Novel PET-pperated rosamine pH-sensor dyes with substitution pattern-tunable pK_a values and temperature sensitivity

Abstract

We present the synthesis and characterization of a family of regioisomerically pure pH-sensitive rosamine fluorophores consiting of xanthene fluorophore cores, which determine the dyes’ photophysical properties such as excitation/emission wavelength,...

Basic Fluorescent Protonation-Type pH Probe Sensitive to Small ΔpKa of Methanol and Ethanol

“…Protonation-type probes, such as methyl red and rhodamines with basic scaffolds, exhibit spectral changes due to protonation at its basic moiety. Deprotonation-type probes, such as bromophenol blue and phenol phthalein, have acidic protons that are deprotonated with color changes; these probes have been well studied and can be utilized for monitoring a wide pH range by carefully tuning their p K a values. ,− In contrast, the pH range monitored by protonation-type probes is generally limited to the acidic region because of the limited p K a (p K BH+ ) tunability of the conjugate acid of the basic moiety. Therefore, only a few strongly basic probes have been reported, − whereas various weakly basic probes have been developed for monitoring acidic and neutral pH conditions. − Protonation-type probes are also utilized as fluorescent probes for the selective detection of highly acidic, harmful organic compounds such as picric acid .…”

Dual color pH probes made from silica and polystyrene nanoparticles and their performance in cell studies

“…The interest in measuring pH in biological systems together with the general advantages offered by fluorescence methods such as relatively simple and inexpensive instrumentation 11,12 , minimal invasiveness, and suitability for the in situ online monitoring of local pH using, e.g., optical microscopy, and remote sensing 11,12 has triggered the development of pH-responsive organic fluorophores from different dye classes. This includes BODIPY and BF 2 -chelated tetraarylazadipyrromethene dyes [13][14][15][16][17][18] , as well as xanthene [19][20][21][22][23][24] , cyanine [25][26][27][28][29] , squaraine 23 , and naphthalimide fluorophores [30][31][32][33] , which exploit intramolecular photoinduced electron transfer (PET), intramolecular charge transfer (ICT), and fluorescence energy transfer processes for the signaling of pH. Optical parameters utilized for the determination and monitoring of pH are pH-induced changes in the spectral position and/or intensity of the dye's absorption and/or emission bands or fluorescence lifetime 31,[34][35][36][37] .…”

Turn-On Fluorescent pH Probes for Monitoring Alkaline pHs Using Bis[2-(2′-hydroxyphenyl)benzazole] Derivatives

“…Commonly known fluorophores are tetraphenylethene, coumarin, naphthalimide, rhodamine, boron dipyrromethene (BODIPY), cyanine (Cy) [ 14 ], and 2-(2-hydroxyphenyl)benzothiazole [ 15 ]. Organic fluorescent pH probes commonly have a characteristic nitrogen- or oxygen-containing group where protonation or deprotonation occurs depending on the pH, changing the fluorescence of the fluorophore [ 14 , 16 ]. Using this property, several researchers have developed fluorescent probes that can monitor various pH ranges.…”