A new zwitterionic, water soluble, Re(I) complex: Synthesis, spectroscopic and computational characterization

A new water soluble Re(I) complex with a zwitterionic structure, Bu 4N[(bpy)Re(CO)3(dcbpy)] (where Bu = butyl; bpy = 4,4′-bipyridine; dcbpy = 2,2′-bipyridine-5,5′-dicarboxylate), was successfully synthesized and characterized by elemental analysis, 1H NMR, FTIR and ESI. Protonation studies in aqueou...

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Autores principales: Martinez Saavedra, H.H., Franca, C.A., Petroselli, G., Erra-Balsells, R., Ruiz, G.T., Wolcan, E.
Formato: JOUR
Materias:
Acid-base equilibriums
MLLCT
Re(I) complex
TD-DFT
Zwitterionic
Acid-base equilibrium
Re complex
Band structure
Protonation
Ultraviolet visible spectroscopy
Carboxylation
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_0022328X_v745-746_n_p470_MartinezSaavedra
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:paper_0022328X_v745-746_n_p470_MartinezSaavedra2023-10-03T14:31:34Z A new zwitterionic, water soluble, Re(I) complex: Synthesis, spectroscopic and computational characterization Martinez Saavedra, H.H. Franca, C.A. Petroselli, G. Erra-Balsells, R. Ruiz, G.T. Wolcan, E. Acid-base equilibriums MLLCT Re(I) complex TD-DFT Zwitterionic Acid-base equilibrium MLLCT Re complex TD-DFT Zwitterionic Band structure Protonation Ultraviolet visible spectroscopy Carboxylation A new water soluble Re(I) complex with a zwitterionic structure, Bu 4N[(bpy)Re(CO)3(dcbpy)] (where Bu = butyl; bpy = 4,4′-bipyridine; dcbpy = 2,2′-bipyridine-5,5′-dicarboxylate), was successfully synthesized and characterized by elemental analysis, 1H NMR, FTIR and ESI. Protonation studies in aqueous solutions of the Re(I) complex showed three acid-base equilibriums with pKa1 = 5.0, pKa2 = 3.0 and pKa3 = 2.0. pKa1 was assigned to the protonation equilibrium at bpy while pKa2 and pKa3 could be ascribed to protonation/deprotonation of the two carboxylates groups in the dcbpy ligand. With the aid of TD-DFT calculations the nature of the electronic transitions responsible for the pH-dependent UV-vis spectroscopy of the Re(I) complex was identified. At pH = 7 the lower energy band of the complex has MLLCTRe(CO)3→dcbpy character while at pH < 2 it switches to MLLCTRe(CO)3→bpy. This change in the nature of the lower energy band is responsible for the overall spectral changes in the 350-500 nm range after protonation of the Re(I) complex. © 2013 Elsevier B.V. All rights reserved. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_0022328X_v745-746_n_p470_MartinezSaavedra
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Acid-base equilibriums
MLLCT
Re(I) complex
TD-DFT
Zwitterionic
Acid-base equilibrium
MLLCT
Re complex
TD-DFT
Zwitterionic
Band structure
Protonation
Ultraviolet visible spectroscopy
Carboxylation
spellingShingle Acid-base equilibriums
MLLCT
Re(I) complex
TD-DFT
Zwitterionic
Acid-base equilibrium
MLLCT
Re complex
TD-DFT
Zwitterionic
Band structure
Protonation
Ultraviolet visible spectroscopy
Carboxylation
Martinez Saavedra, H.H.
Franca, C.A.
Petroselli, G.
Erra-Balsells, R.
Ruiz, G.T.
Wolcan, E.
A new zwitterionic, water soluble, Re(I) complex: Synthesis, spectroscopic and computational characterization
topic_facet Acid-base equilibriums
MLLCT
Re(I) complex
TD-DFT
Zwitterionic
Acid-base equilibrium
MLLCT
Re complex
TD-DFT
Zwitterionic
Band structure
Protonation
Ultraviolet visible spectroscopy
Carboxylation
description A new water soluble Re(I) complex with a zwitterionic structure, Bu 4N[(bpy)Re(CO)3(dcbpy)] (where Bu = butyl; bpy = 4,4′-bipyridine; dcbpy = 2,2′-bipyridine-5,5′-dicarboxylate), was successfully synthesized and characterized by elemental analysis, 1H NMR, FTIR and ESI. Protonation studies in aqueous solutions of the Re(I) complex showed three acid-base equilibriums with pKa1 = 5.0, pKa2 = 3.0 and pKa3 = 2.0. pKa1 was assigned to the protonation equilibrium at bpy while pKa2 and pKa3 could be ascribed to protonation/deprotonation of the two carboxylates groups in the dcbpy ligand. With the aid of TD-DFT calculations the nature of the electronic transitions responsible for the pH-dependent UV-vis spectroscopy of the Re(I) complex was identified. At pH = 7 the lower energy band of the complex has MLLCTRe(CO)3→dcbpy character while at pH < 2 it switches to MLLCTRe(CO)3→bpy. This change in the nature of the lower energy band is responsible for the overall spectral changes in the 350-500 nm range after protonation of the Re(I) complex. © 2013 Elsevier B.V. All rights reserved.
format JOUR
author Martinez Saavedra, H.H.
Franca, C.A.
Petroselli, G.
Erra-Balsells, R.
Ruiz, G.T.
Wolcan, E.
author_facet Martinez Saavedra, H.H.
Franca, C.A.
Petroselli, G.
Erra-Balsells, R.
Ruiz, G.T.
Wolcan, E.
author_sort Martinez Saavedra, H.H.
title A new zwitterionic, water soluble, Re(I) complex: Synthesis, spectroscopic and computational characterization
title_short A new zwitterionic, water soluble, Re(I) complex: Synthesis, spectroscopic and computational characterization
title_full A new zwitterionic, water soluble, Re(I) complex: Synthesis, spectroscopic and computational characterization
title_fullStr A new zwitterionic, water soluble, Re(I) complex: Synthesis, spectroscopic and computational characterization
title_full_unstemmed A new zwitterionic, water soluble, Re(I) complex: Synthesis, spectroscopic and computational characterization
title_sort new zwitterionic, water soluble, re(i) complex: synthesis, spectroscopic and computational characterization
url http://hdl.handle.net/20.500.12110/paper_0022328X_v745-746_n_p470_MartinezSaavedra
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