Diketopyrrolopyrrole–fullerene C₆₀ architectures as highly efficient heavy atom-free photosensitizers: synthesis, photophysical properties and photodynamic activity

Abstract

New diketopyrrolopyrrole–C60 architectures were synthesized as potential heavy atom-free photosensitizers in photodynamic inactivation of microorganisms.

Recent advances in visible light-activated radical coupling reactions triggered by (i) ruthenium, (ii) iridium and (iii) organic photoredox agents

“…Singlet oxygen generation can be accessible through energy transfer processes. 107,108 The [2+2] cycloadditions of alkenes are highly successful processes with energy transfer catalysis. 109,110 The application of quantum dots as energy transfer catalysts in organometallic cross-coupling reactions has increased the efficiency and selectivity of these transformations.…”

A Convenient Synthesis of Diketopyrrolopyrrole Dyes

“…However, it has scarcely been used as precursor to other DPP derivatives and the reported transformations are mainly N -alkylations [ 54 , 55 , 56 , 57 ]. Although it contains two 4-chlorophenyl groups that can be used to get access to other DPP derivatives by direct substitution of the chlorine atoms, this approach has been rarely used [ 28 , 58 , 59 , 60 ]. Here we report that this pigment can be successfully converted into other DPP derivatives, with adequate functional groups for further transformations, by Suzuki–Miyaura cross-coupling reaction with aryl and hetaryl boronic acids.…”

“…Here we report that this pigment can be successfully converted into other DPP derivatives, with adequate functional groups for further transformations, by Suzuki–Miyaura cross-coupling reaction with aryl and hetaryl boronic acids. This method is an excellent alternative to the previously reported one that requires the synthesis of the corresponding diboronate followed by reaction with iodoarenes, with both steps requiring Pd catalysis [ 28 , 60 ]. This new route involves only one Pd catalyzed step, requires mild conditions, and provides the new compounds in higher yields.…”

“…The synthetic procedures to obtain the DPP derivatives are summarized in Scheme 1 . The first step involved the N , N ’-dialkylation of Pigment Red 254 with 1-iodopentane as previously reported [ 28 ]. This step is essential to convert the pigment (insoluble) into a dye (soluble), thus facilitating the following reactions and the purification process of the resulting products.…”

“…In fact, DPP derivatives have applications in materials technology, from paint pigments to dye-sensitized solar cells (DSSC) [ 2 , 3 , 4 , 5 , 6 ], organic solar cells [ 7 , 8 , 9 , 10 , 11 , 12 , 13 ], organic electronics [ 14 , 15 , 16 , 17 ], fluorescent probes [ 18 , 19 , 20 , 21 , 22 , 23 ], materials for lithium-ion batteries [ 24 ], for ionic charge storage [ 25 ], or for the removal of micropollutants from water [ 26 ], etc. Besides that, the studies concerning their potential use in biological applications, namely as antibacterial agents [ 27 , 28 , 29 ], in photodynamic/photothermal therapy [ 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ], or bioimaging/theranostics [ 39 , 40 , 41 , 42 , 43 ], have increased in recent years.…”