Cyclometalated Ir(iii) complexes with styryl-BODIPY ligands showing near IR absorption/emission: preparation, study of photophysical properties and application as photodynamic/luminescence imaging materials

• DOI: 10.1039/c4tb00284a
• Publication Date: 2014-03-04T15:04:26Z
• Authors: Poulomi Majumdar; Xiaolin Yuan; Shengfu Li; Boris Le Guennic; Jie Ma; Caishun Zhang; Denis Jacquemin; Jianzhang Zhao
• Keywords: BODIPY; Stokes shift

Heteroleptic C^N cyclometalated iridium(iii) complexes incorporating a monostyryl/distyryl BODIPY ligand via acetylide bonds of 2,2'-bipyridine (bpy) with both absorption (ca. ε = 8.96 × 104 M-1 cm-1, 9.89 and 7.89 cm-1 at 664 nm, 644 729 nm for Ir-2, Ir-3 Ir-4, respectively) fluorescence emission bands 624-794 Ir-1, Ir-4) in the near infra-red region (NIR) exceptionally long-lived triplet excited states (τ 156.5 μs Ir-2) have been reported. Ir(ppy)3 (Ir-0; ppy 2-phenylpyridine) was used as reference, which gives typical weak visible range (ε 1.51 385 nm). The nanosecond time-resolved transient DFT calculations proposed that styryl BODIPY-localized long lived 3IL were populated Ir-4 (τT 106.6 μs, 92.5 31.4 upon photoexcitation. photosensitizers singlet oxygen (1O2) mediated photooxidation 1,5-dihydronaphthalene to produce juglone. 1O2 quantum yields (ΦΔ) Ir-1 (0.53) Ir-2 (0.81) are ca. 9-fold (0.06) 40-fold (0.02), respectively. has high molar coefficient moderate NIR region, yield (ΦΔ 0.81), exhibits predominate photocytotoxicity over dark cytotoxicity LLC cells (lung cancer cells) irradiation, making it potentially suitable use vivo photodynamic therapy (PDT). Our results useful preparation transition metal show strong light application these photocatalysis theranostics such simultaneous (PDT) luminescent bioimaging.