Kinetics of formation, dissociation, and isomerization reactions in complexes of cyanopyridines and benzonitrile with pentacyanoruthenate(II)
The complexes of pentacyanoruthenate(II) with 3- and 4-cyanopyridines and benzonitrile have been prepared in aqueous solution by mixing [Ru(CN)<inf>5</inf>(H<inf>2</inf>O)]3- with the appropriate ligand. With the cyanopyridines, the reaction proceeds in two stages: the first...
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todo:paper_14727773_v_n10_p1973_Almaraz2023-10-03T16:17:57Z Kinetics of formation, dissociation, and isomerization reactions in complexes of cyanopyridines and benzonitrile with pentacyanoruthenate(II) Almaraz, A.E. Gentil, L.A. Olabe, J.A. The complexes of pentacyanoruthenate(II) with 3- and 4-cyanopyridines and benzonitrile have been prepared in aqueous solution by mixing [Ru(CN)<inf>5</inf>(H<inf>2</inf>O)]3- with the appropriate ligand. With the cyanopyridines, the reaction proceeds in two stages: the first corresponds to the formation of a mixture of pyridine- and nitrile-bonded isomers, and the second to the linkage isomerization of the unstable (nitrile-bonded) isomer to the stable one (pyridine-bonded). The complexes exhibit metal-to- ligand and intra-ligand charge-transfer absorptions. The rate constants for the formation, k<inf>f</inf>, and dissociation, k<inf>d</inf>, of all the complexes have been determined (25 °C), as well as the isomerization rate constant, k<inf>iso</inf>, for the cyanopyridine complexes. Activation parameters were obtained for the formation reaction of the mixture of isomers, as well as for the dissociation reactions of the stable, pyridine-bonded complexes. The results for the formation and dissociation reactions are analysed in terms of dissociative mechanisms. From k<inf>f</inf> and k<inf>d</inf>, values of K<inf>st</inf>, the stability constants of the different complexes, have been calculated. The discussion is supported by previous data obtained for related pentacyanoferrate(II) and penta-ammineruthenium(II) complexes. Thus, the influence of the metal centre, M, as well as that of the auxiliary ligands, X, on the spectral and substitution reactivity properties of MX<inf>5</inf>L systems is described. Fil:Olabe, J.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_14727773_v_n10_p1973_Almaraz |
institution |
Universidad de Buenos Aires |
institution_str |
I-28 |
repository_str |
R-134 |
collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
description |
The complexes of pentacyanoruthenate(II) with 3- and 4-cyanopyridines and benzonitrile have been prepared in aqueous solution by mixing [Ru(CN)<inf>5</inf>(H<inf>2</inf>O)]3- with the appropriate ligand. With the cyanopyridines, the reaction proceeds in two stages: the first corresponds to the formation of a mixture of pyridine- and nitrile-bonded isomers, and the second to the linkage isomerization of the unstable (nitrile-bonded) isomer to the stable one (pyridine-bonded). The complexes exhibit metal-to- ligand and intra-ligand charge-transfer absorptions. The rate constants for the formation, k<inf>f</inf>, and dissociation, k<inf>d</inf>, of all the complexes have been determined (25 °C), as well as the isomerization rate constant, k<inf>iso</inf>, for the cyanopyridine complexes. Activation parameters were obtained for the formation reaction of the mixture of isomers, as well as for the dissociation reactions of the stable, pyridine-bonded complexes. The results for the formation and dissociation reactions are analysed in terms of dissociative mechanisms. From k<inf>f</inf> and k<inf>d</inf>, values of K<inf>st</inf>, the stability constants of the different complexes, have been calculated. The discussion is supported by previous data obtained for related pentacyanoferrate(II) and penta-ammineruthenium(II) complexes. Thus, the influence of the metal centre, M, as well as that of the auxiliary ligands, X, on the spectral and substitution reactivity properties of MX<inf>5</inf>L systems is described. |
format |
JOUR |
author |
Almaraz, A.E. Gentil, L.A. Olabe, J.A. |
spellingShingle |
Almaraz, A.E. Gentil, L.A. Olabe, J.A. Kinetics of formation, dissociation, and isomerization reactions in complexes of cyanopyridines and benzonitrile with pentacyanoruthenate(II) |
author_facet |
Almaraz, A.E. Gentil, L.A. Olabe, J.A. |
author_sort |
Almaraz, A.E. |
title |
Kinetics of formation, dissociation, and isomerization reactions in complexes of cyanopyridines and benzonitrile with pentacyanoruthenate(II) |
title_short |
Kinetics of formation, dissociation, and isomerization reactions in complexes of cyanopyridines and benzonitrile with pentacyanoruthenate(II) |
title_full |
Kinetics of formation, dissociation, and isomerization reactions in complexes of cyanopyridines and benzonitrile with pentacyanoruthenate(II) |
title_fullStr |
Kinetics of formation, dissociation, and isomerization reactions in complexes of cyanopyridines and benzonitrile with pentacyanoruthenate(II) |
title_full_unstemmed |
Kinetics of formation, dissociation, and isomerization reactions in complexes of cyanopyridines and benzonitrile with pentacyanoruthenate(II) |
title_sort |
kinetics of formation, dissociation, and isomerization reactions in complexes of cyanopyridines and benzonitrile with pentacyanoruthenate(ii) |
url |
http://hdl.handle.net/20.500.12110/paper_14727773_v_n10_p1973_Almaraz |
work_keys_str_mv |
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