Photophysics of π-conjugated metal-organic oligomers: Aryleneethynylenes that contain the (bpy)Re(CO)3Cl chromophore

K. A. Walters, K. D. Ley, C. S.P. Cavalaheiro, S. E. Miller, D. Gosztola, M. R. Wasielewski, A. P. Bussandri, H. Van Willigen, K. S. Schanze*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

90 Scopus citations


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 languageEnglish (US)
Pages (from-to)8329-8342
Number of pages14
JournalJournal of the American Chemical Society
Issue number34
StatePublished - 2001

ASJC Scopus subject areas

  • Catalysis
  • General Chemistry
  • Biochemistry
  • Colloid and Surface Chemistry


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