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pH‐Sensitive Bis(2,2′:6′,2"‐terpyridine)ruthenium(II) Complexes – A DFT/TDDFT Investigation of Their Spectroscopic Properties
Author(s) -
Lobello Maria Grazia,
Fantacci Simona,
Credi Alberto,
De Angelis Filippo
Publication year - 2011
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201001260
Subject(s) - time dependent density functional theory , chemistry , protonation , terpyridine , pyridine , excited state , ruthenium , photochemistry , absorption spectroscopy , luminescence , aqueous solution , density functional theory , computational chemistry , atomic physics , metal , organic chemistry , ion , physics , optoelectronics , quantum mechanics , catalysis
We report a DFT/TDDFT study on the geometric, electronic and optical properties of [Ru{4′‐(4‐pyridyl)‐2,2′:6′,2"‐terpyridine} 2 ] 2+ . Because of the presence of the basic nitrogen atom on the terminal pyridyl ligands, in solution the complex can exist in three different protonation states depending on the pH, each with markedly different photophysical properties. We investigated the effect of protonation of the terminal pyridine groups on the electronic and optical properties of this Ru II complex. TDDFT calculations in vacuo and aqueous solution were performed, finding good agreement between the simulated and the experimental absorption spectra, and reproducing the experimentally observed absorption redshift upon pyridine protonation. The calculated excited‐state data provide a rationale for the luminescence properties observed by varying the solution pH, in terms of the different energy separation between MLCT and MC excited states in the complexes.