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1
Spectrochemical Properties of Noncubic Transition Metal Complexes in Solutions. XIII. Angular Overlap Treatment of Diaquabis(salicylideneaminothiazole)cobalt(II)
100%
Kuźniarska-Biernacka I. , Kurzak K.
Polish Journal of Chemistry
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2003
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tom Vol. 77 / nr 1
13-19
EN
Mixed ligand cobalt(II) complex with monodentate (water) and bidentate (Schiff base: salicylidene-2-aminothiazole) ligands has been characterized by elemental analyses, molar conductivities, ultraviolet (UV) and visible (VIS) spectroscopy. The electronic spectra of solids as well as solutions exhibit pseudo-octahedral coordination geometry for the cobalt centre. The molar conductivities indicate their non-electrolytic properties in solvents studied. Combined multi-technique experiments have been used to postulate theC2h geometry for the species in solutions and to determine the coordination properties of ligators and their bonding abilities (ligand-field parameters).
2
Content available remote Z badań nad spektroskopią UV-VIS kompleksów metali przejściowych z zasadami Schiffa w roztworach
100%
Kurzak K. , Kuźniarska-Biernacka I.
Wiadomości Chemiczne
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2001
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tom [Z] 55, 9-10
913--931
EN
Metal complexes derived from Schiff bases have been known for one hundred years. The complexes have occupied a central role in the development of coordination chemistry. This situation is manifested by huge number of publications ranging from the physicochemical to biochemical relevant studies of these complexes. The reason for this sustained interest in those compounds are undoubtedly many but important among them must be their general ease to preparation, and diverse properties, e.g., their ability to reversibly bind oxygen, catalytic activity, photochromic and thermochromic properties. Schiff base are those compound containing the azomethine group (-RHC=N-) and usually formed by the condensation of amine with carbonyl compound. Bases which are effective as coordinating ligands bear a functional group, usually -OH, sufficiently near the site of condensation that a five- or six membered chelate ring can be formed upon reaction with a metal ion. Tautomeric equilibrium of three tautomers is possible for Schiff base compounds: imine, enamine and keto-imine. The presence of the imine and enamine tautomeric forms depends on the formation of intramolecular hydrogen bond. It is claimed that enamine form is dominant in napthaldimines while imine form in salicylaldimines. The distribution of the tautomeric equilibrium is strongly depend on the solvents. The presence of keto-imine form is insignificant for Schiff base compounds, but is found in the case of b-diketones and arylimines of b-ketoethers. The most significant complexes of the salicylaldimines are of the types: bi-, tri- and tetracoordinateSchemat 3. The geometry of Schiff base complexes depends on substituent at the coordinating nitrogen atoms. For tetra-coordinate copper(II) complexes different types of geometry is possible. A planar structure has been established for the copper(II) complexes (with bidentate Schiff base) where the substituent is hydrogen atom, hydroxyl, methyl, n-butyl or n-amyl group. In the other hand the copper(II) complexes where the substituent is isopropyl or tert-butyl are pseudo-tetrahedral. For tetra-coordinate cobalt(II), either a square-planar or pseudo-tetrahedral geometry is possible. A pseudo-tetrahedral structure has been established for the cobalt(II) complexes (with bidentate Schiff base) where the substituent is n-propyl, isopropyl, n-butyl, tert-butyl, cyclohexyl or aryl group. Cobalt(II) complexes with bidentate Schiff bases where the substituent is hydrogen atom or hydroxyl group have a planar geometry, because of formation hydrogen bonding between hydrogen (from hydroxyl group) and oxygen (from aldehyde linkage). Geometry of this type is characteristic for cobalt(II) complexes witch Schiff base tetradentate (e.g., with salicylidene-ethylenediamine). The aim of this account is to summarize the result of studies of structural and spectroscopic properties on Schiff bases and their complexes. These have been reviewed based on 104 articles.
3
Ligand-Field Analysis of Low-Spin N,N'-Propylenebis(naphthyldiiminate)nickel(II) in Ethanol Solution
80%
Kurzak K. , Gonciarz A. , Kuźniarska-Biernacka I.
Polish Journal of Chemistry
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2005
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tom Vol. 79 / nr 1
47-56
EN
Titled complex denoted as [Ni(nappn)]ź0.5H2O, where H2nappn is tetradentate Schiff base: 1,3-bis(naphthylideneimine)propane, has been characterized by elemental analysis, molar conductivity, ultraviolet (UV) and visible (Vis) spectroscopy. The known X-ray structure of this complex shows that Ni atom adopts square-planar coordination. Combined multi-technique experiments have been applied to establish the structure of complex in solution. The molar conductivity value indicates non-electrolytic properties of solution studied. The spectroscopic measurements were used to study the coordination properties of donor-atoms and their bonding abilities. All the experimental transition energies are derived from Gaussian analysis of the solution spectrum. The d-d transition energies were used to derive the angular overlap model (AOM) and crystal-field model (CFM) parameters for the studied complex inD4h symmetry. The first full ligand-field interpretation of the low-spin Schiff base nickel(II) complex in solution has been presented.
4
Content available Study of CuO and V2O5 Effect on IR Spectra of Polycrystalline Bismuth Niobate
80%
Kuźniarska-Biernacka I. , Lisińska-Czekaj A. , Czekaj D.
Archives of Metallurgy and Materials
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2020
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tom Vol. 65, iss. 2
817--821
EN
Bismuth niobate (BiNbO4) ceramics were fabricated by mixed oxide method and sintered by presureless sintering method. BiNbO4 ceramics doped with V2 O5 additive in amount 0.125 wt%, 0.250 wt% and 1 wt% of was sintered at T = 910°C whereas BiNbO4 ceramics doped with 2 wt% of CuO additive was sintered at T = 890°C and T = 910°C. It was found that V2 O5 additive improved morphology of the ceramic samples. However, the chemical composition of BiNbO4 ceramics in relation to bismuth oxide and niobium oxide manifested a tendency of lack of Bi2 O3 component. Absorption bands for the BiNbO4 compound were identified. FTIR band positions associated with NbO6 octahedra suggested that the crystal structure changes after V2 O5 incorporation.
5
Content available X-Ray Diffraction Study of Bismuth Layer-Structured Multiferroic Ceramics
71%
Lisińska-Czekaj A. , Czekaj D. , Garbarz-Glos B. , Bąk W. , Kuźniarska-Biernacka I. , Lisińska-Czekaj A. , Czekaj D. , Garbarz-Glos B. , Bąk W. , Kuźniarska-Biernacka I.
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nr 2
6
Content available X-Ray Diffraction Study of Bismuth Layer-Structured Multiferroic Ceramics
70%
Lisińska-Czekaj A. , Czekaj D. , Garbarz-Glos B. , Bąk W. , Kuźniarska-Biernacka I.
Archives of Metallurgy and Materials
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2020
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tom Vol. 65, iss. 2
811--815
EN
Goal of the present research was to apply a solid state reaction route to fabricate bismuth layer-structured multiferroic ceramics described with the formula Bi5FeTi3O15 and reveal the influence of processing conditions on its crystal structure and phase composition. Simple oxide powders Bi2O3, TiO2 and Fe2O3 were used to fabricate Aurivillius-type bismuth layer-structured ferroelectrics. Pressureless sintering in ambient air was employed and the sintering temperature was TS = 900°C, TS = 1000°C and TS = 1040°C. The phase composition as well as crystal structure of ceramics sintered at various processing conditions was examined with powder X-ray diffraction method at room temperature. The Rietveld refinement method was applied for analysis of X-ray diffraction data. It was found that ceramics adopted orthorhombic structure Cmc21. The unit cell parameters of bismuth layer-structured multiferroic ceramics increased slightly with an increase in sintering temperature.
7
Content available Styrene oxidation by copper(II) complexes salen-type encapsulated into NaY zeolite
61%
Kuźniarska-Biernacka I. , Carvalho M. A. , Correia Neves I. , Fonseca A. M. , Lisińska-Czekaj A. , Czekaj D.
Archives of Metallurgy and Materials
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2013
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tom Vol. 58, iss. 4
1291--1294
EN
The copper(II) complex with a Schiff-base salen-type ligand has been encapsulated in the nanopores of a NaY zeolite by using two different methodologies, the flexible ligand and in situ complex preparation methods. The encapsulated and non-encapsulated copper(II) complexes were screened as catalysts for styrene oxidation by using TBHP as the oxygen source in acetonitrile solvent. Under the optimized conditions, the catalysts exhibited moderate activity with higher selectivity to benzaldehyde. Both heterogeneous catalysts were found to be reusable after the catalytic cycle, but with some loss of activity.
PL
Osadzenie kompleksu miedzi(II) z zasadą Schiffa typu salen na zeolicie typu NaY zostało przepowadzone za pomocą dwóch metod „flexible ligand" i „in situ”. Katalityczne właściwości otrzymanego kompleksu oraz jego heterogenizowanych analogów badano w reakcji utleniania styrenu w obecności TBHP. Jako rozpuszczalnik stosowano acetonitryl. Testowane katalizatory wykazują średnią aktywność katalityczną z tendencją wytwarzania aldehy du benzoesowego. Oba heterogenizowane katalizatory mogą być wykorzystywane ponownie bez utraty aktywności katalitycznych.
8
Content available Styrene epoxidation over heterogeneous manganese (III) complexes
61%
Kuźniarska-Biernacka I. , Lisinska-Czekaj A. , Czekaj D. , Alves M. J. , Fonseca A. M. , Neves I. C.
Archives of Metallurgy and Materials
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2016
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tom Vol. 61, iss. 3
1477--1482
EN
The manganes (III) complex functionalised with 2,3-dihydropyridazine has been encapsulated in the supercages of the NaY zeolite using two different procedures, flexible ligand and in situ complex. The parent zeolite and the encapsulated manganese (LTI) complexes were screened as catalysts for styrene oxidation by using t-BOOH as the oxygen source in acetonitrile. Under the optimized conditions, the catalysts exhibited moderate activity with high selectivity to benzaldehyde.
9
Content available Styrene Epoxidation Over Heterogeneous Manganese(III) Complexes
61%
Kuźniarska-Biernacka I. , Lisińska-Czekaj A. , Czekaj D. , Alves, M. José , Fonseca, A. Mauricio , Neves, I. Correia
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