Synthesis and Structure of Novel Double Flexible Spacer Bridged Biscalix[4]arenes

25, 25′, 27, 27′‐Bis(1,3‐dioxypropane)‐bis(5, 11, 17, 23‐tetra‐tert‐butylcalix[4]arene‐26,28‐diol) (4) and 25, 25′, 27, 27′‐bis(1, 4‐dioxybutane)‐bis (5, 11, 17, 23‐tetra‐tert‐butylcalix‐[4]arene‐26, 28‐diol) (5) were synthesized by the reaction of p‐tert‐butylcalix[4]arene (1) with preorganized 25, 27‐bis(3‐bromoproxyl)calix[4]arene‐26, 27‐diol (2) and 25, 27‐bis(3‐bromobutoxyl)calix[4]arene‐26, 27‐diol (3) in the presence of K₂CO₃ and KI. Compounds 4 and 5 were characterized with X‐ray analysis and the selectivity of 4 and 5 toward K⁺ over other alkali metal ions, alkaline metal ions as well as NH₄⁺ were investigated with an ion‐selective electrode.     

Synthesis of p‐tert‐Butyl‐calix[6] ‐biscrown‐3 via Intramolecular Ring‐closure of 1,4‐Bis (2‐(2‐chloroethoxy) ethoxy) ‐p‐tert‐butyl‐calix[6]arene

With a variation in reaction conditions, 1, 4‐bis (2‐(2‐chloroethoxy)ethoxy)‐calix[6]arene (3) and l,3,5‐tris(2‐(2‐chloroethoxy) ethoxy)‐calix [6] arene (4) or 4 and 4‐chloroethoxyethoxy‐calix[6]crown‐3 (5) were selectively synthesized from p‐tert‐butyl‐calix [6] arene and 2‐(2‐chloroethoxy)ethyltosylate. l,3–4,6‐p‐tert‐butylcalix[6]‐bis‐crown‐3 (6) with (u,u,u,d,d,d) conformation and 1,3–4,5‐p‐tert‐butylcalix[6]‐biscrown‐3 (7) with self‐anchored (u,u, u, u, u, d) conformation were synthesized through an intramolecularly ring‐closing condensation of 1, 4‐bis (2‐(2‐chloroethoxy)ethoxy)‐p‐tert‐butyl‐calix[6]arene (3) in 25% and 15% yield, respectively. Using 5 instead of 3, only 7 was obtained in 65% high yield. 6 and 7 show different complexation properties toward alkali metal and ammonium ions.     

Synthesis of a Tweezer—like Bis（Phenylthiapropoxy）calix[4]—arene as a Cation／π Enhanced Sensor for Ion—Selective Electrodes

Two novel 25,27-dihydroxy-26,28-bis(3-phenylthiapropxy)-calix[4]arene(3) and 25,27-dihydroxy-26,28-bis(3-phenylthiapropoxy)-5,11,17,23-tetra-tert-butylcalix[4] arene (4) were synthesized for the evaluation of their ion-selectivity in ion-selective electrodes(ISEs).ISEs based on 3 and 4 as neutral ionophores were prepared,and their selectivity coefficients for Ag^ (lg KAg,M^pot)were investigated against other alkali metal,alkaline-earth metal,aluminum,thallium(Ⅰ）,Lead and some transition metal ions using the separate solution method (SSM).These ISEs showed excellent Ag^ seletivity over most of the interfering cations examined,except for Hg^2 and Fe^2 having relative smaller interference(lg KAg,M^pot≤-2.1).     

Zweifach und dreifach intramolekular verbrückte p‐tert‐Butylcalix[8]aren‐triphosphate – Synthese,Struktur und Stereochemie

Two‐ and Threefold Intramolecular Brigdging p‐tert‐Butylcalix[8]arene Triphosphates – Synthesis, Structure and Stereochemistry [1] The phosphorylation of p‐tert‐butylcalix[8]arene ( 1 ) with phosphorus pentachloride and hydrolysis gives intramolecular bridging tert‐butylcalix[8]arene triphosphates. The reactivity (esterification, dehydratisation, complexation), the structure (nmr and x‐ray), and the stereochemical behaviour of the phosphates will be discussed.     

Two related lithium calixarene complexes, [p‐tert‐butylcalix[4]arene(OMe)(OH)2(OLi)]2·4MeCN and {p‐tert‐butylcalix[4]arene(OH)2(OLi)[OLi(NCMe)2]}2·8MeCN,determined using synchrotron radiation

The crystal structures of acetonitrile solvates of two related lithium calixarene complexes have been determined by low‐temperature single‐crystal X‐ray diffraction using synchrotron radiation. Bis(μ‐5,11,17,23‐tetra‐tert‐butyl‐26,28‐dihydroxy‐25‐methoxy‐27‐oxidocalix[4]arene)dilithium(I) acetonitrile tetrasolvate, [Li₂(C₄₅H₅₇O₄)₂]·4C₂H₃N or [p‐tert‐butylcalix[4]arene(OMe)(OH)₂(OLi)]₂·4MeCN, (I), crystallizes with the complex across a centre of symmetry and with four molecules of unbound acetonitrile of crystallization per complex. Tetraacetonitrilebis(μ‐5,11,17,23‐tetra‐tert‐butyl‐26,28‐dihydroxy‐25,27‐dioxidocalix[4]arene)tetralithium(I) acetonitrile octasolvate, [Li₄(C₄₄H₅₄O₄)₂(C₂H₃N)₄]·8C₂H₃N or {p‐tert‐butylcalix[4]arene(OH)₂(OLi)[OLi(NCMe)₂]}₂·8MeCN, (II), also crystallizes with the complex lying across a centre of symmetry and contains eight molecules of unbound acetonitrile per complex plus four more directly bound to two of the lithium ions, two on each ion. The cores of both complexes are partially supported by O—H...O hydrogen bonds. The methoxy methyl groups in (I) prevent the binding of any more than two Li⁺ ions, while the corresponding two O‐atom sites in (II) bind an extra Li⁺ ion each, making four in total. The calixarene cone adopts an undistorted cone conformation in (I), but an elliptical one in (II).     

Synthesis,Crystal Structure and Complexing Properties of Calix[4]arene Schiff Bases

Four p‐tert‐butylcalix[4]arene derivatives with different Schiff base groups at the lower rim were efficiently prepared in three steps. p‐tert‐Butylcalix[4]arene was firstly O‐peralkylated with ω‐haloalkylphthalimide in the system of NaH/DMF to give calixarene tetraalkylphthalimides, which were in turn hydrazinolyzed to give tetraaminoalkylcalixarenes. Then by condensation of the latter with salicylaldehyde and 2‐hydroxy‐1‐naphthaldehyde, a series of calixarene Schiff bases were obtained in satisfying yields. The complexing properties of these Schiff bases for transition metal ions were investigated with UV spectroscopy.     

一种基于硫杂杯[4]芳烃的高效银离子载体

合成了基于下缘含有酰肼基团的硫杂杯芳烃衍生物的银离子载体1,其核磁研究证实硫杂杯芳烃以1,3-交替构象存在,并且通过非竞争萃取实验和竞争萃取实验研究了它对碱金属和过渡金属离子（Li⁺, Na⁺, K⁺, Cs⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺ and Ag⁺）的键合能力和选择性。实验结果表明：将酰肼基团引入1,3-交替构象的硫杂杯芳烃骨架的下缘可以提高其对Ag⁺的键合能力和选择性,同时,对Cu²⁺的萃取能力较弱,对碱金属离子和其它的重金属离子几乎没有萃取能力。进一步的核磁滴定和电喷雾质谱实验显示化合物1与银离子形成配合物的配合计量比为1：1,由此推断主要由“N-Ag⁺”配位键以及硫杂杯芳烃骨架的协同作用构成了化合物1与银离子的配合模式。     

Bis‐tert‐Alcohol‐Functionalized Crown‐6‐Calix[4]arene: An Organic Promoter for Nucleophilic Fluorination

A bis‐tert‐alcohol‐functionalized crown‐6‐calix[4]arene (BACCA) was designed and prepared as a multifunctional organic promoter for nucleophilic fluorinations with CsF. By formation of a CsF/BACCA complex, BACCA could release a significantly active and selective fluoride source for S_N2 fluorination reactions. The origin of the promoting effects of BACCA was studied by quantum chemical methods. The role of BACCA was revealed to be separation of the metal fluoride to a large distance (>8 Å), thereby producing an essentially “free” F^?. The synergistic actions of the crown‐6‐calix[4]arene subunit (whose O atoms coordinate the counter‐cation Cs⁺) and the terminal tert‐alcohol OH groups (forming controlled hydrogen bonds with F^?) of BACCA led to tremendous efficiency in S_N2 fluorination of base‐sensitive substrates.     

Amphiphilic p‐tert‐Butylcalix[4]arene Scaffolds Containing Exposed Carbohydrate Dendrons

The best of both worlds. Amphiphilic hybrid molecules, in which water‐exposed glycodendrons are attached to a hydrophobic p‐tert‐butylcalix[4]arene scaffold, display strong affinities for both carbohydrate‐binding proteins and polystyrene surfaces (shown schematically). The molecules can form monolayers useful in bioanalytical devices.     

Development and application of a new 25,27‐bis(l‐phenylalaninemethylester‐N‐carbonylmethoxy)‐26,28‐dihydroxy‐para‐tert‐butylcalix[4]arene stationary phase

A 25,27‐bis(l ‐phenylalaninemethylester‐N‐carbonylmethoxy)‐26,28‐dihydroxy‐ para‐tert‐butylcalix[4]arene‐bonded silica gel stationary phase was synthesized, structurally characterized and used for LC. Its separation mechanism was studied and compared with octadecyl‐bonded stationary phase, as well as our previously prepared para‐tert‐butylcalix[4]arene‐1,2‐crown‐4 stationary phase. Meanwhile, the chromatographic behaviors were investigated by using polycyclic aromatic hydrocarbons, monosubstituted benzenes, anilines, phenols, Tanaka tests solutes, fluoroquinolones, and flavonoids as probes. Mechanisms involved in the chromatographic separation included hydrophobic, π‐π and π‐electron transfer, hydrogen bonding, and inclusion interactions. Moreover, the column was successfully employed for the analysis of the illegal additive of melamine in milk product.     

对叔丁基杯[10]冠醚的合成

首次合成一系列杯[10]冠醚。通过将对叔丁基杯[10]芳烃和乙二醇双对甲苯磺酸酯或多甘醇双对甲苯磺酸酯在K2CO3/甲苯或Cs2CO3/丙酮体系中反应,得到一系列杯[10]冠醚:1,2-杯[10]冠-4、1,3-杯[10]冠-2、1,2-,1,3-杯[10]冠-3、1,4-杯[10]冠-4、和1,6-杯[10]冠-4。     

Hard–Soft Receptors, Tetrakis[(N,N-diethylaminocarbonyl)methoxy] thiacalix[4]arene Derivatives with cone and 1,3-alternate Conformation

Direct O-alkylation of p-tert-butyltetrathiacalix[4]arene with N,N-diethylchloroacetamide afforded two conformational isomers (1,3-alternate and cone) of tetrakis[(N,N-diethylaminocarbonyl)methoxy]thiacalix[4]arene and 1,3-disubstituted bis[(N,N-diethylaminocarbonyl)methoxy]thiacalix[4]arene, depending on the base used. The complaxation behaviors of the tetrakis isomers were assessed by ¹H NMR titration experiments. Evidence of 1:2 (homo- and hetero-dinuclear) complexes formation of 1,3-alternate-tetrakis[(N,N-diethylaminocarbonyl)methoxy]thiacalix[4]arene with alkali (K⁺ and Na⁺) or transition (Ag⁺) metal ions was obtained. Interestingly, it was found that the cone-tetrakis[(N,N-diethylaminocarbonyl)methoxy]thiacalix[4]arene required a prior Ag⁺ complexation to form 1:2 heterodinuclear complex. Received in final form: 26 January 2005     

Potentiometric Ag+ Sensors Based on Conducting Polymers: A Comparison between Poly(3,4‐ethylenedioxythiophene) and Polypyrrole Doped with Sulfonated Calixarenes

Potentiometric Ag⁺ sensors were prepared by galvanostatic electropolymerization of 3,4‐ethylenedioxythiophene (EDOT) and pyrrole (Py) on glassy carbon electrodes by using sulfonated calixarenes as doping ions. Poly(3,4‐ethylenedioxythiophene) (PEDOT) and polypyrrole (PPy) doped with p‐sulfonic calix[4]arene (C4S), p‐sulfonic calix[6]arene (C6S) and p‐sulfonic calix[8]arene (C8S) were compared. PEDOT and PPy doped with poly(styrene sulfonate) (PSS) were also included for comparison. The analytical performance of the conducting polymer‐based Ag⁺ sensors was studied by potentiometric measurements. All conducting polymer and dopant combinations showed sensitivity and selectivity to Ag⁺ compared to several alkali, alkaline‐earth, and transition‐metal cations. The type of the conducting polymer used for the fabrication of the electrodes was found to have a more significant effect on the selectivity of the electrodes to Ag⁺ than the ring size of the sulfonated calixarenes used as dopants. Selected conducting polymer‐based sensors were studied by cyclic voltammetry (CV) and energy dispersive analysis of X‐rays (EDAX) measurements. Results from the EDAX measurements show that both PEDOT‐ and PPy‐based membranes accumulate silver.     

Synthesis and photochemical reaction of cyclic oligomers: Synthesis and photopolymerization of novel C‐methylcalix[4]resorcinarene and p‐alkylcalix[n]arene derivatives containing spiro ortho ether groups

New photoreactive calixarene derivatives containing spiro ortho ester groups (calixarenes 3a–3c ) were synthesized by the reaction of 2‐bromomethyl‐1,4,6‐trioxaspiro[4.4]nonane with 2,8,14,20‐tetramethyl‐4,6,10,12,16,18,22,24‐octakis(carboxymethoxy)calix[4]resorcinarene, 5,11,17,23,29,35‐hexamethyl‐37,38,39,40,41,42‐hexakis(carboxymethoxy)calix[6]arene, and 5,11,17,23,29,35,41,47‐octa‐tert‐butyl‐49,50,51,52, 53,54,55,56‐octakis‐(carboxymethoxy)calix[8]arene, which were prepared by the reaction of C‐methylcalix[4]resorcinarene, p‐methylcalix[6]arene, and p‐tert‐butylcalix[8]arene, respectively. The thermal stability of the obtained calixarene derivatives containing spiro ortho ester groups was examined with thermogravimetric analysis, and it was found that these calixarene derivatives had good thermal stability. The photoinitiated cationic polymerization of spiro ortho ester groups in calixarene derivatives 3a–3c was examined with certain photoacid generators in the film state. Interestingly enough, the reaction of calixarene derivatives did not proceed with only photoirradiation; however, the reaction proceeded smoothly when the photoirradiation was followed by heating. Furthermore, calixarene 3a , composed of a C‐methylcalix[4]resorcinarene structure, showed the highest photochemical reactivity in this reaction system. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1293–1302, 2002     

Electrochemical Properties of Electrode Modified with Langmuir‐Blodgett Film of p‐tert‐Butylcalix[4]arene Derivatives and Its Application in Determining of Silver

A new type of voltammetric sensor, Langmuir‐Blodgett (LB) film of 5,11,17,23‐tetra‐tert‐butyl‐25,27‐di(3‐thiadiazole‐propanoxy)‐26,28‐dihydroxycalix[4]arene modified glassy carbon electrode (LB_TZCA–GCE), was prepared. The electrochemical properties of LB_TZCA–GCE were researched in detail and its recognizing mechanism for silver ion in aqueous solution was discussed. Using this voltammetric sensor, a new stripping voltammetric method for determining of Ag⁺ was erected with good sensitivity, selectivity, reproducibility and recovery. The detection limit was 8×10^?9 M at accumulation time of 180 s. By this method, real samples (lake water, tap water and synthesis sample) were analyzed and the results obtained were well satisfactory.     

One‐Step Synthesis of Singly Bridged Biscalix[4]arenes with Oligooxyethyleneethyl Spacers

Here we describe the one‐step synthesis of a series of singly bridged biscalix[4]arene derivatives connected by ethylene or oligooxyethyleneethyl chain through the reaction of calix[4]arene with corresponding ethylene or oligoethylene glycol ditosylates in the presence of sodium hydride in toluene. A 1,2‐bis(ethylene) doubly bridged bis‐p‐tert‐butylcalix[4]arene was also obtained as a by‐product.     

Density functional theory study of calix[4]arene‐N‐azacrown‐5, calix[4]arene‐N‐phenyl‐azacrown‐5, and their complexes with alkali‐metal cations: Na+, K+, and Rb+

Theoretical studies of 1,3‐alternate‐25,27‐bis(1‐methoxyethyl)calix[4]arene‐azacrown‐5 ( L₁ ), 1,3‐alternate‐25,27‐bis(1‐methoxyethyl)calix[4]arene‐N‐phenyl‐azacrown‐5 ( L₂ ), and the corresponding complexes M⁺/ L of L₁ and L₂ with the alkali‐metal cations: Na⁺, K⁺, and Rb⁺ have been performed using density functional theory (DFT) at B3LYP/6‐31G* level. The optimized geometric structures obtained from DFT calculations are used to perform natural bond orbital (NBO) analysis. The two main types of driving force metal–ligand and cation–π interactions are investigated. The results indicate that intermolecular electrostatic interactions are dominant and the electron‐donating oxygen offer lone pair electrons to the contacting RY* (1‐center Rydberg) or LP* (1‐center valence antibond lone pair) orbitals of M⁺ (Na⁺, K⁺, and Rb⁺). What's more, the cation–π interactions between the metal ion and π‐orbitals of the two rotated benzene rings play a minor role. For all the structures, the most pronounced changes in geometric parameters upon interaction are observed in the calix[4]arene molecule. In addition, an extra pendant phenyl group attached to nitrogen can promote metal complexation by 3D encapsulation greatly. In addition, the enthalpies of complexation reaction and hydrated cation exchange reaction had been studied by the calculated thermodynamic data. The calculated results of hydrated cation exchange reaction are in a good agreement with the experimental data for the complexes. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010     

Improvement of selective d-cation binding by tetrathiacalix[4]arene hydrazides: synthesis and extraction properties

New de-tert-butyltetrathiacalix[4]arenes with acetylhydrazide substituents in cone and 1,3-alternate conformations have been synthesised with good yield by the hydrazinolysis of calix[4]arene ester derivatives. The recognition ability of synthesised macrocycles towards transition and alkali metals has been investigated by the picrate extraction method. The stoichiometry of complexes and the extraction constants have been determined. It has been found that tetrahydrazides do not extract alkali metal ions, but show an excellent affinity towards transition and heavy metal cations. The 1,3-alternate conformer of de-tert-butyltetrathiacalix[4]arene has revealed a remarkable selectivity for Ni²⁺ and Ag⁺ in the row of d-elements and for Cd²⁺ ion among the toxic heavy metals. The experimental data show that the removal of tert-butyl groups from tetrathiacalix[4]arene framework leads to the drastic improvement of extraction efficiency and selectivity of new tetrahydrazides.     

Simultaneous Determination of Thallium and Lead on a Chemically Modified Electrode with Langmuir– Blodgett Film of a p‐tert‐Butylcalix[4]arene Derivative

A new voltammetric sensor, Langmuir–Blodgett (LB) film of a p‐tert‐butylcalix[4]arene derivative modified glassy carbon electrode, was designed and successfully used in simultaneous determination of Tl⁺ and Pb²⁺ by square‐wave anodic stripping voltammetry. Under the optimum experimental conditions, this newly developed sensor reveal good linear response for Tl⁺ and Pb²⁺ in the concentration range of 3×10^?8–4×10^?6 mol L^?1 and 2×10^?7–2×10^?5 mol L^?1 respectively. The detect limits are 2×10^?8 mol L^?1 for Tl⁺ and 8×10^?8 mol L^?1 for Pb²⁺. Using proposed method, Tl⁺ and Pb²⁺ in environment samples were determined with satisfactory results.     

四（对叔丁基）硫杂杯[4]芳烃选择性包合四氟硼酸分子：晶体结构和理论研究

X－射线晶体衍射测定了4－(对叔丁基)硫杂杯[4]芳烃选择性地包合四氟硼酸分子。晶体学数据为：C₄₀H₄₉O₄S₄BF₄，M_r=808.88， 四方锥， 空间群 P4/nmm，a=1.5887(2), b=1.5887(2), c=0.8428(0) nm, V=2.127(2) nm³, Z=2, D_c=1.263 g·cm^-3, R₁=0.0405, _WR[I>2σ(I)]=0.1218. ¹⁹F NMR谱中，在-151.4 ppm处出现的峰，证实了四氟硼酸的存在。用Bader的分子中的原子理论方法计算了分子结构中的非共价键相互作用。结果显示，在四氟硼酸包合物中，除了F…H－C氢键作用和阳离子－阴离子的静电作用外，F^δ--C^δ+静电作用的存在也对4－(对叔丁基)硫杂杯[4]芳烃憎水空腔包合氟硼酸分子起到了稳定作用。