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Absorption and Emission Properties of Di‐ and Trinuclear Ruthenium(II) Rack‐Type Complexes
Author(s) -
Ceroni Paola,
Credi Alberto,
Balzani Vincenzo,
Campagna Sebastiano,
Hanan Garry S.,
Arana Claudia R.,
Lehn JeanMarie
Publication year - 1999
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/(sici)1099-0682(199909)1999:9<1409::aid-ejic1409>3.0.co;2-c
Subject(s) - chemistry , chromophore , bridging ligand , luminescence , photochemistry , ruthenium , ligand (biochemistry) , pyridine , crystallography , absorption spectroscopy , absorption (acoustics) , crystal structure , catalysis , medicinal chemistry , biochemistry , physics , receptor , optoelectronics , quantum mechanics , acoustics
Abstract The absorption spectra and the luminescence properties of three dinuclear Ru II complexes and one trinuclear Ru II complex have been investigated. All the complexes have rack‐type structures. The dinuclear complexes 1 , 2 , and 3 incorporate a bis‐tridentate bridging ligand made up of a pyrimidine and four pyridine moieties, as well as two 2,2′:6′,2′‐terpyridyl (tpy) ligands. The trinuclear complex 4 incorporates a tris‐tridentate bridging ligand made up of two pyrimidine and five pyridine moieties, as well as three tpy ligands. The absorption spectra of the complexes show a large number of ligand‐centered (LC) and metal‐to‐ligand charge‐transfer (MLCT) bands. All the complexes exhibit emission from a triplet MLCT state, with maxima in the spectral range 840–950 nm (lifetimes between 40 and 80 ns) at 298 K in fluid solution, and in the spectral range 760–810 nm (lifetimes between 2 and 3 μs) at 77 K in rigid matrices. A fine tuning of the absorption and luminescence properties of complexes 1 – 3 can be achieved by changing the substituents on the pyrimidine ring of the bridging ligand. Efficient energy transfer within the rack structure 4 occurs from the (upper‐lying) central metal‐based chromophore to the (lower‐lying) peripheral ones.