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1

Synthesis and Characterization of New Thiocyanato Bridged Heterobimetallic Complexes with the General formula: [Cu(diamine)2]3[Cr(NCS)6]2.nH2O

100%

Wrzeszcz G.

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tom Vol. 77 / nr 7

845-854

EN

Four new thiocyanato bridged heteropolynuclear complexes with general formula [Cu(diamine)2]3[Cr(NCS)6]2_nH2O, where diamine = N-ethylethylenediamine (N-Et-en), N-isopropylethylenediamine (N-Pri-en), N-methyl-1,3-propanediamine (N-Me-tn), 1,3-diaminopentane (C-Et-tn), were prepared by treatment of corresponding cationic [Cu(diamine)2]2+ complex with [Cr(NCS)6]3-in aqueous solutions. Solid products were formulated as [Cu(N-Et-en)2]3[Cr(NCS)6]2, [Cu(N-Pri-en)2]3[Cr(NCS)6]2_2H2O, [Cu(N-Me-tn)2]3[Cr(NCS)6]2_H2O and [Cu(C-Et-tn)2]3[Cr(NCS)6]2_H2O and characterized by spectroscopic methods, magnetic measurements and thermal analysis. The formation of end-to-end thiocyanato bridges between tetragonal Cu(II) and octahedral Cr(III) is evident from IR and electronic spectra. The EPR spectra measured at room temperature on solid samples show broad, symmetric signal at g = 2.01-2.03. Variable-temperature magnetic susceptibility measurements reveal the presence of weak antiferromagnetic interactions in [Cu(N-Pri-en)2]3[Cr(NCS)6]2_2H2O and [Cu(C-Et-tn)2]3[Cr(NCS)6]2_H2O. Thermal decomposition after dehydration is multistage and yields CuO and CuCrO2 as final products.

2

Oxidation of 3-Hydroxy-6-methyl-2-pyridinemethanol by Chromium(VI) in Acidic Aqueous Media ; Kinetic and EPR Studies

63%

Kita E. , Wrzeszcz G.

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tom Vol. 77 / nr 3

355-364

EN

Kinetics of oxidation of 3-hydroxy-6-methyl-2-pyridinemethanol (hmpol) by CrVI at HClO4 was studied under the pseudo-first-order conditions. The hmpol oxidation products were the appropriate aldehyde (hmpal) and acid (hmpac) coordinated to the chromium( III). The linear dependence of the pseudo-first-order rate constant (kobs) on [hmpol] at 1.0 and 2.0 M HClO4 and a parabolic dependence of kobs on [H+] were established. The apparent activation parameters were determined from the second-order rate constants at 1.0MHClO4. The presence of the CrII and CrIV intermediates was deduced, based on rate retardation effect caused by O2 and MnII respectively, whereas the presence of CrV was established by EPR. Some correlations between the structure and stability of intermediate chromium(V) complexes have been discussed from EPR spectra, recorded during the redox process.

3

Spectroscopic, Magnetic and Thermal Properties of New Thiocyanato Bridged Complexes of the Type [M(diamine)2]3[Cr(NCS)6]2.nH2O4, where M=Cu(II), Ni(II)

63%

Wrzeszcz G. , Dobrzańska L.

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2003

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tom Vol. 77 / nr 10

1245-1254

EN

Heteropolynuclear complexes of the type [M(diamine)2]3[Cr(NCS)6]2_nH2O, where diamine = N-methylethylenediamine (N-Me-en), 1,2-diaminopropane (pn); M = Ni(II), Cu(II) have been prepared by reacting [Cr(NCS)6]3- with the corresponding cationic [M(diamine)2]2+ complex in an aqueous solution. They have been characterized by elemental analysis, IR, UV-VIS, EPR, variable temperature magnetic susceptibility and thermal analysis. Spectroscopic studies reveal thiocyanato bridges between M(II)-Cr(III) centres. The parameters determined from temperature dependence on magnetic susceptibility (80-300 K) indicate moderate antiferromagnetic interactions for Ni(II)-Cr(III) and negligibly small or very weak ones for Cu(II)-Cr(III) systems. Magnetic studies suggest also presence of diamagnetic Ni(II) ions in the structure of Ni(II)-pn-Cr(III) complex. Thermal analysis shows higher thermal stability of Ni(II)-Cr(III) than Cu(II)-Cr(III) compounds. The process of thermal decomposition after dehydration is multistage and yields NiO + NiCr2O4and CuO + CuCrO2 as final products, respectively.

4

Synthesis, Spectroscopy and Magnetism of New -Thiocyanato Polynuclear Copper(II)-Chromium(III) Complexes

51%

Dobrzańska L. , Wrzeszcz G. , Grodzicki A. , Rozpłoch F.

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tom Vol. 75, nr 11

1689-1694

EN

New heteropolynuclear complexes with general formula [Cu(diamine)2]3 [Cr(NCS)6]2źnH2O, where diamine = N,N-dimethylethylenediamine (1,2-dmen), N,N-dimethylethylenediamine (1,1-dmen), N,N-diethylethylenediamine (1,2-deen), N,N-diethylethylenediamine (1,1-deen), 1,3-diaminopropane (tn) were obtained by reactions of [Cr(NCS)6]3– with the corresponding cationic Cu(II) complexes: [Cu(diamine)2]2+ and characterized by spectroscopic methods and magnetic measurements. The formation of end-to-end thiocyanato bridges between tetragonal Cu(II) and pseudo-octahedral Cr(III) is evident from IR and UV-VIS spectra by appearance of new components of ni(CN) band and shifts in the absorption maxima assigned to copper d-d transitions in comparison with corresponding mononuclear complexes. The EPR spectra measured at room temperature on solid samples show broad, symmetric signal at g = 2.02–2.03.Variable-temperature magnetic susceptibility measurements reveal the presence of weak antiferromagnetic interactions in [Cu(1,1-deen)2]3[Cr(NCS)6]2H2O and [Cu(tn)2]3[Cr(NCS)6]22H2O.

5

Synthesis and characterization of diantipyrylmethanium salts of some pseudo-tetrahedral anionic copper(II) complexes

51%

Wrzeszcz G. , Grodzicki A. , Pawlak R. , Rozpłoch F.

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tom Vol. 72, nr 10

2232-2241

EN

The tetrachlorocuprate(II), tetrabromocuprate(II) and tetrakis(izothiocyanate)cuprate(II) complexes of diantipyrylmethanium cations have been prepared and formulated as (H2DAM)CuCl4, (H2DAM)CuBr4, and (HDAM)2Cu(NCS)4 on the basis of spectral data (IR, UV-VIS) and elemental analysis. The EPR spectra, variable temperature magnetic susceptibility and thermal properties in air have been investigated. The results indicate for all complexes a distored tetrahedral configuration. All studied complexes exhibited Curie-Weiss behaviour between 80-300 K. Thermal decomposition is a multistage process and yields CuO as final product.

6

Synthesis and Characterization of New Thiocyanato Bridged Complexes with the General Formula [MLn}3[Cr(NCS)6]2.mH2O, where M=Cu(II), Ni(II), Co(II); L=Various Substituted Imidazoles

51%

Wrzeszcz G. , Dobrzańska L. , Grodzicki A. , Rozpłoch F.

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tom Vol. 77 / nr 2

147-156

EN

New thiocyanato bridged complexes of the type [CuL4]3[Cr(NCS)6]2_mH2O [L = 1-methylimidazole (1-Meim), 2-methylimidazole (2-Meim), 1,2-dimethylimidazole (1,2- Me2im)] and [M(1-Meim)6]n[{M(1-Meim)4Cr(NCS)6}2n]_mH2O (M = Ni(II), Co(II) were prepared by the reaction of [Cr(NCS)6]3- with the appropriate [MLn]2+ complex in an aqueous solution and characterized by elemental and thermal analysis, IR, UV-VIS, EPR and temperature variable magnetic susceptibility. The presence of NCS bridges between M(II)-Cr(III) centres is evident from IR spectra. The electronic spectra correlate with proposal of different composition of Cu3Cr2 and M3Cr2(M = Ni, Co) systems. The parameters determined from temperature dependence on magnetic susceptibility (80-300 K) indicate weak or negligible antiferromagnetic interaction for obtained Cu(II)-Cr(III), Ni(II)-Cr(III) and Co(II)-Cr(III) systems. Thermal decomposition after dehydration is multistage and yields CuO + CuCrO2 and MIIO+MIICr2O4 as final products, respectively.

7

Synthesis and Properties of New Bimetallic Complexes of General Formula: [Ni(diamine)2]3[Cr(NCS)6]2.nH2O

51%

Dobrzańska L. , Wrzeszcz G. , Grodzicki A. , Rozpłoch F.

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2001

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tom Vol. 75, nr 6

909-914

8

New Polymeric Copper(II) Complexes with Triphenyl Phosphite and Perfluorinated Carboxylates

51%

Szłyk E. , Szymańska I. , Wrzeszcz G. , Rozpłoch F.

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tom Vol. 74, nr 7

909-918

EN

New Cu(II) complexes with triphenyl phosphite and aliphatic perfluorinated carboxylates [Cu{P(OC6H5)3}(u-OH)(u-RCOO)]n (where R=CF3, C2F5, C3F7, C6F13, C7F15, C8F17, C9F19) were obtainedf and their spectroscopic and thermal properties studied. EPR spectra and magnetic susceptibility measurments indicate the formation of polymeric complexes. Examination of COO absorption bands suggests bridging carboxylates as well as a hydro group, whereas triphenyl phosphite is monodentately bonded. Thermal decomposition is a multistage process, which in nitrogen yields a mixture of Cu, Cu2O and Cu2p2O7 but in air - pure u2P2O7.