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Berezin, D. B.; Shukhto, O. V.; Galanin, N. Е.

doi:10.1023/a:1025150018834

Cited by 6 publications

(15 citation statements)

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“…The kinetic parameters of the dissociation of com plexes 3 and 54-56 in glacial acetic acid were deter mined by spectrophotometry (Table 4). 75 Using these parameters, one can estimate the stabilities of zinc tetrabenzoporphyrinates with different number of meso phenyl substituents. It is known 76 that unsubstituted zinc tetrabenzoporphyrinate does not dissociate in glacial ace tic acid, yet dissociating in the presence of 4 M H 2 SO 4 in DMSO (k eff = 3.89•10 -6 s -1 ).…”

Section: Physicochemical and Spectroscopic Properties Of Tetrabenzopomentioning

confidence: 99%

meso-Aryltetrabenzoporphyrins. Synthesis and properties

2008

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The most considerable achievements in the synthesis and investigations of meso aryl tetrabenzoporphyrins and their metal complexes are reviewed. The choice of the route to, and the properties of, these compounds depends on the nature and number of meso aryl substituents. The reviewed synthetic methods are compared. Selected physicochemical and spectroscopic properties of meso aryltetrabenzoporphyrins are analyzed.

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Section: Physicochemical and Spectroscopic Properties Of Tetrabenzopomentioning

confidence: 99%

meso-Aryltetrabenzoporphyrins. Synthesis and properties

2008

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“…In most cases, complexes ML MC have low stability and undergo solvolytic dissociation in solutions of the strong donor solvents (DMSO, DMF, Py, etc. ):In this connection, two possible stoichiometric mechanisms of metal exchange were established for such L MC 2-complexes, namely, the association and dissociation mechanisms [1,6]. The association mechanism is connected with a high-rate formation of bimetallic intermediate: (4) which further decomposes slowly (5)…”

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“…Although some studies [1,2] yielded negative results, they did not consider the nature of these interactions. In this work, an attempt is made to determine the nature of interactions occurring during reactions of metal exchange on the basis of new results obtained and the literature data.…”

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confidence: 99%

“…In the previous report [1], the literature data on the kinetics and mechanisms of metal exchange reactions of macrocyclic complexes (MC) of a nonporphyrin type (1) and metal porphyrinates (2) with metal salts in organic solvents were analyzed: ML MC + M ' X 2 ( solv ) n -2 M ' L MC + MX 2 ( solv ) n -2 , (1)…”

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“…(2) In reactions (1) and (2), MP and M'P are metal porpyrinates, M ' X 2 ( solv ) n -2 is solvated complex of a salt with ï -anion, ML MC and M'L MC are macrocyclic complexes with azacrown, thiacrown, oxaazacrown, and oxathiacrown ethers.…”

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Some peculiarities of metal exchange reactions in porphyrin and phthalocyanine complexes

et al. 2005

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The metal exchange (transmetalation) reactions in porphyrin complexes represent complicated coordination interactions. Although some studies [1, 2] yielded negative results, they did not consider the nature of these interactions. In this work, an attempt is made to determine the nature of interactions occurring during reactions of metal exchange on the basis of new results obtained and the literature data.In the previous report [1], the literature data on the kinetics and mechanisms of metal exchange reactions of macrocyclic complexes (MC) of a nonporphyrin type (1) and metal porphyrinates (2) with metal salts in organic solvents were analyzed:In reactions (1) and (2), MP and M'P are metal porpyrinates, M ' X 2 ( solv ) n -2 is solvated complex of a salt with ï -anion, ML MC and M'L MC are macrocyclic complexes with azacrown, thiacrown, oxaazacrown, and oxathiacrown ethers.Reactions (1) and (2) have intricate activation mechanisms due to a simultaneous formation of several M'-L MC and M'P bonds, dissociation of some M-L MC and MP bonds in the course of a metal exchange, and destruction of one solvated acido complex with the formation of another one. Obviously, reactions (1) and (2) occur through multicenter interactions typical of complexes with macrocyclic effect [3][4][5]. These interactions are determined by a mechanism underlying reactions (1) and (2). In most cases, complexes ML MC have low stability and undergo solvolytic dissociation in solutions of the strong donor solvents (DMSO, DMF, Py, etc.):In this connection, two possible stoichiometric mechanisms of metal exchange were established for such L MC 2-complexes, namely, the association and dissociation mechanisms [1,6]. The association mechanism is connected with a high-rate formation of bimetallic intermediate: (4) which further decomposes slowly (5)The high-rate stage is a bimolecular reaction, while the low-rate stage is a monomolecular reaction.The metal exchange is the second-order reaction in reagents. In the case of nonrigid macrocycles, which include heterosubstituted (N and S) crown ethers, the formation of intermediate is slightly complicated, since due to the low stability of coordination bonds, some of them are transferred by ligand L MC from M to M' with a change in the ligand conformation.When the formation of an intermediate is complicated due to some reasons, for example, when the M-L MC bond is considerably stronger than the M'-L MC bond or when the coordination sphere of M ' X 2 ( solv ) n -2 solvate is stable, the metal exchange reaction can follow the dissociation mechanism: 1Provided that the stability constants of macrocycles of both metals and the rates of their complexation with 1 Charges in reactions (6a) and (6b) are omitted.Abstract -Kinetics of metal exchange reaction Cd(II) Zn(II) and Cd(II) Cu(II) in Cd complexes with tetraphenylporphyrin in DMSO is studied. Reaction with Cu(II) nitrate occurs in both cases more vigorously as compared to that with Zn(II) nitrate. Conditions for metal exchange reactions are studied depending...

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Some peculiarities of metal exchange reactions in porphyrin and phthalocyanine complexes

Berezin¹,

Shukhto²,

Nikol?skaya³

et al. 2005

Russ J Coord Chem

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The metal exchange (transmetalation) reactions in porphyrin complexes represent complicated coordination interactions. Although some studies [1, 2] yielded negative results, they did not consider the nature of these interactions. In this work, an attempt is made to determine the nature of interactions occurring during reactions of metal exchange on the basis of new results obtained and the literature data.In the previous report [1], the literature data on the kinetics and mechanisms of metal exchange reactions of macrocyclic complexes (MC) of a nonporphyrin type (1) and metal porphyrinates (2) with metal salts in organic solvents were analyzed:In reactions (1) and (2), MP and M'P are metal porpyrinates, M ' X 2 ( solv ) n -2 is solvated complex of a salt with ïanion, ML MC and M'L MC are macrocyclic complexes with azacrown, thiacrown, oxaazacrown, and oxathiacrown ethers.Reactions (1) and (2) have intricate activation mechanisms due to a simultaneous formation of several M'-L MC and M'P bonds, dissociation of some M-L MC and MP bonds in the course of a metal exchange, and destruction of one solvated acido complex with the formation of another one. Obviously, reactions (1) and (2) occur through multicenter interactions typical of complexes with macrocyclic effect [3][4][5]. These interactions are determined by a mechanism underlying reactions (1) and (2). In most cases, complexes ML MC have low stability and undergo solvolytic dissociation in solutions of the strong donor solvents (DMSO, DMF, Py, etc.):In this connection, two possible stoichiometric mechanisms of metal exchange were established for such L MC 2-complexes, namely, the association and dissociation mechanisms [1,6]. The association mechanism is connected with a high-rate formation of bimetallic intermediate: (4) which further decomposes slowly (5)The high-rate stage is a bimolecular reaction, while the low-rate stage is a monomolecular reaction.The metal exchange is the second-order reaction in reagents. In the case of nonrigid macrocycles, which include heterosubstituted (N and S) crown ethers, the formation of intermediate is slightly complicated, since due to the low stability of coordination bonds, some of them are transferred by ligand L MC from M to M' with a change in the ligand conformation.When the formation of an intermediate is complicated due to some reasons, for example, when the M-L MC bond is considerably stronger than the M'-L MC bond or when the coordination sphere of M ' X 2 ( solv ) n -2 solvate is stable, the metal exchange reaction can follow the dissociation mechanism: 1Provided that the stability constants of macrocycles of both metals and the rates of their complexation with 1 Charges in reactions (6a) and (6b) are omitted.Abstract -Kinetics of metal exchange reaction Cd(II) Zn(II) and Cd(II) Cu(II) in Cd complexes with tetraphenylporphyrin in DMSO is studied. Reaction with Cu(II) nitrate occurs in both cases more vigorously as compared to that with Zn(II) nitrate. Conditions for metal exchange reactions are studied depending o...

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Untitled

Cited by 6 publications

References 4 publications

meso-Aryltetrabenzoporphyrins. Synthesis and properties

meso-Aryltetrabenzoporphyrins. Synthesis and properties

Some peculiarities of metal exchange reactions in porphyrin and phthalocyanine complexes

Some peculiarities of metal exchange reactions in porphyrin and phthalocyanine complexes

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