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Showing papers on "Aquation published in 1969"




Journal ArticleDOI
TL;DR: In this paper, a kinetic study of the reversible reaction by electrophoresis and neutron activation analysis had led to evaluation of rate and equilibrium constants and a discussion of mechanisms, and the rate constant for aquation of Ir(H2O)Cl52− was studied at 25-50°C and μ = 0·130 M, and k1 = (3·40±0·05) × 10− sec−, Eα1=28·11± 0·57 Mcal mole−1 and log PZ = 16·13 ± 0·40

23 citations



Journal ArticleDOI
TL;DR: In this article, the authors examined the kinetics of the aquation reaction of trans- chloro-tertiary phosphine-Co III -bisdimethyl glyomixato complexes and pKa of the corresponding aquo-complexes.

18 citations





Journal ArticleDOI
TL;DR: In this article, the kinetics of the silver ion induced aquation of iodopentamminecobalt(III) perchlorate was studied at 44·9°C in the range of ionic strengths 4·9 × 10−2 M−8·06 × 10 −2 M.

12 citations




Journal ArticleDOI
TL;DR: The first order rate constants for the solvolytic aquation of the cations: cis-[Co(en)2Cl pyridine]2+, cis-[ Co(en)-2Cl β-picoline]2+ and cis]-Co-en-2Cl γpicoline ]2+ have been determined in this paper.



Journal ArticleDOI
TL;DR: In this paper, a series of aqueous ethanol and formic acid solvent mixtures were used for tris-(1,10-phenanthroline)iron(II) complexes.
Abstract: Rates of aquation of tris-(1,10-phenanthroline)iron(II) complexes have been determined in series of aqueous ethanol and aqueous formic acid solvent mixtures. Variation of aquation rate with solvent composition for the 5-nitro- and 4,7-dimethyl complexes in the two series of solvents suggests that, in the favourable case of the electron-withdrawing nitro-substituent and of aqueous ethanol as solvent, bond-making between iron and incoming water is of some significance in transition-state formation. An attempt is made to extend the use of the Grunwald–Winstein concept of the relation between reactivity and solvating power of solvents to these inorganic systems.

Journal ArticleDOI
TL;DR: In this paper, the dicyano-cobalt(III) complex, cis-[Co(CN)2en2]NO3, has been found to be reduced in three steps at the dropping mercury electrode (DME).
Abstract: In an aqueous solution containing an excess of ethylenediamine, i. e., under the conditions where the aquation is prevented, the dicyano-cobalt(III) complex, cis-[Co(CN)2en2]NO3, has been found to be reduced in three steps at the dropping mercury electrode (DME). The first step, corresponding to the acceptance of one electron, represents the reduction from the cobalt(III) to the cobalt(II) state, while the second and the third step were interpreted as being due to the reduction of two kinds of the cobalt(II) species formed by the overall rearrangement of ligands in solution. One such kind of cobalt species is the binuclear tetracyanocobaltate(II) complex, [Co(CN)4-en-Co(CN)4]4−, which is reduced to the metal through the cobaltate(I) complex, while the other is the cobalt(II) complexes with ethylenediamines in an equilibrium state, which are reduced directly to the metal at the DME. Namely, the second step represents the reduction from the cobalt(II) complex of the former to the cobalt(I) state, while the ...


Book ChapterDOI
01 Jan 1969
TL;DR: The mechanisms of solvent substitution reactions of octahedral complex ions have been the subject of considerable study in recent years as mentioned in this paper, and chromium compounds have played an important role because the d 3electronic configuration of the Cr+3 ion imparts properties to its compounds which make them especially valuable for studies involving kinetics, mechanisms, and the dependence of reaction rates on geometrical and electronic factors.
Abstract: The mechanisms of solvent substitution reactions of octahedral complex ions have been the subject of considerable study in recent years.1-5 In these studies, chromium compounds have played an important role because the d 3electronic configuration of the Cr+3 ion imparts properties to its compounds which make them especially valuable for studies involving kinetics, mechanisms, and the dependence of reaction rates on geometrical and electronic factors. In particular, chromium(III) compounds are sufficiently nonlabile so that intermediates can often be isolated and characterized, and there can be a stepwise replacement of one set of ligands by another set, with widely differing ligand field strength, without incurring a disruptive spin change.

Journal ArticleDOI
TL;DR: The second-order rate constants for the mercury-catalysed aquation of Co en2(RNH2)Cl]2+ cations, where R is H, Me, Et, Prn, and Pri, were measured in aqueous solution over a range of temperatures.
Abstract: The second-order rate constants for the mercury(II)-catalysed aquation of cis-[Co en2(RNH2)Cl]2+ cations, where R is H, Me, Et, Prn, and Pri, have been measured in aqueous solution over a range of temperatures. The results are discussed in terms of the formation of an activated complex Co–Cl–Hg, which yields the aquo-product by a unimolecular aquation. In the case of R = H, the investigations have been extended to the corresponding bromocation, which reacts some 500 times faster than its chloro-analogue.

Journal ArticleDOI
TL;DR: In this paper, the rate of aquation and chloride substitution reactions of Pd dien NH32+ have been studied in acid aqueous solution and the replacement of NH3 by Cl− follows the expected two-term rate law but is preceded by rapid side reactions involving the opening of one ring of the chelated ligand.
Abstract: The rate of aquation and chloride substitution reactions of Pd dien NH32+ have been studied in acid aqueous solution. The replacement of NH3 by Cl– follows the expected two-term rate law but is preceded by rapid side reactions involving the opening of one ring of the chelated ligand.

Journal ArticleDOI
TL;DR: In this paper, a study of acid hydrolysis of acidopentaammines of ruthenium(III) showed that aquation is not the only reaction taking place.
Abstract: A study of acid hydrolysis of acidopentaammines of ruthenium(III) shows that aquation is not the only reaction taking place. For the halopentaammines, both in the presence and absence of light, reduction occurs with the formation of ruthenium(II) and free halogen. When azide, instead of halide ion, is coordinated to the metal, ruthenium(II) nitrogen complexes can be prepared. The solid state decomposition of [Ru(trien)(N3)2]+ ion to [Ru(trien)N3N2]+ is described.


Journal ArticleDOI
TL;DR: In this paper, the first-order kinetics of the reaction of aquo-chloro complex (NH3)4(H2O)Co·NH2·Co(Cl))44+ were studied in the range 15-45° in perchlorate media (µ 0·1 M and 2·0M).
Abstract: The kinetics of the reaction of the aquo-chloro complex (NH3)4(H2O)Co·NH2·Co(Cl)(NH3)44+, in which a hydroxo-bridge is formed, and the corresponding reactions of the aquo-bromo- and diaquo-complexes, (NH3)4(H2O)Co·NH2·Co(Br)(NH3)44+ and (NH3)4(H2O)Co·NH2·Co(H2O)(NH3)45+: [graphic omitted] have been studied in the range 15–45° in perchlorate media (µ 0·1 M and 2·0M). The reactions are first-order in complex, the hydrogen-ion dependence being of the form kobs=k1+k2′[H+]–1 over the pH range 0–3. The rate constant, k1, corresponds to the reaction as in (i), and k2′ in all probabilty to the reaction of the related hydroxo-complex as in (ii): [graphic omitted]. At 25°, rate constants k1 are 101—103 times greater than for the aquation of mononuclear complexes of general formula CoIII(NH3)5Xn+. Enthalpies of activation for k1 are more favourable (ca. 8 kcal.mole–1), and entropies of activation less favourable (10–20 e.u.) than for the corresponding mononuclear complexes. Values for k2′ are very much dependent on the ionic strength, which has been varied over the range 0·001–2·0M for the aquo-chloro-complex. Possible mechanisms are considered.

Journal ArticleDOI
TL;DR: In this article, the first-order and second-order rate constants for chlorobenzylaminebis(ethylenediamine)-cobalt-(III) complexes were derived.
Abstract: Salts of one isomeric series of chlorobenzylaminebis(ethylenediamine)- cobalt-(III) type of cations have been prepared using a variety of benzylamine derivatives as ligands. They are tentatively assigned a cis-configuration on the basis of their visible spectra. The first- order rate constants for their solvolytic aquation have been measured. Both resonance contributions and steric factors from the benzyl radical, as well as inductive effects of its substituents, all have negligibly small influences on the rate of reaction. The second-order rate constants for the hydrolysis of these cations by base have also been determined. The labilizing powers of the benzylamine ligands in this reaction are very similar to those of open-chain aliphatic amines, and significantly different from those of aromatic amines. To see if reactivities depend on the distance of separation between cobalt and the benzene ring, the experiments are extended to the chloro(β- phenylethylamine)bis(ethylenediamine)cobalt(III) type of complexes.

Journal ArticleDOI
TL;DR: In this article, the acid-catalysed aquation of the tetranitrodiamminecobaltate(III) ion has been investigated over the temperature range 25-35° at an ionic strength of 2·5M in hydrochloric, nitric, and perchloric acid media.
Abstract: The acid-catalysed aquation of the tetranitrodiamminecobaltate(III) ion has been investigated over the temperature range 25–35° at an ionic strength of 2·5M in hydrochloric, nitric, and perchloric acid media. In the acid concentration range 0·5–2·5M, the increase in rate may be interpreted in all cases in terms of the reactions of the complex ions Co(NH3)2(NO2)4–, Co(NH3)2(NO2H), and Co(NH3)2(NO2)2(NO2H)2+. The retardation of the rate in hydrochloric and nitric acid media has been shown to involve the formation of ion-pairs. Reaction rate constants and thermodynamic parameters have been derived. Mechanisms of the reactions are discussed.

Journal ArticleDOI
TL;DR: In this paper, the formation equilibria and aquation kinetics of the monomalonatochromium(III) ion were investigated in acid solutions of ionic strength μ = 2.
Abstract: Formation equilibria and aquation kinetics of the monomalonatochromium(III) ion were investigated in acid solutions of ionic strength μ = 2. [Cr(mal)aq4]+ is stable in absence of excess malonate at pH ≳ 2; at lower pH it is progressively aquated, giving eventually complete aquation to [Craq6]+3 below pH 0.6. The aquation reaction is pseudo-first order with k = k0 + k1[H+]. The activation energies are δH = 24.9 and 19.4 kcal/mole for the k0 and k1 paths respectively. A comparison with the corresponding oxalato complexes shows that the smaller stability of the malonatocomplexes is of conditional nature, and depends to a great extent on the much larger protonation constants of the ligand anion. Es wurden das Bildungsgleichgewicht und die Hydrationskinetik des Monomalonatochrom(III)-Ions, [Cr(mal)aq4]+, in saurer Losung bei der Ionenstarke μ = 2 untersucht. Das Ion ist ohne uberschussiges Malonat bei pH ≳ 2 bestandig; in starker Saurem wird es zunehmend hydratisiert, bei pH < 0,6 vermutlich vollstandig zu [Craq6]3+. Der H2O/mal-Austausch verlauft scheinbar nach erster Ordnung, k = k0 + k1[H+]. Die Aktivierungsenergien betragen δH = 24,9 und 19,4 kcal/Mol fur den k0- bzw. k1- Weg. Die Malonato- werden mit bestandigeren Oxalatokomplexen verglichen.

Journal ArticleDOI
TL;DR: The volumes of activation for representative complexes of the series Co(NH3)5X3-n+ are equal (within experimental uncertainty) to the molar volume changes for the respective completed reactions as mentioned in this paper.
Abstract: The volumes of activation for aquation of representative complexes of the series Co(NH3)5X3–-n+ are equal (within experimental uncertainty) to the molar-volume changes for the respective completed reactions.

Journal ArticleDOI
TL;DR: In this article, a number of pure, nonionic compounds have been isolated from these, either in the solid state or in solution, and have been characterised by visible and i.r. spectroscopy.
Abstract: Previously reported sulphatobis(ethylenediamine)cobalt(III) complexes have been shown to be complex mixtures. A number of pure, nonionic compounds have been isolated from these, either in the solid state or in solution, and have been characterised by visible and i.r. spectroscopy. The kinetics of their solvolytic aquation and base hydrolysis have been investigated, and the labilising influence of the sulphato-ligand is briefly discussed. The behaviour of sulphate as a replaced ligand is compared with that of chloride.

Journal ArticleDOI
TL;DR: In this paper, the halogeno- and aquo-bis (dimethyl glyoximato)amminecobalt(III) complexes of the trans-[CoIIIX dg2(NH3)]-type have been found to be reduced to the metal through the cobalt(I) state in a 0.5M Na2SO4 aqueous solution at the dropping mercury electrode (DME), where the ligand, X, denotes the ion, Cl−, Br− or I−, or the molecule, OH2.
Abstract: The halogeno- and aquo-bis(dimethylglyoximato)amminecobalt(III) complexes of the trans-[CoIIIX dg2(NH3)]-type have been found to be reduced to the metal through the cobalt(I) state in a 0.5M Na2SO4 aqueous solution at the dropping mercury electrode (DME), where the ligand, X, denotes the ion, Cl−, Br−, or I−, or the molecule, OH2. The aquation of the halogeno complexes is found to take place more rapidly in solution in this order: Cl−

Journal ArticleDOI
TL;DR: In this article, the kinetics of the reactions trans-Ir(py) 2 Cl 4 −4 + H 2 O ⇌ k31 k13 trans- Ir(py 2 Cl 3 + Cl 4 + Cl − were studied in 0·01-3·7 F HCl or HClO 4 (μ = 0·03-3-7, NaCl and/or NaClO4 ) at 110·00°C.