带内取向柔性多醚链苯炔大环合成

采用分子间Glaser半环闭环法合成了带内取向柔性多醚链的苯炔大环.用1H NMR,13C NMR,HRMS,UV及PL(photduminescence)确证了目标大环结构,凝胶色谱测定了目标大环纯度.经偏光显微镜(POM)和差热分析仪(DSC)测试表明大环没有呈现预期的液晶性质,可能是由于环内柔性链过于拥挤,不能形成与环平面共面结构,以至于难于进行有序堆积的缘故.     

A modular "toolbox" approach to flexible branched multimacrocyclic hosts as precursors for multiply interlocked architectures

Tetralactam macrocycles can be functionalized by a variety of cross-coupling reactions. A modular "toolbox" strategy is presented that allows 1) several tetralactam macrocycles to be covalently connected with each other or with a central spacer, 2) the macrocycles to be substituted with or connected to different chromophores, and 3) metal-coordination sites to be attached to the macrocycles. With this approach a series of different oligo-macrocyclic hosts was obtained with great structural diversity and enormous potential for further functionalization. Rotaxanes made on the basis of these macrocycles have been synthesized to demonstrate their utility in building more complex supramolecular architectures.     

Conjugated macrocycles: concepts and applications

One of the most important objectives in materials, chemical, and physical sciences is the creation of large conjugated macrocycles with well-defined shapes, since such molecules are not only theoretically and experimentally interesting but also have potential applications in nanotechnology. Fully unsaturated macrocycles are regarded as models for infinitely conjugated π systems with inner cavities, and exhibit unusual optical and magnetic behavior. Macrocycles have interior and exterior sites, and site-specific substitution at both or either site can afford attractive structures, such as 1D, 2D, and 3D supramolecular nanostructures. These nanostructures could be controlled through the use of π-extended large macrocycles by a bottom-up strategy. Numerous shape-persistent π-conjugated macrocycles have been synthesized, but only a few are on the nanoscale. This Review focuses on nanosized π-conjugated macrocycles (>1 nm diameter) and giant macrocycles (>2 nm diameter), and summarizes their syntheses and properties.     

Parallel synthesis of peptide-like macrocycles containing imidazole-4,5-dicarboxylic acid

We prepared a series of peptide-like 14-membered macrocycles containing an imidazole-4,5-dicarboxylic acid scaffold by using known coupling reagents and protecting group strategies. Yields of the purified macrocycles were poor on average, yet seemingly independent of amino acid substitution or stereochemistry. The macrocycles retain some level of conformational variability as observed by both molecular modeling and X-ray crystallography. These macrocycles represent a new class of structures for further development and for future application in high-throughput screening against a variety of biological targets.     

Stable silica gel-bound crown ethers. Selective separation of metal ions and a potential for separations of amine enantiomers

Silica gel-bound crown ethers and aza macrocycles have been synthesized with the attaching arm connected to the carbon framework of the macrocycles. The interactions of these bound macrocycles with cations are almost identical to those involving the analogous free macrocycles. This has allowed for predictable cation separation, concentration, and removal processes to be performed on a small scale. Quantum mechanical calculations and NMR measurements indicate that similarly bound chiral macrocycles will be capable of use in separating chiral organic amines.Dedicated to the memory of Professor James J. Christensen who died on 5 September 1987.     

Synthesis of nitrogen and sulfur macrocycles with cis exogenous oxygen and sulfur donor atoms

A series of new N4 and N8 macrocycles has been prepared, that includes cis-exogenous O2, S2 and S/O atoms to allow chelation to a metal external to the macrocyclic ring. We found that thioamide units within the macrocycles were unstable to attack by secondary amines and thus alkylated precursors containing only tertiary amines could lead to exogenous-S2 macrocycles. Cyclisation of alkylated tetraamine precursors with dimethyloxalate or dithiooxamide led to both N4 and N8 macrocycles via 1 + 1 and 2 + 2 cyclisation reactions with exogenous-O2 or S2 respectively. Alkylation of preformed exogenous-O2 macrocycles was explored and led to alkyl substitution at the secondary amine nitrogens in the ring, however synthesis of these species was overall lower yielding than cyclisation using alkylated tetraamine precursors. Thionation of an exo-O2 macrocycle using an analogue of Lawesson's Reagent led to formation of the analogous exogenous-S2 and exogenous-O,S macrocycles. Related S2N2 macrocycles with exogenous-O2 were prepared by a cyclisation route but could not be isolated free of larger ring analogues.     

芳炔类共轭大环化合物

芳炔类大环化合物是最近10年来新兴的一种富碳共轭大环状分子，迅速发展到 近100种，可在光、电、磁、纳米等功能材料中得到广泛应用，引起了人们极大的 兴趣，对芳炔类大环化合物的研究，特别是合成方法和性质进行了综述，并提出了 这一领域的发展方向和需要解决的重点课题。     

pi-Conjugated macrocycles from thiophenes and benzenes

pi-Conjugated macrocycles consisting of thiophenes and benzenes exhibit benzenoid features for 4npi macrocycles, whereas (4n + 2)pi macrocycles are annulenoid due to rapid interconversion between quinoid and Kekule canonical forms in the benzene units.     

A Supramolecular Strategy for the Synthesis of Cyclic Oligomers and Polymers by Ring Expansion

Ring-opening metathesis polymerization (ROMP) of strained macrocycles is a key method to prepare diverse polymers. However, lack of ring strain in most macrocycles is an impediment to polymerization. In this paper, the polymerization/oligomerization of unstrained macrocycles was achieved using a supramolecular approach, leading selectively to cyclic products. Diphenyl thiourea and other guest molecules were used as additives to the ROMP reaction of unstrained macrocycles. An intermediate host-guest complex leads to the stabilization of the open form of the macrocycle after treatment with Grubbs catalysts, thereby favoring polymerization by inhibiting the ring-closing reaction back to the monomer. This proof-of-concept enables ring-expansion polymerization of unstrained macrocycles leading to cyclic polymers with molecular weights up to 6700 Da.     

Highly substituted Schiff base macrocycles via hexasubstituted benzene: a convenient double Duff formylation of catechol derivatives

The synthesis of soluble, shape-persistent macrocycles is important for developing new materials. Double Duff formylation of 4,5-dialkylcatechol derivatives yields 3,6-diformyl-4,5-dialkylcatechols in moderate yields. These hexasubstituted aromatics are useful precursors to highly substituted Schiff base macrocycles. We illustrate convenient routes to these compounds as well as structural studies of two new macrocycles with alkyl substituents.     

Synthesis of nano-scale shape-persistent macrocycles via hydrogen bonding-promoted formation of amide and hydrazone bonds

This paper describes the synthesis of two series of rigid macrocycles from hydrogen bonding-induced folded aryl amide and hydrazone oligomers that bear two amines or one amine and one aldehyde. The diamines reacted with diacyl chloride to produce amide macrocycles, whereas the latter underwent self-coupling reactions to afford imine macrocycles. DFT calculations revealed that the new macrocycles possess rigid planar conformations and their cavity diameters were estimated to be 1.86 nm–2.75 nm.     

Metal induced folding: synthesis and conformational analysis of the lanthanide complexes of two 44-membered hydrazone macrocycles

Six new lanthanide complexes of two 44-membered macrocycles have been prepared and characterised in solution. An analysis of the conformations of the free macrocycles and their lanthanide complexes both in solution (2D NMR) and in solid state (X-ray crystallography) demonstrate that the complexation induces changes in folding of the macrocycles.     

Synthesis, structure, and computational studies of soluble conjugated multidentate macrocycles

[Chemical reaction: See text] Conjugated, shape-persistent macrocycles based on [3 + 3] Schiff-base condensation are of interest for supramolecular materials. In an effort to develop new discotic liquid crystals based on these compounds, a series of macrocycles with peripheral alkoxy groups of varying length have been prepared. The synthesis and mechanism of formation have been probed by isolation of oligomeric intermediates. A single-crystal X-ray diffraction study of one macrocycle revealed a nonplanar, strongly hydrogen-bonded structure. To our surprise, even with very long substituents, the macrocycles were not liquid crystalline. This has been rationalized by ab initio calculations that indicate the macrocycles are undergoing rotation of the dihydroxydiiminobenzene rings that may not allow a stable discotic liquid crystalline phase. These results provide new insight into the formation and properties of these large macrocycles and may provide guidance to developing stable liquid crystalline materials in the future.     

Hydrogen-bonded aryl amide macrocycles: synthesis, single-crystal structures, and stacking interactions with fullerenes and coronene

Six hydrogen-bonded shape-persistent aryl amide macrocycles have been prepared by using one-step and (for some) step-by-step approaches. From the one-step reactions, 3 + 3, 2 + 2, or even 1 + 1 macrocycles were obtained in modest to good yields. The reaction selectivity was highly dependent on the structures of the precursors. The X-ray structural analysis of two methoxyl-bearing macrocycles revealed intramolecular hydrogen bonding and weak intermolecular stacking interaction; no column-styled stacking structures were observed. The 1H (DOSY) NMR, UV-vis, and fluorescent experiments indicated that the new rigidified macrocycles complex fullerenes or coronene in chloroform through intermolecular pi-stacking interaction. The association constants of the corresponding 1:1 complexes have been determined if the stacking was able to cause important fluorescent quenching of the macrocycles or coronene.     

New 2+2, 3+3 and 4+4 macrocycles derived from 1,2-diaminocyclohexane and 2,6-diformylpyridine

Two new Schiff base macrocycles - a 4+4 condensation product and a meso-type 2+2 condensation product - were obtained in a reaction of trans-1,2-diaminocyclohexane and 2,6-diformylpyridine. Reduction of these compounds led to the corresponding 4+4 and 2+2 macrocyclic amines. The macrocycles were characterised by NMR spectroscopy and electrospray mass spectrometry. The symmetry and stereochemistry of these macrocycles, as well as of new 3+3 and 4+4 diastereomers identified in solution, has been established. X-Ray structures of the 2+2 and 4+4 Schiff base macrocycles confirm the configurations determined on the basis of spectroscopic investigations. The crystal structures reveal that the centres of the square-shaped 4+4 macrocycles form channels as a result of columnar stacking.     

Efficient proton-templated synthesis of 18- to 38-membered tetraimino(amino)diphenol macrocyclic ligands: structural features and spectroscopic properties

A whole range of Robson-type tetraiminodiphenol macrocyclic ligands have been prepared as their perchlorate salts [H4L](ClO4)2 in high yield (ca. 90%) by a single-step [2 + 2] condensation reaction between 4-methyl(or tert-butyl)-2,6-diformyl(or diacyl)phenols and alpha,omega-diaminoalkanes (C2-C12) in the presence of acetic acid and NaClO4. The reduction of these 18- to 38-membered macrocyclic salts with NaBH4 have afforded corresponding tetraaminodiphenol macrocycles H2L'. The X-ray crystal structures of two of the tetraiminodiphenol macrocycles with the C2 and C4 lateral chains have been determined, and the optimized configurations for all of the macrocycles have been obtained by molecular mechanics calculations. The macrocycles have been characterized by elemental analysis and by IR, absorption, emission, and NMR spectroscopic study. The protonated tetraiminodiphenol macrocycles exhibit strong fluoroscence in methanol, acetonitrile, and nitromethane and undergo quenching when treated with triethylamine. The neutral macrocycles H2L, isolated by treating [H4L](ClO4)2 with excess of triethylamine, lack luminescence, as do the reduced tetraaminodiphenol macrocycles H2L'. The hydrolytic cleavage of [H4L](ClO4)2 has been studied.     

Cationic shape-persistent macrocycles: the unexpected formation of a nano-size supramolecular dimer

Shape-persistent macrocycles with a rigid pyridyl core and a flexible oligo-alkyl corona aggregate to some extent in nonpolar solvents to form large (tubular) aggregates. To increase the assembling tendency, the intraannular pyridyl groups of the macrocycles were alkylated. Unexpectedly, the quarternized macrocycles show no tendency at all to form tubular micellar-like structures but form well-defined dimers, as determined by X-ray and dynamic light scattering.     

Mass spectrometric study of oligourea macrocycles and their anion binding behavior

Two series, one of tris‐urea macrocycles and another of hexakis‐urea macrocycles, are examined by (tandem) Fourier‐transform ion cyclotron resonance (FTICR) mass spectrometry with respect to their fragmentation patterns and anion binding properties. All macrocycles are based on two different building blocks, one of which is a very rigid xanthene unit and the other one is a more flexible diphenyl ether. The composition and the sequence of these units thus determine their flexibility. During the fragmentation of deprotonated oligourea macrocycles in the gas phase, one urea N? CO bond is cleaved followed by a scrambling reaction within the macrocycle structure. Consequently, fragments are observed that deviate from those that would be expected from the sequence of the subunits. Interesting anion binding properties involve the simultaneous recognition of two chloride anions by one of the hexakis‐urea macrocycles, whose flexibility allows this host to form a double‐helical structure. Flexibility also determines which of the hexameric receptors bears a high sulfate affinity. The interaction energy between some of the macrocycles and sulfate is high enough to even stabilize the intrinsically unstable sulfate dianion. Copyright © 2009 John Wiley & Sons, Ltd.     

Liquid crystalline order from ortho-phenylene ethynylene macrocycles

Triangular ortho-phenylene ethynylene (o-PE) cyclic trimers represent a novel member of shape-persistent macrocycles. Shape-persistent cyclic structures remain of great interest as molecular components in the fields of supramolecular materials, host-guest chemistry, and materials science. Novel discotic liquid crystalline properties are reported from triangular-shaped o-PE macrocycles containing branched alkoxy- and/or triethylene glycol (TEG) side chains using polarized optical microscopy (POM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). The macrocycles self-assemble into thermotropic rectangular columnar (Colr) (for M1), hexagonal columnar (Colh) (for M2), and discotic nematic (for M3) mesophases at room temperature. This work shows clearly that electron-rich PE macrocycles can form LC materials. Alkyl side chains in M1 promote order, while hydrophilic side chains of M2 generate an amphiphilic structure that provides a different driving force for organization. The ability to create ordered self-assembling materials from these novel electron-rich macrocycles is important in nanotechnology.     

Hydrogen bond-assisted macrocyclic oligocholate transporters in lipid membranes

Three macrocyclic oligocholates containing a carboxyl group, a guanidinium ion, and a Cbz-protected amine, respectively, were studied as membrane transporters for hydrophilic molecules. To permeate glucose across lipid bilayers, the macrocycles stacked over one another to form a transmembrane nanopore, driven by a strong tendency of the water molecules in the internal cavities of the amphiphilic macrocycles to aggregate in a nonpolar environment. To transport larger guests such as carboxyfluorescein (CF), the macrocycles acted as carriers to shuttle the guest across the membrane. Hydrogen-bonds between the side chains of the macrocycles strongly affected the transport properties. Surprisingly, the carboxyl group turned out to be far more effective at assisting the aggregation of the oligocholate macrocycles in the membrane than the much stronger carboxylate-guanidinium salt bridge, likely due to competition from the phosphate groups of the lipids for the guanidinium.