Design, synthesis, and molecular docking of new phenothiazine incorporated N-Mannich bases as promising antimicrobial agents.

The present work aims to synthesize four series of phenothiazine incorporation Mannich bases. Therefore, 10-methyl-10H-phenothiazine-3-sulfonamide (4) which was subjected to react with some secondary amines and formaldehyde to give the Mannich bases 5a-f, and 6-13. Compound 13 was then subjected to react with some secondary amines and formaldehyde to give the corresponding Mannich bases 14a-f. In total, twenty-two new compounds were synthesized and evaluated for in vitro growth inhibition activity against P. aeruginosa, E. coli, and S. aureus. Among the tested compounds, compounds 3, 5a, 5c, 6, 12, 13, 14d, and 14e exhibited good activity with a MIC value (12.5 µg/mL), compounds 5b, 10, 11, 14a, and 14c exhibited strong activity against the growth of S. aureus with a MIC value (6.25 µg/mL), and compound 14b superior against S. aureus with a MIC value (3.125 µg/mL) compared to drug reference ciprofloxacin with MIC value (2 µg/mL). The molecular docking investigation revealed the presence of many derivatives with high binding affinities and distinct interaction patterns with the target protein. Derivatives 14a-e emerged as the most promising possibilities, displaying the greatest binding energies and a varied variety of interaction types, including hydrogen bonding and pi interactions, over different distances, with derivative 14b exhibiting the highest binding energy at S = -8.3093 kcal/mol. These derivatives displayed superior binding affinities and various interaction mechanisms with the target protein, suggesting that they have great promise as lead compounds for future development into therapeutic medicines.

Synthesis of New D-π-A Phenothiazine-Based Fluorescent Dyes: Aggregation Induced Emission and Antibacterial Activity.

Highly solid-state fluorescent dyes based on phenothiazine bearing sulfa-drug derivatives were successfully prepared and fully characterized by NMR, mass spectra, and elemental analysis. The prepared phenothiazine dyes bearing sulfadiazine and sulfathiazole 4-(((10-hexyl-10 H-phenothiazin-3-yl)methylene)amino)-N-(pyrimidin-2yl) benzenesulfonamide (PTZ-1) and 4-(((10-hexyl-10 H-phenothiazin-3-yl) methylene) amino)-N-(thiazol-2-yl)benzenesulfonamide (PTZ-2), showed strong emission in polycrystalline form, and significant emission in solution was observed. The quantum yield of the prepared dyes varied and decreased by increasing the solvent polarity, with the maximum recorded value being 0.63 and 0.6 in dioxane. Aggregation-induced emission (AIE) and the effect of the solvent polarity on absorption and emission spectra were investigated. The dyeing application of polyester fabrics using the prepared phenothiazine-based dyes was studied, showing very good affinity to dyed fabrics. The antibacterial affinity against gram-positive and gram-negative bacteria for the dye powder as well as the dyed PET fabric was investigated, with PTZ-2 showing better affinity against bacteria compared to PTZ-1. This multifunctional property highlights the potential uses of PTZ-1 and PTZ-2 for advanced applications in biomedicine and optoelectronics.

Chlorpromazine-Polypyrrole Drug Delivery System Tailored for Neurological Application.

Nowadays, drug delivery systems (DDSs) are gaining more and more attention. Conducting polymers (CPs) are efficiently used for DDS construction as such systems can be used in therapy. In this research, a well-known CP, polypyrrole (PPy), was synthesized in the presence of the polysaccharide heparin (HEP) and chlorpromazine (CPZ) using sodium dodecyl sulfate (SDS) as electrolyte on a steel substrate. The obtained results demonstrate the successful incorporation of CPZ and HEP into the polymer matrix, with the deposited films maintaining stable electrochemical parameters across multiple doping/dedoping cycles. Surface roughness, estimated via AFM analysis, revealed a correlation with layer thickness-decreasing for thinner layers and increasing for thicker ones. Moreover, SEM images revealed a change in the morphology of PPy films when PPy is electropolymerized in the presence of CPZ and HEP, while FTIR confirmed the presence of CPZ and HEP within PPy. Due to its lower molecular mass compared to HEP, CPZ was readily integrated into the thin polymer matrix during deposition, with diffusion being unimpeded, as opposed to films with greater thickness. Finally, the resulting system exhibited the ability to release CPZ, enabling a dosing range of 10 mg to 20 mg per day, effectively covering the therapeutic concentration range.

Hemicyanine-Phenothiazine Based Highly Selective Ratiometric Fluorescent Probes for Detecting Hypochlorite Ion in Fruits, Vegetables and Beverages.

Hypochloric acid (HClO) is a reactive oxygen species (ROS) that functions as a bacteriostatic and disinfectant in food production. Excessive levels of ClO-, however, have been linked to various health issues, including cardiovascular diseases (Halliwell and Gutteridge in Oxford University press, USA, 2015), arthritis, and neurodegenerative diseases (Heinzelmann and Bauer in Biol Chem. 391(6):675-693, 2010). Therefore, synthesizing highly selective and sensitive probes for rapidly detecting endogenous ClO- in daily foods is currently a popular research topic (Kalyanaraman et al. in Redox Biol. 15:347-362, 2018; Winterbourn in Nat Chem Biol. 4(5):278-286, 2008; Turrens in J Physiol. 552(2):335-344, 2003). Thus, we have developed two highly selective ratiometric fluorescent probes (Probe1 and Probe2) based on indole-phenothiazine to detect ClO- in common vegetables, fruits and beverages qualitatively and quantitatively. Moreover, Both Probe1 and Probe2 have shown good specificity and stability, with high fluorescence intensity and long duration (Feng et al. in Adv Sci. 5:1800397, 2018; Wei et al. in Angew Chem. 131(14):4595-4599, 2019; Baruah et al. in J Mater Chem B, 2022).

Design, synthesis, structure elucidation, antimicrobial, molecular docking, and SAR studies of novel urea derivatives bearing tricyclic aromatic hydrocarbon rings.

The targeted compounds were prepared using both (9H-fluoren-9-ylidene)hydrazine (1) and 10H-phenothiazine (2) as starting materials. The treatment of 1 or 2 with different isocyanates afforded the title compounds 7a-d, 8a, and 8b in excellent yield. All compounds were characterized and ascertained by infrared, nuclear magnetic resonance, and elemental analyses as well as single-crystal X-ray diffraction. The antimicrobial efficiency of all was tested in vitro, and a noticeable inhibition activity against Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Candida albicans was obtained by compounds 7a, 7b, 8a, and 8b. Moreover, the biofilm mechanism activity was strongly inhibited by compounds 7b and 8b for all bacterial pathogens, with a percentage ratio of more than 55%. The findings from the molecular docking simulation revealed that compounds 7a, 7b, 8a, and 8b exhibited favorable binding energies and interacted effectively with the active sites of sterol 14-demethylase, dihydropteroate synthase, gyrase B, LasR (major transcriptional activator of P. aeruginosa), and carbapenemase for C. albicans, S. aureus, B. subtills, K. pneumoniae, and P. aeruginosa, respectively. These results suggest that the compounds have the potential to inhibit the activity of these enzymes and demonstrate promising antimicrobial properties. Moreover, the in silico evaluation of drug likeness and absorption, distribution, metabolism, excretion, and toxicity (ADMET) profiles for compounds 7a, 7b, 8a, and 8b demonstrated their compatibility with Lipinski's, Ghose's, Veber's, Muegge's, and Egan's rules. These findings suggest that these compounds possess favorable physicochemical properties, making them promising candidates for continued drug development efforts.

Sedative and cardiorespiratory effects of dexmedetomidine alone or combined with acepromazine in healthy cats.

The purpose of this study was to assess sedation, emesis and cardiovascular effects of dexmedetomidine alone or combined with acepromazine in healthy cats. Fourteen male cats aged 0.9 ± 0.5 years and weighing 3.7 ± 0.7 kg were randomly assigned to one of two experimental groups: GD, dexmedetomidine 5 µg/kg; and GDA, dexmedetomidine 5 µg/kg with acepromazine 0.03 mg/kg, all intramuscularly. Measurements were recorded at baseline, at 20 minutes and then at 10-minute intervals following sedation and included heart rate (HR), respiratory rate (FR), systolic arterial pressure (SAP), rectal temperature (RT), number of episodes of emesis and sedation score (0-4). Data were compared using ANOVA for repeated measures followed by Sídák and Dunnet test. Sedation scores were compared between groups at T20 using Mann-Whitney test. Significance was considered when P <0.05. At T20, HR was significantly lower in GDA (99 ± 14 beats/min) compared with GD (133 ± 19 beats/min) and SAP was significantly lower in both groups compared with baseline (126 ± 14 vs. 148 ± 26 and 111 ± 13 vs. 144 ± 17 mmHg in GD and GDA, respectively). Duration of sedation was similar between groups, although sedation scores differed significantly at T20, with 1 (0-4) in GD and 4 (4-4) in GDA. More episodes of emesis were recorded in GD compared with GDA. The combination of dexmedetomidine and acepromazine produced more profound sedation with faster onset and lower incidence of emesis compared with dexmedetomidine alone in healthy cats.

Formamidinium Lead Iodide-Based Inverted Perovskite Solar Cells with Efficiency over 25 % Enabled by An Amphiphilic Molecular Hole-Transporter.

Formamidinium lead iodide (FAPbI3) represents an optimal absorber material in perovskite solar cells (PSCs), while the application of FAPbI3 in inverted-structured PSCs has yet to be successful, mainly owing to its inferior film-forming on hydrophobic or defective hole-transporting substrates. Herein, we report a substantial improvement of FAPbI3-based inverted PSCs, which is realized by a multifunctional amphiphilic molecular hole-transporter, (2-(4-(10H-phenothiazin-10-yl)phenyl)-1-cyanovinyl)phosphonic acid (PTZ-CPA). The phenothiazine (PTZ) based PTZ-CPA, carrying a cyanovinyl phosphonic acid (CPA) group, forms a superwetting hole-selective underlayer that enables facile deposition of high-quality FAPbI3 thin films. Compared to a previously established carbazole-based hole-selective material (2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl)phosphonic acid (MeO-2PACz), the crystallinity of FAPbI3 is enhanced and the electronic defects are passivated by the PTZ-CPA more effectively, resulting in remarkable increases in photoluminescence quantum yield (four-fold) and Shockley-Read-Hall lifetime (eight-fold). Moreover, the PTZ-CPA shows a larger molecular dipole moment and improved energy level alignment with FAPbI3, benefiting the interfacial hole-collection. Consequently, FAPbI3-based inverted PSCs achieve an unprecedented efficiency of 25.35 % under simulated air mass 1.5 (AM1.5) sunlight. The PTZ-CPA based device shows commendable long-term stability, maintaining over 90 % of its initial efficiency after continuous operation at 40 °C for 2000 hours.

Sequential C-F Bond Transformation of the Difluoromethylene Unit in Perfluoroalkyl Groups: A Combination of Fine-Tuned Phenothiazine Photoredox Catalyst and Lewis Acid.

A sequential process via photoredox catalysis and Lewis acid mediation for C-F bond transformation of the CF2 unit in perfluoroalkyl groups has been achieved to transform perfluoroalkylarenes into complex fluoroalkylated compounds. A phenothiazine-based photocatalyst promotes the defluoroaminoxylation of perfluoroalkylarenes with (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) under visible light irradiation, affording the corresponding aminoxylated products. These products undergo a further defluorinative transformation with various organosilicon reagents mediated by AlCl3 to provide highly functionalized perfluoroalkyl alcohols. Our novel phenothiazine catalyst works efficiently in the defluoroaminoxylation. Transient absorption spectroscopy revealed that the catalyst regeneration step is crucial for the photocatalytic aminoxylation.

Targeting autophagy by antipsychotic phenothiazines: potential drug repurposing for cancer therapy.

Cancer is recognized as the major cause of death worldwide and the most challenging public health issues. Tumor cells exhibit molecular adaptations and metabolic reprograming to sustain their high proliferative rate and autophagy plays a pivotal role to supply the high demand for metabolic substrates and for recycling cellular components, which has attracted the attention of the researchers. The modulation of the autophagic process sensitizes tumor cells to chemotherapy-induced cell death and reverts drug resistance. In this regard, many in vitro and in vivo studies having shown the anticancer activity of phenothiazine (PTZ) derivatives due to their potent cytotoxicity in tumor cells. Interestingly, PTZ have been used as antiemetics in antitumor chemotherapy-induced vomiting, maybe exerting a combined antitumor effect. Among the mechanisms of cytotoxicity, the modulation of autophagy by these drugs has been highlighted. Therefore, the use of PTZ derivatives can be considered as a repurposing strategy in antitumor chemotherapy. Here, we provided an overview of the effects of antipsychotic PTZ on autophagy in tumor cells, evidencing the molecular targets and discussing the underlying mechanisms. The modulation of autophagy by PTZ in tumor cells have been consistently related to their cytotoxic action. These effects depend on the derivative, their concentration, and also the type of cancer. Most data have shown the impairment of autophagic flux by PTZ, probably due to the blockade of lysosome-autophagosome fusion, but some studies have also suggested the induction of autophagy. These data highlight the therapeutic potential of targeting autophagy by PTZ in cancer chemotherapy.

Phenothiazines: Nrf2 activation and antioxidant effects.

Phenothiazines (PTZs) are an emerging group of molecules showing effectiveness toward redox signaling and reduction of oxidative injury to cells, via the activation on Kelch-like ECH-associated protein 1/nuclear factor erythroid 2-related factor 2 (Nrf2). Although several electrophilic and indirect Nrf2 activators have been reported, the risk of "off-target" effect due to the complexity of their molecular mechanisms of action, has aroused research interest toward non-electrophilic and direct modulators of Nrf2 pathway, such as PTZs. This review represents the first overview on the roles of PTZs as non-electrophilic Nrf2 activator and free radical scavengers, as well as on their potential therapeutic effects in oxidative stress-mediated diseases. Here, we provide a collective and comprehensive information on the PTZs ability to scavenge free radicals and activate the Nrf2 signaling pathway, with the aim to broaden the knowledge of their therapeutic potentials and to stimulate innovative research ideas.

Exploring the Theoretical Foundations of Thermally Activated Delayed Fluorescence (TADF) Emission: A Comprehensive TD-DFT Study on Phenothiazine Systems.

This study conducts a thorough theoretical investigation of Thermally Activated Delayed Fluorescence (TADF) in phenothiazine-based systems, examining ten molecular configurations recognized experimentally as TADF-active. Employing Time-Dependent Density Functional Theory (TD-DFT), our analysis spans the investigation of singlet-triplet energy gaps (ΔEST), spin-orbit coupling, and excitation characteristics using Multiwfn. This approach not only validates the adherence to El Sayed's rule across these systems but also provides a detailed understanding of charge transfer dynamics, as visualized through heat maps. A significant aspect of our study is the exploration of different oxidation states of sulfur and site substitutions on phenothiazine. This systematic variation aims to identify additional TADF-active compounds, drawing parallels with properties characterizing other known TADF emitters. Our investigation into Reverse Intersystem Crossing (rISC) rates and the analysis of dihedral angles in relation to ΔEST values offer nuanced insights into the TADF behaviours of these molecules. By integrating rigorous computational analysis with practical implications, we provide a foundational understanding that enhances the design and optimization of phenothiazine-based materials for optoelectronic applications. This work not only advances our theoretical understanding of TADF in phenothiazine derivatives but also serves as a guide for experimentalists and industry professionals in the strategic design of new TADF materials.

A Photoelectrochemical Sensor for the Detection of Hypochlorous Acid with a Phenothiazine-Based Photosensitizer.

This paper presents the development of a photoelectrochemical sensor for hypochlorous acid (HOCl) detection, employing a phenothiazine-based organic photosensitizer (Dye-PZ). The designed probe, Dye-PZ, follows a D-π-A structure with phenothiazine as the electron-donating group and a cyano-substituted pyridine unit as the electron-accepting group. A specific reaction of the phenothiazine sulfur atom with HOCl enables selective recognition. The covalent immobilization of Dye-PZ onto a titanium dioxide nanorod-coated fluorine-doped tin oxide electrode (FTO/TiO2) using bromo-silane coupling agent (BrPTMS) resulted in the fabrication of the photoanode FTO/TiO2/BrPTMS/Dye-PZ. The photoanode exhibited a significant photoresponse under visible-light irradiation, with a subsequent reduction in photocurrent upon reaction with HOCl. The oxidation of the phenothiazine sulfur atom to a sulfoxide diminished the internal charge transfer (ICT) effect. Leveraging this principle, the successful photoelectrochemical sensing of HOCl was achieved. The sensor showed high stability, excellent reproducibility, and selective sensitivity for HOCl detection. Our study provides a novel approach for the development of efficient photoelectrochemical sensors based on organic photosensitizers, with promising applications in water quality monitoring and biosensing.

Synthesis and Dynamic Behavior of Ce(IV) Double-Decker Complexes of Sterically Hindered Phthalocyanines.

Phthalocyanines and their double-decker complexes are interesting in designing rotative molecular machines, which are crucial for the development of molecular motors and gears. This study explores the design and synthesis of three bulky phthalocyanine ligands functionalized at the α-positions with phenothiazine or carbazole fragments, aiming to investigate dynamic rotational motions in these sterically hindered molecular complexes. Homoleptic and heteroleptic double-decker complexes were synthesized through the complexation of these ligands with Ce(IV). Notably, CeIV(Pc2)2 and CeIV(Pc3)2, both homoleptic complexes, exhibited blocked rotational motions even at high temperatures. The heteroleptic CeIV(Pc)(Pc3) complex, designed to lower symmetry, demonstrated switchable rotation along the pseudo-C4 symmetry axis upon heating the solution. Variable-temperature 1H-NMR studies revealed distinct dynamic behaviors in these complexes. This study provides insights into the rotational dynamics of sterically hindered double-decker complexes, paving the way for their use in the field of rotative molecular machines.

"Two-Stage Rocket-Propelled" Strategy Boosting Theranostic Efficacy with Mitochondria-Specific Type I-II Photosensitizers.

Imaging-guided photodynamic therapy (PDT) holds great potential for tumor therapy. However, achieving the synergistic enhancement of the reactive oxygen species (ROS) generation efficiency and fluorescence emission of photosensitizers (PSs) remains a challenge, resulting in suboptimal image guidance and theranostic efficacy. The hypoxic tumor microenvironment also hinders the efficacy of PDT. Herein, we propose a "two-stage rocket-propelled" photosensitive system for tumor cell ablation. This system utilizes MitoS, a mitochondria-targeted PS, to ablate tumor cells. Importantly, MitoS can react with HClO to generate a more efficient PS, MitoSO, with a significantly improved fluorescence quantum yield. Both MitoS and MitoSO exhibit less O2-dependent type I ROS generation capability, inducing apoptosis and ferroptosis. In vivo PDT results confirm that this mitochondrial-specific type I-II cascade phototherapeutic strategy is a potent intervention for tumor downstaging. This study not only sheds light on the correlation between the PS structure and the ROS generation pathway but also proposes a novel and effective strategy for tumor downstaging intervention.

Phenothiazine Derivatives as Small-Molecule Organic Cathodes with Adjustable Dropout Voltage and Cycle Performance.

Compared with conventional inorganic materials, organic electrodes are competitive candidates for secondary battery cathodes due to their resourcefulness, environmental friendliness, and cost-effectiveness. Much effort is devoted at the level of chemical structure, while ignoring the impact of molecular aggregation on battery behavior. Herein, this work designs a series of organic molecules with two electrochemically active phenothiazine groups linked by different lengths of alkyl chain to regulate molecular symmetry and crystallinity. The results emphasize the equally important role of molecular aggregation and chemical structure for battery performance. Among them, 2PTZ-C7 H14 |Li cell exhibits the most impressive cycle and rate performance. At the high rate of 50 C, it can still deliver a capacity of 63.4 mA h g-1 and 74.5% capacity retention after 10 000 cycles. Besides, the dropout voltage of 2PTZ-C9 H18 |Li cell is only 52 mV, which is among the lowest reported for lithium-organic batteries to the best of the author's knowledge.

A PEGylated liposomal formulation of prochlorperazine that limits brain exposure but retains dynamin II activity: A potential adjuvant therapy for cancer patients receiving chemotherapeutic mAbs.

Anti-cancer monoclonal antibodies often fail to provide therapeutic benefit in receptor-positive patients due to rapid endocytosis of antibody-bound cell surface receptors. High dose co-administration of prochlorperazine (PCZ) inhibits endocytosis and sensitises tumours to mAbs by inhibiting dynamin II but can also introduce neurological side effects. We examined the potential to use PEGylated liposomal formulations of PCZ (LPCZ) to retain the anti-cancer effects of PCZ, but limit brain uptake. Uncharged liposomes showed complete drug encapsulation and pH-dependent drug release, but cationic liposomes showed limited drug encapsulation and lacked pH-dependent drug release. Uncharged LPCZ showed comparable inhibition of EGFR internalisation to free PCZ in KJD cells. After IV administration to rats, LPCZ reduced the plasma clearance and brain uptake of PCZ compared to IV PCZ. The results suggest that LPCZ may offer some benefit over PCZ as an adjunct therapy in cancer patients receiving mAb treatment.

In-silico Design, ADMET Screening, Prime MM-GBSA Binding Free Energy Calculation and MD Simulation of Some Novel Phenothiazines as 5HT6R Antagonists Targeting Alzheimer's Disease.

BACKGROUND: Alzheimer's disease is a type of dementia that affects neuronal function, leading to a decline in cognitive functions. Serotonin-6 (5HT6) receptors are implicated in the etiology of neurological diseases. 5HT6 receptor antagonists act as anti-dementia agents. PDB ID: 7YS6 represents a membrane protein, and amplification and overexpression of this protein are associated with Alzheimer's disease. Coumarin-fused phenothiazines are significant anti-Alzheimer's agents due to their inhibitory activity on the Serotonin- 6 receptor. OBJECTIVES: Numerous previously unreported Coumarin-substituted Phenothiazines [A2 to A50] were designed using in-silico methods to evaluate their 5HT6 receptor antagonistic activity. Molecular modeling techniques were employed to study the ligands [A2 to A50] in interaction with the Serotonin-6 receptor (PDB ID: 7YS6) using Schrödinger Suite 2019-4. METHODS: Molecular modeling studies of the designed ligands [A2 to A50] were conducted using the Glide module. In-silico ADMET screening was performed using the QikProp module, and binding free energy calculations were carried out using the Prime MM-GBSA module within the Schrödinger Suite. The binding affinity of the designed ligands [A2 to A50] towards 5HT6 receptors was determined based on Glide scores. Subsequently, ligand A31 underwent a 100 ns molecular dynamics simulation using the Desmond module of Schrödinger Suite 2020-1, which is based in New York, NY. RESULTS: The majority of the designed ligands exhibited strong hydrogen bonding interactions and hydrophobic associations with the serotonin-6 receptor, which hinder its activity. These ligands achieved remarkable Glide scores within the range of -4.2859 to -7.7128, in comparison to reference standards such as Idalopirdine (-7.78149), Intepirdine (-5.20103), Latrepirdine (-5.54853), and the co-crystallized ligand (-7.02889). In-silico ADMET properties for these ligands fell within the recommended values for drug-likeness. It is worth noting that the MM-GBSA binding free energy of the most potent inhibitor was positive, indicating a strong binding interaction. Additionally, the dynamic behavior of the protein (7YS6)-ligand (A31) complex was studied by subjecting ligand A31 to a 100 ns molecular dynamics simulation. CONCLUSION: The results of this study reveal strong evidence supporting the potential of coumarin- substituted phenothiazine derivatives as effective Serotonin-6 receptor antagonists. Ligands [A2 to A50], which exhibited noteworthy Glide scores, hold promise for significant anti- Alzheimer activity. Further in-vitro and in-vivo investigations are warranted to explore and confirm their therapeutic potential.

A New Phenothiazine-Based Fluorescent Sensor for Detection of Cyanide.

A new fluorescent sensor for the detection of CN- was developed based on the conjugation of phenothiazine fluorophore and benzofuran unit. By the nucleophilic attacking of CN- to the fluoroacetylamino group in the sensor, the additional reaction of CN- and carbonyl group induced the ICT (intramolecular charge transfer) effect in the molecule and caused the fluorescence quenching sensor. The titration experiments show that the sensor has good sensitivity, selectivity and quick response for CN-. In addition, the fluorescent detection of CN- in the living cell and zebrafish experiments demonstrated the value of the sensor in tracing the CN- in biological systems.

Phenothiazine-based fluorescent probes for the detection of hydrazine in environment and living cells.

As an important chemical raw material, hydrazine brings convenience to people's lives and provides opportunities for human development. However, the misuse or leakage of hydrazine has brought pollution to the environment, including water, soil and living organisms. At the same time, hydrazine poses a potential threat to human health as a carcinogen. Despite the enormous challenges, it is crucial to develop an effective method to detect hydrazine in environmental samples. In this work, we have synthesized a series of probes based on phenothiazine fluorophore by the introduction of different substituents and developed a novel probe for the detection of hydrazine. The probe is capable of detecting hydrazine in aqueous solutions with high sensitivity and selectivity, and can be easily fabricated into paper test strips for use in in situ samples. In addition, the probe is effective in detecting hydrazine in water, soil, cells, and zebrafish, providing an excellent tool for detecting hydrazine in the environment.

A Dual Functional Fluorescent Probe Based on Phenothiazine for Detecting Hg2+ and ClO- and its Applications.

For the efficient detection of Hg2+ and ClO-, a double-analyte-responsive fluorescent probe PTB was successfully synthesized by combining N-butyl-3-formyl phenothiazine with hydrazine benzothiazole, and designing a specific reaction site for recognizing two analytes (Hg2+ and ClO-) in a compound. It was shown that probe PTB successfully formed a stable complex with Hg2+ in the coordination ratio of 2:1 by using the strong sulfur affinity of Hg2+, which resulted in a remarkable "turn-off" effect, with a quenching efficiency of 92.5% and four reversible cycles of Hg2+ fluorescence detection. For the fluorescence detection of Hg2+, the response time is fast (≤ 2 min) and the detection limit is low (7.8 nM), showing extremely high sensitivity, and the performance is obviously better than that of the reported fluorescent probes for detecting Hg2+. In particular, probe PTB has low toxicity and good biocompatibility, and has been successfully used for imaging of Hg2+ in living cells. Moreover, probe PTB uses thioether bond and carbon-nitrogen double bond as reaction sites to detect ClO-, which has large Stokes Shift (149 nm), good selectivity, high quenching efficiency (96.5%) and fast time response (about 10 s), and successfully detects ClO- in actual water samples. The dual functional fluorescent probe PTB is sensitive for Hg2+ and ClO-. It has been successfully used for making pH fluorescent test paper and imaging detection of exogenous Hg2+ in VSMC cells with low toxicity.