| Abstract
| - Ruthenium, iron, and zinc complexes with ferrocenylterpyridine as a ligand were prepared and characterized by UV−vis, resonance Raman, electrochemical, and photochemical techniques. Resonance Raman results indicate that a visible absorption band at 530 nm is due to a 1[(d(π)Fc)6] → 1[(d(π)Fc)5(π*tpyRu)1] transition. Results also indicate that the ferrocene center and the other metal center are weakly coupled in the ground state. The MLCT excited state decay is greatly accelerated by the presence of the ferrocenyl moiety.
- 4‘-(Ferrocenyl)-2,2‘:6‘,2‘ ‘-terpyridine (Fctpy) and 4‘-(4-pyridyl)-2,2‘:6‘,2‘ ‘-terpyridine (pytpy) were prepared fromthe corresponding ferrocene- and pyridinecarboxaldehyle and 2-acetylpyridine using the Krohnke syntheticmethodology. Metal complexes, [M(Fctpy)2](PF6)2 (M = Ru, Fe, Zn), [Ru(tpy)(Fctpy)](PF6)2 (tpy = 2,2‘:6‘,6‘ ‘-terpyridine), and [Ru(pytpy)2](PF6)2 were prepared and characterized. Cyclic voltammetric analysis indicated RuIII/IIand ferrocenium/ferrocene redox couples near expected potentials (RuIII/II ∼1.3 V and ferrocenium/ferrocene ∼0.6V vs Ag/AgCl). In addition to dominant πtpy → πtpy* UV absorptions near 240 and 280 nm and dπRu → πtpy*MLCT absorptions around 480 nm, the complexes [Ru(Fctpy)2](PF6)2 and [Ru(tpy)(Fctpy)](PF6)2 exhibit an unusualabsorption band around 530 nm. Resonance Raman measurements indicate that this band is due to a 1[(d(π)Fc)6]→ 1[(d(π)Fc)5(π*tpyRu)1] transition. For [Ru(Fctpy)2](PF6)2 and [Ru(tpy)(Fctpy)](PF6)2, excited-state emission andlifetime measurements indicated an upper-limit emission quantum yield of 0.003 and an upper-limit emissionlifetime of 0.025 μs. The influence of the ferrocenyl site on excited-state decay is discussed, and an excited-stateenergy level diagram is proposed.
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