Néstor Katz (Univ. Tucumán)
F. Salomón, N. Vega, T. Parella, F. Morán Vieyra, C. Borsarelli, C. Longo, M. Cattaneo and N. Katz
ACS Omega, 5, 8097-8107 (2020). DOI
Novel Heteroleptic Ruthenium(II) Complexes with 2,2´- bipyridines Containing a Series of Electron Donor and Acceptor Substituents in 4,4´-positions: Syntheses, Characterization and Application as Sensitizers for ZnO Nanowires Based Solar Cells
A novel series of complexes of the formula [Ru(4,4′-X2-bpy)2(Mebpy-CN)](PF6)2 (X = −CH3, −OCH3, −N(CH3)2; Mebpy-CN = 4-methyl-2,2′-bipyridine-4′-carbonitrile) have been synthesized and characterized by spectroscopic, electrochemical, and photophysical techniques. Inclusion of the electron-withdrawing substituent −CN at one bpy ligand and different electron-donor groups −X at the 4,4′-positions of the other two bpy ligands produce a fine tuning of physicochemical properties. Redox potentials, electronic absorption maxima, and emission maxima correlate well with Hammett’s σp parameters of X. Quantum mechanical calculations are consistent with experimental data. All the complexes can be anchored through the nitrile moiety of Mebpy-CN over ZnO nanowires in dye-sensitized solar cells that exhibit an improvement of light to electrical energy conversion efficiency as the electronic asymmetry increases in the series.
P. Abate, G. Pourrieux, F.M. Vieyra, C. Borsarelli, T. Parella, M. Vergara, N. Katz
Polyhedron, 174, 114149 (2019). DOI
A novel mononuclear complex of 4,4´´-azobis-(2,2´- bipyridine) coordinated to tetracyanoruthenium(II) can behave as a “molecular switch”
A novel tetracyanoruthenium(II) complex of formula K2[Ru(4,4″-azobpy)(CN)4], (1), with 4,4″-azobpy = 4,4″-azobis-(2,2′-bipyridine), has been synthesized and characterized by spectroscopic, electrochemical and photophysical techniques. The effects of reduction and protonation of the azo group of coordinated 4,4″-azobpy in the UV–Vis absorption and emission spectra of (1) were explored by spectroelectrochemical techniques and by addition of l-Cysteine. The behavior of (1) as a “molecular switch” could be explained with the aid of quantum–mechanical calculations by using density functional theory.
J.H. Mecchia Ortiz, F.E. Morán Vieyra, C.D. Borsarelli, I. Romero, X. Fontrodona, T. Parella, N.D. Lis de Katz, F. Fagalde and N.E. Katz
Eur. J. Inorg. Chem., 3359 (2014). DOI
Mono- and Dinuclear Complexes of Tricarbonylrhenium(I) with 4-Methyl-2,2.-bipyridine-4.-carbonitrile
Novel mono- and dinuclear tricarbonylrhenium(I) complexes were prepared and characterized by spectroscopic, photophysical, and computational techniques. The increased conjugation in the bipyridyl ring due to the nitrile substituent increases the emission quantum yields of the 3MLCT (metal-to-ligand charge-transfer) lowest-lying excited states with respect to the corresponding bpy complexes.
M. Cattaneo, M.M. Vergara, M.E. García Posse, F. Fagalde, T. Parella and N.E. Katz
Polyhedron, 70, 20 (2014). DOI
Spectroscopic, electrochemical and computational studies of rhenium(I) and ruthenium(II) complexes incorporating the novel tetradentate ligand 1,4-bis(4-(40-methyl)-2,20-bipyridyl)-2,3-diaza-1,3-butadiene (BBDB) and its derivatives
A new bridging ligand (BBDB) useful for building novel coordination compounds, has been synthetized and characterized by analytical, spectroscopic and electrochemical techniques. Synthesis of novel coordination compounds of tricarbonylrhenium(I), polypyridylruthenium(II) and ammineruthenium(II) moieties containing BBDB were carried out and hydrolysis products with ruthenium bipyridyls and cyanides were characterized. The determined comproportionation constant Kc for the dinuclear BBDB mixed-valent complex with ruthenium ammines indicates a considerable coupling for the imposed metal-metal distance. Lack of luminescence of all complexes is explained by the fast non-radiative decay from the LUMO orbital mainly localized at the delocalized bridging unit with the azabutadiene linker. Luminescence could be recovered either by introducing modified bpy ligands or by photoisomerization or reduction of the azo functionality.
J.H. Mecchia Ortiz, N. Vega, D. Comedi, M. Tirado, I. Romero, X. Fontrodona, T. Parella, F.E. Morán Vieyra, C.D. Borsarelli and N.E. Katz
Inorg. Chem., 52, 4950 (2013). DOI
Improving the Photosensitizing Properties of Ruthenium Polypyridyl Complexes Using 4‑Methyl-2,2′-bipyridine-4′-carbonitrile as an Auxiliary Ligand
We report the synthesis and spectroscopic, electrochemical, spectroelectrochemical, and photophysical characterization of a novel series of ruthenium polypyridyl complexes. A new dinuclear complex with Mebpy-CN as a bridging ligand has also been prepared and characterized by physicochemical techniques which displays a considerable metal−metal electronic coupling due to the delocalization effect of a nitrile group in the 4′ position of the bpy ring.
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