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Aquation

About: Aquation is a research topic. Over the lifetime, 1443 publications have been published within this topic receiving 17507 citations.


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Journal ArticleDOI
TL;DR: In this paper, pressure dependencies of the rates of Hg(II) induced aquation of Co(NH 3 ) 5 Cl 2+, CoNH 3 5 Br 2+ Cr(NH3 ) 4 Cl 2 +, and Rh (NH 3 ] 5 Cl2+ were studied at 15°C, with the exception of the latter which was investigated at 25°C.

9 citations

Journal ArticleDOI
TL;DR: In this article, photoaccelerated aquation was found to proceed in the case of aquocyanochromates(III): [Cr(CN)5H2O]2− and [Cr (CN)3(H 2O)3].

9 citations

Journal ArticleDOI
TL;DR: The second-order kinetics of base-hydrolysis in perchlorate medium of I= 0.5-5.7 have been investigated in this paper, where the authors showed that the acid dissociation constant of co-ordinated imidazole is 105 times stronger as an acid than free imidaze.
Abstract: The kinetics of hydrolysis of cis-[CoX(imH)(en)2]2+(imH = imidazole; en = ethylenediamine; X = Cl or Br) cations have been investigated in perchlorate medium of I= 0.3 mol dm–3. In the range pH 0.5–5.7 the rate law for aquation takes the form –dln[CoIII]/dt=k1+k2KNH[H+]–1 where k1 and k2 are the aquation rate constants of [CoX(en)2(imH)]2+ and [CoX(im)(en)2]+ respectively and KNH is the acid dissociation constant of the co-ordinated imidazole. At 50 ° C the values of k1,k2KNH, ΔH‡, and ΔS‡ for the k1 path are (1.21 ± 0.02)× 10–5 s–1, (4.95 ± 0.11)× 10–11 mol dm–3 s–1, 92.3 ± 1.2 kJ mol–1, –54 ± 3 J K–1 mol–1 for the chloro-, and (5.52 ± 0.10)× 10–5 s–1, (33.4 ± 0.7)× 10–11 mol dm–3 s–1, 94.5 ± 0.3 kJ mol–1, and –34 ± 1 J K–1 mol–1 for the bromo-complex respectively. Values of k2 obtained from the base-hydrolysis studies are (1.28 ± 0.17)× 10–2 and (2.46 ± 0.22)× 10–2 s–1 at 31.8 °C for the chloro- and bromo-complexes respectively, and the imido-complex [CoCl(im)(en)2]+ also undergoes second-order base hydrolysis with a rate constant of 5.1 ± 1.0 dm3 mol–1 s–1 at the same temperature. The labilizing action of imidazole and its conjugate base on the Co–X bond appears to be comparable to that of pyridine and hydroxide respectively. Co-ordinated imidazole is 105 times stronger as an acid than free imidazole. The sulphate- and mercury(II)-catalysed aquations of both the substrates have also been studied. The value of kip/k1, where kip and k1 are the rate constants of aquation of [CoX(imH)(en)2]2+, [SO4]2– and [CoX(imH)(en)2]2+ species respectively, is 2.3 ± 0.2 at 60 °C for X = Cl and 4.6 ± 0.1 at 50 °C for X = Br. The mercury(II)-catalysed aquation follows second-order kinetics, –dln[CoIII]/dt=kHg[Hg2+] : at 30.5 °C the rate constant (kHg) and activation enthalpy and entropy are (3.48 ± 0.03)× 10–2 dm3 mol–1 s–1, 68.4 ± 0.7 kJ mol–1. and –48 ± 2 J K–1 mol–1 for the chtoro- and 12.4 ±0.5 dm3 mol–1 s–1, 53.4 ± 0.4 kJ mol–1, and –48 ± J K–1 mol–1 for the bromo-complex respectively.

9 citations

Journal ArticleDOI
TL;DR: In this article, the Stern-Volmer relationship was obtained for quenching of the uranyl emission by the complex, with the quench constant of 38 M−1.
Abstract: A monochromatic 436 nm irradiation of Co(CN)63− in a degassed aqueous phosphoric acid solution in the presence of the uranyl ion led to photoaquation of the complex without chemical changes in the uranyl ion, with the apparent quantum yield of 0.1, whereas direct photoaquation in the absence of the sensitizer was negligible under similar conditions. No thermal reaction was found. Stern-Volmer relationship was obtained for the quenching of the uranyl emission by the complex, with the quenching constant of 38 M−1. Energy transfer from the lowest triplet state of the uranyl ion to the lowest ligand field triplet state of the complex was likely involved.

9 citations

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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20232
20226
202111
202010
201914
20187