Phosphite ligands derived from distally and proximally substituted dipropyloxy calix[4]arenes and their palladium complexes: Solution dynamics, solid-state structures and catalysis

Two bisphosphite ligands, 25,27-bis-(2,2′-biphenyldioxyphosphinoxy)-26,28-dipropyloxy-p-tert-butyl calix[4]arene (3) and 25,26-bis-(2,2′-biphenyldioxyphosphinoxy)-27,28-dipropyloxy-p-tert-butyl calix[4]arene (4) and two monophosphite ligands, 25-hydroxy-27-(2,2′-biphenyldioxyphosphinoxy)-26,28-dipropyloxy-p-tert-butyl calix[4]arene (5) and 25-hydroxy-26-(2,2′-biphenyldioxyphosphinoxy)-27,28-dipropyloxy- p-tert-butyl calix[4]arene (6) have been synthesized. Treatment of (allyl) palladium precursors [(η³-1,3-R,R′-C₃H₄)Pd(Cl)]₂ with ligand 3 in the presence of NH₄PF₆ gives a series of cationic allyl palladium complexes (3a-3d). Neutral allyl complexes (3e-3g) are obtained by the treatment of the allyl palladium precursors with ligand 3 in the absence of NH₄PF₆. The cationic allyl complexes [(η³-C₃H₅)Pd(4)]PF₆ (4a) and [(η³-Ph₂C₃H₃)Pd(4)]PF₆ (4b) have been synthesized from the proximally (1,2-) substituted bisphosphite ligand 4. Treatment of ligand 4 with [Pd(COD)Cl₂] gives the palladium dichloride complex, [PdCl₂(4)] (4c). The solid-state structures of [{(η³-1-CH₃-C₃H₄)Pd(Cl)}₂(3)] (3f) and [PdCl₂(4)] (4c) have been determined by X-ray crystallography; the calixarene framework in 3f adopts the pinched cone conformation whereas in 4c, the conformation is in between that of cone and pinched cone. Solution dynamics of 3f has been studied in detail with the help of two-dimensional NMR spectroscopy.The solid-state structures of the monophosphite ligands 5 and 6 have also been determined; the calix[4]arene framework in both molecules adopts the cone conformation. Reaction of the monophosphite ligands (5, 6) with (allyl) palladium precursors, in the absence of NH₄PF₆, yield a series of neutral allyl palladium complexes (5a-5c; 6a-6d). Allyl palladium complexes of proximally substituted ligand 6 showed two diastereomers in solution owing to the inherently chiral calix[4]arene framework. Ligands 3, 6 and the allyl palladium complex 3f have been tested for catalytic activity in allylic alkylation reactions.     

Calix[4]arene Schiff bases—potential ligands for fluorescent studies

A series of novel double-armed calix[4]arene derivatives incorporating imine substituents were synthesised from the Schiff-base reaction of 25,27-bis[2-[(1-formyl-2-phenyl)oxy]ethyl]-p-tert-butylcalix[4]arene (1) with the appropriate amine or hydrazone. All compounds were characterised by various spectroscopic and analytical techniques, and in three cases, by X-ray crystallographic studies. In the case of compound 2, inclusion compounds were synthesised with both m-xylene and dimethylformamide and their X-ray structures revealed these inclusion sites—between the pendant arms and in the upper cavity, respectively. In all cases, the pendant arms are bent away from each rather than adopting a face-to-face conformation.     

Calix[4]quinones. Part 4: The ClO2 oxidation of calix[4]arene dialkyl ethers

Except for the special case of calix[4]arene diethyl ether 1, the chlorine dioxide oxidation of dialkyl ethers 2-5 yielded only the corresponding calix[4]diquinone dialkyl ethers 8-11. Chlorine dioxide oxidation of calix[4]arene diethyl ether 1 produced two isomeric products 6 and 7, which were stable enough to be isolated by column chromatography. However, a slow conformational interconversion between isomeric pair 6 and 7 was observed at room temperature, and the equilibrium was reached after 400 h at 18 °C with an amount of 5:3 in favor of syn-isomer.     

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.     

杯[4]芳烃衍生物的合成和构象研究

以对取代酚亚甲基桥三聚体和２，６－二溴甲基对取代酚为原料，在ＴｉＣｌ４催化下环化得到６种新的含不同取代基［Ｃｌ，Ｂｒ，ＣＨ３，Ｃ（ＣＨ３）３］的杯［４］芳烃衍生物，核磁共振谱研究表明：它们在溶液中的优势构象为锥形构象。     

杯[4]芳烃的构象间转换机理的CNDO/2法研究

利用CNDO／2近似方法对25，26，27，28－四羟基杯［4］芳烃的四种不同构象的平衡几何构型以及所有可能发生的构象间转换的势垒能量进行了计算．在此基础上提出了合理的杯［4］芳烃的构象间转换机理，指出部分锥形构象是必经途径．利用该机理可以圆满地解释某些实验现象．     

Calix [ 4 ] arene Polyaza Derivatives： Novel Effective Neutral Receptors for Cations and α-Amino Acids

IntroductionCalixarenes are one of the most important supra-molecular building blocks, which can be modified byintroducing different functional and/or structural groupsto create a specific interaction between the host and thetarget molecules, such as meta…     

Calix[4]arene Polyaza Derivatives: Novel Effective Neutral Receptors for Cations and (a)-Amino Acids

Introduction Calixarenes are one of the most important supramolecular building blocks, which can be modified by introducing different functional and/or structrual groups to create a specific interaction between the host and the target molecules, such as metal cations and small organic molecules[1,2]. In particular, the recognition of amino acids is an interesting theme in biomimetic chemistry[3].     

N-硫脲基套索杯[4]冠醚与四硫脲基杯[4]芳烃的合成

控制反应物的物质的量比, 杯式对叔丁基杯[4]-1,3-二乙酸乙酯衍生物1与5或50倍二乙烯三胺反应, 分别得到杯[4]氮杂冠醚2和开链的氮杂杯[4]芳烃衍生物3. 化合物2和3进一步与异硫氰酸苯酯反应得到首例侧链含硫脲基的套索杯[4]氮杂冠醚4和含4个硫脲基的杯[4]芳烃衍生物5, 产率为92%和87%. 新化合物的结构与构象经元素分析、红外、质谱、核磁共振谱等表征证实.     

Chlorination of Calix[4]arene Derivatives

New convenient method for synthesis of p-chlorinated calix[4]arenes is reported. The sulfuryl chloride was used for chlorination of unsubstituted at the lower rim calix[4]arenes. The products of this reaction were very suitable for further O-alkylation.     

Syntheses and Binding Properties of Novel Calix[4]arene Derivatives Containing Multiple Azo-groups

Introduction Calixarenes are excellent scaffolds that can bemodified by introducing various functional groups tocreate specific interactions between the host and guestmolecules. Thus, many calixarene derivatives contai-ning special functional groups, such as ester, amideand thiourea, have been synthesized and their excellentcomplexing capability for cations have also been stud-ied[1—4]. Lately, calixarene derivatives containing twoor more sorts of functional groups have attracted muchattentio…     

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     

杯[4]芳烃四丁醚的选择性硝化

硝化反应;杯[4]芳烃四丁醚的选择性硝化     

Palladium and platinum complexes of chiral and achiral calix[4]arene bisphosphite ligands

Chiral and achiral p-tert-butyl-calix[4]arene bisphosphites (L¹–L³) have been synthesized by the reaction of p-tert-butyl-calix[4]arene and the phosphorodichloridites, ROPCl₂ [R = (1S,2R,5R)-(+)-iso-menthyl (L¹), (1R,2S,5R)-(−)-menthyl (L²) or C₆H₄Bu^t-4 (L³)]. These bisphosphites function as chelating ligands in palladium(II) and platinum(II) complexes which are formed in good yields by the reaction of PdCl₂(PhCN)₂, MCl₂(COD) (M = Pd or Pt) or PdMeCl(COD) with the respective calix[4]arene bisphosphite. Single crystal X-ray diffraction studies performed on the complexes [PdCl₂(L¹)], [PdCl₂(L²)], [PdCl₂(L³)] and [PtCl₂(L³)] reveal a near square planar geometry around the metal with the two chloride ligands in a cis disposition. The crystal packing in the complexes [PdCl₂(L¹)] and [PdCl₂(L²)], which crystallize in the chiral (P6₁22) space group, shows different hydrophobic channels with intermolecular C–H?Cl hydrogen bonding. The complexes [PdCl₂(L³)] and [PtCl₂(L³)] are isostructural and the molecules in the crystal lattice are linked by intermolecular C–H?Cl and C–H?O hydrogen bonds.     

Calix[4]arene based neutral receptor for dihydrogen phosphate anion

A series of novel calix[4]arene hydrazone and semicarbazone based neutral receptors have been synthesized and characterized by IR, UV-vis, and NMR spectroscopies. The preliminary UV-vis and ¹H NMR titration experiments revealed that 25,26,27,28-tetrapropoxycalix[4]arene tetra-semicarbazone can recognize H₂PO₄⁻ through a 1:1 binding-stoichiometry in preference over other anions (Cl⁻, Br⁻, I⁻, HSO₄⁻, ClO₄⁻, and CH₃COO⁻).     

酰胺型杯[4]聚硅氧烷用作气相色谱固定相的研究

将合成的两种酰胺型杯「４」聚硅氧烷（ＰＳＯ－Ｃ「４」Ａ和Ｍ－Ｃ「４」Ａ－ＰＳＯ）用作毛细管柱气相色谱固定液,考察了产的色谱特性,柱效、极性及选择性,相变温度和稳定性。结果表明,两种酰胺型杯「４」聚硅氧烷固定液具有优良的色谱性能、多环芳主一些芳香族位置异构体得到较好的分离。     

新型杯[4]芳烃衍生物的合成

以对叔丁基杯[4]芳烃为起始原料,通过一步或两步取代反应合成了对叔丁基杯[4]芳烃的衍生物(1和2),其结构经FT-IR,^1H NMR,FAB-MS表征．     

Salicylate Ion‐Selective Electrode Based on a Calix[4]arene as Ionophore

A salicylate‐selective electrode based on calix[4]arene derivative was developed and its response characteristics were investigated. The optimum membrane composition was 1 % ionophore, 30 % PVC, 69 % DOS. The electrode exhibited a Nernstian slope of 58.8±0.5 mV/pSal in the range of 1.0×10^?5–1.0×10^?1 M with a detection limit of 4.3×10^?6 M at pH 4.0, 20±1 °C. The potentiometric response of the electrode in the presence of different anions was investigated by the separate solution method. The lifetime was found at least 4 months, and its response time was 5–10 s. It was successfully used for the potentiometric determination of salicylate in pharmaceutical preparations.     

单炔基桥联双杯[4]芳烃的合成与对溶剂分子的包合性能

对叔丁基杯[4]芳烃直接与1,4-二氯-2-丁炔反应,一步制备了单炔基单桥联双杯[4]芳烃和单炔基双桥联双杯[4]芳烃,并证实单桥联双杯[4]芳烃是双桥联双杯[4]芳烃的中间产物.经¹HNMR,¹³CNMR和ESI-MS分析证实了产物的结构.ESI-MS结果表明两种产物对DMF和H₂O有不同的包合能力.     

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.