杯芳烃接枝超细SiO2的制备及其对Cu2+、Ag+萃取性能的研究

通过对杯[4]芳烃以及杯[6]芳烃上缘进行烯丙基化和硅氢加成2步衍生化反应得到硅氢化杯[4]芳烃以及硅氢化杯[6]芳烃,再将这2种硅氢化杯芳烃衍生物分别接枝到超细SiO₂上。在不同的pH值条件下,就2种杯芳烃接枝超细SiO₂衍生物对水合Cu²⁺及Ag⁺的萃取性能进行了研究。结果表明,与对叔丁基杯芳烃相比较,杯芳烃接枝超细SiO₂衍生物对Cu²⁺和Ag⁺的萃取率都有所提高,其中杯[4]芳烃接枝超细SiO₂对Ag⁺的最高萃取率达到98.78%,杯[6]芳烃接枝超细SiO₂对Cu²⁺的最高萃取率达到67.74%。     

Calixarene Complexes of Anion-bridged Oligouranyl Species

The syntheses and structures of uranyl complexes of p-t-Bu-calix[6]arene (calix[6]H₆) and p-t-Bu-calix[9]arene (calix[9]H₉) are reported, further developing the role of calixarenes as 'cluster keepers'. The calix[6]arene complex, formulated as [(HO){UO₂(calix[6]H₄)(dmso)}₃H], is trinuclear and linked symmetrically by the hydroxyl O atom. The calix[9]arene complex is binuclear, with a carbonate atom bridging between the two uranyl cations to give the complex, (HNEt₃)₃[(OCO₂)(UO₂)₃(calix[9]H₄)].     

ABSORPTIVE IONOPHORES FOR Fe3+ CATION BY PARENT CALIX[n]ARENES

The absorption of Fe³⁺ ion from the aqueous phase to the solid phase was carried out by using p-tert-butyl calix[6]arene (L₁), calix[6]arene (L₂), p-tert-butyl calix[8]arene (L₃), and calix[8]arene (L₄). The effect of varying pH upon the absorption capability of parent calixarenes was examined. It was found that the compounds (L₁, L₂, L₃, and L₄) showed the highest extractability toward Fe³⁺ ion at 4.5–5.4. The calixarene L₂ shows a strong binding ability to Fe³⁺ ion. Based on the continuous variation method, calixarene L₂ formed 1:1 complex with Fe³⁺ ion.     

Extraction properties of 25,27-bis(carbonylmethoxy)calix[4]arenes towards Sr2+: competitive extraction and extraction in a synthetic groundwater

The Sr²⁺ extraction properties of some 25,27-bis(carbonylmethoxy)calix[4]arenes, in which ester (–CH₂CO₂Et), keto (–CH₂COCH₃) and acid functionalities (–CH₂CO₂H) have been attached to the lower rim, are reported. Strontium ion extraction experiments were performed in a chloroform/water system, and the extraction performance analyzed by radiotracing using the short-lived radio nuclide ⁸⁵Sr. Effects of pH value, ligand to metal ratio, temperature, extraction time and strontium species on the extraction behavior were examined. It was observed that the 25,27-bis(carboxymethoxy)calix[4]arene derivatives are potent extracting agents towards the strontium ion, showing remarkable extraction performance in competition with a series of organic and inorganic impurities and in a synthetic groundwater. The crystal structure of 25,27-bis(acetonyloxy)calix[4]arene is also reported.     

The Preorganization Effect of the Calix[4]arene Platform on the Extraction Properties of Acetylhydrazide Groups with Transition Metal Ions

The binding properties of the cone conformer of O,O,O,O-tetrakis[hydrazinocarbonylmethyl]-4-tert-butylcalix[4]arene, the cone and the 1,3-alternate conformers of the corresponding thia analogue have been evaluated by means of liquid–liquid extraction for a large variety of metal ions. The extraction constants and the stoichiometries of the complexes formed have been determined. Comparison of the extraction properties of calix[4]arenes with their acyclic monomeric analogue clearly demonstrated, that the preorganization of acetylhydrazide groups on the calix[4]arene platform is the cause for a significant improvement of its binding properties. The presence of additional “soft” nitrogen binding sites in acetylhydrazide derivatives of calix[4]arenes compared to their amide derivatives leads to a shift from their classical selectivity for alkali and alkaline earth cations to transition metals. The cone conformer of tetrathiacalix[4]arene shows higher selectivity in a series of d-metal ions compared with its “classical” analogue. The 1,3-alternate conformer exhibits an excellent extraction selectivity for Cu²⁺ and Hg²⁺.     

Exploration of Pb2+ Selective Behavior of Calix[6]arene Ester Derivative

The selective behavior of calix[n]arene ester derivatives in two-phase extraction systems using polarographic technique has been investigated. Calix[4]arene tetraester derivative shows remarkable Na⁺ over Pb²⁺ selectivity; whereas calix[6]arene hexaester derivative shows Pb²⁺ over Na⁺ selectivity. The interference of some selected cations (Na⁺, K⁺, Cu²⁺ and Mg²⁺) were also examined and no significant effect on the selectivity behavior as well as extraction ability of these ionophores was found except Na⁺. The study reveals for the first time that the calix[6]arene hexaester derivative is highly Pb²⁺ selective ionophore and can be employed in the field of sensor as well as separation science and technology. The work also highlights the usefulness of polarographic technique in trace metal determination.     

Synthesis, characterization and electrochemical properties of two new calix[4]arene derivatives bearing two ferrocene imine or ferrocene amine units at the upper rim

A novel calix[4]arene derivative with two ferrocenyl Schiff-base groups at the upper rim 3 has been synthesized from 5,17-diformyl-25,27-dipropoxy-26,28-dihydroxy calix[4]arene and 4-ferrocenylaniline via condensation reaction. Reduction of 3 with sodium borohydride led to calix[4]arene derivative 4 with two amino ferrocenyl groups at the upper rim. The ferrocenyl Schiff-base calix[4]arene and its corresponding reduced amine have been purified and characterized by elemental analysis,¹H NMR, FTIR, Mass and UV-vis spectral data. Electrochemical properties of compounds 3 and 4 have been investigated. Cyclic voltammograms of 3 and 4 show reversible redox couples of ferrocene/ferrocinium at E_1/2=0.401 V and 0.346 V, respectively. Electrochemical studies show these redox active compounds electrochemically recognize trivalent lanthanides La³⁺ and Ce³⁺ and divalent Pb²⁺ and Cu²⁺cations. With ferrocenyl Schiff-base calix[4]arene 3 an anodic shift as large as 130 mV is observed on addition of one equivalent of Ce³⁺ ion. Also extraction properties of compound 4 towards some metal cations have been described. It has been observed that compound 4 has a good selectivity for metal cations Fe³⁺, Cu²⁺, Pb²⁺ and Cd²⁺ against Ni²⁺ and Co²⁺.     

Effect of p-tert-butylcalix[4]arene fitted with phosphinoyl pendant arms as synergistic agent in the solvent extraction of trivalent lanthanoids with 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione and structural study of solid complexes by IR,NMR and X-ray

The synergistic solvent extraction of five selected lanthanoid ions (La³⁺, Nd³⁺, Eu³⁺, Ho³⁺ and Lu³⁺) with 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione (HL) and 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrakis-(dimethylphosphinoylmethoxy)calix[4]arene, (S) in CHCl₃ has been studied. It was found that in presence of this phosphorus-containing calix[4]arene the lanthanoid ions have been extracted as [LnL₃S₂]. The values of the equilibrium constants and the separation factor have been calculated. The influence of the synergistic agent on the extraction process has been discussed.     

Organoclay modified with lignin as a new adsorbent for removal of Pb2+ and UO2 2+

This study investigated a new adsorbent prepared from lignin modified organoclay for the removal of Pb²⁺ and UO₂ ²⁺ from aqueous solutions. The characterization of new adsorbent was performed by FT-IR and XRD. Adsorption of Pb²⁺ and UO₂ ²⁺ species in aqueous solution as a function of ion concentration, pH, temperature and time of adsorption was investigated in detail. The adsorption data were analyzed by using the Langmuir, Freundlich and Dubinin-Radushkevich models. The monolayer adsorption capacities of organoclay–lignin were 0.12 mol kg^?1 and 0.42 mol kg^?1 for Pb²⁺ and UO₂ ²⁺, respectively. The experimental kinetic data were analyzed by using pseudo-second-order kinetic and intra-particle diffusion models. The proposed adsorption mechanism follows a pseudo-second-order kinetic and endothermic because of increasing disorderliness at adsorbate/adsorbent interface.     

单氧代-二硒烷基-1, w-二氧取代杯[4]衍生物的合成,结构及萃取性能研究

Novel macrocyclic monooxa-diselkylene-1,ω-dioxy substituted calix[4]arene derivatives 1a-5a were synthesized by the reaction of calix[4]arene dibromides 1-5 with the disodium salt of bis（2-selenylethyl）ether in the yields between 28% and 64%. Their structures were characterized by proton and carbon NMR spectra. X-Ray structure analysis of la further confirmed the cone conformation of compounds 1a-5a. An interesting host-guest complex of la with dichloromethane via CH/π and C1/π interactions was elucidated. Extraction experiments showed that these novel monooxa-diselkylene-1,ω-dioxy substituted calix[4]arene derivatives 1a-5a had strong extraction ability towards mercury ion. The interaction of Hg^2＋with the calix ligand has also been investigated by 1^H NMR titration.     

Oligomeric calix[4]arene‐thiacrown ether for toxic heavy metals

A new oligomeric calix[4]arene‐thiacrown‐4 ( 5 ) was synthesized via a condensation reaction of 5,11,17,23‐tetra‐tert‐butyl‐25,27‐bis‐(4‐aminobenzyloxy)‐calix[4]arene‐thiacrown‐4 ( 4 ) with adipoyl dichloride. In this oligomerization reaction only five/six calix[4]arene‐thiacrown‐4 units were linked in the oligomeric chain. The complexation studies of 5 were made with liquid–liquid‐ extraction and solid–liquid‐sorption procedures. For comparison, the extraction efficiencies of monomers 1 , 3 , and 4 to selected transition metals are reported. The selectivity of monomers 3 and 4 toward Cu²⁺, Hg²⁺, and Pb²⁺ was lost after oligomerization in the two‐phase extraction systems. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 186–193, 2004     

Effect of p-tert-Butylcalix[4]arene Fitted with Phosphinoyl Pendant Arms as Synergistic Agent in the Solvent Extraction and Separation of Some Trivalent Lanthanoids with 4-Benzoyl-3-methyl-1-phenyl-5-pyrazolone

The synergistic solvent extraction of five selected lanthanoid ions (La³⁺, Nd³⁺, Eu³⁺, Ho³⁺ and Lu³⁺) with a 4-benzoyl-3-methyl-1-phenyl-5-pyrazolone(HP) and the 5,11,17,23-tert-butyl-25,26,27,28-tetrakis(dimethylphosphinoylmethoxy)calix[4]arene, (S) in CHCl₃ has been studied. It was found that in presence of this phosphorus-containing calix[4]arene the lanthanoids have been extracted as LnP₃ · S. On the basis of the experimental data, the values of the equilibrium constants have been calculated. The influence of the synergistic agent on the extraction process has been discussed. A synergistic effect of almost three orders of magnitude occurs in the extraction of Ln(III) with mixture of HP and S. The values of the separation factors (S.F.) between the adjacent elements have been evaluated. On the basis of the IR and NMR spectra the stoichiometry and the structure of the solid complexes of Eu(III) with HP and Eu(III) with HP and S were proposed.     

Complexation and extraction of non-ferrous metals by calix[n]arene phosphine oxides

The extraction of non-ferrous metal (M²⁺) nitrates by the calix[4,6]arenes (L), bearing four or six phosphine oxide donor groups at the upper or at the lower rim, was quantitatively described in the form of [M_n(NO₃)_2nL] (n = 1, 2) complexes. The extraction constants (Zn²⁺ > Cu²⁺ > Co²⁺ > Ni²⁺) for the both types of L coincide with Irving-Williams sequence. Calix[4]arenes, phosphorylated at the lower (narrow) rim, provide better stability of ML complexes because of the best spatial fitting of M²⁺ by the donor groups. For the upper (wide) rim phosphorylated calix[4]arenes M₂L and ML₂ complexes are more stable. Unusual zwitterionic [Co₂(NO₃)₄L] complex of the lower rim tetraphosphorylated calix[4]arene 1 was determined by X-ray structural analysis.     

Synthesis and characterization of azocalix[4]arene ester and ketone derivatives incorporated in a polymeric backbone with bisphenol-A and their cation-binding properties

This study comprises synthesis and characterization of azocalix[4]arene compounds having copolymeric structures. The novel bisazocalixphenol-A and copolymer containing pendant azocalix[4]arene units with ester (5) and ketone (6) functionalities at their lower rim have been synthesized via diazo-coupling reaction. The phase transfer study is performed by liquid?Cliquid extraction method. It has been deduced from the observations that their precursors 25,26,27-tribenzoyloxy-28-hydroxy-5-(4-aminophenylazo)calix[4] arene (3), 25,27-diacetoniloxy-26,28-dihydroxy-5,17-(4-aminophenylazo)calix[4]arene (4) and bisazocalixphenol-A (5) show a good phase transfer affinity towards selected transition metal cations, unlike copolymer (6). These compounds are studied by the selective extraction of Fe³⁺ cation from the aqueous phase into the organic phase and it is carried out using compounds 1?C6. It is observed that the reduced azocalix[4]arene 4 is the most efficient (82.93?%) carrier of all compounds (3?C6) in the extraction of Fe³⁺ at pH 5.4.     

A tetraester derivative of fluorescent calix[4]arene bearing a proton-ionizable moiety for highly sensitive extraction-fluorometric determination of sodium ion

In this study, we report the highly sensitive extraction-fluorometric detection system of Na⁺ using flow injection analysis with a tetraester derivative of fluorescent calix[4]arene. In liquid-liquid extraction experiments, the fluorescent intensity of calix[4]arene derivative 1 bearing a p-nitrophenol moiety was highly dependent on pH and the Na⁺ concentration in the aqueous phase. On the other hand, such phenomenon was not observed in the case of calix[4]arene derivative 2, which is almost the same structure as 1 except for a p-nitrophenol moiety. These results show that the proton dissociation of the p-nitrophenol moiety decisively affects the fluorescence intensity of 1. Owing to these fluorescence responsiveness, a calibration graph of the Na⁺ concentration could be successfully prepared using flow injection analysis with good linearity at the tens of nanomolar level. The tetraester scaffold of calix[4]arene was essential to the detection of Na⁺ in such a very low concentration range.     

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     

DFT-calculated structure of protonated tetraphenyl p - tert -butylcalix[4]arene tetraketone

Using DFT calculations, two of the most probable structures (A, B) of the tetraphenyl p-tert-butylcalix[4]arene tetraketone·H₃O⁺ cationic complex species were derived. The hydroxonium ion H₃O⁺, placed in the coordination cavity formed by the calix[4]arene lower-rim groups, is bound by strong hydrogen bonds to the phenoxy oxygen atoms of the calix[4]arene ligand (structures A, B) and also to one carbonyl oxygen (structure B).     

Impact of environmental conditions on the sorption behavior of UO<Subscript>2</Subscript><Superscript>2+</Superscript> onto attapulgite studied by batch experiments

The sorption of UO₂ ²⁺ from aqueous solution on attapulgite was investigated as a function of contact time, solid content, pH, ionic strength, foreign ions, humic acid (HA), and fulvic acid (FA) under ambient conditions by using batch technique. The attapulgite sample was characterized by XRD and FTIR in detail. The results indicated that the sorption of UO₂ ²⁺ was strongly dependent on pH and ionic strength. The sorption of UO₂ ²⁺ on attapulgite increased quickly with rising pH at pH < 6.5, and decreased with increasing pH at pH > 6.5. The presence of HA or FA enhanced the sorption of UO₂ ²⁺ on attapulgite obviously at low pH because of the strong complexation of surface adsorbed HA/FA with UO₂ ²⁺ on attapulgite surface. Sorption of UO₂ ²⁺ on attapulgite was mainly dominated by ion-exchange or outer-sphere surface complexation at low pH values, but by inner-sphere surface complexation at high pH values. The results indicate that attapulgite is a very suitable adsorbent for the preconcentration and solidification of UO₂ ²⁺ from large volumes of aqueous solutions because of its negative surface charge and large surface areas.     

Synthesis of novel chiral Schiff base and amino alcohol derivatives of calix[4]arene and chiral recognition properties

In the present study, the synthesis and liquid phase extraction properties towards some amino acid methylesters and amino alcohols of Schiff base and amino alcohol substituted calix[4]arene are reported. The Schiff base substituted calix[4]arene 5 has been synthesized via condensation reaction involving 5,17-diformyl-11,23-di-tert-butyl-25,27-di[3-(4-formylphenoxy)propoxy]-26,28 dihydroxycalix[4]arene 4 and (R)-(?)-2-phenylglycine methyl ester in CHCl₃:MeOH. To give the amino alcohol substituted calix[4]arene 6, the synthesized chiral compound 5 was reduced by LiAlH₄. The new chiral Schiff base and amino alcohol derivatives of calix[4]arene have been characterized by a combination of FT-IR, ¹H NMR, ¹³C NMR, FAB-MS and elemental analysis. Also, the extraction behaviors of 5 and 6 towards some selected amino acid methylesters and amino alcohols have been studied by liquid–liquid extraction.     

Adsorption of Eu(III) ions on silicas with noncovalently immobilized thiacalix[4]arene derivatives

Using the noncovalent immobilization of some thiacalix[4]arene derivatives on the surface of silanized silica, we obtained efficient adsorption materials for the extraction of Eu(III) ions from aqueous solutions of medium mineralization. The specific surface area of the adsorbents is 200–370 m²/g. It is shown that adsorbents containing thiacalix[4]arenes with phosphoryl groups selectively extract up to 99% of europium ions from aqueous solutions at pH 5.5–6; they are characterized by adsorption capacity of 7.5–14.5 mg/g and high distribution coefficients. The studied adsorbents exhibit high selectivity with respect to Eu(III) ions, wherein the distribution coefficients for Cs, Sr, Tb(III), Sm(III), Gd(III), La(III), and UO₂²⁺ are five times or more smaller.