Multiple emissions from charge transfer excited states of ruthenium(II)—polypyridine complexes

✍ Scribed by B.P. Sullivan; H. Abruna; Harry O. Finklea; Dennis J. Salmon; Jeffrey K. Nagle; Thomas J. Meyer; Hertha Sprintschnik

• Publisher: Elsevier Science
• Year: 1978
• Tongue: English
• Weight: 472 KB
• Volume: 58
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(78)85059-3

✦ Synopsis

The complex a-s-[(bpy)aRu(~-CHs)s14* (bpy is 2 ,2'-bipyndine) has been prepared by methylation of (bpy)+Ru(~~~a]**_ Electrochemical studies show that introduction of the bound pyridinium group creates a chemically attached electron acce tor site (EXn = -0.76 V in 0.1 M [El@-C4H& ] PFs-acetonitnle versus the SSCE). Evidence for a low-ly$ng dn -rr*(CH$-N&j charge transfer (CT) state has been obtained by the appearance of a low energy emission at Amax 680 mn imxet&itrile (ro = 104 ns) and for sn upper dr; in a methanol glass at "17 K (r. = -d@py) state by a higher energy emission at 580 nm 7.59 JIS). Both emissions appear in a water-ethylene glycol solution containing 5% by weight polyvinyl alcohol at room temperature-Complexes of ruthenium(R) containing ligands with low-iylngrr* orbitals characteristically have intense visible n* (Lj +-dn(Ru) absorption bands [I] _ Especially interesting in this regard are Ru(bpy)y (bpy is 2,2'bipyridine) and related comp!exes where excitation in the visible can give relatively long-lived excited states [Z-4] which have been shown to undergo both oxidative [S-7] and reductive f8j quenching reactions [9].