Expeditious ethanol quantification present in hydrocarbons and distilled spirits: Extending photophysical usages of the pyrazolo[1,5-a]pyrimidines

Structural, Photophysical, and Water Sensing Properties of Pyrazolo[1,5‐a]pyrimidine‐Triphenylamine Hybrid Systems

“…[25,27] For example, the emission wavelength in the solid-state in 2-aryl substituted TPA-PP hybrid systems increases with decreasing the dihedral angle in the hybridization bond (TPA to PP) due to a better ICT phenomenon (i. e., TPA!PP!4-O 2 NPh). [17,26] Pleasingly, structures of the novel dyes (D2, D3, D4, and D5) were solved by X-ray crystallography (Figure 10 and Table S3), and the crystal structure of dye D1 has already been recently discussed. [26] Thus, the crystallographic results of the five hybrids studied in this work could be usefully analyzed and correlated in their structural and optical properties.…”

“…[13,14] For example, pyrazolo[1,5-a]pyrimidine (PP) derivatives are a family of fused N-heterocycles that have been mainly studied for their broad spectrum of biological activities. [15,16] Nevertheless, most of these motifs have recently emerged as functional fluorophores with attractive photophysical properties due to their green and straightforward synthesis and applications in sensors of cyanide [17,18] and cancer cell biomarkers [19] (Figure 1a).…”

“…More recently, we found a new TPA-PP hybrid system evidencing exceptional optical changes upon increasing the solvent dipolarity (SdP) and acidity (SA), which was used for ethanol sensing with assistance from a liquid-liquid extraction. [17] However, up to now, the PP core has been studied systematically only at positions 2 and 7 (Figure 1b). [1,17,26] Herein, we present and investigate a family of TPA-PP hybrid systems equipped with different groups at position 3, probes D2 to D5 (Figure 1c).…”

“…[17] However, up to now, the PP core has been studied systematically only at positions 2 and 7 (Figure 1b). [1,17,26] Herein, we present and investigate a family of TPA-PP hybrid systems equipped with different groups at position 3, probes D2 to D5 (Figure 1c). These probes form crystalline materials with excellent optical properties and strong emission around the green region in solid-phase under UV wavelength excitation.…”

“…Recently, pyrazolo[1,5‐ a ]pyrimidines containing triphenylamine (TPA) to sense water in tetrahydrofuran (THF) were designed by us; [26] however, their moderate solvatofluorochromism, due to an absence of good electron‐acceptor groups (EAGs), [27] restricted their use to some extent. More recently, we found a new TPA–PP hybrid system evidencing exceptional optical changes upon increasing the solvent dipolarity (SdP) and acidity (SA), which was used for ethanol sensing with assistance from a liquid‐liquid extraction [17] . However, up to now, the PP core has been studied systematically only at positions 2 and 7 (Figure 1b) [1,17,26] …”