18485-07-9

Upstream product

• 14587-87-2 trans-dibromobis(ethylenediamine)cobalt(III) nitrate 
• 87183-71-9 [Co(NH₂CH₂CH₂NH₂)2(OH₂)(O₃POC₆H₄NO₂)]⁽¹⁺⁾*ClO₄^(1-)*H₂O=[Co(NH₂CH₂CH₂NH₂)2(OH₂)(O₃POC₆H₄NO₂)]ClO₄*H₂O 

Relevant academic research and scientific papers

Oxygen Exchange and Cleavage of the Glycinate Chelate 2+ in Strongly Alkaline Solution

Cleavage of the carboxylate chelate 2+ has been studied in 0.75 mol dm-3 NaOH. 18O-tracer results are interpreted as 16percent C-O and 84percent Co-O bond fission, the products ultimately being +, Co(II), and glyO-.The major Co-O cleavage path is interpreted as an SN1 (CB) process leading to both recapture of carboxylate oxygen(50percent, kex=4.8 * 10-6 s-1) and capture of solvent leading to + (50percent).

Photochemical and thermal decomposition of (ΔΔ,ΛΛ)-(μ-hydroxo)(μ-peroxo) bis[bis(ethylenediamine)cobalt(III)] ions in basic aqueous solution

The title ion in aqueous basic solution does not undergo deoxygenation in the dark, but it does on irradiation with ultraviolet light to give the photoinduced equilibration (Equation Presented) The quantum yield determined in the presence of excess EDTA is ca. 2.2 × 10-3 on irradiation at 366 nm at 5°C and is virtually independent of pH (8.1-10.4). The yield on irradiation at 515 nm at ca. 25°C is -6. The ligand(O2)-to-metal charge-transfer excited state is relevant to the deoxygenation reaction. Continuous irradiation leads to subsequent irreversible decomposition to give cobalt(III) species including [CoIII(en)2(H2O)2]3+. Such an irreversible decomposition is much slower in the dark (ca. 5 × 10-7 s-1 at 5°C, pH 8.9, and I = 0.1 M (NaClO4); 1 M = 1 mol dm-3).

Enhanced Base Hydrolysis of Coordinated Phosphate Esters: The Reactivity of an Unusual Cobalt(III) Amine Dimer

The hydrolysis of the dimeric cation bis(μ-4-nitrophenyl phosphato)bis(2+) has been studied at pH 10 and over the hydroxide concentration range 0.05-1.0 M.Product distribution, kinetics (involving 4-nitrophenol release), and 31P NMR and 18O tracer studies were carried out to establish the course of the reaction.In a rapid first step, the eight-membered ring of the dimer is opened by rupture of one of the Co-O bonds (SN1cB) to give a cis hydroxo complex.The ring-opened species reacts further via two competing pathways: (a) intramolecular attack of the coordinated hydroxide upon the bridging phosphate ester moiety and (b) further cleavage of the dimer by base-catalyzed (SN1cB) rupture of some Co-O bonds.Route a results in ester hydrolysis with the concomitant formation of a chelated bridging phosphate species whereas route b yields cis- and trans-hydroxy(p-nitrophenyl phosphate)bis(1,2-ethanediamine)cobalt(III).The phosphate chelate ring in the initial product of path a is subsequently opened by Co-O bond rupture and the resultant dimeric bridging phosphato species slowly decomposes to cis- and trans-hydroxo(phosphato)bis(1,2-ethanediamine)cobalt(III).Comparison of the rate data for hydrolysis of the dimer and the cis-hydroxo(4-nitrophenyl phosphato)bis(1,2-ethanediamine)cobalt(III) ion indicates that the attack by the intramolecular nucleophile is largely responsible for the enhanced rate of ester hydrolysis (ca 1E5) with a smaller contribution from charge neutralization at the P center by the metal ion (ca 10-100).Parallel kinetic studies on the analogous dimer bis(μ-4-nitrophenyl phosphato)bis(2+), previously incorrectly formulated as a monomeric species containing chelated phosphate ester, indicate that ester hydrolysis in this complex proceeds by a similar mechanism to that for the 1,2-ethanediamine complex.In total, the results are rationalized in relation to a possible mechanism for the Zn2+ containing enzyme E. coli alkaline phosphatase.

Hydrolysis of Phosphate Esters Bound to Cobalt(III). Kinetics and Mechanism of Intramolecular Attack of Hydroxide on Coordinated 4-Nitrophenyl Phosphate

The hydrolysis of coordinated 4-nitrophenyl phosphate ester in cis-has been studied over the pH range 7-14 by 31P NMR spectroscopy and by monitoring nitrophenol release at 400 nm.Intramolecular attack by 18O labeled coordinated hyd

ECE mechanisms as a tool for the investigation of unstable metal complexes. 3. Polarographic studies of ligand dissociation of dibromocobalt(II) and dibromocobalt(III) complexes

The electrode reaction of trans-[CoBr2(N)4]+ ((N)4 = (en)2, (pn)2, (tn)2, and (NH3)4; en = ethylenediamine, pn = propylenediamine, tn = trimethylenediamine) has been examined in 0.1 M sodium acetate buffer solutions at mercury electrodes. All complexes exhibit the complicated electrode processes in which both the parallel ECE reaction and the Br- dissociation of cobalt(III) complexes take place. The dissociation rates of Br- from the Co(III) and Co(II) complexes are determined. The Br--dissociation rate constant (s-1) at 25°C, ΔH≠ (kcal mol-1), and ΔS≠ (cal K-1 mol-1) for trans-[CoIIIBr2(N)4]+ complexes are as follows: en, 1.51 × 10-4, 27.2, +15; pn, 3.30 × 10-4, 19.1, -10; NH3, 4.20 × 10-3, 26.8, +20; tn, 2.12 × 10-2, 15.2, -15. Also, the Br--dissociation rate constant (s-1) at 25°C, ΔH≠ (kcal mol-1), and ΔS≠ (cal K-1 mol-1) for trans-[CoIIBr2(N)4] complexes are as follows: en, 0.508, 1.3, -55; pn, 0.538, 2.9, -50; NH3, 0.610, 1.3, -55; tn, 0.571, 6.5, -38.