ANNUAL INDEXES

ABSTRACTS

Preparation and Thermophysical Properties of
New Cobalt(II), Nickel(II) and Copper(II) Complexes

by A.S. El-Tabl¹ and M.M. Abou-Sekkina²

¹Department of Chemistry, Faculty of Science, El-Menoufia University, Shebin El-Kom, Egypt
²Department of Chemistry, Faculty of Science, Tanta University, Tanta, Egypt

(Received April 19th, 1999; revised manuscript August 16th, 1999)

3,4,3¢,4¢-Tetraaza-(vinylidene-2,4-pentanedione) biphenyl ligand (H₄L) and its cobalt(II), nickel(II), and copper(II) complexes were prepared. The nickel(II) complex reacted with excess of ethylenediamine to yield a new type of macrocyclic complex. These compounds have been characterized by elemental analysis, IR, UV-VIS spectra, molar conductances, magnetic moment, mass fragmentation spectra, thermal analyses and ESR measurements. Spectral assignments show that the metal ions are coordinated through- out both chelate carbonyl oxygen and nitrogen atoms of the NH groups or the nitrogen atoms of the imino- and the NH groups. Molar conductance of the complexes in DMF points on non-ionic character. The ESR spectrum of the copper(II) complex exhibits an axial type symmetry (d_x2–y2) with a covalent bond character. However, the  cobalt(II) complex shows an isotropic type of octahedral geometry. The thermal stability of the complexes goes down in the sequence: Ni  > Cu > Co. The copper(II) complex exhibits a semiconductor behaviour.

Synthesis of N,N'-Bis(diethylphosphoryl) Sulfamide

by G. Mielniczak and A. Łopusiński

Centre of Molecular and Macromolecular Studies,
Polish Academy of Sciences 90-363 ŁódŸ, Sienkiewicza 112, Poland

(Received April 21st, 1999; revised manuscript August 19th, 1999)

The reaction of phosphoroamidates 5a–c with an excess of sulfuryl chloride, as well as the reaction of 5a with sulfur trioxide were investigated. In both reactions, the formation of a new type of phosphoroorganic compound namely, N,N¢-bis(diethylphosphoryl) sulfamide (6) was observed. This unexpected reaction pathway is rationalized as a result of the formation of dialkyl phosphorosulfonyl amide 3, a reactive common intermediate in both processes.

Sigmatropic Rearrangements of Ylides Generated
from N-(a-Cyano)benzyl-N,N-dimethyl-N-substituted
Ammonium Salts with a Base

by T. Zdrojewski, R. Gołębiowski, A. Mirkowska and A. Jończyk

Warsaw University of Technology, Faculty of Chemistry, Koszykowa 75, PL-00-662 Warszawa, Poland
Fax: (internat.) +48 22 628 27 41; E-mail: anjon@ch.pw.edu.pl

(Received August 20th, 1999)

Quaternary ammonium salts 1–4, treated with four different base-solvent systems A–D, generated ylides YI and YII which in turn, rearranged with formation of the products 6, 9 and/or 7, 8, as the products of [1,2] or [2,3] shift, respectively. The products 9a,d eliminated dimethylamine, when refluxed in methanol to afford methy(Z)-b-cyanocinnamates 10a,d. The salts 2 and 4 generated ylides, which formed rearranged products in better yields than the salt 3.

Terpenic Alcohols – Source of Chirality
in Condensing Reagents in Peptide Chemistry

by Z.J. Kamiński, B. Kolesińska, S.W. Markowicz and K. Pokrzeptowicz

Institute of Organic Chemistry, Technical University of ŁódŸ, Żwirki 36, 90-924 ŁódŸ (Lodz), Poland

(Received June 18th, 1999; revised manuscript August 30th, 1999)

Chiral 2,4-dichloro-6-terpenyloxy-1,3,5-triazines 3a–d obtained by treatment of cyanuric chloride with isomyrtanol (1), nopol (2), isopinocampheol (3) and borneol (4) are useful as enantiodifferentiating coupling reagent in the synthesis of dipeptides.

Vicarious Nucleophilic Substitution of Hydrogen
in 2,4-Dinitroanilines and Cyanonitroanilines

by M. Mąkosza, S. Voskresensky, M. Białecki and A. Kwast

Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, PL. 01-224 Warsaw, Poland

(Received September 7th, 1999)

Orientation of the VNS reaction in nitroaniline derivatives is mostly governed by the conjugation between the nitro groups and the amino group, which could be also deprotonated under the reaction conditions.

Structural Constitution of the LaMo₆Se₈
Superconductor

by A. Wojakowski, R. Horyń and M. Wołcyrz

Institute of Low Temperature and Structure Research, Polish Academy of Sciences,
50950 Wrocław, P.O.Box 937, Poland

(Received June 14th, 1999)

The ternary phase diagram La–Mo–Se shows a broad homogeneity range around the superconducting Chevrel phase LaMo₆Se₈. A series of single-phase samples of general formula “LaMo_(6+x)Se_(8–x)” (0 < x < 0.75), located inside the domain of homogeneity of the superconducting Chevrel phase LaMo₆Se₈, has been synthesized at 1200°C and characterized through X-ray, ac-magnetic susceptibility and density measurements. It has been found that the increasing contribution of molybdenum (x) in the series does not affect much the critical temperature (T_c) of the matrix, which remains pratically constant and close to 10 K. The same is true as far as samples’ densities are concerned. Based on crystallographical considerations, several models of different distribution of the excess molybdenum (x) have been analytically determined. The resulting densities (d calc), when compared to the experimental values (d exp), served as a basis to evaluate distribution of molybdenum in real samples. The final result,  supported by the X-ray powder patterns simulation, indicates on mixed occupation of the Se sublattice consisting of (8-x) Se and the excess molybdenum (x).

Correlation Between Temperature Coefficients
of Ag⁺L Cryptate Stability Constant
and of Ag|Ag⁺ Electrode Potential

by A. Lewandowski and M. Galiński

Institute of Chemistry, Poznań University of Technology, PL - 60 965 Poznań, Poland

(Received April 6th, 1999; revised manuscript July 12th, 1999)

The temperature coefficients, dlogK/dT, of the stability constants of Ag⁺ complexes with cryptands 221 and 222 were obtained directly from van’t Hoff linear plots logK = a + bT ^–1 in 10 aprotic solvents: acetone, acetonitrile, propanenitrile, butyronitrile, benzonitrile, N,N-dimethylacetamide, N,N-dimethylformamide,  dimethylsulfoxide, propylene carbonate and in tetramethylene sulphone (sulfolane). It has been shown, that while the stability constants of the Ag⁺221 and Ag⁺222 cryptates can be correlated with the potentials E of the Ag|Ag⁺ couple as logK = const. + (F/2.3RT)E, the corresponding relation between the temperature coefficients is dlogK/dT = const.’ – (F/2.3RT)(E/T + dE/dT).

Charge Accumulation in the Conducting
Polymer–Electrolyte Systems. The Redox Capacitance

by M. Grzeszczuk

Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland
e-mail: maria@wchuwr.chem.uni.wroc.pl

(Received June 7th, 1999; revised manuscript July 22nd, 1999)

The redox capacitances for polyaniline, poly(3-octylthiophene), and polypyrrole electrodes have been compared. They are of the order of 10⁺² F/cm³. The observed dependence on the polymer nature correlates well with the theoretical charge capacity of the polymers. It evidences the redox origin of the capacitive characteristics of the conducting polymer electrodes. The capacitances were determined by electrochemical spectroscopy measurements.

Transient Period Adding Phenomena
in the Belousov-Zhabotinsky
Reaction at Low Flow Rates in a CSTR

by O.Z. Didenko¹, P.E. Strizhak¹ and A.L. Kawczyński²

¹L.V. Pisarzhevskii Institute of Physical Chemistry, National Academy of Sciences of Ukraine,
Prospekt Nauky 31, Kyiv (Kiev), 252039, Ukraine
²Institute of Physical Chemistry, Polish Academy of Sciences,
Kasprzaka 44/52, 01-224 Warsaw, Poland, E-mail:alk@ichf.edu.pl

(Received June 9th, 1999; revised manuscript August 5th, 1999)

Period adding phenomena in transient dynamics of the Belousov-Zhabotinsky reaction (bromate – malonic acid – ferroin) in a CSTR have been observed for decreasing residence time at various inflow concentrations of malonic acid. Oscillations showing similar transient patterns are obtained in a simple model proposed recently for a qualitative description of transient and asymptotic oscillations observed in the BZ system.

Aggregation of Free-Base Octacarboxyphthalocyanine in Aqueous Solutions

by A. Suchan, J. Hurek, W. Wacławek, J. Nackiewicz and K. Ejsmont

Institute of Chemistry, University of Opole, ul. Oleska 48. P.O. Box 313, PL-45-957 Opole, Poland
E-mail: waclawek@uni.opole.pl

(Received July 2nd, 1999; revised manuscript August 6th, 1999)

Results of spectral (UV-VIS) investigations on the aggregation phenomena of the free- base 2,3,9,10,16,17,23,24-octacarboxyphthalocyanine are reported. Phthalocyanine exists mainly in associated (aggregated) forms in water. The aggregates are present even in very diluted (10^–7–10^–6 mol dm^–3) solutions. The hydrogen bonding between the carboxyl groups of the adjacent molecules is considered. The increase in pH and temperature, as well as the presence of the cationic surfactant and alcohols (in an appropriate quantity) cause a partial or full disaggregation. The spectrum of the monomeric phthalocyanine form has been observed. The increase in H₂Pc(COOH)₈ concentration, the decrease in pH, as well as ethanol in the solutions favour the phthalocyanine association.

Distribution of Trace Amounts of Some M²⁺ Ions
During Nickel(II) Chloride Crystallization

by M. Smolik

Institute of Chemistry, Inorganic Technology and Electrochemistry, Silesian Technical University,
ul. B. Krzywoustego 6, 44-100 Gliwice, Poland

(Received June 29th, 1999; revised manuscript August 9th, 1999)

Distribution coefficients, D, of trace amounts of metal ions M²⁺ (Mg²⁺, Co²⁺, Zn²⁺, Cd²⁺, Cu²⁺, Mn²⁺, Fe²⁺, Ca²⁺, and Sr²⁺) have been determined during crystallization of NiCl₂×6H₂O from water solutions as well as from hydrochloric acid solutions of different concentrations. Their dependencies on the electron configurations of metal ions, their ionic radii as well as solubilities and structures of the corresponding chlorides have been analyzed. The D values are comprised in the range < 0.01(D_Mg) – 2.4(D_Co) and depend mainly on the structures of the corresponding chlorides as well as electron configurations of M²⁺ ions, whereas they depend on neither ionic radii of M²⁺ ions nor solubilities in water of corresponding chlorides.

pH Dependent Enantioselection of Amino Acids
by Phosphorous-Containing Calix[4]resorcinarene
in Langmuir Monolayers

by M. Pietraszkiewicz¹, P. Prus¹ and R. Bilewicz²

¹Institute of Physical Chemistry, Polish Academy of Sciences, 01224 Warsaw, Kasprzaka 44/52, Poland
²Department of Chemistry, University of  Warsaw, 02093 Warsaw, Pasteura 1, Poland
e-mail: pietrasz@ichf.edu.pl, bilewicz@chem.uw.edu.pl, viayner@ichf.edu.pl

(Received July 9th, 1999; revised manuscript September 3rd, 1999)

Lipophilic calix[4]resorcinarene with phosphorous acid amide groups linking oxygen atoms is a rigid system of the cavitand type, in which conformational flexibility is strongly limited. These chiral receptors form stable Langmuir monolayers on water surface with surface area per molecule in the compressed layer being almost pH-independent. Enantiomeric recognition of amino acids was found to depend on the pH of the subphase containing selected amino acids. This dependence reflected different modes of interactions between both the nonprotonated, and protonated forms of the receptor molecule and the amino acid. The magnitude and the sign of enantiomeric discrimination could be regulated by the pH of the subphase. At low pH the recognized enantiomer was L, as proved by the surface-pressure and surface potential vs molecular area isotherms recorded for L-tryptophan and L-valine.

Molecular Recognition of Pyrimidine and
Xanthine Bases by Lipophilic Calixarenes Derived
from Resorcinol and Pyrogallol

by O. Pietraszkiewicz¹, Z. Brzózka² and M. Pietraszkiewicz¹

¹Institute of Physical Chemistry, Polish Academy of Sciences,
01224 Warsaw, Kasprzaka 44/52, Poland, e-mail: pietrasz@ichf.edu.pl
²Department of Analytical Chemistry, Warsaw University of Technology,
Noakowskiego 3, 00664 Warsaw, Poland, e-mail: brzozka@ch.pw.edu.pl

(Received June 24th, 1999; revised manuscript September 30th, 1999)

Two lipophilic calixarenes, derived from resorcinol (R1) and pyrogallol (R2), were investigated as receptors for pyrimidine and xanthine bases in extraction experiments. Extraction abilities sequence for R1 in chloroform is: cytosine > uracil > thymine, whereas for R2: thymine > uracil > cytosine. For xanthine bases, the appropriate extraction abilities sequence is: for R1 – dyphylline > theophylline > theobromine and  R2 – theobromine > theophylline > dyphylline. Competitive molecular recognition of pyrimidine and xanthine bases by lipophilic calixarenes, incorporating resorcinol and pyrogallol units, was studied in extraction experiments in various solvents. Xanthine bases: theophylline, theobromine and dyphylline were extracted more easily into toluene and chloroform than to diethyl sebacate. Among pyrimidine bases, no clear pattern of extraction was observed: uracil was extracted most effectively to toluene phase, thymine – into diethyl sebacate, cytosine into – chloroform.

Synthesis and Magnetism of Binuclear Nickel(II) Complexes with Tetraacetylethylene Dianion as Bridging Ligand

by S.C. Zhu¹, J.Q. Xu², J.M. Shi¹, Z.D. Zhang¹, S.C. Shang¹, C.J. Wu¹ and J.J. Lu¹