Sensitive Naked Eye Detection of Hydrogen Sulfide and Nitric Oxide by Aza-BODIPY Dyes in Aqueous Medium

Abstract

With an objective to develop optical probes for biologically important anions and neutral molecules, we synthesized three novel NIR absorbing aza-BODIPY derivatives, 3a-3c, and have systematically tuned their photophysical properties by changing the peripheral substitution. A profound red-shift was observed in the absorption and fluorescence spectra of the aza-BODIPY dyes with the change in substitution from azido (3a) to amino (3b) to dimethylamino (3c) groups. Theoretical calculations of 3a-3c showed a consistent decrease in bandgap, which supports the observed spectral changes. The study of their interactions with various analytes revealed that the azido-aza-BODIPY 3a selectively interacts with hydrogen sulfide (H2S) when compared to other molecules. Uniquely, the detection of H2S can be visualized through a change in color from bright blue to purple with a detection limit of 0.5 ppm. The sensitivity of the probe was observed to be ~20-fold higher than the allowed exposure limits of H2S as defined by EPA (10 ppm). The aza-BODIPY derivative 3b, on the other hand, exhibited selective interactions with nitrite ions (NO2(-)) and nitric oxide (NO) in aqueous medium through a visible color change from blue to green with a sensitivity of 20 and 0.15 ppb, respectively. In contrast, the dimethylamino-aza-BODIPY derivative, 3c, showed negligible affinity for the anions and neutral molecules tested. By tuning the photophysical properties through the judicious functionalization, the aza-BODIPY dyes thus synthesized can be utilized for the sensitive on-site detection and analysis of H2S, NO2(-), and NO in the aqueous medium.

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.…”

An ICT-Based Hydrogen Sulfide Sensor with Good Water Solubility for Fluorescence Imaging in Living Cells

“…Naphthalimide dye is the favorable building block for constructing fluorescent probes because of its excellent photophysical properties, such as high extinction coefficients, excellent quantum yields, and great photostability. In addition, azido group is well-known for sensitively and selectively responding to H 2 S, the electron withdrawing azide is very easy reduced by H 2 S affording the electron donating amine [17][18][19][20][21][22][23][24][25][26]. Thus, in this work, we employed the naphthalimide chromophore as the signal reporter and azido group as the responding site for H 2 S to construct a H 2 S probe based on internal charge transfer (ICT) process (Scheme 1).…”

Chemistry, Biochemistry and Pharmacology of Hydrogen Sulfide

“…An aza-BODIPY dye (44) has been reported by Ramaiah and co-workers ( Fig. 20) (Adarsh et al 2014). Reaction of 44 (12 μM) in THF with 2 equiv.…”