Rhenium(I) tricarbonyl polypyridine complexes showing strong absorption of visible light and long-lived triplet excited states as a triplet photosensitizer for triplet-triplet annihilation upconversion.
The preparation of rhenium(I) tricarbonyl polypyridine complexes that show a strong absorption of visible light and long-lived triplet excited state and the application of these complexes as triplet photosensitizers for triplet-triplet annihilation (TTA) based upconversion are reported. Imidazole-fused phenanthroline was used as the N^N coordination ligand, on which different aryl groups were attached (Phenyl, Re-0; Coumarin, Re-1 and naphthyl, Re-2). Re-1 shows strong absorption of visible light (ε = 60,800 M(-1) cm(-1) at 473 nm). Both Re-1 and Re-2 show long-lived T(1) states (lifetime, τ(T), is up to 86.0 μs and 64.0 μs, respectively). These properties are in contrast to the weak absorption of visible light and short-lived triplet excited states of the normal rhenium(I) tricarbonyl polypyridine complexes, such as Re-0 (ε = 5100 M(-1) cm(-1) at 439 nm, τ(T) = 2.2 μs). The photophysical properties of the complexes were fully studied with steady state and time-resolved absorption and emission spectroscopes, as well as DFT calculations. The intra-ligand triplet excited state is proposed to be responsible for the exceptionally long-lived T(1) states of Re-1 and Re-2. The Re(I) complexes were used as triplet photosensitizers for TTA based upconversion and an upconversion quantum yield up to 17.0% was observed.
State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, E 208 Western Campus, 2 Ling-Gong Road, Dalian 116012, PR China.
Xiuyu
X
Yi
Jianzhang
J
Zhao
Wanhua
W
Wu
Dandan
D
Huang
Shaomin
S
Ji
Jifu
J
Sun
D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry*; D007093:Imidazoles / Q000737:chemistry; D008027:Light; D017319:Photosensitizing Agents / Q000138:chemical synthesis / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry*; D011789:Quantum Theory; D012211:Rhenium / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet
D056831:Coordination Complexes; D007093:Imidazoles; D017319:Photosensitizing Agents; D011725:Pyridines; D012211:Rhenium; C029899:imidazole