A one-pot synthesis of a self-included bisester-functionalized copillar[5]arene

A bisester-substituted copillar[5]arene was synthesized by a one-pot reaction presenting a symmetrical selfincluded conformation in solution and an asymmetrical structure with only one selfincluded side in the cavity of pillar[5]arene in the solid state. This compound was characterized by 1D and 2D NMR and X-ray diffraction.     

Synthesis and applications of copillar[5]arene dithiols

Abstract

A novel copillar[4+1]arene incorporating alkylthiol substituents was synthesised in three steps and structurally characterised as the first example of a pillar[n]arene to incorporate two terminal thiols on the same aromatic ring. The macrocycle was attached to gold electrodes through a standard dipping technique. Cyclic voltammetry demonstrated selectivity for Li⁺ over other alkali metal cations. The copillar[4+1]arene was also used as a capping agent in the preparation of 3 nm gold nanoparticles.     

Synthesis and crystal structure of Ni,Cu complexes of 5-methyl-10,10,15,15,20,20-hexaethylcalix[4]pyrrole mono-Schiff bases

The functionalized calix[4]pyrrole meso-substituted Schiff bases were conveniently prepared by fourstep synthetic route. Furthermore, the nickel and copper complexes of calix[4]pyrrolemeso-substituted Schiff base with 1:2 stoichiometry were obtained. The crystal structures of the calix[4]pyrroles and their metal complexes were determined by X-ray diffraction.     

含席夫碱和酰胺单元的新型双杯[4]芳烃的合成

对叔丁基杯[4]芳烃-1,3-二醛基衍生物2与对叔丁基杯[4]-1,3-二酰肼衍生物4在稀释条件下进行“1＋1”分子间缩合反应, 高产率地合成了含席夫碱和酰胺单元的新型双杯[4]芳烃衍生物5. 所有新化合物的结构经元素分析、质谱、核磁共振谱等表征证实, 杯[4]芳烃单元均为1,3-桥联且采取锥式构象.     

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.     

Synthesis, characterization and photochromic studies of three novel calix[4]arene-Schiff bases

Synthesis and characterization of three novel Schiff bases based on calix[4]arene are described. The synthesis of these compounds had been achieved by the condensation of salicylaldehyde derivatives with the amine group of upper rim of de-butylcalix[4]arene in ethanol. The structures of new compounds were confirmed on the basis of IR, (1)H NMR, (13)C NMR, MS and elementary analysis. Photochromic properties of compounds were studied in CH(3)CN by UV/vis and fluorescence spectra. These Schiff base-calix[4]arene can be used in certain 'supermolecular electronic devices' through combining the photochromic behaviors with others such as non-linear optical or charge transfer properties.     

A Bodipy-bearing pillar[5]arene for mimicking photosynthesis: Multi-fluorophoric light harvesting system

Herein, we submitted to the original synthesis, characterization, energy transfer mechanism of the Bodipy-bearing pillar[5]arene Bodipy and its reactants by employing of infrared, ¹H, ¹¹B, ¹³C, ¹⁹F-NMRs, UV–vis, fluorescence spectroscopy, melting point apparatus, CHN elemental analysis and mass spectroscopy. Preliminary UV–vis, fluorescence and excitation measurements were carried out in CH₂Cl₂ and the results revealed an effective fluorescence resonance energy transfer (FRET) system based on the interaction of pillar[5]arene and Bodipy derivative. ε_max of target molecule reached to a maximum value and it was found as 955 000?M^?1?cm^?1. This fluorescent macromolecule worked well for mimicking a light harvesting system with an energy transfer efficiency up to 92%.     

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     

Transition metal complexes of bidentate p-tert-butylcalix[4]arene S-alkyldithiocarbazate Schiff bases

The calix[4]arene-based podand, which incorporates two Schiff-base functions derived from S-alkyldithiocarbazate in 1,3-alternate positions on the lower rim has been prepared and reacted with transition metal ions. X-ray single crystal diffraction of nickel and copper complexes shows that two iminothiolate domains are monoanionic bidentate planar chelators to coordinate one metal in distorted tetrahedral geometry.     

Synthesis of pillar[7]arene

The first synthesis of pillar[7]arene is reported with two methods.Method A:the FeCl₃-catalyzed condensation reaction of 1,4- dimethoxybenzene（1） with paraformaldehyde in CHCl₃ gave dimethoxypillar[7]arene（3）.Method B:the p-toluenesulfonic acid catalyzed condensation reaction of 2,5-bis（benzyloxymethyl）-1,4-dimethoxybenzene（2） in CH₂Cl₂ gave compound 3.Demethylation of 3 with BBr₃ gave pillar[7]arene（4）.The pillar[7]arene might be a perspective macrocyclic host in host-guest chemistry.     

An Interesting Approach to Bis-calix[5]arene Analogue from Calix[6]arene

Calix [n] arenas {n = 4, 6 or 8} are easily prepared from formaldehyde and para-substituted phenols via cyclic condensation under alkaline conditions in one step. It is not surprising that the calyx [n] arene (n = 4, 6, 8) chemistry has been developing very rapidly during the latest 20 years1. However, it is not the case for calixarenes with odd benzene rings (for example, n = 5). The yield of p-tert-butylcalix [5] arene synthesized in one-step from p-tert-butylphenol and formaldehyde was a…     

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.     

四氨基柱[5]芳烃二聚体的合成、结构及性质研究

构象固定的刚性多环主体分子为构筑高级复杂的机械互锁结构提供了重要平台. 为挑战合成刚性多环主体并进一步构筑多层次机械互锁结构, 氧杂杯[4]芳烃桥连的柱[5]芳烃二聚体经过Raney Ni催化氢化还原硝基、与叔丁氧羰基(Boc)-β-丙氨酸缩合和脱去N-Boc保护基三步反应, 生成了四氨基柱[5]芳烃二聚体. X射线单晶衍射实验表明三环目标主体分子具有双桶望远镜形状, 并且构象刚性, 随取代基不同仅有微小变化. 此外, 该四氨基二聚体可作为主体与己二腈形成高稳定性的1∶2络合物. 该研究为制备复杂超分子体系提供了新的机会.     

Synthesis and characterization of a new pillar[5]arene-based [1]rotaxane

In this study, we reported the synthesis of three kinds of mono-functional pillar[5]arene derivatives PRI, PRII and R and their structures were studied by 1D and 2D NMR spectra and mass spectra. The 2D NMR spectra including ¹H-¹³C HSQC, ¹H-¹H COSY and NOESY spectra indicated that PRI and PRII are both stable self-included pseudo[1]rotaxanes in CDCl₃. These original structures are promising compounds for the design of pillar[5]-based [1]rotaxane. And the results showed that R could exist stable in CDCl₃ and DMSO because of the coordination of N-H?O hydrogen bonding interaction and C-H?π interaction.     

Axle length- and solvent-controlled construction of (pseudo)[1]rotaxanes from mono-thiourea-functionalised pillar[5]arene derivatives

A series of thiourea-functionalised pillar[5]arene derivatives 3ⁿm were constructed from a series of mono-amide-functionalised pillar[5]arenes 2ⁿ. The formation of their free forms or (pseudo)[1]rotaxane structures were controlled by their axle lengths or solvents, which were investigated by ¹H NMR spectroscopy. Some of (pseudo)[1]rotaxane structures were also supported by their single-crystal structures.     

Crystal and moleclar structures of 5-allyl-25-methoxy-26,27,28-tribenzoylcalix[4]arene

The crystal and molecular structures of 5-allyl-25-methoxy-26,27,28-tribenzoylcalix[4]arene, an unsymmetrically substituted macrocycle, are reported. The space group is orthorhombic,P2₁2₁2₁, witha=13.4181(6),b=16.6652(10) andc=18.9936(14) Å andZ=4. Refinement by least-squares calculations converged with aR=0.060 for 4018 observed reflections. The molecule assumes a 1,3 alternate conformation with 2 benzoate rings and the disordered allyl side chain on one side and the third benzoate ring and the methoxy group on the opposite side of the mean plane of the methylene bridging groups. The four phenyl rings that comprise the macrocycle are approximately parallel in pairs; the members of a pair are 5.6 Å apart. The carbonyl oxygen atoms of the 3 benzoate groups are oriented away from the center of the cavity while the ester oxygen atoms and the methoxy oxygen atom are oriented toward the cavity center. Supplementary Data relating to this article are deposited with the British Library as Supplementary Publication No. SUP 82033 (26 pages).     

p-tert-Butylcalix[5]arene: a New Synthetic Pathway and Crystal Structure of the N,N-Dimethylformamide Complex

The formation of p-tert-butylcalix[5]arene by the opening ofp-tert-butyldihomooxacalix [4]arene and the addition of a monomer has beenstudied. Various facets, including the effects of bases and the nature ofthe monomer added to the p-tert-butyldihomooxacalix[4]arene, have beeninvestigated. p-tert-Butylcalix[5]arene can be prepared in yields up to30%. The structure of its 1 : 2 complex with DMF has been determinedby X-ray crystallography. Crystals are triclinic, space group P¯1, a =1428.2(3) pm, b = 1837.3(3) pm, c = 1276.1(2) pm, = 108.98(1)°, = 105.02(2)°, = 95.21(1)°, Z = 2, D _c = 1.059 kg m^-3,final R value = 0.087. The macrocycle adopts a cone conformation, one guestenclosed inside the cavity, the other one outside.     

Pillar[5]arene based conjugated macrocycle polymers with unique photocatalytic selectivity

The development of heterogeneous catalysts with substrate shape, size or electronic constitution selectivity is a huge challenge in photocatalysis. Reported herein is a host-guest interaction strategy to endow photocatalysts with special selectivity. By adjusting the precursors, conjugated macrocycle polymers (CMPs) with pillar[5]arene struts (CMP-1 and CMP-2) and a corresponding non-pillar[5]arene-contained conjugated organic polymer (COP-1) were prepared and the photocatalytic activities toward sulfide derivatives were investigated. The sulfides showed similar conversions when COP-1 was used as a photocatalyst, but exhibited significant differences when it turned to the CMPs. Remarkably, the conversion yield of S-1 achieved near 18 folds over the one of S-2 when CMP-2 was used as a catalyst. Mechanism studies confirmed that the “host-guest” effect of pillar[5]arene struts in CMPs was the main cause of the difference. The present work establishes CMPs as novel heterogeneous photocatalysts with substrate selectivity, and such a method will inspire the researchers concerning preparation of heterogeneous catalysts with excellent selectivity.     

A Schiff basep-tent-butylcalix[4]arene. Synthesis and metal ion complexation

This communication describes the synthesis of Schiff base calix[4]arene (1) in which the Schiff base unit bridges two opposite hydroxy groups ofp-tert-butylcalix[4]arene. The synthesis of (1) has been achieved by refluxing in acetonitrile-methanol the appropriate 1,3-dicarbaldehyde-p-tert-butyl-calix[4]arene (4) with 1,3-diaminopropane. The yield of the reaction is 19%. Ligand (1) possesses a compartment containing two nitrogen atoms, four ether-type oxygen atoms, and two ionizable hydroxy groups likely to complex metal cations.