Calix[4]arene derivatives monosubstituted at all four methylene bridges

The scope of the reaction of the tetrabromocalixarene derivative 2b with alcohols under solvolytic conditions in trifluoroethanol (TFE) or hexafluoroisopropanol (HFIP) was explored. The reaction proceeded readily with MeOH, EtOH, n-PrOH, ethylene glycol and i-PrOH affording preferentially the rccc isomer of the tetrasubstituted product. The methoxy derivative 6a undergoes isomerization upon attempted recrystallization from CHCl3/MeOH and its rcct and rctt forms were characterized by X-ray crystallography. Incorporation of hydroxy groups on the bridges was accomplished via solvolysis in AcOH, followed by LiAlH4 reduction of the acetoxy groups. Reaction of the tetra-(2-methylfuranyl)calixarene derivative 11 with benzyne followed by deoxygenation with Me3SiCl/NaI afforded in low yield the tetra-(4-methylnaphthyl)calix[4]arene derivative 12. Reaction of de-tert-butylated tetrabromo derivative 2a with m-xylene in HFIP followed by methylation of the crude product afforded the tetraxylyl derivative 14.     

Conformationally restricted calix[8]arenes substituted at all methylene bridges

Reaction under S(N)1 conditions of the octabromocalix[8]arene derivative 2d with alcohols proceeds in nonstereoselective fashion, but all-cis octaryl derivatives are the single major products in the reaction with arenes. The incorporation of aryl substituents at the bridges rigidifies the calix[8]arene skeleton.     

Calix[4]arenes with two different chemical modifications at the bridges

Hexabromocalix[4]arene derivatives (3a and 3b) possessing pairs of dibromomethylene and bromomethylene groups located at distal or proximal positions of the calix scaffold were prepared via photochemical bromination of tetramethoxycalix[4]arene. The dibromomethylene groups undergo hydrolysis to afford calix[4]arenes possessing pairs of carbonyl groups and bromomethylene groups located at distal or proximal bridges (4a and 4b, respectively). The bromomethylene groups of 4 undergo reactions with nucleophiles under S(N)1 conditions to afford a wide array of derivatives possessing two different chemical modifications at the bridges.     

含酰胺和席夫碱单元的杯[4]芳烃衍生物的合成与配合性能

杯[4]-1,3-二乙酸乙酯衍生物1与水合肼反应生成杯[4]芳烃酰肼衍生物2, 然后进一步与相应的芳醛反应, 高产率地合成了三个新型的含酰胺和席夫碱单元的杯[4]芳烃衍生物3a～3c和一例新型杯[4]冠醚4. 阳离子萃取实验表明新型杯芳烃衍生物比只含有酰胺基或席夫碱基的杯芳烃衍生物有更强的软金属离子配合性能, 杯[4]冠醚4还对Ag^＋有较好的选择性萃取能力.     

Supramolecular incorporation of fullerenes on gold surfaces: comparison of C60 incorporation by self-assembled monolayers of different calix[n]arene (n = 4, 6, 8) derivatives

[reaction: see text] Two new calix[6]arene derivatives 3 and 4 in a 1,4-anti conformation and one calix[8]arene derivative 5 were synthesized. SAMs of calix[n]arene (n = 4, 6, 8) derivatives 1-5 were formed on gold bead electrodes. Cyclic voltammetry with Ru(NH3)6(3+/2+) as a redox probe, together with impedance spectroscopy and reductive desorption, indicates that SAMs of 5 have a higher coverage than those of 3 and 4 due to the presence of hydrogen bonding and possibly its conformation. Noncovalent immobilization of C60 on gold surfaces was achieved with SAMs of calix[8]arene derivative 5 but not with those of 1-4.     

杯[4]芳烃黄原酸酯衍生物的合成与阳离子萃取性能

以二氧六环作溶剂, 杯[4]芳烃二甲氧基二羟乙氧基衍生物2与氢氧化钾、二硫化碳作用合成了杯芳烃黄原酸盐衍生物3, 并进一步与碘甲烷或氯化苄反应首次合成了含黄原酸酯基的杯芳烃衍生物4a和4b. 阳离子萃取试验表明该新型杯芳烃衍生物比单硫杂杯芳烃衍生物具有更好的过渡金属离子萃取性能.     

Multiple proton ionizable calixarene derivatives with different ring sizes and complexation ability as efficient ionophores for complexation and solvent extraction of trivalent indium

The solvent extraction behavior of multiple proton ionizable p-tert-butylcalix[4]arene and [6]arene carboxylic acid derivatives towards indium has been investigated along with an acyclic monomeric analogue from weakly acidic media into chloroform. The extraction mechanism is ion exchange and carboxylic acid groups are adequate ligating sites for extraction. The cyclic structure of calixarene ligands to accommodate the potential guest species and the cooperativity effect of multifunctional groups significantly affect the complexation behavior and calixarene derivatives are found to be excellent extractants over the monomeric analogue. The composition of the extracted complex depends on the solution pH and attempts to determine the composition of the extracted complex for the extraction of indium have been stymied by complications arising from the formation of polynuclear species of indium and bridged polymeric species of calixarene carboxylic acid derivatives. One mole of calix[4]arene derivative extracts 2.5 moles of indium whereas the calix[6]arene derivative tends to extract 4.0 moles of indium. The loaded indium is back extracted with 1 mol dm(-3) hydrochloric acid solution. Though quantitative back extraction of indium was achieved from the fully loaded calix[6]arene derivative, it was only achieved up to 85% in the case of the calix[4]arene derivative.     

邻甲氧基羰基苄氧基取代杯[4]芳烃衍生物的合成及其性？…

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…     

Rational synthesis of multicyclic bis[2]catenanes

Bis-loop tetraurea calix[4]arene 6 has been prepared by acylation of the wide-rim calix[4]arene tetraamine 1 with the activated bis(urethane) 8 under dilution conditions. Similarly the bis(Boc-protected) tetraamine 2 is converted into the mono-loop derivative 3 which after deprotection and acylation gives the bisalkenyl derivative 5. In apolar solvents this tetraurea calix[4]arene 5 forms regioselectively a single hydrogen-bonded homodimer, from which the bis[2]catenane 10a is formed in 49% by a metathesis reaction followed by hydrogenation. Bis-loop derivative 6 forms no homodimers for steric reasons, but a stoichiometric mixture with the open-chain tetraalkenyl derivative 7a contains exclusively the heterodimer. Metathesis and subsequent hydrogenation now yields 65 % of the pure bis[2]catenane 10a which could not be isolated from the complex reaction mixture obtained from the homodimer 7a.7a. The chirality of 10a (D(2) symmetry) has been verified by optical resolution using HPLC on a chiral stationary phase.     

三桥联杯[6]酰腙衍生物和相关化合物的合成

以杯[6]芳烃和杯[6]-1,4-冠-4为起始原料,经过醚化引入酯基,接着用水合肼肼解得到杯[6]酰肼衍生物2和6,然后再与水杨醛进行缩合反应,高产率合成了两例杯[6]酰腙衍生物3和7.化合物6与2倍的二水杨醛乙二醚进行"1+2"缩合反应,得到了一例新型结构的杯[6]-1,4-2,6-3,5-三桥联酰腙衍生物8,产率73%.新化合物2,3,6,7和8的结构经元素分析、红外光谱、质谱、核磁共振谱等证实.     

Enhanced thermodynamic and kinetic stability of calix[4]arene dimers locked in the cone conformation

Wide rim tetraurea derivatives (2a,b) have been prepared from a calix[4]arene rigidified in the cone conformation by two diethyleneglycol ether bridges between adjacent oxygens. In comparison to the analogous tetraurea derivatives (3a,b) of a tetrapentoxy calix[4]arene, 2a,b show an increased thermodynamic stability in mixtures of CDCl(3) and DMSO-d(6). Their kinetic stability as expressed by the rate of guest exchange (benzene or cyclohexane against the solvent benzene-d(6)) is also strongly increased by factors of 30-38. Noticeable differences for the inclusion of selected guests are found.     

Synthesis of Flavin–Calix[4]arene Conjugate Derivatives

The synthesis of two new flavin substituted calix[4]arene derivatives, 9 and 10 , is described. The first flavin substituted calix[4]arene derivative 9 was synthesized by the reaction of 3‐methylalloxazine ( 5 ) with 25,27‐bis(3‐bromopropoxy)‐26,28‐dihydroxy‐5,11,17,23‐tetra(tert‐butyl)calix[4]arene ( 4 ) in high yield (92%). The other derivative 10 was prepared from 3‐methylalloxazine‐1‐acetic acid ( 7 ) and 25,27‐bis(3‐cyanopropoxy)calix[4]arene ( 3 ). All new compounds were characterized by a combination of FT‐IR and ¹H‐NMR spectroscopy, and elemental‐analysis techniques.     

Selectively formylated and bridged calix[6]arene derivatives at the upper rim

The strategy of bridging the anisole units at the upper rim of calix[6]arene has been applied to strain the conformations of calix[6]arene. Based on the selective formylation of the 1,3,5-tri-p-tert-butylcalix[6]arene, several new calix[6]arene derivatives with different 1,3-bridged chains or a 1,3,5-tripod bridge at the upper rim have been prepared with moderate yields. The ¹H NMR spectra indicate that these calix[6]arene derivatives adopt a cone conformation, which has also been confirmed by the theoretical calculation at AM1 level. X-ray crystal structure of 1,3,5-tripod bridged compound 5 discloses that the calix[6]arene host stands in a cone conformation with approximate C_3v symmetry, and that a methanol molecule is enclosed in its hydrophobic cavity and stabilized by multi hydrogen bonds.     

Liquid membrane transport of cytochrome c using a calix[6]arene carboxylic acid derivative as a carrier

The present study examined the liquid membrane transport of the cationic protein cytochrome c, using the macrocyclic compound calix[6]arene, which is a carboxylic acid derivative, as a carrier. The transport rate was governed by carrier concentration and the pH gradient between the feed and the receiving phases, as well as the salt concentration in the aqueous phases. Transport of cytochrome c was examined using a series of calix[n]arene carboxylic acid derivatives (n = 4, 6 and 8). Cytochrome c successfully permeated membranes in the presence of the calix[6]arene derivative. Liquid membrane separation of cytochrome c from a mixture of cationic proteins was demonstrated under optimal conditions. Cytochrome c was selectively extracted by the calix[6]arene carboxylic acid derivative and 77% of the extracted cytochrome c was recovered into the receiving phase. In this liquid membrane system, which discriminates between the number of lysine residues on the surface of proteins, cationic proteins with similar molecular weights and pIs were separated with macrocyclic compounds.     

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%。     

Phosphorus-based p-tert-butylcalix[5]arene ligands

New calix[5]arene trivalent phosphorus derivatives have been synthesized which should be excellent ligands with which to study and control the interaction of a ligand atom with a metal. The larger cavity of the calix[5]arene (compared to calix[4]arene) provides a good balance between constraint and flexibility. Treatment of p-tert-butylcalix[5]arene with 2 equiv of either tris(dimethylamino)phosphine or dichlorophenylphosphine inserts two RP moieties into the calix[5]arene framework to give calix[5](PR)2(OH) (1, R = Me2N; 2, R = Ph). Further treatment of 1 with 4 equiv of HCl gives calix[5](PCl)2(OH) (3). Heating a solution of the monophosphorus compound calix[5](PNMe2)(OH)3 (4) releases dimethylamine to yield both monomeric calix[5](P)(OH)2 (6) and dimeric [calix[5](P)(OH)2](2) (7), the latter having a tubelike geometry. X-ray crystallographic studies confirm the structures and show that 1 and 2 have approximate cone conformations while 3 has an approximate 1,2-alternate conformation. The orientations of the phosphorus lone pairs and oxygen atoms in all derivatives provide a framework for both soft and hard ligand interactions within the calix[5]arene.     

Intramolecular AR--O--AR bond formation in calixarenes

The formal dehydration of two vicinal phenol moieties of p-tert-butylcalix[6]arene was achieved in two steps by mild oxidation of the calixarene followed by treatment of the resulting monospirodienone derivative (9c) with an ionic hydrogenation mixture (Et(3)SiH/CF(3)COOH). Reaction of 9c yielded the unsubstituted xanthenocalix[6]arene 11d, while treatment of the monospirodienone derivative of a spherand-type calixarene (13) with Et(3)SiH/CF(3)COOH afforded the dibenzofuran derivative 15. The formation of the latter product indicates that, at least for 13, the rings forming the Ar--O--Ar bond in the product are not those connected by the spiro bond in the starting material. Methylation of the phenolic hydroxyl groups of 11d with methyl p-toluenesulfonate/K(2)CO(3) or dimethyl sulfate/base afforded its dimethyl and tetramethyl ether derivatives. The parent xanthone calix[6]arene derivative 17b was prepared by O-methylation of the phenol groups followed by CrO(3) oxidation of the xanthene methylene group and deprotection of the OH groups. McMurry coupling of calixanthone 17a afforded the dixanthylene 18. Calixarenes 11d and 15 (which possess a xanthene and dibenzofuran group, respectively) were structurally characterized by X-ray crystallography.     

Luminescence behavior of a water soluble calix[4]arene derivative complex with terbium ion(III) in gelation solution

The complexation luminescence behavior of a water soluble calix[4]arene derivative, 5,11,17,23-tetra-sulfonate-25,26,27,28-tetra-carboxymethoxycalix[4]arene (L) with lanthanoid ion (Tb(3+)) has been investigated in gelation solution at 25 degrees C by using UV-vis and fluorescence spectra. The results obtained indicated that the water soluble calix[4]arene derivative can form an efficient energy transfer complex with terbium ion(III). The fluorescence of L x Tb(3+)complex is partially quenched by gelatin in gelation solution. The quenching intensity is related to the concentration and the hydrolysis degree of gelatin. Absorption and fluorescence spectra analysis show that the -COO(-) groups on gelatin have a definite binding ability to Tb(3+), and then, gelatin could compete binding with calix[4]arene derivative upon complexation with Tb(3+), leading to the relative fluorescence quenching of the formation complex of terbium(III) ion with calix[4]arene derivative.     

Effect of the glutaraldehyde derivatives of Calix[n]arene as cross-linker reagents on lipase immobilization

Synthesis of the glutaraldehyde derivatives calix[n]arene (n = 4,6,8) (Calix[n]-GA) and using as cross-linkers for immobilization of Candida rugosa lipase (CRL) have been discussed in this paper. The amino functional calix[n]arene derivatives (Calix[n]-NH ₂) were synthesized via reduction of dinitrile, hexanitrile and octanitrile derivatives of calix[n]arenes. These amino functional calix[n]arene derivatives (Calix[n]-NH ₂) were converted to their aldehyde derivativatives with glutaraldehyde. The calix[n]arene derivatives were used in lipase immobilization in order to see the role of calix[n]arene binding site on the lipase activitiy and stability. The activity recovery of calix[n]arene-supported lipases (Calix[n]-CRL) based on the Calix[4]-CRL, Calix[6]-CRL and Calix[8]-CRL reaches to 53.5, 66.1 and 76.4%, respectively.     

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).