A Viologen–Perylenediimide Conjugate as an Efficient Base Sensor with Solvatochromic Property

Abstract

A viologen-perylenediimide conjugate, denoted PDEV, is prepared for efficient base sensing. The conjugate shows solvatochromic behavior as well. The base sensitivity of viologen is purposefully coupled with the emission property of perylenediimide (PDI) to lower the detection limit. PDEV shows base-sensing ability at the ppb level, which is at least three orders of magnitude lower than those of previously reported sensors. The probe is sensitive toward solvent polarity and generates different shades of colors according to the polarity of the medium (solvent). The photophysical properties show a linear correlation with the solvent polarity, and this makes it an efficient solvatochromic agent. On the other hand, the generation of viologen radical cations by bases affects the aggregation and consequently the absorption and emission behavior of the PDI core. The effect of bases can also be visualized, because the probe generates different colors in the presence of bases, both under normal and under UV light. Organic amines can be detected even in the crystalline state, since the dark red color of the PDEV crystals changes to purple in a reversible fashion on exposure to amine vapors. An easy and practical paper-based tool created by using the probe can efficiently be used to detect solvent polarity and presence of bases optically.

Self‐Aggregation of a Naphthalene‐Monoimide Amphiphile and Its Charge‐Transfer‐Complex Driven Morphogenesis in Water

“…This pattern is common with arylenediimides and this change can be attributed to self-aggregation induced quenching of emission above this particular concentration. [11] The concentration dependent emission spectra, as shown in Figure 1B, similar to the absorption, showed an inflection at 9.1 mM. In case of UV-Visible spectra, at higher concentration, the absorbance crossed the limit of 1 and thus the concentration versus absorption plot at higher concentration of A-1 was ignored.…”

A DNA-NDI Hybrid to Efficiently Detect Histone in Parts per Trillion (ppt) Level

“…Unless otherwise mentioned all the reported experiments are carried out in 10 mM phosphate buffer pH 7.4. The absorption spectra of all NDIs showed two prominent vibronic bands at ∼ 380, 360 and a shoulder at 340 nm attributed to the 0–0, 0–1 and 0–2 vibrational transitions (Figures S1‐5, Supporting Information) . The emission spectra of these NDI derivatives are mirror images of the respective absorption spectra and show two prominent bands at ∼393 and ∼412 nm (Figures S1‐5, Supporting Information) .…”

“…The absorption spectra of all NDIs showed two prominent vibronic bands at~380, 360 and a shoulder at 340 nm attributed to the 0-0, 0-1 and 0-2 vibrational transitions (Figures S1-5, Supporting Information). [24][25][26][27] The emission spectra of these NDI derivatives are mirror images of the respective absorption spectra and show two prominent bands at~393 and~412 nm (Figures S1-5, Supporting Information). [25] As self-assembly through p-p stacking is common with NDI molecules, concentration dependent DLS studies were performed for all these compounds and it was observed that the first sign of any aggregation was seen above 15 mg mL À1 concentration for all the samples.…”

Mono- and Di-Quaternized 4,4′-Bipyridine Derivatives as Key Building Blocks for Medium- and Environment-Responsive Compounds and Materials

“…Specifically, the crystals become green upon loss of water and the crystal structure changes significantly (dehydration was tested at temperatures up to 250 °C). The dehydration apparently affects the CT in a drastic way from the carboxylate to the viologen, and the electronic properties of dehydrated crystals (green) are very [46]. The viologen-based compound ( Figure 10) was found to exhibit a marked solvatochromic and base-sensitive behavior.…”