Abstract
Quenching of the 3MLCT excited state of [Ru(bpy)3]2+ (bpy = bipyridine) by the reduction products (MV+ and MV0) of methyl viologen (MV2+) was studied by a combination of electrochemistry with laser flash photolysis or femtosecond pump-probe spectroscopy. Both for the bimolecular reactions and for the reactions in an Ru(bpy)3 2+-MVn+ dyad, quenching by MV+ and MV0 is reductive and gives the reduced ruthenium complex [Ru(bpy)3]+, in contrast to the oxidative quenching by MV2+. Rate constants of quenching (kq), and thermal charge recombination (krec) and cage escape yields (φce) were determined for the bimolecular reactions, and rates of forward (kf) and backward (kb) electron transfer in the dyad were measured for quenching by MV2+, MV+, and MV0. The reactions in the dyad are very rapid, with values up to kf= 1.3 × 1012 s-1 for * Ru(bpy)3 2+-MV+. In addition, a long-lived (τ=15ps) vibrationally excited state of MV+ with a characteristically structured absorption spectrum was detected; this was generated by direct excitation of the MV+ moiety both at 460 and 600 nm. The results show that the direction of photoinduced electron transfer in a Ru(bpy)3-MV molecule can be switched by an externally applied bias.
| Original language | English |
|---|---|
| Pages (from-to) | 102-110 |
| Number of pages | 9 |
| Journal | Chemistry - A European Journal |
| Volume | 8 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - Jan 4 2002 |
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Keywords
- Electrochemistry
- Electron transfer
- Molecular devices
- Ruthenium
- Viologens
ASJC Scopus subject areas
- Chemistry(all)
Cite this
Redox-switchable direction of photoinduced electron transfer in an Ru(bpy)3 2+ - Viologen dyad. / Lomoth, Reiner; Häupl, Tilmann; Johansson, Olof; Hammarström, Leif.
In: Chemistry - A European Journal, Vol. 8, No. 1, 04.01.2002, p. 102-110.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Redox-switchable direction of photoinduced electron transfer in an Ru(bpy)3 2+ - Viologen dyad
AU - Lomoth, Reiner
AU - Häupl, Tilmann
AU - Johansson, Olof
AU - Hammarström, Leif
PY - 2002/1/4
Y1 - 2002/1/4
N2 - Quenching of the 3MLCT excited state of [Ru(bpy)3]2+ (bpy = bipyridine) by the reduction products (MV+ and MV0) of methyl viologen (MV2+) was studied by a combination of electrochemistry with laser flash photolysis or femtosecond pump-probe spectroscopy. Both for the bimolecular reactions and for the reactions in an Ru(bpy)3 2+-MVn+ dyad, quenching by MV+ and MV0 is reductive and gives the reduced ruthenium complex [Ru(bpy)3]+, in contrast to the oxidative quenching by MV2+. Rate constants of quenching (kq), and thermal charge recombination (krec) and cage escape yields (φce) were determined for the bimolecular reactions, and rates of forward (kf) and backward (kb) electron transfer in the dyad were measured for quenching by MV2+, MV+, and MV0. The reactions in the dyad are very rapid, with values up to kf= 1.3 × 1012 s-1 for * Ru(bpy)3 2+-MV+. In addition, a long-lived (τ=15ps) vibrationally excited state of MV+ with a characteristically structured absorption spectrum was detected; this was generated by direct excitation of the MV+ moiety both at 460 and 600 nm. The results show that the direction of photoinduced electron transfer in a Ru(bpy)3-MV molecule can be switched by an externally applied bias.
AB - Quenching of the 3MLCT excited state of [Ru(bpy)3]2+ (bpy = bipyridine) by the reduction products (MV+ and MV0) of methyl viologen (MV2+) was studied by a combination of electrochemistry with laser flash photolysis or femtosecond pump-probe spectroscopy. Both for the bimolecular reactions and for the reactions in an Ru(bpy)3 2+-MVn+ dyad, quenching by MV+ and MV0 is reductive and gives the reduced ruthenium complex [Ru(bpy)3]+, in contrast to the oxidative quenching by MV2+. Rate constants of quenching (kq), and thermal charge recombination (krec) and cage escape yields (φce) were determined for the bimolecular reactions, and rates of forward (kf) and backward (kb) electron transfer in the dyad were measured for quenching by MV2+, MV+, and MV0. The reactions in the dyad are very rapid, with values up to kf= 1.3 × 1012 s-1 for * Ru(bpy)3 2+-MV+. In addition, a long-lived (τ=15ps) vibrationally excited state of MV+ with a characteristically structured absorption spectrum was detected; this was generated by direct excitation of the MV+ moiety both at 460 and 600 nm. The results show that the direction of photoinduced electron transfer in a Ru(bpy)3-MV molecule can be switched by an externally applied bias.
KW - Electrochemistry
KW - Electron transfer
KW - Molecular devices
KW - Ruthenium
KW - Viologens
UR - http://www.scopus.com/inward/record.url?scp=0037016542&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0037016542&partnerID=8YFLogxK
U2 - 10.1002/1521-3765(20020104)8:1<102::AID-CHEM102>3.0.CO;2-S
DO - 10.1002/1521-3765(20020104)8:1<102::AID-CHEM102>3.0.CO;2-S
M3 - Article
VL - 8
SP - 102
EP - 110
JO - Chemistry - A European Journal
JF - Chemistry - A European Journal
SN - 0947-6539
IS - 1
ER -