Articolo in rivista, 2006, ENG

A Triad Based on an Iridium(III) Bis-Terpy Complex Leading to a Charge Separated-State with 120 ms Lifetime at Room Temperature

L. Flamigni, E. Baranoff, J.-P. Collin, J.-P. Sauvage,

Instituto ISOF-CNR, Via P. Gobetti 101, 40129 Bologna (Italy) Laboratoire de Chimie Organo-Minerale, UMR 7513 CNRS, UniversitD Louis Pasteur, Institut Le Bel 4, rue Blaise Pascal, 67070 Strasbourg (France)

Abstract: A triad D-Ir-A, where Ir is an IrIII bisterpyridine complex connected through an amidophenyl spacer to D, a triphenylamine electron donor, and to A, a naphthalene bisimide electron acceptor, has been synthesized and electrochemically investigated. The photoinduced processes in the triad, which is more than 4-nm long, have been characterized by steady-state and time-resolved optical spectroscopy by comparison with the model dyads D-Ir, Ir-A, and the reference monomers D, Ir, and A. A sequential electron transfer occurs upon excitation of the D and Ir units, leading to the charge-separated state D+-Ir-A in 100% yield and subsequently to D+-Ir-A in about 10% yield. The final charge-separated state has a lifetime at room temperature of 120 ms in air-free acetonitrile and of 100 ms in air-equilibrated solvent. Excitation of the A units does not yield intramolecular reactivity, but the resulting triplet-excited state localized on the acceptor, D-Ir-3A, displays intermolecular reactivity.

Chemistry (Weinh., Print) 12 , pp. 6592–6606

Keywords

charge separation, electron transfer, iridium, photochemistry, supramolecular chemistry

CNR authors

Flamigni Lucia

CNR institutes

ISOF – Istituto per la sintesi organica e la fotoreattività