On the mechanism of racemisation of dichlorobis(ethylenediamine)-metal chlorides [metal=cobalt(III) or chromium(III)] in the solid state
TL;DR: In this paper, the results were only in accord with a rhombic twist mechanism of the type originally proposed by Ray and Dutt for [M(AA)3] complexes.
Abstract: In the solid state l-cis-[M(en)2Cl2]Cl [M=cobalt(III) or chromium(III)] undergoes thermal racemisation smoothly at 158 °C without anycis-trans interconversion. The values of krac, ΔH‡ and ΔS‡ are 6 × 10−6s−1, 218 kJM−1 and 156.1 JK−1M−1 for the cobalt(III) complex and 3.5 × 10−5s−1, 229.7 kJM−1 and 197.9 JK−1M−1 for the chromium(III) complex, respectively. The results are only in accord with a rhombic twist mechanism of the type originally proposed by Ray and Dutt for [M(AA)3] complexes.
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TL;DR: In this paper, thermal decomposition of the trans and cis isomers of [Co(en)2Cl2]Cl has been studied using the TG-FTIR and TG-DSC-MS techniques.
Abstract: Thermal decompositions of the trans-[Co(en)2Cl2]Cl and cis-[Co(en)2Cl2]Cl complex isomers have been studied using the TG–FTIR and TG–DSC–MS techniques. The measurements were carried out in argon atmosphere over the temperature range 293–873 K. The influence of the configurational geometry on the pathways of thermal transformations was discussed. Furthermore, kinetic studies on the reaction of the cis–trans isomerization of the [Co(en)2Cl2]Cl complex salt in methanolic solutions were performed using UV–Vis spectrophotometry at five temperatures in the 293–313 K temperature range. The observed rate constants were computed using the “Glint” program based on the global analysis. It has been found that the cis–trans isomerization of [Co(en)2Cl2]Cl is a first order reaction. Furthermore, the cis/trans [Co(en)2Cl2]Cl isomerization proceeds according to the dissociative mechanism.
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TL;DR: In this article, a hexadentate pyrazole-based bispidine-ligand and its first-row transition metal complexes (FeII, CoII, NiII, CuII and ZnII) were synthesized.
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TL;DR: In this paper, the movement of the cationic complexes on cellulose in different electrolytes was also studied, and the properties of the complexes formed have been characterized by elemental analysis, conductance measurements, eguivalent weight determination, electronic and infrared spectra, and magnetic susceptibility measurements.
Abstract: Substituted biguanides and ethylenediamine (C2H8N2) react readily with diammine(ethylenedibiguanide)cobalt(III) hydroxide sulfate, [Co(NH3)2(EBG)](OH)SO4.(EBG = N1, N1-ethylenedibiguanide, C6H16N10), to form mixed chelates of the types [Co(AA)(EBG)]X3-nH2O (AA = methylbiguanide (C3H9N5), ethylbiguanide (C4 H11.N5), n-propylbiguanide (C5H13N5), isopropylbiguanide (C5H13N5), phenylbiguanide (C8H11N5)) and [Co(en)(EBG)]X3-nH2O (X = Cl, I, l/2SO4; n = 1, 2, 3, etc.). The complexes formed have been characterized by elemental analysis, conductance measurements, eguivalent weight determination, electronic and infrared spectra, and magnetic susceptibility measurements. They are red in color, highly crystalline, and very soluble in water. The movement of the cationic complexes on cellulose in different electrolytes was also studied. Conductance values indicate that the salts are tri-univalent electrolytes in water. Vibrational spectra provide useful information regarding the bonding sites of the title lig...
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TL;DR: Le mecanisme de racemisation concerne des complexes chlores du cobalt and du chrome avec le diaminoethane as mentioned in this paper, a.k. a.
Abstract: Le mecanisme de racemisation concerne des complexes chlores du cobalt et du chrome avec le diaminoethane
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TL;DR: The only tetrahedral coordination compounds that are known to be stereochemically stable are the spirans as discussed by the authors, and the kinetics of racemization of these has not been investigated.
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