Ewa Wagner-Wysiecka

Pyrrole Azocrown Ethers. Synthesis, Complexation, Selective Lead Transport and Ion-Selective Membrane Electrode Studies

New 21-membered lipophilic crown ethers, each incorporating a pyrrole unit and two azo groups as macrocyclic ring components, have been synthesized. The complexation behavior of these and two further macrocycles has been investigated in acetonitrile. These ligand systems have been employed as ionophores in transport experiments involving the competitive transport behavior of an equimolar mixture of Co2 + , Ni2 + , Cu2 + , Zn2 + , Cd2 + , Ag+ and Pb2 + across a water (pH 4.9)/chloroform/water (pH 3) bulk membrane system. In each case transport selectivity for lead(II) was obtained. The macrocycles have been incorporated in solvent polymeric membrane electrodes and their behavior towards a selection of metal ions, including those mentioned above, is reported.

Anion recognition by α-arylazo-N-confused calix[4]pyrroles

The first example of substitution reaction in the free α-position of N-confused calix[4]pyrroles is reported: azo-coupling with various arenediazonium salts. The obtained azocompounds were used for studies of their anion-binding properties by UV-Vis spectroscopy.

Chromogenic azocrown ethers with peripheral alkyl, alkoxy, hydroxy or dimethylamino group

Abstract New derivatives of azobenzene crown ethers have been obtained. They include compounds with alkyl, alkoxy, hydroxy or dimethylamino group in aromatic residue(s) as side substituents. Their chromoionophoric properties and properties in ion-selective membrane electrodes have been studied. Structures of two azocrown ethers with peripheral hydroxy group in benzene ring were confirmed by X-ray analysis. Effect of metal ion complexation by hydroxyazobenzocrown ethers on hydroxyazo-quinone hydrazone tautomerism was studied.

Chromoionophores with Chromophores as Integral Part(s) of the Macrocycle in Crown Ethers

Several new types of ionizable chromoionophores have been synthesized. Their reactions with metal cations have been studied by spectroscopic methods. Preferential complexation of lithium ions was found for many of these reagents.

Azo group(s) in selected macrocyclic compounds

Azobenzene derivatives due to their photo- and electroactive properties are an important group of compounds finding applications in diverse fields. Due to the possibility of controlling the trans–cis isomerization, azo-bearing structures are ideal building blocks for development of e.g. nanomaterials, smart polymers, molecular containers, photoswitches, and sensors. Important role play also macrocyclic compounds well known for their interesting binding properties. In this article selected macrocyclic compounds bearing azo group(s) are comprehensively described. Here, the relationship between compounds’ structure and their properties (as e.g. ability to guest complexation, supramolecular structure formation, switching and motion) is reviewed.

Naphthyl- vs. anthrylpyridine-2,6-dicarboxamides in cation binding studies. Synthesis and spectroscopic properties

Abstract Pyridine-2,6-carboxamides bearing α- or β-naphthyl- and α- or β-anthryl residues were prepared using simple method from pyridine-2,6-carboxylic acid dichloride and the respective aromatic amines. For the obtained receptors, selective binding of lead(II) and copper(II) was found. Ion–receptor interactions were studied using UV–vis spectroscopy, spectrofluorimetry, 1H NMR and FTIR spectroscopy. The reversible lead(II) and copper(II) binding was discussed in regard of type of aromatic residue and amide bond localisation in aromatic ring, and binding model was proposed.

Mid-infrared spectroscopy for characterization of Baltic amber (succinite)

Natural Baltic amber (succinite) is the most appreciated fossil resin of the rich cultural traditions dating back to prehistoric times. Its unequivocal identification is extremely important in many branches of science and trades including archeology, paleontology, chemistry and finally mineralogical and gemological societies. Current methods of modification of natural succinite are more and more sophisticated making the identification of natural Baltic amber often challenging. In article the systematic analytical approach for identification of natural and modified under different conditions succinite, using mid-infrared spectroscopy (transmission, Drifts and ATR techniques) is presented. The correlation between spectral characteristics and properties of succinite is discussed pointing that the understanding of the nature of changes is the key of identification of this precious material.

Correction to: Azo group(s) in selected macrocyclic compounds

In the original publication of the article, a part of the scheme 12 was missed. The correct version of the scheme 12 was provided in this correction article. The original article has also been corrected.

A chemical recognition element for lithium ions based on optical electronic absorption

Xerogel samples with entrapped series of four optical absorption chemosensors were prepared by sol-gel process. These materials are proposed as chemical recognition elements of an optical chemical sensor. The roles of the chemosensors play proton-dissociable chromogenic azocrown ethers bearing phenol and two azo groups as parts of macrocycles. Occurrence of the alkali ion—receptor interaction is signalled by the chemosensors changing their electronic absorption spectra. By this way chemosensor 4O-CH3 is able to distinguish Li+ ions from other alkali metal ions present in aqueous solution, if the chemosensor is entrapped in Glymo-silica (1:1) xerogel matrix. The proposed recognition element for Li+ has been exposed to the cycles chemisorption—desorption many times. Besides DRIFT spectra of the used xerogel matrices were analyzed.