Azobenzene disperse dye-based colorimetric probe for naked eye detection of Cu2+ in aqueous media: Spectral properties, theoretical insights, and applications

New tricks and emerging applications from contemporary azobenzene research

“…A known isosbestic point can be used as the reference and the measured absorbance is related to this reference value, increasing the robustness of the measurement against variance due to changes in sample concentration or detection light path. Such colorimetric azobenzene sensors have been used to detect several metal cations, such as Hg 2+ [40], Al 3+ [41], Cu 2+ [42], Pb 2+ [43] as well as organic molecules relevant to applications in biology, such as sugar [44] and cysteine [45]. Li et al recently demonstrated sensors for humidity based on the deprotonation of protonated azobenzenes in azobenzene/acid binary systems [46].…”

A Quinoxaline−Naphthaldehyde Conjugate for Colorimetric Determination of Copper Ion

“…This can be recognised by the naked eye and easy monitoring can be possible. Several works have been reported for colorimetrically Cu 2+ detection (Table S1) [9,[18][19][20][21][22][23][24][25][26][27]. Quinoxaline moiety is one of the units that has recently grabbed our attention due to its excellent colorimetric signalling unit behaviour [28,29].…”

Azophenyl appended Schiff base probe for colorimetric detection of Cu2+ in semi‐aqueous medium and live cell imaging

“…There are a very few colorimetric detection probes for the detection of Cu 2+ available in the literature, and most of them suffer with various issues such as expensive and complex synthetic route, [23] weak limit of detection values [24] and less selectivity [23,[25][26][27] and solvent pH sensitivity. [28] Hence, an easy and inexpensive route to obtain the colorimetric chemosensor is much desirable in this regard which can overcome the above mentioned issues. The fact has encouraged us to undertake design of some simpler Schiff bases with additional photoactive functional group, such as azo function (-N=N-), which may serve as chromophore and may enhance the molar extinction coefficient to make more sensitive to Cu 2+ in the visible region.…”