Preparation and reactivity of metal-containing monomers

Vinylporphyrins containing one vinyl group at the pyrrole or benzene ring and their complexes with Cu²⁺ and Zn²⁺ have been obtained by the Wittig reaction. Compounds obtained were characterized by physicochemical methods. X-ray diffraction analysis of 5-(4-vinylphenyl)-10,15,20-triphenylporphyrin has been carried out. It is likely that the inclusion of the vinyl group is accompanied by weak electron effects on the macrocycle. No nonequivalence of N-H bonds is observed in initial macrocycles.     

Studies on the interaction of iron(III) with tetraaza macrocycles

Tetraaza macrocycles and their Fe³⁺ complexes have been prepared and characterized by elemental analysis, i.r., n.m.r., and e.s.–m.s. spectroscopic techniques. The solution behaviour of the macrocycles and their complexes was studied by potentiometric titrations.     

Synthesis of 15‐, 16‐, and 17‐Membered Bis‐C‐Pivot Macrocycles Consisting of N2O2 Donor‐Type Crown Ethers and Dialkyl Phosphonates

Bis‐C‐pivot macrocycles containing aminophosphonate functions ( 5–10 ) have been synthesized and characterized by elemental analysis, FTIR, MS, 1D ¹H, ¹³C and ³¹P NMR, and 2D HETCOR techniques. The phosphorylation reaction of dibenzo‐bis‐imino crown ethers ( 1–4 ) with dimethyl and diethyl phosphite used here has the potential to provide bis‐C‐pivot macrocycles ( 5–10 ), which possess two stereogenic C‐centers giving rise to diastereoisomers (meso and racemic). Detailed spectral assignments for the meso and racemic forms of the compounds are reported on the basis of chemical shifts, signal intensities, spin–spin coupling constants, and splitting patterns. The bis‐C‐pivot macrocycles ( 5–10 ) may serve as a potential new class of supramolecular host molecules.     

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]:     

New one step synthesis of crown compounds containing a 1,3,4‐thiadiazole moiety

New macrocyclic polyether compounds containing a 2,5‐bis(2‐hydroxyphenyl)‐1,3,4‐thiadiazole moiety have been prepared by a nucleophilic substitution reaction involving ethylene or polyethylene glycol ditosylate and a bisphenol, the 2,5‐bis(2‐hydroxyphenyl)‐1,3,4‐thiadiazole, with solid anhydrous carbonate as a base. The structures of the macrocycles obtained were firmly established by ¹H and ¹³C nmr spectroscopy and their mass spectra.     

Synthesis and ring‐opening polymerization of macrocyclic (arylene thioether ketone) oligomers

Macrocyclic (arylene thioether ketone) oligomers together with a linear poly(phenylene sulfide ketone) oligomer were synthesized by a one‐step reaction. The macrocycles and linear oligomer were fully characterized by ¹³C‐NMR, H‐NMR, matrix assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF‐MS), differential scanning calorimetry (DSC) and FT‐IR. Uncatalyzed, simultaneously ring‐opening polymerization (ROP) of the macrocycles and the mixture of macrocycles and linear oligomer were carried out under dynamic heating conditions. The ROP temperature of the macrocycles decreased upon mixing it with the linear oligomer. The ROP conditions and mechanism were investigated and discussed. The macrocycles and their mixture show potential applications in high temperature adhesives and sealants. Copyright © 2006 John Wiley & Sons, Ltd.     

An Original Electrochemical Pathway for the Synthesis of Porphyrin Oligomers

An electrosynthesis process has allowed the formation of four oligomers, containing three, four, or five macrocycles. This method is based on the nucleophilic attack of porphyrins substituted by several pendant pyridyl groups to the electrogenerated radical cation of zinc β‐octaethylporphyrin (ZnOEP), according to an ECEC processes. Thus, a control of the number of macrocycles and of the geometry of the oligomers can be performed. These new compounds have been characterized by HRMS as well as ¹H NMR, UV/Vis, and fluorescence spectroscopy, and electrochemistry. The results show a strong influence of the pyridinium spacers on the macrocycles.     

π‐Conjugated [2]Catenanes Based on Oligothiophenes and Phenanthrolines: Efficient Synthesis and Electronic Properties

Novel π‐conjugated topologies based on oligothiophenes and phenanthroline have been assembled by combining their outstanding electronic and structural benefits with the specific properties of the topological structure. Macrocycles and catenanes are prepared by using an optimized protocol of transition metal‐templated macrocyclization followed by efficient Pd‐catalyzed cross‐coupling reaction steps. By using this method, [2]catenanes comprising two interlocked π‐conjugated macrocycles with different ring sizes have been synthesized. The structures of the [2]catenanes and corresponding macrocycles are confirmed by detailed ¹H NMR spectroscopy and high resolution mass spectrometry. Single crystal X‐ray structural analysis of the quaterthiophene–diyne macrocycle affords important insight into the packing features and intermolecular interaction of the new systems. The fully conjugated interlocked [2]catenanes are fully characterized by spectroscopic and electrochemical measurements.     

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.     

Synthesis,alkali metal picrate extraction,and alkali metal cation binding selectivities of some new cage‐annulated polyoxamacrocyclic crown ethers

Five new cage‐annulated crown ethers, i.e., 4a, 4b, 6b, 11a, and 11b, have been synthesized and their respective alkali metal picrate extraction profiles along with that of a previously synthesized host molecule, 6a, have been obtained. These results are compared with the corresponding results obtained for electrospray ionization mass spectrometric (ESI‐MS) measurements of relative binding selectivities displayed by the same hosts toward a series of alkali metal chlorides. Among the crown‐5 hosts studied, 6a displays enhanced avidity toward complexation with K⁺ picrate in liquid‐liquid extraction experiments. Among the three crown‐6 hosts, 4b proved to be the best alkali metal picrate extractant and displayed significant levels of avidity toward complexation with the larger alkali metal cations (i.e., K⁺, Rb⁺, and Cs⁺). The trends in the picrate extraction and the ESI‐MS results obtained herein show several notable similarities and some differences. The similarities generally stem from size‐selective binding properties that are intrinsic to the different cavity sizes of the cage‐annulated macrocycles, whereas the differences reflect the important influence of solvation effects on the binding properties of the macrocycles.     

Synthesis of new macrocyclic rhodium(III) compounds and their utility as catalysts for the oxidation of ascorbic acid

Ten new macrocyclic Schiff base Rh(III) compounds were synthesized by treating the corresponding macrocycles with rhodium chloride in 1:1 ratio. The resulting compounds were characterized by elemental, IR, ¹H NMR, ¹³C NMR, mass, electronic spectral analysis, and their structures have been proposed. These compounds were utilized as catalysts in the development of an efficient and environmentally friendly catalytic method for the oxidation of ascorbic acid (AA) to dehydroascorbic acid (DHAA). DHAA was determined spectrophotometrically by treating with orthophenylenediamine (OPDA) and the yields were found to be in the range 72–84%. The catalytic oxidation and spectrophotometric determination methods were found to be faster and more accurate than those reported previously.     

Crowned Macrocycles Containing Two Pyrrolo[1,2-a] Indoles Created By Intramolecular Fusion

Heterocyclic fused-ring systems are of utmost importance because of their presence in many natural products with biological activity. Pyrroloindoles are tricyclic heterocycles that are present in various bioactive and medicinally valuable compounds. Herein, we report the synthesis of phenylene-bridged bis-pyrrolo[1,2-a]indole crowned macrocycles 1 – 3 in which the pyrrolo[1,2-a]indole moieties were formed via intramolecular fusion. The macrocycles were thoroughly characterized by 1D and 2D NMR, HRMS and X-ray crystallographic studies. The X-ray structure revealed that the two pyrrolo[1,2-a]indole moieties were parallel to each other, and one pyrrolo[1,2-a]indole unit was deviated by an angle of 9.54° while the other pyrrolo[1,2-a]indole unit was deviated by an angle of 12.0° from the mean plane defined by 28 core atoms. The macrocycles 1 – 3 absorb in the visible region and readily undergo oxidations because of their electron rich nature. The macrocycles 1 – 3 upon treatment with trifluoroacetic acid (TFA) generates the corresponding cation radicals 1 – 3 ^.+ which were stable in the open air for a week. The cation radicals 1 – 3 ^.+ absorb strongly in the NIR region and the experimental observations on crowned macrocycles 1 – 3 were corroborated by DFT and TD-DFT studies.     

Chiral macrocycles,part II: Transport of amino acid Li+ salts

Complexation of amino acids in both their zwitterionic and Li⁺ salt forms by macrocycles, and carrier-mediated transport of the Li⁺ salts through a CH₂Cl₂ membrane have been investigated: the transport study of four amino acids by a new series of tetrapyrazolic macrocycles with functionalized sidearms shows wide variations of the transport rates depending on both the macrocyclic sidearm and the amino acid structure.     

Synthesis and Characterization of a Novel Two‐Dimensional Network Polymer Containing 18‐ and 26‐Membered Organotin Macrocycles

The reaction of 4‐mercaptophenylacetic acid with dimethyltin dichloride in the presence of sodium ethoxide in ethanol affords a novel two‐dimensional organotin network structure compound 1, which is an unusual network containing dinuclear 18‐membered and tetranuclear 26‐membered organotin macrocycles. The compound has been characterized by elemental analysis, IR, and ¹H, ¹³C, and ¹¹⁹Sn NMR spectroscopy. Furthermore, we have also characterized the compound by X‐ray crystallography.     

Synthesis, characterization and crystal structure of a novel 3D network triorganotin(IV) polymer containing two types of macrocycles

A novel triorganotin(IV) complex 1 has been synthesized and structurally characterized by elemental analysis, FT-IR, NMR (¹H, ¹¹⁹Sn) spectra and X-ray crystallography. This complex displays a 3D network structure, which contains two types of chair form macrocycles.     

Intense Molar Circular Dichroism in Fully Conjugated All-Carbon Macrocyclic 1,3-Butadiyne Linked pseudo-meta [2.2]Paracyclophanes**

The synthetic access to macrocyclic molecular topologies with interesting photophysical properties has greatly improved thanks to the successful implementation of organic and inorganic corner units. Based on recent reports, we realized that pseudo-meta [2.2]paracyclophanes (PCPs) might serve as optimal corner units for constructing 3D functional materials, owing to their efficient electronic communication, angled substituents and planar chirality. Herein, we report the synthesis, characterization and optical properties of four novel all-carbon enantiopure macrocycles bearing three to six pseudo-meta PCPs linked by 1,3-butadiyne units. The macrocycles were obtained by a single step from enantiopure, literature-known dialkyne pseudo-meta PCP and were unambiguously identified and characterized by state of the art spectroscopic methods and in part even by x-ray crystallography. By comparing the optical properties to relevant reference compounds, it is shown that the pseudo-meta PCP subunit effectively elongates the conjugated system throughout the macrocyclic backbone, such that already the smallest macrocycle consisting of only three subunits reaches a polymer-like conjugation length. Additionally, it is shown that the chiral pseudo-meta PCPs induce a remarkable chiroptical response in the respective macrocycles, reaching unprecedented high molar circular dichroism values for all-carbon macrocycles of up to 1307 L mol⁻¹ cm⁻¹.     

Pendant-Arm Macrocycles Derived from the Cyclocondensation Reaction of Sodium 2,6-Diformyl-4-substitutedphenolates and Tris-(2-aminoethyl)amine Derivatives. Preparation, Characterization and Properties of their Dinuclear Copper(II) Complexes

A series of pendant-arm Schiff base macrocycles have been obtained via the cyclocondensation reaction between sodium 2,6-diformyl-4-substitutedphenolates and tris-(2-aminoethyl)- amine derivatives followed by transmetallation with Cu(ClO₄)₂·6H₂O. The resulting dinuclear copper(II) complexes have been characterized by elemental analysis, infrared and mass spectra as well as magnetic moments at room temperature. All complexes have been electrochemically investigated, and two typical compounds have been studied with ESR spectra as well.     

Tétraazamacrocycles greffés sur polymère,synthèse et propriétés complexantes

A new macrocyclic exchanger has been prepared and characterized by anchoring to chloromethylated polystyrene, 1,4,8,11-tetraazacyclotetradecane (cyclam). The influences of temperature, molar ratio of cyclam to chlorine or sodium hydride and time of reaction on the properties of the resin (mainly the number of NC bonds), the porosity and the ion-binding ability have been investigated. The synthesis has been extended to two other macrocycles viz. 1,5,9,13-tetraazacyclohexadecane and 1,5,10,14-tetraazacyclo-octadecane. The parameters involved in the extraction of Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺ and Pb²⁺ by these resins have been studied.     

Double Cycloadditive Macrocyclization: An Efficient Method for Cyclophane

A series of macrocycles containing isoxazoline and [1,4,2]dioxazole were synthesized for the first time. The structures of the newly synthesized macrocycles were characterized and confirmed by IR, ¹H NMR, mass spectra, and elemental analysis. The solid‐state structure of macrocycle ( 6d ) was further studied by single‐crystal X‐ray diffraction analysis.     

Encapsulation of Pd(II) by N4 and N2O2 macrocyclic ligands: their use in catalysis and biology

New macrocyclic Schiff base Pd(II) compounds were synthesized by treating N₄ and N₂O₂ macrocycles with palladium chloride in a 1 : 1 ratio. The resulting macrocyclic compounds were characterized by elemental, IR, ¹H-NMR, ¹³C-NMR, mass, molar conductance, magnetic susceptibility, electronic spectra, and thermal analysis. These compounds were used as catalysts in the development of an efficient catalytic method for reduction of organic substrates having nitro, olefinic, acetylenic, and aldehyde groups under mild reaction conditions. The biological activities of all the macrocycles and macrocyclic Pd(II) compounds have been tested against gram positive (Bacillus subtilis and Staphylococcus aureus) and gram negative (Escherichia coli and Klebsiella pneumonia) bacteria and found to be more active than commercially available antibacterial drugs like Streptomycin and Ampicillin.