Metal-ion catalysed aquation of transition metal complexes

Banerjee, Rupendranath

doi:10.1016/0010-8545(85)80033-3

Cited by 21 publications

(7 citation statements)

References 115 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Mercury(II) aquaion is known to efficiently induce aquation of both halide and pseudo-halide ligands in robust classical complexes [13] as well as in organometallic species. [14] A rate enhancement of up to four orders of magnitude [10,11] has been observed for thiocyanato ligand aquation due to coordination of mercury(II) to the uncoordinated sulfur atom of this ligand.…”

Section: Kinetics Of the Mercury(ii)-induced Aquation Reactionmentioning

confidence: 99%

Kinetics and Mechanism of Ligand Substitution in Some Chromium(III) Tetraaza Macrocyclic Complexes in Acidic Media: Differences in Reactivity Between cis and trans Isomers

et al. 2006

View full text Add to dashboard Cite

Thiocyanate anation of the macrocyclic complexes cis‐[Cr(cycb)(OH2)2]3+ and trans‐[Cr(cyca)(OH2)2]3+ (cycb and cyca are rac‐ and meso‐5,5,7,12,12,14‐hexamethyl‐1,4,8,11‐tetraazacyclotetradecane, respectively), and mercury(II)‐induced aquation of the product thiocyanato‐N complexes, has been studied in acidic solution. The rate retardation with an increase of the acid concentration for both types of reactions follows the rate expression kobs = (k1 + k2Ka/[H+(aq)])/(1 + Ka/[H+(aq)]), corresponding to parallel reaction paths through aqua and hydroxo complexes. Some general trends in the differences in reactivity between the two geometrical isomers have been observed and are discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

show abstract

Section: Kinetics Of the Mercury(ii)-induced Aquation Reactionmentioning

confidence: 99%

Kinetics and Mechanism of Ligand Substitution in Some Chromium(III) Tetraaza Macrocyclic Complexes in Acidic Media: Differences in Reactivity Between cis and trans Isomers

et al. 2006

View full text Add to dashboard Cite

show abstract

“…Hydrolysis of square-planar halide complexes is also activated by Hg 2+ ion, and halide abstraction by the use of Hg(II) and Ag(I) is an established method for preparation of solvento complexes. , However, except for early studies of the mercury(II)-assisted aquation of [Pt(glycine)(NH 3 )X], X = Cl, Br, , and a few investigations of metal ion activated hydrolysis of cisplatin and some sterically hindered palladium complexes, − no quantitative mechanistic investigations of metal-assisted square-planar substitutions seem to have been published. The interpretation of the data in the few previous studies of square-planar systems conform to the halide bridge mechanism generally used for octahedral systems …”

Section: Introductionmentioning

confidence: 85%

“…Metal-assisted hydrolysis is well-known for octahedral complexes and has been reviewed . In particular, mercury(II)-promoted reactions of octahedral halide transition metal complexes have been extensively studied.…”

Section: Introductionmentioning

confidence: 99%

“…In particular, mercury(II)-promoted reactions of octahedral halide transition metal complexes have been extensively studied. The mechanism usually proposed for these reactions involves rapid formation of an M−X−Hg bridged intermediate followed by a rate-determining cleavage of the M−X bond . Occasionally, saturation kinetics have been observed and attributed to formation of halide-bridged intermediates.…”

Section: Introductionmentioning

confidence: 99%

“…Occasionally, saturation kinetics have been observed and attributed to formation of halide-bridged intermediates. These reactions have been perceived as essentially dissociative, and evidence of 5-coordinate intermediates has been obtained . In general terms, they can be regarded as chloride transfer processes to mercury(II) from another metal center.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Kinetics and Mechanism for Reversible Chloride Transfer between Mercury(II) and Square-Planar Platinum(II) Chloro Ammine, Aqua, and Sulfoxide Complexes. Stabilities, Spectra, and Reactivities of Transient Metal−Metal Bonded Platinum−Mercury Adducts

et al. 2000

View full text Add to dashboard Cite

The Hg2+aq- and HgCl+aq-assisted aquations of [PtCl4]2- (1), [PtCl3(H2O)]- (2), cis-[PtCl2(H2O)2] (3), trans-[PtCl2(H2O)2] (4), [PtCl(H2O)3]+ (5), [PtCl3Me2SO]- (6), trans-[PtCl2(H2O)Me2SO] (7), cis-[PtCl(H2O)2Me2SO]+ (8), trans-[PtCl(H2O)2M32SO]+ (9), trans-[PtCl2(NH3)2] (10), and cis-[PtCl2(NH3)2] (11) have been studied at 25.0 degrees C in a 1.00 M HClO4 medium buffered with chloride, using stopped-flow and conventional spectrophotometry. Saturation kinetics and instantaneous, large UV/vis spectral changes on mixing solutions of platinum complex and mercury are ascribed to formation of transient adducts between Hg2+ and several of the platinum complexes. Depending on the limiting rate constants, these adducts are observed for a few milliseconds to a few minutes. Thermodynamic and kinetics data together with the UV/vis spectral changes and DFT calculations indicate that their structures are characterized by axial coordination of Hg to Pt with remarkably short metal-metal bonds. Stability constants for the Hg2+ adducts with complexes 1-6, 10, and 11 are (2.1 +/- 0.4) x 10(4), (8 +/- 1) x 10(2), 94 +/- 6, 13 +/- 2, 5 +/- 2, 60 +/- 6, 387 +/- 2, and 190 +/- 3 M-1, respectively, whereas adduct formation with the sulfoxide complexes 7-9 is too weak to be observed. For analogous platinum(II) complexes, the stabilities of the Pt-Hg adducts increase in the order sulfoxide << aqua < ammine complex, reflecting a sensitivity to the pi-acid strength of the Pt ligands. Rate constants for chloride transfer from HgCl+ and HgCl2 to complexes 1-11 have been determined. Second-order rate constants for activation by Hg2+ are practically the same as those for activation by HgCl+ for each of the platinum complexes studied, yet resolved contributions for Hg2+ and HgCl+ reveal that the latter does not form dinuclear adducts of any significant stability. The overall experimental evidence is consistent with a mechanism in which the accumulated Pt(II)-Hg2+ adducts are not reactive intermediates along the reaction coordinate. The aquation process occurs via weaker Pt-Cl-Hg or Pt-Cl-HgCl bridged complexes.

show abstract

Kinetics of acid- and iron(III)-catalysed aquation of cis-(salicylato)-(methyl/ethylamine) bis(ethylenediamine)cobalt(III)

Pradhan

1993

Transition Met Chem

View full text Add to dashboard Cite

Metal-ion catalysed aquation of transition metal complexes

Cited by 21 publications

References 115 publications

Kinetics and Mechanism of Ligand Substitution in Some Chromium(III) Tetraaza Macrocyclic Complexes in Acidic Media: Differences in Reactivity Between cis and trans Isomers

Kinetics and Mechanism of Ligand Substitution in Some Chromium(III) Tetraaza Macrocyclic Complexes in Acidic Media: Differences in Reactivity Between cis and trans Isomers

Kinetics and Mechanism for Reversible Chloride Transfer between Mercury(II) and Square-Planar Platinum(II) Chloro Ammine, Aqua, and Sulfoxide Complexes. Stabilities, Spectra, and Reactivities of Transient Metal−Metal Bonded Platinum−Mercury Adducts

Kinetics of acid- and iron(III)-catalysed aquation of cis-(salicylato)-(methyl/ethylamine) bis(ethylenediamine)cobalt(III)

Contact Info

Product

Resources

About