Synthesis, Structure, and Reactivity of Enediyne Macrocycles

The reaction of bis-propargyl bromide enediyne 4 with weakly basic nucleophiles allows the facile synthesis of acyclic and macrocyclic enediynes. Depending on the bis-nucleophile employed, 12- to 16-membered enediyne macrocycles were obtained. The thermal stability of the new cyclic enediynes was investigated by differential scanning calorimetry. Upon coordination of the macrocycle 5c with Hg(O(2)CCF(3))(2), a drop of the enediyne cyclization temperature of nearly 100 K was observed.     

苯炔体系大环合成、自组装及其应用

含苯炔结构的大环(aryleneethynylenemacrocycle,AEMs)体系具有独特的性质和潜在的应用前景,在过去的数年中被广泛研究和探索。本文系统地介绍了AEMs的合成方法,包括不同关环方法、固相合成、模板合成和聚集驱动关环法等。在研究AEMs性质方面,重点介绍了它们的自组装性能。同时也介绍了AEMs在构造三维纳米结构、液晶、管状通道、主客体复合物等超分子化学领域的应用。     

Heterocyclic π-Donors,Macrocycles and Cage Molecules

Abstract

π-Donors based on TIT-units have been intensively studied due to their potential use in conducting molecular materials. It therefore appeared of interest to use the readily avaible dithiolate (1) for the syntheses of macrocycles, exemplified by (3) and (4) and the lTF-cage molecules (5) - (7) obtained by intramolecular coupling^[1]:     

苯炔体系大环合成、自组装及其应用

含苯炔结构的大环（arylene ethynylene macrocycle,AEMs）系具有独特的性质和潜在的应用前景,在过去的数年中被广泛研究和探索。本文系统地介绍了AEMs的合成方法,包括不同关环方法、固相合成、模板合成和聚集驱动关环法等。在研究AEMs性质方面,重点介绍了它们的自组装性能。同时也介绍了AEMs在构造三维纳米结构、液晶、管状通道、主客体复合物等超分子化学领域的应用。     

Macrocycles, catenanes, oligomers and polymers in gold chemistry

A critical review is given of the chemistry of macrocycles, catenanes, oligomers and polymers in gold chemistry. Because gold centres are typically labile towards ligand substitution, there may be an easy equilibrium between the cyclic and linear oligomeric or polymeric forms and the preferred products of self-assembly are usually determined by thermodynamic control. The ways in which the self-assembly of complex structures from simple building blocks by dynamic coordination chemistry can be manipulated by ligand design or by the use of secondary bonding forces is emphasized (39 references).     

大环化合物(macrocycles)酶模型

对大环化合物的结构特点及催化作用进行了综述。     

Macrocycles from perhalogenated heterocycles

Perhalogenated heteroaromatic systems, such as trichloro-s-triazine and pentafluoropyridine, are multifunctional "building blocks" that react with a number of appropriate difunctional nucleophiles to provide access to a variety of macrocyclic and even cage-like molecular architectures. Unusual structural and complexation characteristics of the systems reported so far, such as the recognition of anions, provide a further stimulus for the development of this area.     

Calixarenes,Macrocycles with (Almost) Unlimited Possibilities

The condensation reaction between p-tert-butylphenol and formaldehyde leads in a single step to good yields of cyclic oligomers in which, depending on the reaction conditions, either four, six, or eight phenol units are joined by methylene bridges. The beakerlike shape of the most stable conformation of the tetramer has led to their being given the name “calixarenes” (calix = chalice). Resorcinol can undergo condensation in a similar manner with a variety of aldehydes to afford cyclic tetramers with the same basic structure (the resorcarenes). In both cases the reaction does not require the use of dilution techniques, so that large quantities of product can be readily obtained. In addition, the parent compounds can be modified in various ways, in particular at the phenolic hydroxy groups or the phenyl residues; these approaches can be used separately or in combination. Calixarenes are thus ideal starting materials for the synthesis of various types of host molecules and can also act as building blocks for the construction of larger molecular systems with defined structures and functions. Their potential applications range from use as highly specific ligands for analytical chemistry, sensor techniques and medical diagnostics to their use in the decontamination of waste water and the construction of artificial enzymes and the synthesis of new materials for non-linear optics or for ultrathin layers and sieve membranes with molecular pores.     

Macrocycles from pentafluoropyridine and tetrafluoropyrimidine

Macrocycles were synthesised by sequential nucleophilic aromatic substitution processes involving pentafluoropyridine and tetrafluoropyrimidine and various diamines as the structural components.     

Macrocycles containing azo groups: recognition,assembly and application

In this review the authors present an overview of different molecular modeling campaigns dealing with the study and characterization of cyclodextrins (CDs) inclusion complexes with applicability to diverse biomedical and technological domains. The aim of this review is to present in a concise manner the new tendencies towards CDs molecular modeling studies in the context of a scientific computing era characterized by detailed and exhaustively validated molecular modeling protocols combined with and enormous and continuously growing computing power. Therefore, the present review covers research efforts reported in the last 5 years, including the simulation of native and modified CDs in a new and more detailed manner than what was possible in the past as well as their inclusion complexes with bioactive molecules studied by detailed protocols and exhaustive free-energy of binding calculations. Also, particular emphasis is devoted to the molecular modeling simulation of CDs included as part of drug delivery matrixes and intelligent nanodevices such as CD-based molecular motors.     

Gold-catalyzed Synthesis of Pyridine Containing Macrocycles, Related to Porphyrin

Porphyrins are very important substances used in a wide range of model systems in many areas, such as biomimic chemistry and material science. This kind of macrocycle generally consists of 5-membered ring to form a cyclic extended aromatic network. Recently much work have been done concerning the modification of porphyrins core structures, and many kinds of analogues have been recorded. One of the important aspects was the research of the porphyrinogen ligand.These macrocycles bear functional resemblance to certain kind of polydentate ligand, and provide a variety of tri-dimensional binding cavities for metal ions. In addition, some other kinds of analogues have been recorded, involving the introduction of a CH unit to replace one of the nitrogen atoms. We also notice the fact that pyridine is a very effective ligand, and it can coordinate with many kinds of metals. Based on these observations, we would like to design and synthesize a new porphyrinogen (5) analogue containing a NNNN core, two of the N atoms from pyrrole and the other two N from pyridine. Such core modifications may alter the electronic structure of the ring and provide variable cavity for metal coordination.     

"Swollen" Macrocycles: Palladium(II)-Directed Template Syntheses of Pendant-Arm 14-, 16-, and 18-Membered Macrocycles

The bis(diamine)palladium(II) cations (diamine = ethane-1,2-diamine, propane-1,3-diamine, or butane-1,4-diamine) all undergo condensation reactions with formaldehyde and nitroethane to produce macromonocycles where each pair of cis-disposed primary amines has been converted to a -NH-CH(2)-C(CH(3))(NO(2))-CH(2)-NH- strap. The 14-membered-ring macrocycle has been previously prepared by condensation around copper(II) and nickel(II), but this does not permit synthesis of the larger ring macrocycles. The macrocyclic complex (6,13-dimethyl-6, 13-dinitro-1,4,8,11-tetraazacyclotetradecane)palladium(II) perchlorate crystallizes in the triclinic space group P&onemacr;, a = 8.105(3) ?, b = 8.370(2) ?, c = 9.437(4) ?, alpha = 69.04(3) degrees, beta = 68.60(3), gamma = 71.53(3) degrees. Complexes of the 16- and 18-membered macrocycles (3,11-dimethyl-3,11-dinitro-1,5,9,13-tetraazacyclohexadecane)palladium(II) perchlorate and (3,12-dimethyl-3,12-dinitro-1,5,10,14-tetraaazacyclooctadecane)palladium(II) perchlorate crystallize in the monoclinic space group P2(1)/c, with a = 8.391(2) ?, b = 12.816(3) ?, c = 23.925(9) ?, and beta = 93.18(2) degrees, and the triclinic space group P&onemacr;, with a = 7.746(5) ?, b = 9.912(5) ?, c = 18.96(2) ?, alpha = 91.76(6) degrees, beta = 101.73(7) degrees, and gamma = 112.83(5) degrees respectively. The larger macrocycles are "swollen" by incorporating longer methylene chains, "swelling" leading to an increase in Pd-N distance and in tetrahedral distortion, with the dominant geometric isomer apparently changing with macrocycle size from anti-disposed nitro pendants (14-membered) to the syn isomer (16-, 18-membered). An irreversible Pd(II/IV) oxidation occurs at ca +1 V (vs Ag/AgCl), varying slightly with ring size, with a multi-electron nitro group reduction observed near -0.8 V in each case. Electronic spectra also vary slightly with ring size.     

Macrocycles and cavitands containing phosphorus

Macrocycles and cavitands containing phosphorus represent two interesting and promising classes with special properties and applications as catalysts or in biology. In this paper we tried to review the progress in synthesis of macrocycles and cavitands containing phosphorus.     

Binding of AMP,ADP, and ATP Nucleotides by Polyammonium Macrocycles

The macrocyclic polyamines 4 – 6 , when protonated, bind strongly and selectively nucleotides (AMP, ADP, ATP) and pyrophosphate in aqueous solution. The stoichiometry of the complexes formed was determined by titration experiments followed by ³¹ P-NMR spectroscopy. Compounds 4 and 5 form 1:1 complexes with ATP, ADP, and pyrophosphate, whereas 6 forms complexes with ATP and ADP involving 2 nucleotides and 1 receptor molecule. The stability constants of these complexes have been determined by pH-metric measurements. At pH 7, both 5 and 6 give complexes of mainly the fully protonated species 5 . 6H ⁺ and 6 . 8H ⁺, whereas 4 yields predominantly complexes of 4 . 5H ⁺ and 4 . 4H ⁺.