14403-82-8

Usage

InChI:InChI=1/Co.5H3N.H2O/h;5*1H3;1H2/q+3;;;;;;

Upstream product

• 7732-18-5 water 
• 19173-64-9 pentaammineformatocobalt(III) perchlorate 
• 940-75-0 (4-hydroxyphenyl)phosphoric acid 
• 136545-43-2 {(NH₃)5CoOC(CH₂)2CON}⁽²⁺⁾*2(CF₃SO₃)^(1-)*H₂O=C₂F₆S₂O₆N₅H₁₅CoOC₃H₄CONH₂O 
• 136545-45-4 succinimido-N-pentaamminecobalt(III) perchlorate salt 

Downstream Products

• 22541-53-3 cobalt(II) 
• 22541-88-4 ruthenium(III) 

Relevant academic research and scientific papers

Photochemistry of 2+: Wavelength, Pressure, and Medium Dependence of Redox and Aquation

The ratio of redox to aquation of 2+ has been shown to be constant at about 2 for irradiation wavelengths (nm) of 254, 275, 313, and 365, falling close to zero at 514.5.With increasing pressure, quantum yields for redox and aquation decrease, the former somewhat faster, and in a wavelength-dependent fashion, so that the apparent volumes of activations (mL mol-1) for redox and aquation are respectively 6.0+/-0.6 and -0.4+/-3.2 at 365 nm and 4.8+/-0.3 and 2.5+/-2.7 at 313 nm.At ordinary pressure at redox yield falls 8-fold and the aquation yield increases 50percent in 40 wtpercent glycerol/water.The equations relating volumes of activation for individual reaction steps to the overall apparent volumes of activation for the lifetime and quantum yield are derived.It is shown that all of the above observations are supportive of a mechanism involving generation of a caged radical pair which has no memory of the excitation enrgy of its progenitor.

Photochemistry of μ-Amido-μ-hyperoxo-dicobalt(III) Complexes with Ammine and Polyamine Ligands in Aqueous Solutions: Effects of Ligand and pH

Photolyses of μ-amido-μ-hyperoxo-dicobalt(III) complexes, -2)CoL>4+ (L=4NH3 (1), en+2NH3 (2), 2en (3), tren (4)), (tren: 2,2',2''-triaminotriethylamine, en: ethylenediamine) were investigated.The photolysis of complex 4 in a neutral aqueous solution produced a μ-hydroxo-μ-peroxo-dicobalt(III) complex, 2-2)Co(tren)>3+, together with a mononuclear cobalt(III) complex, 3+.A mononuclear complex and Co2+ were produced in the photolyses of μ-hyperoxo complexes 1 and 2 containing NH3 ligand in neutral aqueous soltuions.In acidic media, only mononuclear complex and Co2+ were produced in the photolysis of all μ-hyperoxo complexes examined.Quantum yields of the complexes with NH3 increased with increasing the number of coordinated NH3 (ψ=0.25, 0.11, 0.023, and 0.028 for complexes 1, 2, 3, and 4, respectively, at 365 nm irradiation in neutral region).The quantum yields obtained in acidic solutions were similar in magnitude to those obtained in neutral solutions.

Synthesis and reactivity of the pentaamminecobalt(III) linkage isomers of succinimide

The linkage isomers of (succinimido)pentaamminecobalt(III) have been selectively synthesized and characterized by 1H and 13C NMR, IR, and UV-visible spectroscopies. The deprotonated imide ligand bonds to the metal through oxygen or nitrogen. The oxygen-bonded isomer is the less stable form. In water (ksON = 1.7 × 10-4 s-1, 25°C) and Me2SO (ksON = 5.1 × 10-5 s-1) it spontaneously isomerizes to the nitrogen-bonded form; in aqueous acid (pKa = 2.7, I = 0.1 M, LiClO4) and acidified Me2SO it protonates and rapidly solvolyzes; the protonated species in water has reactivity comparable (kH = 2.3 × 10-2 s-1, I = 0.1 M, LiClO4, 25°C) to the most reactive isolable [(NH3)5CoX]n+ species known. In aqueous base three competing reactions have been detected, namely solvolysis (40%, 25°C), base-catalyzed O- to N-bonded linkage isomerization (30%), and nucleophilic attack on the coordinated carbonyl group by hydroxide ion leading to the formation of the carboxylate-bonded isomer of (succinamato)pentaamminecobalt(III) (30%) (kOH(obsd) = 9.0 × 10-2 M-1 s-1, I = 0.1 M, KF, 25°C). The individual rates and rate laws for all these reactions have been determined. In acid and base the nitrogen-bonded imido complex is less reactive than the O-bonded form. It is base hydrolyzed relatively slowly, and a term second order with respect to hydroxide ion is dominant in the rate law (kN = 6.1 × 10-3 M-2 s-1, I = 1.0 M, NaClO4, 25°C); 18O studies establish the reversible addition of OH- in the first step. The product is the nitrogen-bonded succinamato complex, which has been characterized through crystallization in its basic and acidic forms (pKa = 1.8 (amide) and 3.55 (carboxylic acid), I = 1.0 M, NaCl, 25°C). The succinimido-N complex is protonated in water and Me2SO only in very strong acid. The protonated species has been crystallized and characterized; it is a strong acid (pKa 1/2 = days, 25°C). A N- to O-bonded isomerization reaction has not been detected. The structure and reactivity of these imide complexes are compared with those of the related amide and urea complexes.

Cobalt-induced facile degradation of phenylurea to ammonia, carbon dioxide, and anilinium ion and other reactions of linkage isomeric cobalt(III) complexes of phenylurea

A search for metal ion promoted hydrolysis of urea and the factors influencing linkage isomerization on a metal has led us to prepare and examine reactivities of N- and O-bound phenylurea complexes of pentaamminecobalt(III). The N-bonded isomer reacts in aqueous acid to yield principally [Co(NH3)6]3+, CO2, and anilinium ion (ca. 70%) but also via parallel paths leading to [(NH3)5CoOC(NH2)NHC6H 5]3+ (linkage isomerization) and [(NH3)5CoOH2]3+ (aquation). The major path involves an elimination reaction of [(NH3)5CoNH2CONHC6H 5]3+ to give anilinium ion and [(NH3)5CoNCO]2+. The latter complex, which has been isolated and characterized, is known to undergo rapid hydration (pH 3)5CoNH2CO2H]3+, which subsequently decomposes along three parallel paths to [Co(NH3)6]3+ and traces of [(NH3)5CoOH2]3+ and [(NH3)5CoOCONH2]3+. Kinetic data for the three parallel reactions of [(NH3)5CoNH2CONHC6H 5]3+ in aqueous HClO4 (1.0 M, 25.0°C) are kelim = 1.04 × 10-2s-1 (elimination), kNO = 2.39 × 10-3s-1 (isomerization), and kaq = 1.13 × 10-3s-1 (aquation). A single-crystal structure reveals that the urea exo C-N bond is 0.11 A? longer than the endo C-N bond and, as in uncoordinated phenylurea, the electron-with-drawing phenyl ring is neither planar with nor conjugated to the urea moiety. These features are likely retained in the protonated form and account for the facility of the elimination path. By contrast, neither elimination nor hydrolysis of the O-bonded phenylurea complex was detected; instead it slowly undergoes parallel aquation and O- to N-linkage isomerization. Both processes are base-catalyzed, and each obeys a rate law of the form k(obsd) = ks + kOH[OH-]. The equilibrium constant (K′NO = kNO/kON = 166) reflects the strong thermodynamic preference for the O rather than the N terminus of the neutral phenylurea molecule. However, the observed equilibrium is pH-dependent (K′(obsd) = K′NO[H+]/(Ka + [H+])); for pH > 3, the N-bonded isomer is more stable due to its selective deprotonation (K′NO(obsd) ≈ 10-5, pH 6.2). The single-crystal structure determination of [(NH3)5CoNHCONHC6H5](ClO 4)2·H2O shows the cobalt in an approximately octahedral environment with phenylurea bonded as its anion through the indicated nitrogen center. As observed for the free ligand, the phenyl substituent is twisted (37°) with respect to the approximately planar urea moiety. The compound crystallizes in the monoclinic system (β = 91.64°), with V = 1887.0 A?3, space group C2/c, Z = 8, a = 15.751 (6) A?, b = 12.277 (5) A?, c = 9.762 A?, and R = 0.046 and Rw = 0.043 for 1381 diffractometer data (244 variables) with I ≥ 3σ(I), μ = 105.47 cm-1, and F(000) = 1023.96.

Partitioning of Reaction Paths in Ce(IV) Induced Electron Transfer in Azidopentaamminecobalt(III) Perchlorate

Cerium(IV) induces electron transfer in azidopentaamminecobalt(III) perchlorate yielding N2 (ca. 95percent), Co(II) (ca. 20percent) and aquopentaamminecobalt(III) (ca. 80percent) as products.The decrease in absorbance at 520 nm for cobalt(III) complex corresponds to nearly 90percent of initial absorbance, as part of the azide complex becomes aquopentaamminecobalt(III) complex which absorbs to some extent at this wavelength.Though the stoichiometry of cerium(IV) to unbound N3(-) is 1 : 1, the ratio of Ce(IV) to azidocobalt(III) complex is about 1 : 0.87, accounting for about 20percent reduction at one of the Co(III) in dimeric complex, III - N6 - CoIII>(4+).The kinetic and stoichiometric results have been accounted for by a suitable mechanism involving such a dimeric complex.

Photochemistry of Co(III)-penta-ammine Oxalate and Co(III)-tetra-ammine bis-Oxalate Complexes

Photochemistry of Co(III)-penta-ammine oxalate and Co(III)-tetra-ammine bis-oxalate complexes has been studied in aqueous solution (pH = 4.63-2.7) using different wavelengths of irradiation under both aerobic and anaerobic media.Quantum yields of redox and aquated products have been determined.For penta-ammine oxalate complex the redox yield increases in the order 490 .- radical by oxygen (evidenced by formation of H2O2) in the latter case.In general the simple radical pair model is not sufficient to explain the photochemical behaviour of the complexes; the distribution of product yields depends on the spectroscopic state of excited species.

Kinetics and mechanism of Bromine Oxidation of Coordinated Formate

The kinetics and mechanism of bromine oxidation of formatopentaamminecobalt(III) perchlorate have been investigated.The rate of loss of bromine was found to bee first order in and .The observed second order rate constant, kobs for decrease of bromine is given by the expression, kobs=k/->+> HOBr seems to be the active oxidant species.The values for the rate and activation parameters have been computed and a possible mechanism has been suggested