Absorption and Emission Properties of Di- and Trinuclear Ruthenium(II) Rack-Type Complexes

✍ Scribed by Paola Ceroni; Alberto Credi; Vincenzo Balzani; Sebastiano Campagna; Garry S. Hanan; Claudia R. Arana; Jean-Marie Lehn

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 302 KB
• Volume: 1999
• Category: Article
• ISSN: 1434-1948
• DOI: 10.1002/(sici)1099-0682(199909)1999:9<1409::aid-ejic1409>3.0.co;2-c

✦ Synopsis

The absorption spectra and the luminescence properties of charge-transfer (MLCT) bands. All the complexes exhibit emission from a triplet MLCT state, with maxima in the three dinuclear Ru II complexes and one trinuclear Ru II complex have been investigated. All the complexes have spectral range 840-950 nm (lifetimes between 40 and 80 ns) at 298 K in fluid solution, and in the spectral range 760-810 rack-type structures. The dinuclear complexes 1, 2, and 3 incorporate a bis-tridentate bridging ligand made up of a nm (lifetimes between 2 and 3 µs) at 77 K in rigid matrices.

A fine tuning of the absorption and luminescence properties pyrimidine and four pyridine moieties, as well as two 2,2Ј:6Ј,2"-terpyridyl (tpy) ligands. The trinuclear complex 4 of complexes 1-3 can be achieved by changing the substituents on the pyrimidine ring of the bridging ligand. incorporates a tris-tridentate bridging ligand made up of two pyrimidine and five pyridine moieties, as well as three tpy Efficient energy transfer within the rack structure 4 occurs from the (upper-lying) central metal-based chromophore to ligands. The absorption spectra of the complexes show a large number of ligand-centered (LC) and metal-to-ligand the (lower-lying) peripheral ones.