Abstract
Three Ru(bpy)32+derivatives tethered to multiple viologen acceptors, [Ru(bpy)2(4,4′-MV2)]6+, [Ru(bpy)2(4,4′-MV4)]10+, and [Ru(bpy)(4,4′-MV4)2]18+[bpy=2,2′-bipyridine, 4,4′-MV2=4-ethoxycarbonyl-4′-(N-G1-carbamoyl)-2,2′-bipyridine, and 4,4′-MV4=4,4′-bis(N-G1-carbamoyl)-2,2′-bipyridine, where G1=Asp(NHG2)-NHG2and G2=-(CH2)2-N+C5H4-C5H4N+-CH3] were prepared as “photo-charge separators (PCSs)”. Photoirradiation of these complexes in the presence of a sacrificial electron donor (EDTA) results in storage of electrons per PCS values of 1.3, 2.7, and 4.6, respectively. Their applications in the photochemical H2evolution from water in the presence of a colloidal Pt H2-evolving catalyst were investigated, and are discussed along with those reported for [Ru(bpy)2(5,5′-MV4)]10+, [Ru(4,4′-MV4)3]26+, and [Ru(5,5′-MV4)3]26+(Inorg. Chem. Front. 2016, 3, 671–680). The PCSs with high dimerization constants (Kd=105–106m−1) are superior in driving H2evolution at pH 5.0, whereas those with lower Kdvalues (103–104m−1) are superior at pH 7.0, where Kd=[(MV+)2]/[MV+.]2. The (MV+)2site can drive H2evolution only at pH 5.0 as a result of its 0.15 eV lower driving force for H2evolution relative to MV+., whereas the PCSs with lower Kdvalues exhibit higher performance at pH 7.0 owing to the higher population of free MV+.. Importantly, the rate of electron charging over the PCSs is linear to the apparent H2evolution rate, and shows an intriguing quadratic dependence on the number of MV2+units per PCS.
| Original language | English |
|---|---|
| Pages (from-to) | 12381-12390 |
| Number of pages | 10 |
| Journal | Chemistry - A European Journal |
| Volume | 22 |
| Issue number | 35 |
| DOIs | |
| Publication status | Published - Jan 1 2016 |
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All Science Journal Classification (ASJC) codes
- Catalysis
- Chemistry(all)
- Organic Chemistry
Cite this
Tris(2,2′-bipyridine)ruthenium Derivatives with Multiple Viologen Acceptors : Quadratic Dependence of Photocatalytic H2Evolution Rate on the Local Concentration of the Acceptor Site. / Kitamoto, Kyoji; Sakai, Ken.
In: Chemistry - A European Journal, Vol. 22, No. 35, 01.01.2016, p. 12381-12390.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Tris(2,2′-bipyridine)ruthenium Derivatives with Multiple Viologen Acceptors
T2 - Quadratic Dependence of Photocatalytic H2Evolution Rate on the Local Concentration of the Acceptor Site
AU - Kitamoto, Kyoji
AU - Sakai, Ken
PY - 2016/1/1
Y1 - 2016/1/1
N2 - Three Ru(bpy)32+derivatives tethered to multiple viologen acceptors, [Ru(bpy)2(4,4′-MV2)]6+, [Ru(bpy)2(4,4′-MV4)]10+, and [Ru(bpy)(4,4′-MV4)2]18+[bpy=2,2′-bipyridine, 4,4′-MV2=4-ethoxycarbonyl-4′-(N-G1-carbamoyl)-2,2′-bipyridine, and 4,4′-MV4=4,4′-bis(N-G1-carbamoyl)-2,2′-bipyridine, where G1=Asp(NHG2)-NHG2and G2=-(CH2)2-N+C5H4-C5H4N+-CH3] were prepared as “photo-charge separators (PCSs)”. Photoirradiation of these complexes in the presence of a sacrificial electron donor (EDTA) results in storage of electrons per PCS values of 1.3, 2.7, and 4.6, respectively. Their applications in the photochemical H2evolution from water in the presence of a colloidal Pt H2-evolving catalyst were investigated, and are discussed along with those reported for [Ru(bpy)2(5,5′-MV4)]10+, [Ru(4,4′-MV4)3]26+, and [Ru(5,5′-MV4)3]26+(Inorg. Chem. Front. 2016, 3, 671–680). The PCSs with high dimerization constants (Kd=105–106m−1) are superior in driving H2evolution at pH 5.0, whereas those with lower Kdvalues (103–104m−1) are superior at pH 7.0, where Kd=[(MV+)2]/[MV+.]2. The (MV+)2site can drive H2evolution only at pH 5.0 as a result of its 0.15 eV lower driving force for H2evolution relative to MV+., whereas the PCSs with lower Kdvalues exhibit higher performance at pH 7.0 owing to the higher population of free MV+.. Importantly, the rate of electron charging over the PCSs is linear to the apparent H2evolution rate, and shows an intriguing quadratic dependence on the number of MV2+units per PCS.
AB - Three Ru(bpy)32+derivatives tethered to multiple viologen acceptors, [Ru(bpy)2(4,4′-MV2)]6+, [Ru(bpy)2(4,4′-MV4)]10+, and [Ru(bpy)(4,4′-MV4)2]18+[bpy=2,2′-bipyridine, 4,4′-MV2=4-ethoxycarbonyl-4′-(N-G1-carbamoyl)-2,2′-bipyridine, and 4,4′-MV4=4,4′-bis(N-G1-carbamoyl)-2,2′-bipyridine, where G1=Asp(NHG2)-NHG2and G2=-(CH2)2-N+C5H4-C5H4N+-CH3] were prepared as “photo-charge separators (PCSs)”. Photoirradiation of these complexes in the presence of a sacrificial electron donor (EDTA) results in storage of electrons per PCS values of 1.3, 2.7, and 4.6, respectively. Their applications in the photochemical H2evolution from water in the presence of a colloidal Pt H2-evolving catalyst were investigated, and are discussed along with those reported for [Ru(bpy)2(5,5′-MV4)]10+, [Ru(4,4′-MV4)3]26+, and [Ru(5,5′-MV4)3]26+(Inorg. Chem. Front. 2016, 3, 671–680). The PCSs with high dimerization constants (Kd=105–106m−1) are superior in driving H2evolution at pH 5.0, whereas those with lower Kdvalues (103–104m−1) are superior at pH 7.0, where Kd=[(MV+)2]/[MV+.]2. The (MV+)2site can drive H2evolution only at pH 5.0 as a result of its 0.15 eV lower driving force for H2evolution relative to MV+., whereas the PCSs with lower Kdvalues exhibit higher performance at pH 7.0 owing to the higher population of free MV+.. Importantly, the rate of electron charging over the PCSs is linear to the apparent H2evolution rate, and shows an intriguing quadratic dependence on the number of MV2+units per PCS.
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U2 - 10.1002/chem.201601554
DO - 10.1002/chem.201601554
M3 - Article
VL - 22
SP - 12381
EP - 12390
JO - Chemistry - A European Journal
JF - Chemistry - A European Journal
SN - 0947-6539
IS - 35
ER -