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Title: Spectroscopic and photophysical properties of complexes of 4{prime}-ferrocenyl-2,2{prime}:6{prime},2{double_prime}-terpyridine and related ligands

4{prime}-(Ferrocenyl)-2,2{prime}:6{prime}2{double_prime}-terpyridine (Fctpy) and 4{prime}-(4-pyridyl)-2,2{prime}:6{prime},2{double_prime}-terpyridine (pytpy) were prepared from the corresponding ferrocene- and pyridinecarboxaldehyle and 2-acetylpyridine using the Krohnke synthetic methodology. Metal complexes, [M(Fctpy){sub 2}](PF{sub 6}){sub 2} (M = Ru, Fe, Zn), [Ru(tpy)(Fctpy)](PF{sub 6}){sub 2} (tpy = 2,2{prime}:6{prime},6{double_prime}-terpyridine), and [Ru(pytpy){sub 2}](PF{sub 6}){sub 2} were prepared and characterized. Cyclic voltammetric analysis indicated Ru(III/II) and ferrocenium/ferrocene redox couples near expected potentials (Ru{sup III/II} {approximately}1.3 V and ferrocenium/ferrocene {approximately}0.6 V vs Ag/AgCl). In addition to dominant {pi}{sub tpy} {r_arrow} {pi}{sub tpy}{sup *} UV absorptions near 240 and 280 nm and d{sub {pi}}{sup Ru} {r_arrow} {pi}{sub tpy}{sup *} MLCT absorptions around 480 nm, the complexes [Ru(Fctpy){sub 2}](PF{sub 6}){sub 2} and [Ru(tpy)(Fctpy)](PF{sub 6}){sub 2} exhibit an unusual absorption band around 530 nm. Resonance Raman measurements indicate that this band is due to a {sup 1}[(d({pi}){sub Fc}){sup 6}] {r_arrow} {sup 1}[(d({pi}){sub Fc}){sup 5}({pi}{sup *}{sub tpy}{sup Ru}){sup 1}] transition. For [Ru(Fctpy){sub 2}](PF{sub 6}){sub 2} and [Ru(tpy)(Fctpy)](PF{sub 6}){sub 2}, excited-state emission and lifetime measurements indicated an upper-limit emission quantum yield of 0.003 and an upper-limit emission lifetime of 0.025 {micro}s. The influence of the ferrocenyl site on excited-state decay is discussed, and an excited-state energy level diagram is proposed.
Authors:
; ; ;  [1] ; ;  [2] ;  [3]
  1. Univ. of North Carolina, Greensboro, NC (United States). Dept. of Chemistry
  2. Wayne state Univ., Detroit, MI (United States). Dept. of Chemistry
  3. Los Alamos National Labs., Los Alamos, NM (United States)
Publication Date:
OSTI Identifier:
354364
Resource Type:
Journal Article
Resource Relation:
Journal Name: Inorganic Chemistry; Journal Volume: 38; Journal Issue: 10; Other Information: PBD: 17 May 1999
Sponsoring Org:
USDOE, Washington, DC (United States)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; PYRIDINES; RUTHENIUM COMPLEXES; IRON COMPLEXES; ZINC COMPLEXES; REDOX POTENTIAL; ENERGY-LEVEL TRANSITIONS; QUANTUM EFFICIENCY; LIFETIME