Fluorescent materials for pH sensing and imaging based on novel 1,4-diketopyrrolo-[3,4-c]pyrrole dyes

Abstract

Fluorescent pH-sensors based on 1,4-diketopyrrolo-[3,4-c]pyrrole indicator dyes are presented. Their key advantages are excellent suitability for fluorescence imaging and tunability of the sensitive range.

Transition metal-free one-pot synthesis of nitrogen-containing heterocycles

“…For example, five-membered heterocycles are present in more than hundred drugs available in the market and approximately thousands of heterocyclic derivatives are under clinical trials [37]. Apart from this, they have also been known for their catalytic [38,39], fluorescent [40][41][42], and dying properties [43,44].…”

New highly fluorescent pH indicator for ratiometric RGB imaging of pCO2

“…Low solubility prevents the dyes from application as indicators in optical sensors. We previously demonstrated that the dyes are pH-sensitive due to the deprotonation of the lactam nitrogen [29,34]. Modification of the phenyl rings with bulky substituents rendered the pigments soluble in organic solvents and polymers and the pH sensitivity was preserved.…”

“…So far only a few applications of DPPs as fluorescent probes are found in the literature [29,[44][45][46]. The new DPP-based pH indicators were shown to be highly promising for application in optical pH and carbon dioxide sensors [29,34]. Particularly, dual emission from the protonated and deprotonated forms enabled ratiometric read-out, but the emission from the deprotonated form was much weaker than that of the protonated form ( prot ≈ 1 and deprot ≈ 0.1).…”

“…in photovoltaics [37][38][39]. So far only a few applications of DPPs as fluorescent probes are found in the literature [29,[44][45][46]. The new DPP-based pH indicators were shown to be highly promising for application in optical pH and carbon dioxide sensors [29,34].…”

“…The read-out with RGB cameras is a simple and low cost technique for imaging different parameters such as CO 2 [25], pH [26][27][28][29] or oxygen [30][31][32][33], to name only a few. Recently, we presented a new class of pH-sensitive indicator dyes based on diketo-pyrrolo-pyrroles (DPPs) [29,34]. DPPs are usually insoluble in organic solvents and are mainly used as pigments [35].…”