Two-photon absorption properties and 1O2 generation ability of Ir complexes: unexpected large cross section of [Ir(CO)2Cl(4-(para-di-n-butylaminostyryl)pyridine)

ALESSIA COLOMBO, CLAUDIA DRAGONETTI, DOMINIQUE ROBERTO, ADRIANA VALORE; CAMILLA FERRANTE, ILARIA FORTUNATI, A. LORENA PICONE, FRANCESCO TODESCATO ; J. A. GARETH WILLIAMS

DALTON TRANSACTIONS

ROYAL SOC CHEMISTRY

Lugar: CAMBRIDGE; Año: 2015 vol. 44 p. 15712 - 15720

1477-9226

The new complexes cis-[Ir(CO)2Cl(4-(para-di-n-butylaminostyryl)pyridine)] (1) and [Ir(cyclometallated-2-phenylpyridine)2(4,4´-(para-di-n-butylaminostyryl)-2,2´-bipyridine)][PF6] (3) were synthesized andfully characterized along with the known complex Ir(cyclometallated-2-phenylpyridine)2(5-Me-1,10-phenanthroline)][PF6] (2). Remarkably, complex 1, with an Ir(I) centre, displays fluorescence - as opposed to the phosphorescence typical of many Ir(III) complexes -with a modestly high quantum yield 15 in solution, opening a new route for the design of iridium-based emitters which should not be limited to the +3 oxidation state. It is also characterized by an unexpectedly large two-photon absorption (TPA)cross section, an order of magnitude higher than that previously reported for Ir(III) or Pt(II) complexes.The great potential of cyclometallated Ir(III) complexes for photodynamic therapy was confirmed, with 2 and 3 showing a good singlet oxygen generation ability, coupled with a modest TPA activity for 2.