The synthesis of novel polysiloxanes with pendant hand-basket type calix[6]crowns and their transporting properties for metal ions in a liquid membrane

Two novel polysiloxanes with pendant hand-basket type calix[6]-1,3-crown-3 and calix[6]-1,4-crown-4 were prepared by hydrosilylation of p-tert-butylcalix[6]-(2′-allyloxymethyl)-1,3-crown-3 (CA[6]C3) and p-tert-butylcalix[6]-[2′-(ω″-undecenyloxymethyl)]-1,4-crown-4 (CA[6]C4) followed by condensation reaction with silanol-terminated polydimethylsiloxane. The monomeric calix[6]crowns and two calix[6]crown-based polysiloxanes were used as carriers in a bulk membrane. All carriers showed the transport rate of the cations decreased in the order Li⁺ < Na⁺ < K⁺. The flux of K⁺ for the monomeric calix[6]crown was higher than that for polymeric carrier. In comparison with other carriers, the transport rate of calix[6]crown-4-functionalized polysiloxanes (CA[6]C4PS) towards cesium ions were increased greatly. Competitive transport experiments known to be more useful in industrial fields also revealed to give high cesium transfer rate.     

Main-group-element calix[4]arenes: variable coordination and conformational isomerism at phosphorus and silicon

Treatment of calix[4]arene (1b) with trichloromethylsilane yields two conformers of calix[4]SiMe(OH), the cone 2b-C and the partial cone 2b-PC. These are isolated and structurally characterized, and their thermodynamic activation parameters are determined in solution [Ea = 117(3) kJ/mol, delta H = 5(4) kJ/mol]. Similar parameters are found for the p-tert-butylcalix[4]arene analogues 2a-C and 2a-PC. Deprotonation of 2b with butyllithium yields calix[4]SiMe(OLi) (8b). The structure of 8b is solvent dependent: 8b contains a five-coordinate silicon in THF and a four-coordinate silicon in benzene. Similar behavior is found for the p-tert-butylcalix[4]arene analogues. The five-coordinate phosphorus analogue of the anion in 8, p-tert-butylcalix[4]PMe (11a), is synthesized from the phosphonium triflate salt p-tert-butylcalix[4]PMe(OH)OTf (10a(OTf)) via treatment with butyllithium. The structure of 11a shows the geometry around phosphorus to be very close to a pure trigonal bipyramid. The X-ray structure of 10a(OTf) cannot be obtained, but its iodide analogue 10a(T) is synthesized and structurally characterized. The cation in 10a(I) adopts the partial cone conformation in the solid state, similar to 2b-PC. Treatment of 8b with methyl trifluoromethanesulfonate yields the methyl phenyl ether calix[4]SiMe(OMe) (3b). This species and its p-tert-butyl analogue 3a are structurally characterized. Both adopt the partial cone conformation. The SiMe group in 3b can be removed via treatment with fluoride to yield the monomethylated calix[4]arene 4b in 50-60% overall yield based on 1b.     

Lower rim substituted tert-butylcalix[4]arenes. Part 8: Calix[4]arenes with dialkoxyphosphoryl functions. Synthesis and complexing properties

New compounds: 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrakis(3-diisopropoxyphosphorylpropoxy)calix[4]arene (1) and 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrakis(3-methoxyethoxyphosphorylpropoxy)calix[4]arene (2) were synthesized and their ionophoric properties in ion-selective membrane electrodes were studied in comparison with already described by us 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrakis(3-diethoxyphophorylpropoxy)calix[4]arene (3). Complexes of 1 with calcium(II), lanthanum(III), europium(III) and gadolinium(III) nitrates were prepared in direct reaction of the ligand and appropriate metal salts. They were characterized by spectral data (IR, UV/Vis, luminescence, NMR, ESI-MS) and elemental analysis. The similarity in complexing behavior of the (dialkoxyphosphoryl)propoxy-calix[4]arenes toward calcium and some lanthanides was observed.     

Synthesis of Macrocyclic Lactones Building on Double Calix[4]arenes

Naturalmacrocycliclactonesandlactamsastheionophoreshaveabsorbedextensiveinterestsbecauseoftheirveryhighselectiverecognitionforalkalimetals.rorexample,nactinslandvalinomycin'havethehighestselectivityforpotassiumamongalltheionopohores.Artificialmacrocycliclactonesalsoshowedselectivityforcanons,althoughthebindingstrengthwaslowerthanthatofcommoncrownethers3.Calixareneswereaveryimportantkindofartificialreceptors,whosederivativeshaveshowedthehighestselectivityforNa ,K andCs amongthesynthesizedmacro…     

对磺酸基苯偶氮杯[4]芳烃电化学行为研究

以杯[4]芳烃和对氨基苯磺酸为原料,经重氮化-偶联反应合成了对磺酸基苯偶氮杯[4]芳烃,并使用紫外吸收光谱、红外吸收光谱、核磁共振等技术对其进行表征分析. 首次以CH₃COOH-CH₃COONa为缓冲溶液,使用循环伏安法研究对磺酸基苯偶氮杯[4]芳烃的电化学行为. 结果表明,当扫描电位在-0.5 ~ 1 V时,有1对氧化还原峰,其中氧化峰电位为0.302 V,还原峰电位为-0.003 V,且峰电流与峰电位均与扫描速率呈线性关系,推测该峰的形成受扩散控制影响,反应为动力学准一级可逆反应. 进一步利用多种电化学手段研究该电极反应,并求得动力学参数,反应活化能为14.84 kJ•mol^-1.     

邻甲氧基羰基苄氧基取代杯[4]芳烃衍生物的合成及其性能研究

杯芳烃是继冠醚、环糊精之后的第三代主体分子[1].据文献[2,3]报道,在杯[4]芳烃下沿酚氧原子上连接乙酸酯得到的四取代衍生物对Na+有很高的选择性,核磁与晶体结构研究均证实这是由于羧酸酯的羰基和酚氧基参与了对Na+的配位,而且配位基团所形成的包络空间大小与钠离子相匹配.一般认为,随着包络空间改变,对金属离子的识别作用会有所变化[4].但目前对这方面的工作并没有给予更多的重视.我们发现,用2-溴甲基苯甲酸甲酯与杯[4]芳烃反应,得到了一种新的四取代杯[4]芳烃衍生物[2]萃取研究结果表明,该化合物对钾离子有较好的选择性.此外,在合成该衍生物的过程中,还得到了另一新的二取代衍生物(3).     

Synthesis of Schiff Base Calix [4] arene Crowns

This letter reports the synthesis of Schiff base calix [4] arene crowns containing m-xylylene phenol subunit, in which calix [4] arene Schiff base crowns 2a,2b and 2c were formed by 1:1 condensation of calix [4] arene diamine 1 with dialdehydes (2,6-diformyl-4-chlorophenol 3a,2,6-diformyl-4-methylphenol 3b,2,6-diformyl-4-tert-butylphenol 3c)under high dilute condition in refluxing anhydrous ethanol in 65-70% yield.     

Upper rim allyl- and arylazo-coupled calix[4]arenes as highly sensitive chromogenic sensors for Hg2+ ion

The syntheses and chromogenic properties of calix[4]arenes, carrying 5,17-bisallyl-11,23-bis(p-X-phenyl)azo 3a-c, 5,11,17-triallyl-23-(p-X-phenyl)azo 4a-c, and 5,17-bis(hydroxypropyl)-11,23-bis(p-X-phenyl)azo groups on the upper rims 5a,b, are described. Unexpectedly, UV/vis spectra of the very popular 4-(4-nitrophenyl)azophenol-coupled calix[4]arenes 3c and 4c did not show any shift in lambda(max) when 10 different metal perchlorates were added separately to the host in a methanol-chloroform (v/v = 1/399) cosolvent. In contrast, the absorption spectra of calix[4]arenes with either 4-methoxyphenylazo (3b-5b) or 4-phenylazo (3a-5a) on the upper rim showed substantial bathochromic shifts (Deltalambda = 128-162 nm) upon the addition of soft metal ions (such as Hg(2+), Cr(3+), and Cu(2+)). The 4-(4-methoxyphenyl)azophenol-coupled calix[4]arenes (the 3b-5b series) are found to be highly sensitive for mercury ion (Hg(2+)) among the 10 different metal ions screened. Strong interactions between Hg(2+) ion and the 4-(4-methoxyphenyl)azophenol(s) as well as the p-allyl groups are corroborated by the (1)H NMR studies of 3a,b.Hg(2+) complexes. Furthermore, Job's plots revealed 1:1 binding stoichiometry for all these p-allyl- and arylazo-coupled calix[4]arenes with transition metal ions, and Benesi-Hilderbrand plots were used for the determination of their association constants.     

Titanium and zirconium complexes of a phosphorus-containing p-tert-butylcalix[5]arene ligand: importance of metal and conformation on ligand/metal binding

Binding of a calix[5]arene containing a single phosphorus ligand and three hydroxyl groups, calix[5]PNMe2(OH)3, 1, toward titanium and zirconium is investigated to yield insight into the factors that determine the strength of the phosphorus/metal interaction within the constraint of the calix[5]arene. Treatment of 1 with tetrakis(dimethylamino)titanium yields three complexes, 4a, 4b, and 4c, each of which shows the loss of 3 mol of dimethylamine in the reaction with the titanium bound to three oxygens. Treatment of 1 with tetrakis(diethylamino)zirconium proceeds similarly, although only two products, 5a and 5b, were isolated. X-ray structures of the products were obtained. Complexes 4a and 5a show similar geometries, with the calix[5]arene in an approximate cone conformation and the phosphorus lone pair directed toward the metal. The P...M distances are, however, markedly different: 3.69 A in 4a and 3.18 A in 5a, the former indicative of no interaction and the latter a weak one. Complexes 4b and 5b each are dimers, featuring a planar four-membered M-O-M-O ring; however, the titanium is five-coordinate in 4b with no phosphorus/metal bond, while the zirconium in 5b is six-coordinate with a P-Zr distance of 2.95 A. Complex 4c is monomeric with the calix[5]arene in an approximate 1,2-alternate conformation with a P...Ti distance of 2.90 A. The two most significant aspects controlling the phosphorus/metal contact are the metal, with the larger zirconium showing stronger interaction, and the calix[5]arene conformation, with the cone conformation showing the weaker interaction.     

(硫杂)杯[4]芳烃缩氨基(硫)脲(桥联)衍生物的合成

对叔丁基(硫杂)杯[4]芳烃-1,3-二醛基衍生物4a和4b与苯基氨基硫脲进行“1＋2”缩合反应, 合成了杯[4]芳烃缩氨基硫脲衍生物5a和5b, 产率为84%和85%. 化合物4a和4b与1,6-己基双氨基脲发生“1＋1”缩合反应, 合成了杯[4]芳烃双缩氨基脲桥联衍生物6a和6b, 产率为83%和80%. 新化合物的结构与构象经元素分析、质谱、核磁共振谱等表征证实.     

Synthesis and crystal structure of a germanium(II) calix[6]arene containing unusual diamidosilyl ether groups

The reaction of Ge[N(SiMe₃)₂]₂ with calix[6]arene furnishes a novel macrocyclic product having two divalent germanium atoms incorporated into a Ge₂NO rhombus which contains a μ₂-oxygen atom and a μ₂-NH₂ group. The crystal structure of the product indicates the presence of a conformationally rigid molecule where three of the six oxygen atoms of the calix[6]arene are bound to the germanium atoms while the remaining three have been converted into –OSiMe₃ or unusual –OSi(H)(NH₂)₂ groups. Spectral (¹H, ¹³C, and ²⁹Si NMR) data in solution are consistent with the solid-state structure and indicate the germanium calix[6]arene retains its structure in solution.     

含杯[4]芳烃毛细管固定相的制备与色谱性能

杯芳烃是由对位取代的苯酚在邻位通过亚甲基连接起来的环状化合物,由于具有可调节大小的空腔,不仅能络合无机离子,而且还可络合有机分子,在分析分离方面有极好的应用前景［１,２］．杯芳烃已用于气相色谱［３,４］、离子选择性萃取［５,６］、液相色谱［７,８］和...     

Synthesis and nitration of calix[4] (aza)crowns

Calix[4] (aza) crowns containing amide groups 3a-d were synthesized by the reactions of calix[4]arene (1a) or p-tert-butylcalix[4]arene (1b) with N, N'-ethylenebis(2-chloroac-etamide) (2a) or N, N'-1,2-phenylenebis(2-chloroacetamide) (2b) by one step procedure in yields of 85-90% . Calix[4]-(aza) crowns 4a-b could be obtained by the reduction of 3a-b with LiAlH4 in yields of 51 and 67% , respectively. The nitration of 3a or 3c afforded new chromogenic calix[4]arenes 5a bearing two nitrophenol moieties and 5c bearing one nitro-phenol and one quinone moiety, respectively. The ipso-nitrations of 3b and 3d were also studied. Both gave the products containing one nitrophenol and one quinone moiety. Moreover, a very interesting calix[4]arene derivative 5d containing one cyclohexadienone moiety was also separated as the main product when 3d was ipso -nitrated.     

Synthesis and thermal properties of novel calix[4]arene derivatives containing 1,2,3-triazole moiety via K2CO3-catalyzed 1,3-dipolar cycloaddition reaction

Two calix[4]arene derivatives containing 1,2,3-triazole moiety were synthesized via K2CO3-catalyzed1,3-dipolar cycloaddition reaction between calix[4]arene-based azide and active methylene compounds in good yields.The structures of the two compounds synthesized herein were fully confirmed by 1HNMR,,（13）C NMR,and MS（ESI）.The thermal analysis showed that the mass losses of the synthesized compounds 4 and 5 containing 1,2,3-triazole groups are similar to each other.     

Bis-calix[4]arenes bridged by an electroactive tetrathiafulvalene unit

Syntheses of the first bis-calixarenes systems bridged by a tetrathiafulvalene (TTF) framework 5a,b have been carried out in good yields through triethyl phosphite-mediated dechalcogenation-dimerizations of the corresponding 1,3-dithiole-2-(thi)ones 3 or 4. X-ray structures of the calix[4]arene-TTF-calix[4]arene assembly 5b and of the calix[4]arene-thione intermediate 3b are analyzed and confirm the cone conformations adopted by the calix[4]arene parts, as it is also observed by (1)H NMR analysis of these systems. The solid-state organization in 5b leads to alternate layers of calixarene and TTF units. The cyclic voltammograms of 5a,b show as expected a two-step redox behavior but display a CV deformation for the second redox process.     

Aminolysis reaction of calix [ 4 ] arene esters and crystal structures and conformational behaviors of calix[4]arene amides

We first make use of aminolysis of calix[4]arene esters to synthesize calix[4]arene amides. When the two ethyl esters of the calix[4]arene esters are aminolysized, the 1, 3-amide derivative is formed selectively. The crystal structures of the calix-[4]arene with two butyl amide (3b) and four butyl amide moieties (4b) were determined. The intermolecular hydrogen bonds make 4b form two-dimensional net work insolid state. The 1H NMR spectra prove that 3b is of a pinched cone conformation, while 4b and tetraheptylamide-calix[4]arene (6b) take fast interconversion between two C2v isomers in solution and appear an apparent cone conformation at room temperature. As decreasing temperature, the interconversion rate decreases gradually and, finally, the interconversion process is frozen at Tc = -10℃, which makes both conformations of 4b and 6b the pinched cone structures. The hydrogen bond improves the interconversion barrier, and the large different values of the potential barrier between 6b and 4b (or 6b) may     

A Facile Method to Synthesize Spiro-calix[4]arenes

Calixarenes have absorbed considerable interests for their outstanding abilities of recognition for cations, anions and organic molecules1. In order to include larger and more complex molecules, polytopic receptors were designed from two or more host macrocycles linked by one or several links. Therefore, double-calixarenes and oligocalixarenes have been synthesized and reviewed2. Among these polytopic receptors, double-calixarenes can be used as the mimic of ion channel or to self-organize koi…     

2]Catenane assembly from calix[4]arene crown ethers [In Process Citation

A variety of novel calix[4]arene-incorporating crown ethers with or without intramolecular hydrogen bonding have been prepared by two efficient methods and utilized as donor rings to assemble calix[4]arene [2]catenanes based on pi-stacking interaction between hydroquinone and bipyridinium units. Treatment of calix[4]arene crown ethers 4, 10a, or 10b, whose cone conformation was fixed by intramolecular hydrogen bonding within the calix[4]arene moiety, with dicationic salt 15 x 2PF6 and dibromide 16 afforded the corresponding [2]catenanes 17a x 4PF6, 17b x 4PF6, and 17c x 4PF6 in 20%, 53%, and 55% yields, respectively, whereas from the reactions of 15 x 2PF6 and dibromide 16 in the presence of conformationally flexible 11 or 12 with a cone conformation kept by two propyl groups, [2]catenanes 18 x 4PF6 and 19 x 4PF6 were obtained in 12% and 6% yields. [2]Catenanes 21a x 4Cl, 21b x 4Cl, and 21c x 4Cl, incorporating calix[4]arene in both the donor and acceptor rings, were also successfully assembled from 10a or 10b, 16, and dicationic salts 20a x 2PF6 or 20b x 2PF6. The dynamic 1H NMR and absorption spectra of the [2]catenanes have been investigated, which revealed a strongest donor-acceptor interaction in 17a x 4PF6 and that the cone [2]catenanes 17a-c x 4PF6 can isomerize to the partial cone isomer at high temperature. The difference of the dynamic properties of these catenanes was discussed. The results demonstrate that catenation is one new general method to change the conformational distributions of calix[4]arenes.     

Missing-link macrocycles: hybrid heterocalixarene analogues formed from several different building blocks

The synthesis and structural characterization of hybrid heterocalix[4]arene analogues containing pyrrole, benzene, methoxy-substituted benzene, and pyridine subunits is described. Macrocycles 1 and 2, examples of calix[2]benzene[2]pyrrole and calix[1]benzene[3]pyrrole systems, respectively, are synthesized by the condensation of pyrrole and an appropriate phenylbis(carbinol). Macrocycles 3 and 7, examples of calix[2]benzene[1]pyridine[1]pyrrole and calix[1]pyridine[3]pyrrole, respectively, are synthesized by the use of a carbene-based pyrrole-to-pyridine ring-expansion procedure. Single-crystal X-ray analysis reveals that compounds 1a, 1b, and 2b adopt 1,3-alternate conformations in the solid state, whereas compounds 3 and 7 display structures that are best described as "flattened partial cones" in terms of their conformation. (Series a refers to pure benzene-derived systems, whereas series b indicates macrocycles containing 5-methoxyphenyl subunits). In the solid state, the methoxy-functionalized macrocycles 1b and 2b, and the chloropyridine-containing macrocycle 7 exist as dimers. In the case of 1a and 7, these compounds interact with neutral solvent in the solid state. The conformations of the macrocycles in solution were explored by temperature-dependent proton NMR and NOESY spectral analysis. At 188 K, macrocycles 1a and 2a adopt flattened 1,3-alternate conformations, whereas macrocycles 3 and 7 exist in the form of flattened partial-cone conformations. Standard proton NMR titration analyses were carried out in the case of macrocycles 1a and 2a, and reveal that at least the second of these systems is capable of binding fluoride and chloride anions in CD(2)Cl(2) solution at room temperature (K(a)=571 and 17M(-1) in the case of 2a and F(-) and Cl(-), respectively).     

Synthesis of Calix[6]arene-Porphyrin Receptors and Study on their Catalytic Performance in Epoxidation of Styrene

The artificial receptors with multiple recognition site had been synthesized by linking two unsymmetrical monofunctionalized porphyrin to p-tert-butyl calix[6]-arene via two flexible chain, followed by inserting metal ion into the porphyrin species.The structures (see Fig 1) of these calix[6]arene-diporphyrins and their metal complexes were confirmed by UV-vis spectra, IR spectra, mass spectra, ¹NMR spectra(600 MHz) and/or ¹³C NMR. Their conformations were investigated preliminarily by UV-vis spectra and computer simulation. In constrast with the correspounding porphyrin monomer, the soret bond of calix[6]arene-diporphyrins in UV-vis spectra showed hypsochromic shift. This phenomenon suggested that two porphyrin rings maintain a face to face parallel conformation, as confirmed by computer simulation that showed the conformation energy is the lowest as two porphyrin rings hold such a conformation. Besides, simplicity of the ¹NMR spectra indicates that the conformation of calix[6]arene-diporphyrin possesses high symmetry. Therefore,the calix[6]arene must be cone conformation.