Ítem


Fine Tuning of MLCT States in New Mononuclear Complexes of Ruthenium(II) Containing Tris(1-pyrazolyl)methane, 2,2 -Bipyridine and Aromatic Nitrogen Heterocycles

The syntheses of new mononuclear ruthenium(II) complexes of the type: [Ru(bpy)(L)(tpm)](PF6)2 {tpm = tris(1-pyrazolyl)methane; bpy = 2,2′-bipyridine; L = pz (pyrazine; 1), 4,4′-bpy (4,4′-bipyridine; 2), and bpe [trans-1,2-bis(4-pyridyl)ethylene; 3]} are described, together with their spectroscopic, electrochemical, and photophysical properties. A complete assignment of the NMR resonances of the three species could be made in CD3CN by bidimensional techniques. A fine tuning of the energies of MLCT (metal-to-ligand charge transfer) states in these complexes is disclosed when comparing, in CH3CN, the values of their maximum absorption wavelengths for the most intense visible bands (λmax) and their redox potentials for the RuIII/RuII couples; this effect, relevant to the design of efficient photocatalysts, can be attributed to a decreasing order of dπ(Ru) → π*(2,2′-bpy) backbonding when decreasing the distance between both N atoms in the aromatic nitrogen heterocycle L that acts in a monodentate manner. Only the species with L = bpe emits at room temperature, pointing to the conclusion that MLCT excited states in this series become higher in energy than dd excited states when the value of λmax is lower than 400 nm. These species are also useful building blocks for new dinuclear mixed-valent complexes

This research has also been financed by MCYT of Spain through projects BQU2000-0458, BQU2003-02884, and BQU2003-01677. We would also like to thank the CIRIT Generalitat de Catalunya (Spain) for a Distinction award and the aid SGR2001-UG-291

© European Journal of Inorganic Chemistry, 2005, vol. 2005, núm. 2, p. 272-277

Wiley-VCH Verlag

Autor: Katz, N.
Romero García, Isabel
Llobet Dalmases, Antoni
Parella Coll, Teodor
Benet Buchholz, Jordi
Data: gener 2005
Resum: The syntheses of new mononuclear ruthenium(II) complexes of the type: [Ru(bpy)(L)(tpm)](PF6)2 {tpm = tris(1-pyrazolyl)methane; bpy = 2,2′-bipyridine; L = pz (pyrazine; 1), 4,4′-bpy (4,4′-bipyridine; 2), and bpe [trans-1,2-bis(4-pyridyl)ethylene; 3]} are described, together with their spectroscopic, electrochemical, and photophysical properties. A complete assignment of the NMR resonances of the three species could be made in CD3CN by bidimensional techniques. A fine tuning of the energies of MLCT (metal-to-ligand charge transfer) states in these complexes is disclosed when comparing, in CH3CN, the values of their maximum absorption wavelengths for the most intense visible bands (λmax) and their redox potentials for the RuIII/RuII couples; this effect, relevant to the design of efficient photocatalysts, can be attributed to a decreasing order of dπ(Ru) → π*(2,2′-bpy) backbonding when decreasing the distance between both N atoms in the aromatic nitrogen heterocycle L that acts in a monodentate manner. Only the species with L = bpe emits at room temperature, pointing to the conclusion that MLCT excited states in this series become higher in energy than dd excited states when the value of λmax is lower than 400 nm. These species are also useful building blocks for new dinuclear mixed-valent complexes
This research has also been financed by MCYT of Spain through projects BQU2000-0458, BQU2003-02884, and BQU2003-01677. We would also like to thank the CIRIT Generalitat de Catalunya (Spain) for a Distinction award and the aid SGR2001-UG-291
Format: application/pdf
Cita: https://doi.org/10.1002/ejic.200400487
ISSN: 1434-1948 (versió paper)
1099-0682 (versió electrònica)
Accés al document: http://hdl.handle.net/10256/13088
Editor: Wiley-VCH Verlag
Col·lecció: CICYT/PN 2000-2003/ BQU2000-0458
Reproducció digital del document publicat a: https://doi.org/10.1002/ejic.200400487
És part de: © European Journal of Inorganic Chemistry, 2005, vol. 2005, núm. 2, p. 272-277
Drets: Tots els drets reservats
Matèria: Ruteni -- Compostos
Ruthenium compounds
Títol: Fine Tuning of MLCT States in New Mononuclear Complexes of Ruthenium(II) Containing Tris(1-pyrazolyl)methane, 2,2 -Bipyridine and Aromatic Nitrogen Heterocycles
Tipus: info:eu-repo/semantics/article
Repositori: DUGiDocs

Matèries

Autors