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The Effects of Pendant vs. Fused Thiophene Attachment upon the Luminescence Lifetimes and Electrochemistry of Tris(2,2′‐bipyridine)ruthenium(II) Complexes
Author(s) -
Nurkkala Lasse J.,
Steen Robert O.,
Friberg Henrik K. J.,
Häggström Johanna A.,
Bernhardt Paul V.,
Riley Mark J.,
Dunne Simon J.
Publication year - 2008
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.200800456
Subject(s) - chemistry , ruthenium , thiophene , pyridine , bipyridine , luminescence , 2,2' bipyridine , substituent , electrochemistry , photochemistry , quantum yield , ring (chemistry) , tris , cyclic voltammetry , crystallography , stereochemistry , medicinal chemistry , crystal structure , organic chemistry , fluorescence , biochemistry , physics , optoelectronics , electrode , quantum mechanics , catalysis
The electrochemical and photophysical properties for a range of tris(2,2′‐bipyridine)ruthenium(II) complexes in which a thiophene substituent is attached to one of the bipyridine ligands by either a pendant or a fused mode have been determined. The fused mode of attachment eliminates torsional movement between the thiophene unit and the chelating bipyridine, thereby offering optimal overlap between the π‐systems of the chelating unit and the attached thiophene unit. The electrochemical properties of these complexes were found to be similar; however, the luminescence lifetimes and intensities (in CH 3 CN at room temperature) were found to be correlated to the mode of attachment. The longest luminescence lifetime was observed for the complex [Ru(bpy) 2 {4‐(thiophen‐2‐yl)‐2,2′‐bipyridine}] 2+ (3000 ns), as compared to the prototypic [Ru(bpy) 3 ] 2+ (1745 ns). This complex also had the highest quantum yield (0.045). In the four isomeric complexes, where the thiophene ring was fused to the b or c face of the pyridine ring, the lifetimes fell in the interval 275–1510 ns, and the quantum yield ranged between 0.0047 and 0.014. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)