Fluorescence of p-hydroxyazobenzocrowns - Tautomeric equilibrium effect.

The spectroscopic properties of a series of para-hydroxyazobenzocrowns, including three novel compounds, were investigated using UV-Vis absorption and emission spectroscopy. This study presents, for the first time, determined quantum yield (QY) values for macrocycles of this category, ranging between 0.122 and 0.

Do Phenyl Substituents Affect the Properties of Azobenzocrown Derivatives?

New products of photo- and thermal rearrangements of 19-membered azoxybenzocrown with phenyl substituents in benzene rings in the para positions to oligooxyethylene fragments are characterized in this work. The yields of photochemical transformations depend on the solvent. Para-hydroxyazocrown is formed with yields over 50 % in propan-2-ol.

Simple colorimetric copper(II) sensor - Spectral characterization and possible applications.

New o-hydroxyazocompound L bearing pyrrole residue was obtained in the simple synthetic protocol. The structure of L was confirmed and analyzed by X-ray diffraction. It was found that new chemosensor can be successfully used as copper(II) selective spectrophotometric regent in solution and can be also applied for the preparation of sensing materials generating selective color signal upon interaction with copper(II).

Products of Photo- and Thermochemical Rearrangement of 19-Membered di--Butyl-Azoxybenzocrown.

The preparation and characterization of products of the photochemical and thermochemical rearrangements of 19-membered azoxybenzocrowns with two, bulky, -butyl substituents in benzene rings in the positions to oligooxyethylene fragments ( positions to azoxy group, i.e., have been presented.

Novel Diazocrowns with Pyrrole Residue as Lead(II)Colorimetric Probes.

Novel 18- and 23-membered diazomacrocycles were obtained with satisfactory yields by diazocoupling of aromatic diamines with pyrrole in reactions carried under high dilution conditions. X-ray structure of macrocycle bearing five carbon atoms linkage was determined and described. Compounds were characterized as chromogenic heavy metal ions receptors.

Photochemical Rearrangement of a 19-Membered Azoxybenzocrown: Products and their Properties.

The preparation and characterization of products of the chemical and photochemical rearrangements of a 19-membered o,o'-azoxybenzocrown are presented. In photochemical rearrangement, besides the expected product i. e.

Iron(iii)-selective materials based on a catechol-bearing amide for optical sensing.

The synthesis and ion-binding properties of a new amide L derived from 3,4-dihydroxybenzoic acid are described. Due to the presence of a catechol unit, the compound interacts selectively with iron(iii) in organic solvent (dimethyl sulfoxide, DMSO) to produce a color change from pale yellow to green. The incorporation of the ligand L into polymeric matrices or its encapsulation into surfactant-based spheres enables analyte detection in aqueous solutions.

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 isomerization, azo-bearing structures are ideal building blocks for development of e.g.

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.

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

[This corrects the article DOI: 10.1007/s10847-017-0779-4.].

Anion binding by p-aminoazobenzene-derived aromatic amides: spectroscopic and electrochemical studies.

The synthesis and complexing properties of p-aminoazobenzene-derived mono-, bis-, and trisamides were described. Ligands 3 and 4 bind anions, including fluorides, chlorides, bromides, acetates, benzoates, dihydrogen phosphates, hydrogen sulfates, and p-toluenesulfonates, in chloroform forming 1 : 1 complexes. The highest value of stability constant was evaluated for the 4-F complex (log K = 5.

Synthesis of thiol derivatives of azobenzocrown ethers. The preliminary studies on recognition of alkali metal ions by gold nanoparticles functionalized with azobenzocrown and lipoic acid.

The article presents the synthesis of novel 13- and 16-membered azobenzocrown derivatives with peripheral thiol moieties and preliminary studies assessing their possible application in plasmonic sensors based on gold nanoparticles. The effect of the length of the chain connecting the macrocycle with the thiol group and the effect of the presence of the additional functional compound, i.e.

pH-tunable equilibria in azocrown ethers with histidine moieties.

The crown ethers with electro- and photoactive azo moieties containing substituents with mobile protons such as in the -COOH groups of histidine, show unique effect of pH switched on/off presence of the azo form. The differences observed for the electrochemical behavior of azocrown ethers with N-acetylhistidine and imidazole moieties reveal the interference of a chemical reduction pathway in strongly acidified solutions. This chemical reduction process leads to the formation of a hydrazine derivative which can be detected by its further electroreduction on the electrode surface.

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

The first example of substitution reaction in the free alpha-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.