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

Abstract

Heteroleptic C^N cyclometalated iridium(iii) complexes showing strong NIR absorption were prepared.

Photocatalytic Activity of the Molecular Complexes of meso‐Tetraarylporphyrins with Lewis Acids for the Oxidation of Olefins: Significant Effects of Lewis Acids and meso Substituents

“…The singlet‐oxygen quantum yield ( φ Δ ) of the photosensitizers has been used as a criterion to evaluate the relative efficacy of different photocatalysts. The singlet‐oxygen quantum yields of the free‐base porphyrins and the molecular complexes determined relative to that of methylene blue ( φ Δ = 0.57) using DPBF as the singlet‐oxygen quencher are summarized in Table .…”

“…Singlet‐Oxygen Quantum‐Yield Measurements: The quantum yield of the singlet‐oxygen formation of the photosensitizers was measured by using 1,3‐diphenylisobenzofuran (DPBF) as the quencher of singlet oxygen and methylene blue ( φ Δ = 0.57 in dichloromethane) as a reference photosensitizer . The equation proposed by Murata et al[23c] [ Φ Δ = Φ Δ std (υ i × I std /υ i std × I )] was used to evaluate the φ Δ values. In a control reaction it was found that exposure of the dichloromethane solution of DPBF (8.0 × 10 –4 m ) to the 10 W red LED lamp led to no detectable degradation of DPBF (Supporting Information, S8).…”

Green to Blue Annihilated Upconversion from a Simple Iridium(III) Sensitizer with Carboxylic Group

“…Triplet‐triplet annihilation (TTA) with multi‐chromophores system comprising a triplet sensitizer and an acceptor is an effective approach to generating upconverted fluorescence using low‐power laser (<100 mW/cm 2 , equal to the sunlight), which was firstly demonstrated by Parker and Hatchard in 1962 and has significant applications so far, such as photovoltaics, photocatalysis and bioimaging . According to the revealed mechanism, TTA‐upconversion undergoes a series of multiple quantum processes: (i) the sensitizer first absorbs one photon to the excited singlet state and goes across its triplet excited state by intersystem crossing (ISC); (ii) then, the triplet–triplet energy transfer (TTET) occurs from the sensitizer to the acceptor, and then two triplet acceptors undergo the triplet‐triplet annihilation (TTA) with the result that photon‐upconversion is produced.…”

“…However, due to the weak absorption in visible light regions, the applications of iridium(III) complexes in the emerging TTA upconversion technology have been intensely limited. In order to tackle the disadvantage of iridium(III) sensitizer in TTA upconversion, it's a compromise approach to modify the chelating ligands by incorporating light‐harvesting groups, such as diketopyrrolopyrrole (DPP), naphthalenediimide (NDI) group, coumarin derivatives and boron dipyrromethene (BODIPY) . Recently, Duan et al also reported a novel iridium(III) sensitizer has moderate absorbance in visible light regions and exhibits excellent performance in upconversion studies .…”

Iridium-Based Dual-Functional Nanoparticles for Far-Red Imaging and Photodynamic Therapy

“…In this respect, iridium complexes are ideal phosphorescent oxygen probes [18][19][20], and have been widely utilized to sense cellular oxygen or to image tumor hypoxia [21,22]. More recently, NIR phosphorescent iridium complexes have expanded their application as photodynamic therapy (PDT) agents [23][24][25]. Under light illumination, the interaction between molecular oxygen and excited MLCT states generates reactive singlet oxygen ( 1 O 2 ), which leads to cell death and tissue destruction.…”