothiocyanates with amidoamine derivatives of calix[4]resorcinarene and p‐tert‐butylcalix[n]arenas (n=6, 8) in high yields (40–75%). All the glycoside‐containing calixarenes were characterized by ¹H NMR, IR spectroscopy, and elemental analysis.     

Structural Characterization of l-proline and Morpholine Appended Chiral Calix[4]resorcinarene Molecules

Calix[4]resorcinarenes serve as host molecules for small guest molecules. Recently calixarenes have been appended to chiral molecules in an attempt to promote chiral recognition. To take advantage of both cavity host and chiral substituent properties the position of the chiral moiety is important. We report the synthesis and structural characterization of two calix[4]resorcinarene based molecules that have helical chirality in the solid state. The calix[4]resorcinarene 1 has chiral l-proline ethyl ester substituents positioned perpendicular to the cavity whereas the calix[4]resorcinarene 2 has morpholines positioned parallel to the cavity which extend the depth of the cavity. Compound 1 is one of the first compounds to show the position of chiral centers with respect to the calixarene cavity. 1H and 13C NMR spectroscopy indicate that the helical chirality of 2 is retained at low temperature in nonpolar solvents.     

丙醛间苯二酚杯[4]芳烃烷基化衍生物的合成

以间苯二酚和丙醛为原料合成了丙醛杯[4]芳烃(1),1经不同的烷基化反应合成了新的丙醛杯[4]芳烃烷基化衍生物,其结构经1H NMR和IR表征。     

Ternary Complexes of Lanthanide–Calix[4]Arene with Sulphophthalein Dyes

The formation of ternary complexes of lanthanide–calix[4]arene with sulphophthalein dyes was studied. The extraction of model system Gd(III)–calix[4]arene–bromothymol blue was characterized and the distribution, extraction, and stability constants were determined. The applicability of studied system for spectrophotometric determination of lanthanides was demonstrated and parameters of calibration dependences were calculated.     

Synthesis of phosphorylated calix[4]arene derivatives for the design of solid phases immobilising uranyl cations

With the aim of developing supports for uranyl cations immobilisation, new 1,3-alternate calix[4]arenes bearing both phosphonic acid functions as chelating sites and N-succinimide-4-oxabutyrate as the anchoring arm were synthesised in good yields. The coupling of such calixarenes to a gel was performed and a successful immobilisation of uranyl cations was obtained.     

The Synergistic Extraction of Lanthanide Ions by a Mixture of Calix[4]resorcinarene or its Dimethylamino-, Piperidyl- or Trimethylammoniummethylated Derivatives and 1,10-Phenanthroline in n-Heptanol

The alkylaminomethylatedcalix[4]resorcinarene derivatives, modified bydimethylamino-, piperidyl- and trimethylammoniummoieties, have been synthesised to investigate theirextractability towards lanthanide ions and to comparewith the extractability of calix[4]resorcinarene. Both calix[4]resorcinarene and its derivatives have beenshown to synergistically affect lanthanide ionextraction from neutral aqueous solutions by1,10-phenanthroline through outer-sphere interactionof lanthanide bis-phenanthrolinate cations withdeprotonated forms of calix[4]resorcinarene. Thederivatives with dimethylamino- andpiperidylmethylated moieties are shown to be moreeffective extractants in comparison with theunsubstituted one.     

Proximal heteroalkylation of monoalkoxycalix[4]arenes in synthesis of inherently chiral molecules

Proximal heteroalkylation of monoalkyl ethers of calix[4]arenes or p-tert-butylcalix[4]arenes in NaH/CH₃CN or NaOH/DMSO, respectively, was applied for synthesis of inherently chiral calixarenes with ABHH substitution pattern. The introduction by the method of (R)- or (S)-N-(α-phenylethyl)acetamide chiral auxiliary group gives mixtures of diastereomeric derivatives of inherently chiral calixarenes, which were separated by column chromatography. The chiral calixarenes were thoroughly characterized by ¹H, ¹³C NMR, and X-ray diffraction methods.     

Microwave‐Assisted Synthesis of Calix[4]resorcinarene Hydroxamic Acids

New calix[4]resorcinarenes bearing hydroxamic acid groups, calix[4]resorcinarene hydroxamic acids (CRAHAs), have been synthesized.     

Unusual reactivity of upper-rim bridged calix[4]arenes – Friedel–Crafts alkylation via cleavage of the macrocyclic skeleton

Upper-rim bridged derivatives of calix[4]arenes, prepared by the direct introduction of mercury into the meta position of the basic skeleton followed by Pd-catalyzed intramolecular bridging, represent a novel type of calixarenes bearing an additional single bond between the meta positions of neighboring aromatic units. Due to the presence of this short bridge, these compounds exhibit extremely distorted cavities when compared with common calix[4]arenes. As a consequence of highly enhanced inner strain, the bridged compounds can be cleaved under acidic conditions to form open oligomeric species (benzylic type carbocation) that can be used for the Friedel–Crafts alkylation of aromatic compounds. This behavior, never observed in common calix[4]arenes, demonstrates a reasonably amended reactivity invoked by the additional bridge.     

Liquid extraction of La<Superscript>III</Superscript>, Gd<Superscript>III</Superscript>, and Yb<Superscript>III</Superscript> ions by phosphorylated calix[4]resorcinarene derivatives

New phosphorylated calix[4]resorcinarene and cavitands were synthesized. Their extraction ability toward La^III, Gd^III, and Yb^III ions was studied. The cavitands are more efficient extracting agents than octasubstituted calix[4]resorcinarenes. The nature of substituents at the nitrogen atom at the upper rim and hydrophobic substituents at the lower rim exerts a substantial effect on the solubility of the extracted complex in chloroform. Coordination of two lanthanide ions with an extragent molecule results in their efficient but non-selective extraction. The literature and our spectral (³¹P NMR) data suggested that the ligand in the extracted complex has most probably a “kite” conformation. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 303–308, February, 2007.     

新型正丁醛杯[4]芳烃醚衍生物的合成

以正丁醛间苯二酚杯[4]芳烃为原料,经酯化、水解、酰氯化后再与9-蒽甲醇反应,合成了蒽单取代的正丁醛间苯二酚型杯[4]芳烃醚衍生物。其结构经1H NMR和IR表征。     

无溶剂法合成杯[4]芳烯星形化合物

以对苯二甲醛、乙酸酐为原料合成对苯二甲醛单缩醛, 接着与间苯二酚反应, 制备了含醛基杯[4]芳烯. 利用季戊四醇与含醛基杯[4]芳烯反应, 进而再与3-[4-(2,5-二氧杂环戊基)苯基]-9-[4-二(甲羰氧基)甲基苯基]-2,4,8,10-四氧杂螺环[5.5]十一烷反应, 合成了杯[4]芳烯星形化合物, 收率为65.2%. 产品结构经 IR, ¹H NMR, MS 和元素分析进行了表征.     

Competitive solvent extraction of alkaline earth metals by ionizable nano-baskets of calixarene

The competitive solvent extraction of alkaline earth metals using different nano-baskets was investigated. The novelty of this work is to study the correlations between the isomer structure of calixarenes and their extraction properties. The objective was to quantify the effects of aryl groups in the ionisable pendant moieties, calixarene conformation, steric orientations (cis- and trans-) and relative positions (ortho- and para-) of pendant moieties upon the extraction efficiency, pH_1/2 and the selectivity of calix[4]arene complexes. Alkaline earth metals were extracted from aqueous solutions into chloroform by di-ionisable calix[4]arenes and were measured using ion chromatography. The results revealed that alternation of aryl group in the pendant moieties, changing their orientation from cis- to trans-analogues as well as from ortho- to para- analogues, showed no changes in the selectivity, the extraction efficiency and the pH_1/2 of calix[4]arene complexes. Changing the scaffold of calixarene's ring to the cone, 1,2-alternate and partial-cone conformers altered their complexation ability towards alkaline earth metals and their extraction efficiency.     

Interaction of monolayers of calix[4]resorcinarene derivatives with copper ions in the aqueous subphase

Stable monolayers of novel amphiphilic calix[4]resorcinarene derivates at the air–water interface were prepared. Their interactions with copper ions from the aqueous subphase were investigated by measuring surface pressure–area and surface potential–area isotherms, as well as by Brewster angle microscopy. Theoretical aspects of interpreting the dependence of the surface pressure on the bulk copper ions concentration were discussed. The interaction of copper ions with calix[4]resorcinarene derivates was interpreted in terms of Gibbs–Shishkovsky adsorption equation.     

Physicochemical Characterization of Hydrated 4-Sulphonato-Calix[n]arenes: Thermal,Structural, and Sorption Properties

In this study, the thermal behavior of three hydrated water-soluble 4-sulphonato calix[n]arenes was investigated. The melting points, heats of fusion, and heats of solution of the calix[4]arene, calix[6]arene and calix[8]arene were 277, 262, and 270°C; 192, 242 and 351 kJ/mol; and 30, 58 and 63 kJ/mol, respectively. Lower heat of fusion, smaller increase in entropy and smaller heat of solution of the calix[4]arene compared to the calix[6]arene and calix[8]arene showed that less heat was required to break up the crystal lattice of the smaller macromolecule. This apparent anomaly is rationalized in terms of smaller cooperativity of interaction between the molecules of calix[4]arene in the crystal lattice, although the strength of the individual interactions is stronger as evidenced by the higher melting point. TGA analysis indicated that about 17–20% of water was associated with the calix[n]arenes. Both TGA and hot stage microscopy results indicated that upon heating these molecules underwent stepwise water loss. TGA kinetics showed that the 4-sulphonato-calix[8]arene lost water easier than the other two calixarenes. The moisture adsorption behavior of all calixarenes followed type II isotherms. For the same amount of material, the calix[6]arene adsorbed more moisture than the calix[4]arene and the calix[8]arene. Moreover, dehydrated less crystalline 4-sulphonic-calix[n]arenes powders are hydroscopic.

     

Synthesis of rccc- and rctt-diastereoisomers of novel triazole-containing calix[4]resorcinols

Novel calix[4]resorcinols containing four triazole fragments on the aromatic substituents of the calixarene framework were synthesized via a one-step condensation of resorcinol and its derivatives with 4-(1-benzyl-1H-[1,2,3]triazol-4-ylmethoxy)benzaldehyde. The macrocyclic products are rctt- and/or rccc-isomers, which were isolated and characterized by NMR and single crystal X-ray diffraction studies. The same products were also prepared via the click-reaction of benzyl azide with previously synthesized calix[4]resorcinols containing four alkyne terminal groups on the aromatic substituents. In this case, only rctt-diastereomers of the corresponding calixarenes were isolated, which is governed by conformational features of the starting macrocycles.     

Synthesis and mesomorphic properties of calix[4]resorcinarene–triphenylene oligomers

By controlling the mol ratios of reactants, novel calix[4]resorcinarene–triphenylene monomer, dimer and tetramer were designed and synthesised in yields of 50–60% via Click chemistry. Their structures were characterised by NMR and MS. Their liquid crystalline behaviours were studied by differential scanning calorimetry, polarising optical microscopy and X-ray diffraction analysis. The more triphenylene units on calix[4]resorcinarene resulted in the wider temperature scopes of mesophase and higher phase transition temperatures. The monomer 6 and dimer 7 showed the mixed columnar mesophase with hexagonal columnar structure and disordered lamellar columnar structure, and compound 8 possessed only disordered lamellar columnar mesophase. These research results suggest that calix[4]resorcinarene was a good platform to construct columnar liquid crystal and the mesomorphic properties were greatly influenced by the substituted numbers of mesogen units on calix skeleton.     

基于杯[4]芳烃的手性识别*

手性杯芳烃是一类重要的主体化合物,在手性识别、对映体分离和不对称催化等方面有着广泛的用途。[4]芳烃引其稳定的构象和易于修饰的特点,成为研究最为广泛的杯芳烃分子,其中大量的文献报道了能够用于对映体识别和检测的手性[4]芳烃。在手性识别的研究中,荧光、紫外和核磁是3中最常见的研究方法,本文根据这3种方法进行分类,综述了近年来以杯[4]芳烃为分子骨架的手性受体的合成及其在手性识别中的应用。最后对手性[4]芳烃的发展前景作了展望。     

多光子光刻用的杯[4]芳烃分子玻璃正性光刻胶

分子玻璃材料和多光子光刻技术分别是近年来光刻胶和光刻技术领域的研究热点.本文对分子玻璃正性光刻胶在多光子光刻中的应用进行了探索,设计合成了叔丁氧基羰基保护的杯[4]芳烃衍生物分子玻璃材料,将其作为主体材料与光生酸剂三氟甲磺酸三苯锍鎓盐进行复配,制备了分子玻璃正性光刻胶,探讨并优化了光刻胶的成分配比及其在紫外光曝光下的显影工艺.利用780nm波长飞秒激光对所制备的分子玻璃正性光刻胶进行了多光子光刻特性的评价,实验得到了最低线宽180nm的线条和复杂的二维微结构图形,结果表明杯[4]芳烃衍生物分子玻璃正性光刻胶有望应用于多光子光刻技术.     

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.