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Hexacyanochromates(III) and Hexacyanocobaltates(III) of Copper(II) with Tridentate and Tetradentate N-donor Ligands. Crystal Structure of [{Cu(ept)}3{Co(CN)6}2]źH2O (ept = N-(2-aminoethyl)-1,3-propandiamine)

Mamulová Kutláková K., Smékal Z., Neels A., Önal M., Šindelář Z.

Polish Journal of Chemistry

2009

Vol. 83, nr 10

1707-1716

The following complexes [{Cu(ept)}3{Cr(CN)6}2]ź5H2O, [{Cu(hatce)}3{Cr(CN)6}2]ź ź15H2O, [{Cu(hatco)}3{Cr(CN)6}2]ź14H2O, [{Cu(ept)}3{Co(CN)6}2]ź5H2O, [{Cu(hatce)}3{Co(CN)6}2]ź18H2O and [{Cu(medpt)}3{Co(CN)6}2]źH2O (ept = N-(2-amino ethyl)-1,3-propandiamine, hatce = 1,3,6,10,12,15-hexaaza tricyclo [13.3.1.16,10]eicosane, hatco = 1,3,6,9,11,14-hexaaza tricyclo[12.2.1.16,9]octadecane and medpt = N,N-bis-(3-aminopropyl)methylamine) have been synthesized by the reactions of Cu(ClO4)2ź6H2O or Cu(NO3)2ź3H2O and ept or medpt, or [Cu(hatce)](ClO4)2ź2H2O and [Cu(hatco)Cl]ClO4źH2O, and K3[Cr(CN)6] or K3[Co(CN)6] in aqueous solution, respectively. All the compounds have been characterized by elemental analyses, IR and UV-Vis spectroscopies and magnetic measurements and the three selected complexes were studied using thermal analysis. The crystal structure of [{Cu(ept)}3{Co(CN)6}2]ź źH2O has been determined by single-crystal X-ray analysis – the studied compound can be for mulated as [{Cu(ept)}6{Co(CN)6}3][Co(CN)6]ź2H2O. The copper atom is five-coordinated by two cyanide-nitrogen and three ept-nitrogen atoms, in a distorted square-pyramidal arrangement. The structure of the other complexes with cyanide bridges between hexacoordinated chromium(III) (S = 3/2) or cobalt(III) (S = 0) and penta- or hexacoordinated copper(II) (S = 1/2) is proposed.

Synthesis and Characterization of Nickel(II), Cobalt(III) and Iron(III) Complexes of the Schiff Base 1-(2,3-Dihydroxybenzylidene)thiosemicarbazone

Kubaisi A., El-Metwally N., Eltayeb M.

Polish Journal of Chemistry

2004

Vol. 78 / nr 4

515-520

Ni(II), Co(III) and Fe(III) complexes of the Schiff base 1-(2,3-dihydroxybenzylidene) thiosemicarbazone (Hdhbtsc) have been prepared and characterized by elemental analysis, infrared spectra, thermal analysis, molar conductivity and magnetic measurements. The results indicate the formation of 1:2 metal to ligand complexes with empirical formulae [Ni(Hdhbtsc)2(Cl)2] and [M(dhbtsc)2(Cl)(H2O)], (Hdhbtsc = the Schiff base; dhbtsc = anionic form of the Schiff base; M = Fe3+ or Co3+ ). The three new complexes are six coordinate and octahedral, where the ligands behave as bidentate chelating agents in the neutral form with Ni2+ and in the uninegatively charged form with Fe3+ or Co3+.

Kinetics and mechanism of the acid-catalyzed hydrolysis of [carbonatotetra(1-methylimidazole)cobalt(III)](+) ion

Chatłas J., Danilczuk E., Nasiadko M.

Polish Journal of Chemistry

1998

Vol. 72, nr 4

777-785

The kinetics of acod-catalyzed hydrolysis of the [Co(1-Meim)4(CO3)](+) ion follows the rate law -d ln[complex]/d t=k(1)K[H(+)]/(1 + K[H(+)]) (25:45 degree C, [H(+)]=0.05:1.0 M and I=1.0 M(NaClO4)). The reaction course consists of rapid pre-equilibrium protonation followed by a rate determining ring opening process and the subsequent fast relase of monodentate carbonato ligand. Kinetic parameters, k(1) and K, at 25 degree C are 5.1x 10(-3)s(-1) ans 0.48 M(-1) respectively, and activation parameters for k(1) are Delta H(1)=84.4+:-0.8kJ mol(-1) and DeltaS(1)=-5.8+:-3.7J mol(-1) K(-1). The hydrolysis rate increases with the ionic strengh. The results are compared with those for similar cobalt(III) complexes.