Robust and long-lived excited state Ru (II) polyimine photosensitizers boost hydrogen production
S Guo, KK Chen, R Dong, ZM Zhang, J Zhao… - ACS Catalysis, 2018 - ACS Publications
S Guo, KK Chen, R Dong, ZM Zhang, J Zhao, TB Lu
ACS Catalysis, 2018•ACS PublicationsThe prototypical [Ru (bpy) 3] 2+(bpy= 2, 2′-bipyridine, Ru-1) with 3MLCT state (metal-to-
ligand charge-transfer, πM→ πL*) is one of the most widely used photosensitizers (PSs) for
photocatalytic hydrogen production. However, its photostability and excited state lifetime (< 1
μs) are eagerly to be improved to further enhance the performance of hydrogen production.
Herein,[Ru (bpy) 2 (3-pyrenyl-1, 10-phenanthroline)] 2+(Ru-3) with 3IL/3MLCT equilibrated
state and [Ru (bpy) 2 (3-pyrenyl ethynylene-1, 10-phenanthroline)] 2+(Ru-4) with 3IL state …
ligand charge-transfer, πM→ πL*) is one of the most widely used photosensitizers (PSs) for
photocatalytic hydrogen production. However, its photostability and excited state lifetime (< 1
μs) are eagerly to be improved to further enhance the performance of hydrogen production.
Herein,[Ru (bpy) 2 (3-pyrenyl-1, 10-phenanthroline)] 2+(Ru-3) with 3IL/3MLCT equilibrated
state and [Ru (bpy) 2 (3-pyrenyl ethynylene-1, 10-phenanthroline)] 2+(Ru-4) with 3IL state …
The prototypical [Ru(bpy)3]2+ (bpy = 2,2′-bipyridine, Ru-1) with 3MLCT state (metal-to-ligand charge-transfer, πM → πL*) is one of the most widely used photosensitizers (PSs) for photocatalytic hydrogen production. However, its photostability and excited state lifetime (<1 μs) are eagerly to be improved to further enhance the performance of hydrogen production. Herein, [Ru(bpy)2(3-pyrenyl-1,10-phenanthroline)]2+ (Ru-3) with 3IL/3MLCT equilibrated state and [Ru(bpy)2(3-pyrenyl ethynylene-1,10-phenanthroline)]2+(Ru-4) with 3IL state (intraligand charge transfer, πL → πL*) as lowest excited state were first introduced into the photocatalytic hydrogen evolution system. Photophysical and photocatalytic characteristics manifest that the 3IL state complex (Ru-4) shows a long-lived excited state (up to 120 μs) and much enhanced photostability with no photobleaching over 13 h in stark contrast to Ru-1 and [Ru(bpy)2(1,10-phenanthroline)]2+ (Ru-2). Photocatalytic reactions with these Ru(II) complexes as PSs, Co(dmgH)2pyCl (C-1) as a catalyst, and N, N-dimethyl-p-toluidine (DMT) as an electron donor indicate that the catalytic performance of Ru-4 and Ru-3 is dramatically enhanced compared to that of Ru-2 and Ru-1, and the TON and TOF toward Ru-4 can reach up to 9140 and 6.3 min–1 under the optimized condition. Photoluminescence studies reveal that the Stern–Volmer quenching constant of excited state Ru-4 by DMT is determined as 2.8 × 104 M–1, which is 4.5-, 42-, and 44-fold higher than those of Ru-3 (6.2 × 103 M–1), Ru-2 (6.7 × 102 M–1), and Ru-1 (6.3 × 102 M–1), respectively. Transient absorption spectra confirmed that the reductive quenching mechanism is the dominated process, and the quenching constant of electron transfer from reduced PSs of Ru-1–Ru-4 to C-1 catalyst has the same order of magnitude (∼105 M–1). The increased photocatalytic activity of Ru-3 and Ru-4 is due to their prominent photostability and efficient electron transfer from DMT to PSs. This work not only contributes to a deep understanding in the photocatalytic process with the PSs of three different excited state types but also opens up an avenue to explore robust and long-lived PSs with 3IL state for efficient hydrogen production.
ACS Publications以上显示的是最相近的搜索结果。 查看全部搜索结果