AcetylacetonateBODIPY−biscyclometalated Iridium(III) complexes: effective strategy towards smarte fluorescentphotosensitizer agents

Biscyclometalated Ir(III) complexes involving BODIPYbased ancillary ligands, where the BODIPY unit is grafted to different chelating cores (acetylacetonate for Ir-1 and Ir-2, and bipyridine for Ir-3) by the BODIPY meso position, have been synthesized and characterized. Complexes having the BODIPY mo...

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Bibliographic Details
Authors: Palao, Eduardo, Sola Llano, Rebeca, Tabero, Andrea, Manzano Moro, Hegoi, Agarrabeitia, Antonia R., Villanueva, Angeles, López Arbeloa, Iñigo María, Martínez Martínez, Virginia, Ortiz, María J.
Format: article
Publication Date:2017
Country:España
Institution:Universidad del País Vasco
Repository:Addi. Archivo Digital para la Docencia y la Investigación
OAI Identifier:oai:addi.ehu.eus:10810/65165
Online Access:http://hdl.handle.net/10810/65165
Access Level:Open access
Keyword:Iridium(III) complex
BODIPYs
singlet oxygen
fluorescent-photosensitizers
photodynamic therapy
HeLa cells
Description
Summary:Biscyclometalated Ir(III) complexes involving BODIPYbased ancillary ligands, where the BODIPY unit is grafted to different chelating cores (acetylacetonate for Ir-1 and Ir-2, and bipyridine for Ir-3) by the BODIPY meso position, have been synthesized and characterized. Complexes having the BODIPY moiety directly grafted to acetylacetonate (Ir-1 and Ir-2) exhibit higher absorption coefficient (ca. ε = 4.46 104 M-1 cm-1 and 3.38 104 M-1cm-1 at 517 nm and 594 nm, respectively), higher moderate-fluorescence emission (ca. fl = 0.08 and 0.22 at 528 nm and 652 nm, respectively) and, especially, more efficient singlet oxygen generation upon visible-light irradiation (ca.  = 0.86 and 0.59, respectively) than that exhibited by Ir-3 (ca.  = 0.51, but only under UV light). Phosphorescence emission, nanosecond time-resolved transient absorption and DFT calculations suggest that BODIPY-localized long-lived 3IL states are populated for Ir-1 and Ir-2. In-vitro photodynamic therapy (PDT) activity studied for Ir-1 and Ir-2 in HeLa cells shows that such complexes are efficiently internalized into the cells, exhibiting low dark- and high photo-cytoxicity, even at significant low complex concentration, making them potentially suitable as theranostic agents.

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