New paradigm of transition metal polypyridine complex photochemistry.
Using polarization sensitive ultrafast transient absorption spectroscopy we have studied energy transfer and excited state relaxation pathways in a tetranuclear transition metal [(osmium)(ruthenium)3] polypyridine complex. Contrary to the generally accepted picture of transition metal complex photochemistry we find that ultrafast energy transfer (< or =60 fs) occurs from the excited singlet MLCT state of the peripheral Ru-chromophores to the central Os-core, in efficient competition with intersystem crossing. Energy transfer between relaxed triplet MLCT states is more than an order of magnitude slower (600 fs).
Department of Chemical Physics, Lund University, S-221 00 Lund, Sweden.
Johan
J
Andersson
Fausto
F
Puntoriero
Scolastica
S
Serroni
Arkady
A
Yartsev
Torbjörn
T
Pascher
Tomas
T
Polivka
Sebastiano
S
Campagna
Villy
V
Sundström
D010777:Photochemistry; D011108:Polymers; D011725:Pyridines / Q000737:chemistry*; D013053:Spectrophotometry
D011108:Polymers; D011725:Pyridines