Reversible multi-electron reduction of 9,11,20,22-tetraaza-tetrapyridopentacene (tatpp) as axial ligand in the [(bpy)2ru(tatpp)]cl2 complex

The ruthenium complex, [(bpy)2Ru(tatpp)]2+ (12+; bpy is 2,2’-bipyridine where tatpp is 9,11,20,22-tetraaza tetrapyrido[3,2-a:2’3’-c:3”,2”-l:2”’,3”’]-pentacene) is a promising candidate for homogeneous solar photocatalysis, based on the coupling of light absorption by the (bpy)2Ru2+ chromophore moiet...

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Autores principales: Lezna, Reynaldo Oscar, Tacconi, Norma R. de, Janaratne, T., Muñoz Zúñiga, Jackeline, MacDonnell, F. M.
Formato: Articulo
Lenguaje:Inglés
Publicado: 2009
Materias:
Química
photocatalisis
renewable energy
solar hydrogen
spectroelectrochemistry
mechanisms
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/177407
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-177407
record_format dspace
spelling I19-R120-10915-1774072025-03-14T20:12:16Z http://sedici.unlp.edu.ar/handle/10915/177407 Reversible multi-electron reduction of 9,11,20,22-tetraaza-tetrapyridopentacene (tatpp) as axial ligand in the [(bpy)2ru(tatpp)]cl2 complex Lezna, Reynaldo Oscar Tacconi, Norma R. de Janaratne, T. Muñoz Zúñiga, Jackeline MacDonnell, F. M. 2009 2025-03-14T17:30:16Z en Química photocatalisis renewable energy solar hydrogen spectroelectrochemistry mechanisms The ruthenium complex, [(bpy)2Ru(tatpp)]2+ (12+; bpy is 2,2’-bipyridine where tatpp is 9,11,20,22-tetraaza tetrapyrido[3,2-a:2’3’-c:3”,2”-l:2”’,3”’]-pentacene) is a promising candidate for homogeneous solar photocatalysis, based on the coupling of light absorption by the (bpy)2Ru2+ chromophore moiety with the tatpp ability to receive and reversible store electrons in aqueous media. In the present communication, a combination of spectroelectrochemistry and voltammetry was applied to compare the electroreduction processes of tatpp in complex 12+ and as a Zn-tatpp adduct. For complex 12+, the radical [(bpy)2Ru(tatpp•-)]+(1•+) is the first electroreduced species that then converts to doubly-reduced, single-protonated [(bpy)2Ru(Htatpp-)]+ (H1+) and doubly-protonated [(bpy)2Ru(H2tatpp)]2+(H212+) by subsequent electron transfer (ET) and proton transfer (PT) reactions. Contrastingly, spectroelectrochemistry of the Zn-tatpp adduct showed negligible amounts of intermediate tatpp•- radical and dominance of double reduced Zn-(Htatpp-) and Zn(H2tatpp) species. Upon further electroreduction, doubly-reduced species form quadruply reduced, protonated species, in both systems. The four electrons uptake in complex 12+ is followed by a rapid homogeneous comproportionation reaction with the initial 12+ reactant leading to the regeneration of intermediate double-reduced species, H212+, while no comporportionation occurs for Zn-tatpp because the reduced species are film-confined, that is, restrained to move to the bulk solution for encounter with the initial reactant. El complejo de rutenio, [(bpy)2Ru(tatpp)]2+ (12+; bpy es 2,2’-bipiridilo donde tatpp es 9,11,20,22-tetraaza tetrapirido[3,2-a:2’3’-c:3”,2”-l:2”’,3”’]-pentaceno,) es un candidato promisorio para fotocatálisis solar homogénea, considerando su habilidad para acoplar la absorción de luz por medio del cromóforo (bpy)2Ru2+ con la propiedad del grupo tatpp para recibir y almacenar reversiblemente electrones en medio acuoso. En este trabajo se empleó una combinación de espectroelectroquímica y voltametría para comparar los procesos de electroreducción de tatpp en el complejo 12+y en el aducto Zn-tatpp. En el caso del complejo 12+, el radical [(bpy)2Ru(tatpp•-)]+(1•+) es el primer producto electroreducido que luego da lugar a la especie doble reducida, monoprotonada [(bpy)2Ru(Htatpp-)]+ (H1+) y a la doble protonada [(bpy)2Ru(H2tatpp)]2+(H212+) por reacciones de transferencia de electrones (ET) y de protones (PT). Por el contrario, la espectroelectroquímica del aducto Zn-tatpp mostró cantidades mínimas del intermediario radical tatpp•- con predominancia de las especies Zn-(Htatpp-) y Zn(H2tatpp). En una electroreducción adicional las especies doble reducidas forman, en ambos sistemas, especies protonadas cuadruple reducidas. El almacenamiento de cuatro electrones en el complejo 12+es seguido por una rápida comproporcionación homogénea con el reactivo inicial 12+conduciendo a la regeneración del intermediario doble reducido H212+mientras que Zn-tatpp no muestra tal comproporcionación debido a que las especies reducidas se encuentran confinadas en una película adsorbida, impedidas de moverse hacia el seno de la solución para reaccionar con el reactivo inicial. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas Articulo Articulo http://creativecommons.org/licenses/by-nc-sa/4.0/ Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0) application/pdf 273-288
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Química
photocatalisis
renewable energy
solar hydrogen
spectroelectrochemistry
mechanisms
spellingShingle Química
photocatalisis
renewable energy
solar hydrogen
spectroelectrochemistry
mechanisms
Lezna, Reynaldo Oscar
Tacconi, Norma R. de
Janaratne, T.
Muñoz Zúñiga, Jackeline
MacDonnell, F. M.
Reversible multi-electron reduction of 9,11,20,22-tetraaza-tetrapyridopentacene (tatpp) as axial ligand in the [(bpy)2ru(tatpp)]cl2 complex
topic_facet Química
photocatalisis
renewable energy
solar hydrogen
spectroelectrochemistry
mechanisms
description The ruthenium complex, [(bpy)2Ru(tatpp)]2+ (12+; bpy is 2,2’-bipyridine where tatpp is 9,11,20,22-tetraaza tetrapyrido[3,2-a:2’3’-c:3”,2”-l:2”’,3”’]-pentacene) is a promising candidate for homogeneous solar photocatalysis, based on the coupling of light absorption by the (bpy)2Ru2+ chromophore moiety with the tatpp ability to receive and reversible store electrons in aqueous media. In the present communication, a combination of spectroelectrochemistry and voltammetry was applied to compare the electroreduction processes of tatpp in complex 12+ and as a Zn-tatpp adduct. For complex 12+, the radical [(bpy)2Ru(tatpp•-)]+(1•+) is the first electroreduced species that then converts to doubly-reduced, single-protonated [(bpy)2Ru(Htatpp-)]+ (H1+) and doubly-protonated [(bpy)2Ru(H2tatpp)]2+(H212+) by subsequent electron transfer (ET) and proton transfer (PT) reactions. Contrastingly, spectroelectrochemistry of the Zn-tatpp adduct showed negligible amounts of intermediate tatpp•- radical and dominance of double reduced Zn-(Htatpp-) and Zn(H2tatpp) species. Upon further electroreduction, doubly-reduced species form quadruply reduced, protonated species, in both systems. The four electrons uptake in complex 12+ is followed by a rapid homogeneous comproportionation reaction with the initial 12+ reactant leading to the regeneration of intermediate double-reduced species, H212+, while no comporportionation occurs for Zn-tatpp because the reduced species are film-confined, that is, restrained to move to the bulk solution for encounter with the initial reactant.
format Articulo
Articulo
author Lezna, Reynaldo Oscar
Tacconi, Norma R. de
Janaratne, T.
Muñoz Zúñiga, Jackeline
MacDonnell, F. M.
author_facet Lezna, Reynaldo Oscar
Tacconi, Norma R. de
Janaratne, T.
Muñoz Zúñiga, Jackeline
MacDonnell, F. M.
author_sort Lezna, Reynaldo Oscar
title Reversible multi-electron reduction of 9,11,20,22-tetraaza-tetrapyridopentacene (tatpp) as axial ligand in the [(bpy)2ru(tatpp)]cl2 complex
title_short Reversible multi-electron reduction of 9,11,20,22-tetraaza-tetrapyridopentacene (tatpp) as axial ligand in the [(bpy)2ru(tatpp)]cl2 complex
title_full Reversible multi-electron reduction of 9,11,20,22-tetraaza-tetrapyridopentacene (tatpp) as axial ligand in the [(bpy)2ru(tatpp)]cl2 complex
title_fullStr Reversible multi-electron reduction of 9,11,20,22-tetraaza-tetrapyridopentacene (tatpp) as axial ligand in the [(bpy)2ru(tatpp)]cl2 complex
title_full_unstemmed Reversible multi-electron reduction of 9,11,20,22-tetraaza-tetrapyridopentacene (tatpp) as axial ligand in the [(bpy)2ru(tatpp)]cl2 complex
title_sort reversible multi-electron reduction of 9,11,20,22-tetraaza-tetrapyridopentacene (tatpp) as axial ligand in the [(bpy)2ru(tatpp)]cl2 complex
publishDate 2009
url http://sedici.unlp.edu.ar/handle/10915/177407
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