Synthesis of BF₂chelates of tetraarylazadipyrromethenes and evidence for their photodynamic therapeutic behaviour

Abstract

The synthesis, spectroscopic characteristics and in vitro cellular uptake properties of a new class of therapeutic window photosensitiser, namely the BF2 chelates of 3,5-diaryl-1H-pyrrol-2-yl-3,5-diarylpyrrol-2-ylidene amines (tetra-arylazadipyrromethenes), are described with the aim of developing a novel class of photodynamic therapeutic agents.

Azadipyrromethenes: from traditional dye chemistry to leading edge applications

“…The most important impact of this derivatization is that the boron chelate is fluorescent whereas the azadipyrromethene itself is not. The most common synthetic approach to these BF 2 chelates is to use BF 3 OEt 2 with a weak organic base such as triethylamine (TEA) 11,24 or diisopropylethylamine (DIPEA) 7,26 in CH 2 Cl 2 at rt or (CH 2 Cl) 2 at reflux (Scheme 13). Alternative conditions, such as toluene at 80 °C 18 or benzene at reflux 23,24 , have been reported but often giving lower yields.…”

Visible‐Light Photoactive, Highly Efficient Triplet Sensitizers Based on Iodinated Aza‐BODIPYs: Synthesis, Photophysics and Redox Properties

“…Owing to their advantageous and tunable photophysical properties and ability to generate singlet oxygen ( 1 O 2 )c oupled with absorption of light from the socalled "therapeuticw indow"( 600 nm-1100 nm), aza-BODIPY dyes have been proposed as potential triplet photosensitizers for both anti-microbiala nd anti-cancer photodynamic therapy. [20,[30][31][32][33][34][35][36][37][38][39][40][41] Aza-BODIPYs continue to attracta ttention as chemosensors for the detection of ammonia, [42] cysteine, homocysteine and glutathione in living cells, [43] Hg 2 + , [44][45][46] F À , [47,48] in vivo detection of H 2 S, [49] carbon dioxide, [50] glucosei nw hole blood, [51] detection of saxitoxin [52] and pH-sensitive sensors. [52] Furthermore, aza-BODIPYs have been proposed as photoactive components in photovoltaic devices [54][55][56] and nonlinear optical materials.…”

Optical signatures of borico dyes: a TD-DFT analysis

“…Indeed, BOD-IPY (boron-dipyrromethene), aza-BODIPY and boranil derivatives, that can all be viewed as constrained cyanines, have become key tools for biological, medicinal and analytical applications due to their excellent photophysical properties [1,2]. These molecules that are highly photostable and develop very large quantum yields, have found applications in several fields, e.g., ion sensing [3,4], nonlinear optics [5], photodynamic therapy [6], as well as fluorescence imaging [7]. Of course, more traditional series of fluorescent dyes have already found practical applications, and the two most well-known families of organic fluorophores remain coumarins and naphthalimides, that can be used as paper brighteners [8,9].…”