Photoinduced energy transfer between Re(I) and Ru(II) termini connected through a new exo-ditopic bis-phenanthroline ligand fused to a central macrocycle spacer: Synthesis, structure, and electrochemical and photophysical properties of a heterodinuclear complex

 
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2007 (EN)
Photoinduced energy transfer between Re(I) and Ru(II) termini connected through a new exo-ditopic bis-phenanthroline ligand fused to a central macrocycle spacer: Synthesis, structure, and electrochemical and photophysical properties of a heterodinuclear complex (EN)

Lazarides, T. (EN)

Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας (EL)
Lazarides, T. (EN)

A new ligand L-1 has been prepared in which two 1,10-phenanthroline fragments are separated by an 18-crown-6 macrocyclic spacer. This was used to prepare the heterodinuclear complex [(bipy)(2)Ru(mu-L-1)Re(CO)(3)Cl][PF6](2) [Ru(L-1)Re] in which the {Ru(bipy)(2)(phen)}(2+) and {Re(CO)Cl(phen)} chromophores are separated by a saturated and fairly flexible crown-ether fragment. On the basis of photophysical studies on Ru(L-1)Re and associated mononuclear Ru(II) and Re(I) complexes, Re -> Ru photoinduced energy-transfer occurs with a rate constant of 1.9 x 10(8) s(-1) in solution room temperature leading to near-complete quenching of the Re(I)-based luminescence. At 77 K the Re(I)-based luminescence component is completely quenched. Calculations on the efficiency of both Forster and Dexter energy-transfer as a function of (ReRu)-Ru-... distance in this system suggest that a folded conformation of the complex, in which the (ReRu)-Ru-... separation is much shorter than that implied by the extended conformation detected crystallographically, is responsible for the energy-transfer, since neither Forster nor Dexter Re -> Ru energy-transfer should be possible with the complex in an extended conformation. Addition of K+ or Ba2+ salts to solutions of Ru(L-1)Re had no effect on the photophysical properties, probably because the association constants are too low to give significant metal-ion binding in the macrocycle at the low concentrations employed. (c) 2006 Elsevier B.V. All rights reserved. (EN)

ruthenium (EN)

Πανεπιστήμιο Ιωαννίνων (EL)
University of Ioannina (EN)

Inorganica Chimica Acta (EN)

English

2007

<Go to ISI>://000244364600011

Elsevier (EN)



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