Mechanistic Diversity Covering 15 Orders of Magnitude in Rates:  Cyanide Exchange on [M(CN)4]2- (M = Ni, Pd, and Pt)1

Monlien, Florence J.; Helm, Lothar; Abou-Hamdan, and Amira; Merbach, André E.

doi:10.1021/ic010917e

Cited by 21 publications

(13 citation statements)

References 41 publications

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“…As we descend the periodic table, however, Dq increases markedly, further stabilizing the square planar species, with the result that Pd(CN) 4 2À and Pt(CN) 4 2À have much increased stability relative to five-coordinate intermediates and undergo cyanide exchange much more slowly (Table 8.8). 152,153 For M(H 2 O) 4 2þ , substitution of an aqua ligand by A zÀ takes place some 10 5 -fold faster for M ¼ Pd than for M ¼ Pt; typical rate constants are given in Table 8.9, which also shows that the charge on A is not important-the fastest reactions listed are with neutral thiourea-and hence ion pairing is not a prerequisite for reaction, in contrast to I a processes. Recent evidence 96 that at least one (and probably two) extra water molecule(s) is (are) located at relatively long M-OH 2 distances above (and below) the MO 4 plane in aqueous solution implies that the intimate mechanism may not be the simple A process that is commonly invoked.…”

Section: Substitution In Square Planar Complexesmentioning

confidence: 98%

Ligand Substitution Dynamics in Metal Complexes

Swaddle

2010

Physical Inorganic Chemistry

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On the base of our previous studies due to the presence of halides in our complexes there is strong probability for obtaining coordination polymers. Crystal engineering well-defined as the understanding of intermolecular interactions in the context of crystal packing and the utilization of such understanding in the design of new solids with desired physical and chemical properties. Owing to the fact that the small changes in the ligands may play a significant role in the complexes, the organic ligand (1-naphtyl pyridine-2-carboxylate) (L), was synthesized. In order make more steric repulsion around of the complexes resulted in the substitution effect around of the naphtyl moiety was hired in the design. Relocation in the position of functional group was fulfilled our expectations. Three new mercury (II) halide complexes, [Hg(L)2Cl2] (1), [Hg(L)2Br2] (2) and [Hg(L)2I2] (3) were synthesized. All of the compounds were fully characterized using FT-IR, TGA, DSC, mass spectrometry, CHNOS elemental analyses, PXRD, NMR and SCXRD. The results indicate that metal-ligand polymerization controlled by substitution effect. The coordination geometry around the Hg (II) ion is seesaw shape in distorted tetrahedral geometry for compounds (1), (2) and (3) with τ4 of 0.74, 0.76 and 0.78, respectively. Due to the replacement of the functional group (mentioned substitution effect), flexibility of coodinated ligand was decreased. In the previously reported structures, the angle between two planes of aromatic rings in the analogous ligand was 78.37o which changed to the 59.47o, 50.75o and 64.90o for mercury halide series complexes. In present study these angles are 89.09, 89.73 and 88.90 for titled complexes based on new designed ligand. Consequently, this study emphasize that the substitution effect can play the significant role through the flexibility of designed ligand to control the metal-ligand polymerization.

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Section: Substitution In Square Planar Complexesmentioning

confidence: 98%

Ligand Substitution Dynamics in Metal Complexes

Swaddle

2010

Physical Inorganic Chemistry

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“…PGM adsorption studies by Vorob'ev-Desyatovskii et al (2012) Monlien et al (2002) suggested that pentacoordinated species for Pt and Pd do occur while Sharpe (1976) proposed Eq. (1) for Pd.…”

Section: Temperaturementioning

confidence: 99%

Factors affecting the elution of Pt, Pd and Au cyanide from activated carbon

Snyders

Bradshaw

Akdogan

et al. 2015

Minerals Engineering

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“…This group have also examined the kinetics of CN Ϫ exchange down the group Ni, Pd and Pt for the square planar complexes [M(CN) 4 ] 2Ϫ and also for protonated species. 223 2 nd order kinetics and an associative mechanism prevail throughout the group for CN Ϫ exchange, but there is an enormous variation in rate constants, quoted as 1 : 7 : 200 000 for Pt, Pd, Ni complexes respectively. From a molecular dynamics study of [Gd(egta)(H 2 O)] Ϫ in aqueous solution, the mean volume determined for the loss of H 2 O (7.2 cm 3 mol Ϫ1 ) is in reasonable agreement with experiment.…”

Section: -Coordinationmentioning

confidence: 99%

26 Mechanisms of reactions in solution

Davies

2003

Annu. Rep. Prog. Chem., Sect. A: Inorg. Chem.

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This year has seen the first Dalton Discussion in Inorganic Reaction Mechanisms. 1 This was an extremely interesting development. The overall theme was Inorganic Reaction Mechanisms: insights into chemical challenges and there were Dalton Perspectives papers in each of the themes: Applications of advanced experimental techniques, Advanced computational techniques, Small molecule activation, homogenous catalysis, Electron and energy transfer processes and Bioinorganic applications. These are to be found in the special March issue of Dalton and form a very good in-depth overview of the subject. The sessions on advanced instrumental and computational techniques covered the areas which will undoubtedly have a major effect on inorganic reaction mechanisms in the future: one by eventually allowing routine rate measurements of faster and faster reactions and the other by providing the theoretical background to the subject.As in previous years this review does not cover mechanisms of heterogeneous or solid state process, homogeneous catalysis of organic reactions, fluxional, electrochemical and photochemical processes, redox reactions involving organic substrates or organic reactions of the p-block elements.The fundamentals of theoretical modelling techniques used to calculate molecular energies and rate parameters for inorganic reactions have been described 2 and the phenomenon of so-called "phantom activation volumes" has been investigated and shown to be real activation volumes. 3 Redox reactions Long range electron transferReviews have appeared on aspects of charge-transfer processes in DNA, 4 the application of high pressure techniques to electron transfer reactions particularly in proteins and related species 5 and a theoretical analysis of donor-acceptor electron transfer, particularly super-exchange and thermally activated, mechanisms involving linear molecular bridges has appeared. 6 Electron transfer rates between the non-covalently bound flavine group at the active site to the surface of the protein in flavocytochrome c 3 from Shewanella frigidimarima

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Mechanistic Diversity Covering 15 Orders of Magnitude in Rates: Cyanide Exchange on [M(CN)₄]^2- (M = Ni, Pd, and Pt)¹

Cited by 21 publications

References 41 publications

Ligand Substitution Dynamics in Metal Complexes

Ligand Substitution Dynamics in Metal Complexes

Factors affecting the elution of Pt, Pd and Au cyanide from activated carbon

26 Mechanisms of reactions in solution

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