Tuning the photophysical properties of a (P,N)Re-I complex by adding a -NH- fragment into a P,N-bidentate ligand: The case of [P,N{(C6H5)(2)(C5H4N)NHPRe(CO)(3)Br]
Author
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Mella, Pablo
Author
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Carlos Palma, Juan
Author
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Cepeda Plaza, Marjorie
Author
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Aguirre Álvarez, Pedro
Author
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Manzur Saffie, Jorge
Author
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Günther Sapunar, Germán
Author
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Pizarro, Nancy
Author
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Vega, Andrés
Admission date
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2016-11-18T15:31:07Z
Available date
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2016-11-18T15:31:07Z
Publication date
dc.date.issued
2016
Cita de ítem
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Polyhedron 111 (2016) 64–70
es_ES
Identifier
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10.1016/j.poly.2016.03.014
Identifier
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https://repositorio.uchile.cl/handle/2250/141273
Abstract
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The spectroscopic, electrochemical and photophysical properties of the new complex [P,N-{(C6H5)(2)(C5H4N)NHP)Re(CO)(3)Br] (RePNN) are reported. The UV-Vis spectrum in dichloromethane (DCM)' shows an absorption maximum centered at 300 nm and a shoulder at 350 nm. These absorption bands have been characterized, having a pi(py) -> pi*(py) and a MLCT character. Excitation at the first wavelength (higher energy) leads to an emission band centered at 365 nm. Cyclic voltammetry shows a eully irreversible oxidation wave around +1.45 V, assigned to Re-I/Re-II couple, whereas two irreversible reduction signals centered at -0.75 and-1.20 V are assigned to ligand reduction processes. The photophysical results show that emission from the RePNN complex comes exclusively from the ligand. The MLCT excited state shows to be non-emissive by coupling to vibrational modes leading to non-radiative decay path to ground state. The luminescent decay fits to a bi-exponential function. DFT calculations suggest that intra-ligand pi(py) -> pi*(py) and pi(py) -> pi*(py) excited states may account for the existence of these two decay lifetimes. The additional -NH-fragment present in the 2-(diphenylphosphinoamino)pyridine ligand compared to 2-pyridylphosphine, makes it more flexible and in consequence, enhances the non-radiative decay rate constant from the (MLCT)-M-3 to the ground state in the RePNN complex compared to those of 2-pyridylphosphine, [P,N-{(C6H5)(2)(C5H4N)PRe(CO)(3)Br] (RePN).
es_ES
Patrocinador
dc.description.sponsorship
Comision Nacional de Ciencia y Tecnologia, grants FONDECYT
1120865
1120149
ACE-03
Tuning the photophysical properties of a (P,N)Re-I complex by adding a -NH- fragment into a P,N-bidentate ligand: The case of [P,N{(C6H5)(2)(C5H4N)NHPRe(CO)(3)Br]