Abstract
A comprehensive study of a series of four monodisperse, metal-organic π-conjugated oligomers of varying length is reported. The oligomers are based on the aryleneethynylene architecture, and they contain a 2,2′-bipyridine-5,5′-diyl (bpy) metal binding unit. The photophysical properties of the free oligomers and their complexes with the (L)ReI(CO)3X chromophore (where L = the bpy-oligomer and X = Cl or NCCH3) were explored by a variety of methods including electrochemistry, UV-visible absorption, variable temperature photoluminescence (PL), transient absorption (TA), and time-resolved electron paramagnetic spectroscopy (TREPR). The absorption of the free oligomers and the metal complexes is dominated by the π,π* transitions of the π-conjugated oligomers. The free oligomers feature a strong blue fluorescence that is quenched entirely in the (L)ReI(CO)3X complexes. The metal-oligomers feature a weak, relatively long-lived red photoluminescence that is assigned to emission from both the 3π,π* manifold of the π-conjugated system and the dπ Re → π* bpy-oligomer metal-to-ligand charge transfer (3MLCT) state. On the basis of a detailed analysis of the PL, TA, and TREPR results an excited-state model is developed which indicates that the oligomer-based 3π,π* state and the 3MLCT states are in close energetic proximity. Consequently the photophysical properties reflect a composite of the properties of the two excited-state manifolds.
| Original language | English |
|---|---|
| Pages (from-to) | 8329-8342 |
| Number of pages | 14 |
| Journal | Journal of the American Chemical Society |
| Volume | 123 |
| Issue number | 34 |
| DOIs | |
| Publication status | Published - 2001 |
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ASJC Scopus subject areas
- Chemistry(all)
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Photophysics of π-conjugated metal-organic oligomers : Aryleneethynylenes that contain the (bpy)Re(CO)3Cl chromophore. / Walters, K. A.; Ley, K. D.; Cavalaheiro, C. S P; Miller, S. E.; Gosztola, D.; Wasielewski, Michael R; Bussandri, A. P.; Van Willigen, H.; Schanze, K. S.
In: Journal of the American Chemical Society, Vol. 123, No. 34, 2001, p. 8329-8342.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Photophysics of π-conjugated metal-organic oligomers
T2 - Aryleneethynylenes that contain the (bpy)Re(CO)3Cl chromophore
AU - Walters, K. A.
AU - Ley, K. D.
AU - Cavalaheiro, C. S P
AU - Miller, S. E.
AU - Gosztola, D.
AU - Wasielewski, Michael R
AU - Bussandri, A. P.
AU - Van Willigen, H.
AU - Schanze, K. S.
PY - 2001
Y1 - 2001
N2 - A comprehensive study of a series of four monodisperse, metal-organic π-conjugated oligomers of varying length is reported. The oligomers are based on the aryleneethynylene architecture, and they contain a 2,2′-bipyridine-5,5′-diyl (bpy) metal binding unit. The photophysical properties of the free oligomers and their complexes with the (L)ReI(CO)3X chromophore (where L = the bpy-oligomer and X = Cl or NCCH3) were explored by a variety of methods including electrochemistry, UV-visible absorption, variable temperature photoluminescence (PL), transient absorption (TA), and time-resolved electron paramagnetic spectroscopy (TREPR). The absorption of the free oligomers and the metal complexes is dominated by the π,π* transitions of the π-conjugated oligomers. The free oligomers feature a strong blue fluorescence that is quenched entirely in the (L)ReI(CO)3X complexes. The metal-oligomers feature a weak, relatively long-lived red photoluminescence that is assigned to emission from both the 3π,π* manifold of the π-conjugated system and the dπ Re → π* bpy-oligomer metal-to-ligand charge transfer (3MLCT) state. On the basis of a detailed analysis of the PL, TA, and TREPR results an excited-state model is developed which indicates that the oligomer-based 3π,π* state and the 3MLCT states are in close energetic proximity. Consequently the photophysical properties reflect a composite of the properties of the two excited-state manifolds.
AB - A comprehensive study of a series of four monodisperse, metal-organic π-conjugated oligomers of varying length is reported. The oligomers are based on the aryleneethynylene architecture, and they contain a 2,2′-bipyridine-5,5′-diyl (bpy) metal binding unit. The photophysical properties of the free oligomers and their complexes with the (L)ReI(CO)3X chromophore (where L = the bpy-oligomer and X = Cl or NCCH3) were explored by a variety of methods including electrochemistry, UV-visible absorption, variable temperature photoluminescence (PL), transient absorption (TA), and time-resolved electron paramagnetic spectroscopy (TREPR). The absorption of the free oligomers and the metal complexes is dominated by the π,π* transitions of the π-conjugated oligomers. The free oligomers feature a strong blue fluorescence that is quenched entirely in the (L)ReI(CO)3X complexes. The metal-oligomers feature a weak, relatively long-lived red photoluminescence that is assigned to emission from both the 3π,π* manifold of the π-conjugated system and the dπ Re → π* bpy-oligomer metal-to-ligand charge transfer (3MLCT) state. On the basis of a detailed analysis of the PL, TA, and TREPR results an excited-state model is developed which indicates that the oligomer-based 3π,π* state and the 3MLCT states are in close energetic proximity. Consequently the photophysical properties reflect a composite of the properties of the two excited-state manifolds.
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U2 - 10.1021/ja015813h
DO - 10.1021/ja015813h
M3 - Article
VL - 123
SP - 8329
EP - 8342
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 34
ER -