New σ-bonded bisalkyl and alkyl-aryl cobalt complexes of bis(diacetylmonoxime-imino)propane 1.3

Costa, G.; Mestroni, G.; Licari, T.; Mestroni, E.

doi:10.1016/0020-1650(69)80030-9

Cited by 25 publications

(11 citation statements)

References 5 publications

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“…5 shows some curvature at high acid concentration and a zero intercept, which can be interpreted in terms of the protonation mechanism outlined in eqn (10) and (11), for which the [H + ] dependence of k obs can also be expressed by eqn (9), where [L] = [H + ]. The protonated intermediate formed in eqn (10) is formulated in a general way since it is uncertain on which site of the ligands the proton is located. The subsequent reaction step leads to the displacement of a methyl group accompanied by the release of methane.…”

Section: R Co Hdmgmentioning

confidence: 92%

“…The kinetic data reported for the protonation reaction sequence, (eqn (10) and ( 11)), presented in Fig. 5 exhibits some curvature from which K = 0.56 ± 0.06 M -1 and k = 120 ± 12 s -1 were estimated.…”

Section: R Co Hdmgmentioning

confidence: 99%

“…It is well known that mono-alkylated complexes such as trans-[(R)Co((DO)(DOH)pn)H 2 O] + and trans-[(R)Co(Hdmg) 2 H 2 O] do not undergo dealkylation in acidic media. However, dialkyl iminooxime complex in dilute acid generates the mono alkylaqua complex and methane according to eqn (10) and (11). The products of the reaction suggest that a heterolytic cleavage of the cobalt-carbon bond takes place.…”

Section: R Co Hdmgmentioning

confidence: 99%

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Mechanistic behaviour of alkylcobaloximes and imino-oxime complexes related to vitamin B12

et al. 2009

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The ligand substitution reactions of complexes of the type trans-[(R)Co(Chel)S](+/0) with L, where chel = (DO)(DOH)pn = 2,2'-(1,3-diaminopropanebis(2-methyl-3-butanone)oxime), R = CH(3), L = imidazole, pyrazole, 1,2,4-triazole and 1-methylimidazole, and S = water and MeOH, and chel = (Hdmg)(2) = bis(dimethylglyoximate), R = CH(2)Cl, CH(2)Br, and CH(2)I, L = thiourea and pyridine, and S = water, were studied in detail as a function of temperature and pressure. The reported activation parameters (DeltaH, DeltaS and DeltaV) support the operation of a dissociative interchange (I(d)) mechanism. Complexes of the type trans-[RCo(Hdmg)(2)L] (R = CH(2)Cl, CH(2)Br, and CH(2)I; L = H(2)O and Py) were fully optimized at the B3LYP/LANL2DZp level, and the structural data support the mechanistic assignment based on the reported activation parameters. For the reaction of trans-[(CH(3))(2)Co((DO)(DOH)pn)] with acid, the activation parameters (DeltaH, DeltaS and DeltaV) were found to be 37 +/- 1 kJ mol(-1), -86 +/- 3 J mol(-1) K(-1) and -18.9 +/- 0.7 cm(3) mol(-1), respectively, and support a protonation mechanism.

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Section: R Co Hdmgmentioning

confidence: 92%

Section: R Co Hdmgmentioning

confidence: 99%

Section: R Co Hdmgmentioning

confidence: 99%

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Mechanistic behaviour of alkylcobaloximes and imino-oxime complexes related to vitamin B12

et al. 2009

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“…This represents only the second report of such compounds (44). The formation of these substances implies the existence of an intermediate nucleophile containing both cobalt(I) and a Co-C bond, for the second alkyl bond is formed by first reducing the cobalt ( III )-monoalkyl complex and then letting it function as a nucleophile in displacing halide from an alkyl halide.…”

Section: New Vitamin B12 Coenzyme Modelsmentioning

confidence: 96%

Chemical Foundations for the Understanding of Natural Macrocyclic Complexes

Busch

Farmery

Goedken

et al. 1971

Advances in Chemistry

118

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Studies on template effects, condensation reactions, oxida tive dehydrogenations, catalytic hydrogenations and ligand deprotonations have made it possible to synthesize almost any tetradentate macrocyclic ligand one might choose. The principle of multiple juxtapositional fixedness is ex plained and applied to metal binding in enzymes. The inflexibility of the metal ion site in the porphyrin ring is contrasted to those in synthetic macrocycles. TAAB, a related tetraazaannulene, can vary its inner site while other rings fold when the metal ion is too large. Many model compounds for high-spin, five-coordinate deoxyhemoglobin and deoxymyoglobin are presented. The Fe III -O-Fe III bridge is extremely hard to break when iron is bound to a tetraazaannulene (TAAB). Iron is a better catalyst for oxi dative dehydrogenation of its own ligand than is nickel.

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“…Preparation of (CH3)2Co(BDMl,3pn). The complex was prepared by a modification of the method used by Costa et al 29 [Co-(BDM1,3pn)(H20) 2] (C104) 2 was used as the starting material instead of [Co(BDMl,3pn)I2]. In this way, contamination of the product by [CH3Co(BDMl,3pn)I] was avoided and yields in excess of 85% were obtained with regularity.…”

Section: Introductionmentioning

confidence: 99%

Methylation of zinc(II), cadmium(II), and lead(II) by a trans-dimethylcobalt complex

Witman¹,

Weber²

1976

Inorg. Chem.

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New σ-bonded bisalkyl and alkyl-aryl cobalt complexes of bis(diacetylmonoxime-imino)propane 1.3

Cited by 25 publications

References 5 publications

Mechanistic behaviour of alkylcobaloximes and imino-oxime complexes related to vitamin B12

Mechanistic behaviour of alkylcobaloximes and imino-oxime complexes related to vitamin B12

Chemical Foundations for the Understanding of Natural Macrocyclic Complexes

Methylation of zinc(II), cadmium(II), and lead(II) by a trans-dimethylcobalt complex

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