Andrzej Cygan
University of Gdańsk
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Featured researches published by Andrzej Cygan.
Tetrahedron | 1992
Jan F. Biernat; E⋖bieta Luboch; Andrzej Cygan; Yurij A. Simonov; Aleksandr A. Dvorkin; E⋖bieta Muszalska; Renata Bilewicz
Abstract A chromogenic 13-membered crown ether with a cis azo unit in the macrocycle has been obtained as a side product during the reduction of 1,5-bis (2′-nitrophenoxy)-3-oxapentane. The electrochemical properties of this compound have been studied by the voltammetric method. Its behaviour as an ionophore in ion-selective membrane electrodes has also been investigated. The X-ray structures of the new crown ether 3 and the parent compound 1 have been determined.
Inorganica Chimica Acta | 1983
E. Luboch; Andrzej Cygan; Jan F. Biernat
Stability constants have been determined at 25 °C in aqueous 0.1 M Et4NClO4 medium by potentiometric method of the following ligands: 1,7-dioxa-4,10-diazacyclododecane 5, 1,4,10-trioxa-7,13-diazacyclopentadecane 6, 1,4,7,13-tetraoxa-10,16-diazacyclooctadecane 7, 1,4,10,13-tetraoxa-7,16-diazacyclooctadecane 8, 1,4,7-trioxa-10,13-diazacyclopentadecane 9 and 1,10-dioxa-4,7,13,16-tetraazacyclooctadecane 10 with Co2+, Ni2+, Cu2+ and Zn2+ ions. The values of the stability constants are discussed in terms of the relative size of the metal ion and macrocyclic cavities, the spatial arrangement of the donor nitrogen atoms and the macrocyclic effect.
Tetrahedron | 1990
Elżbleta Luboch; Andrzej Cygan; Jan F. lernat
Abstract The synthesis of alkyl, nitro and halogeno derivatives of benzo-15-crown-5, benzo- 18-crown-6 and naphtho-15-crown-5 has been reported. Also some novel ester type bis(crown ether)s have been prepared. Some of the compounds have been characterized as electroactive substances in PVC membrane Ion-selective electrodes.
Inorganica Chimica Acta | 1985
Wolfgang Dreissig; Zbigniew Dauter; Andrzej Cygan; Jan F. Biernat
Abstract The structures of trichlorocuprates of benzo-15-crown-5 complexed sodium and dibenzo-18-crown-6 complexed sodium were determined from diffractometer data by direct methods and refined by least-squares to R(F) = 0.059 and 0.039 respectively. Both complexes, (C 14 H 20 O 5 ) 2 Na 2 Cu 2 Cl 6 and(C 20 H 24 O 6 ) 2 Na 2 Cu 2 Cl 6 , are centrosymmetric and consist of very similar Cu 2 Cl 6 2− units lying across the centre of symmetry. Two Na + cations, surrounded individually by crown ether ligands, are located on opposite sides of the anion. The dimeric structure of the anion is very characteristics for chlorocuprates of very bulky cations and resembles the anions present in tetraphenylphosphonium and tetraphenylarsonium chlorocuprates. This gives a further supportto the «super heavy” alkali metal cations concept.
Journal of Inclusion Phenomena and Macrocyclic Chemistry | 1993
Jan F. Biernat; Andrzej Cygan; Elżbieta Luboch; Yurij A. Simonov; Alexandr A. Dvorkin
The presented azoxy compound is an example of a new crown ether analogue. It has been synthesized by the reduction of an open chain dinitro compound with stannite under strongly alkaline conditions. A method for the separation of the azo and azoxy compounds formed simultaneously has been proposed. The structures of two crystallographically independent molecules of compound2 have been determined. In spite of the small size of the macroring in compound2, the phenyl residues around the azoxy group have atrans orientation.
Tetrahedron | 1991
Elżbieta Luboch; Andrzej Cygan; Jan F. Biernat
Abstract Synthetic procedures based on the condensation of benzocrown ether derivatives leading to bis (benzocrown ether)s with nonhydrolyzable polymethylene bridges have been elaborated. The obtained compounds may have identical or different macrocyclic units. Methods for introducing lipophilic substituents into these compounds also have been described. The synthesized compounds have been applied in ion-selective electrodes and exhibit high selectivities for potassium, rubidium and cesium ions.
Journal of Inclusion Phenomena and Macrocyclic Chemistry | 1988
Andrzej Cygan; El bieta Luboch; Jan F. Biernat
Ion-selective electrodes, containing derivatives of crown ethers with aromatic rings, have been investigated. The electrodes were characterized by determining their detection limits and selectivity coefficients. Thet-butyl derivative of naphtho-15-crown-5 was found to exhibit the best properties (Ld=1×10−5,KNa/K=6×10−4).
Journal of Inclusion Phenomena and Macrocyclic Chemistry | 1993
Jan F. Biernat; Andrzej Cygan; Elżbieta Luboch; Yurii A. Simonov; Tadeush I. Malinovski; Vitalii K. Bel'skii; Nadezda F. Bolotina
The structure of the trichlorocuprate of naphtho-15-crown-5 complexed potassium has been determined by X-ray analysis. The crystal contains the complex cations [K(naphtho-15-crown-5)2]+, the anion [Cu2Cl6]2− and water molecules. The full composition of the compound in the solid state is represented by the formula [K(naphtho-15-crown-5)2]2[Cu2Cl6]·nH2O), wheren≌3. The sandwich type cations are similar to those found previously for potassium complexes with benzo-15-crown-5. The coordination number of potassium is equal to 10; the coordination polyhedron is a 15-crown-5. The coordination number of potassium is equal to 10; the coordination polyhedron is a pentagonal antiprism. The water molecules are disordered and occupy six symmetrically independent positions with a probability of ∼0.5 in the crystal. The lack of close contacts between water molecules and the remaining components enabled the treatment of the complex as a clathrate.
Journal of Coordination Chemistry | 1992
Andrzej Cygan; Elizbieta Luboch; Jan F. Biernat
Abstract The stability constants for the complexes of several benzo-15-crown-5 and naphtho-15-crown-5 derivatives containing various substituents in the aromatic ring have been determined in methanol. The potentiometric method with glass ion-selective electrodes has been employed. The stability constants have been compared to the selectivity coefficients (log kpot K,Na ) of membrane electrodes based on the mentioned compounds. No significant relationship has been stated.
Journal of Coordination Chemistry | 1992
Jan F. Biernat; Elizbieta Luboch; Andrzej Cygan
Abstract A new macroring closure reaction leading to crown-like macrocycles containing the azoxy group as a new macroring subunit has been introduced. The possibility of complex formation with cations has been examined by studying these compounds in membrane ion-selective electrodes.