How close can you get? Studies of ultrafast light-induced processes in ruthenium-[60] fullerene dyads with short pyrazolino and pyrrolidino links.
Two pyrazoline- and one pyrrolidine-bridged Ru(II)bipyridine-[60]fullerene dyads have been prepared and studied by ultrafast time-resolved spectroscopy. A silver-assisted synthesis route, in which Ag(I) removes the chlorides from the precursor complex Ru(bpy) 2Cl 2 facilitates successful coordination of the [60]fullerene-substituted third ligand. Upon light excitation of the ruthenium moiety, the emission was strongly quenched by the fullerene. The main quenching mechanism is an exceptionally fast direct energy transfer ( k obs > 1 x 10 (12) s (-1) in the pyrazoline-bridged dyads), resulting in population of the lowest excited triplet state of fullerene. No evidence for electron transfer was found, despite the extraordinarily short donor-acceptor distance that could kinetically favor that process. The observations have implications on the ongoing development of devices built from Ru-polypyridyl complexes and nanostructured carbon, such as C 60 or nanotubes.
Karlsson
Susanne
S
Department of Biochemistry and Organic Chemistry, Uppsala University, Box 576, SE- 751 24 Uppsala, Sweden.
Modin
Judit
J
Becker
Hans-Christian
HC
Hammarström
Leif
L
Grennberg
Helena
H
D000042:Absorption; D004563:Electrochemistry; D004579:Electron Transport; D004735:Energy Transfer; D037741:Fullerenes / Q000737:chemistry*; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D011720:Pyrazoles / Q000737:chemistry*; D011759:Pyrrolidines / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D013997:Time Factors
D037741:Fullerenes; D009942:Organometallic Compounds; D011720:Pyrazoles; D011759:Pyrrolidines; C031280:pyrazole; D012428:Ruthenium; C032519:pyrrolidine; C069837:fullerene C60