Synthesis of Phenol-Hydrazide-Appended Tetraphenylethenes as Novel On-Off-On Cascade Sensors of Copper and Glutathione.

This study reports the synthesis of novel fluorescent probes, phenol-hydrazide-appended tetraphenylethenes (TPEs I and II), and explores their photochemical properties. The probes exhibit aggregation-induced emission (AIE) in increasing water content, as observed using fluorescence spectroscopy. Further investigation with UV-vis and fluorescence techniques revealed their potential as ion sensors. Both TPE I and TPE II act as "turn-off" sensors for Cu2+ ions, showing decreased fluorescence intensity in their presence. Their limit of detection (LOD) and association constant (K a) for Cu2+ were found to be comparable at 747 nM/597 nM, and 2.46 × 105 M-1/2/1.78 × 105 M-1/2, respectively. Moreover, the quantum yields of TPE I and TPE II were also calculated and found to be 0.651 and 0.325, respectively. Interestingly, these probes also function as "turn-on" sensors for glutathione (GSH) in the presence of copper. This means their fluorescence can be reversibly switched off and on by alternating CuCl2 and GSH additions. Moreover, the LOD values for GSH with TPE II-Cu2+ were calculated to be 544 nM. In addition, the investigation also employed visual analysis to assess the color alterations of TPEs on filter paper and in real water samples. Overall, this research introduces promising new probes with potential applications in copper ion detection and biomolecule glutathione sensing in real water samples.

Off-On-Off Cascade Recognition of Cyanide, Mercury, and Aluminum Using N/5-Monosubstituted Rhodanines.

This study aims to synthesize N- and 5-monosubstituted rhodanine derivatives as ion-sensing organics and investigate their sensing abilities. Following an easy and green approach to synthesis, the anion-sensing properties of the rhodanines were studied using colorimetric detection and spectroscopic methods. As a result of studies, rhodanines are found to be highly solvent-controlled colorimetric and fluorescent cyanide, mercury, and aluminum sensors. The stoichiometry of the interaction between CN- and both probes was determined to be 1:1 using Job's plot analysis. The binding constants (Ks) of CN- to 5-arylRh and N-arylRh were calculated to be 3.25 × 104 and 7.07 × 104 M-1, respectively, demonstrating their high affinity for cyanide ions. The limits of detections for the 5-arylRh and N-arylRh were also determined as 356 and 617 nM, respectively. In addition to detecting CN-, 5-arylRh also serves as a specific turn-off sensor for mercury and aluminum when cyanide and hydroxide are present. This enables the fluorescence intensity to be toggled on/off by alternating the addition of CN-/OH- and Hg2+/Al3+. Furthermore, the LOD values for Hg2+ and Al3+ with 5-arylRh-CN- and 5-arylRh-OH- were determined to be 414 nM and 1.35 µM, respectively. Furthermore, the turn-on binding mechanisms of 5-arylRh and N-arylRh with cyanide ions were elucidated, and the experimental band gap (highest occupied molecular orbital/least unoccupied molecular orbital) energy values corroborated the proposed mechanism. Additionally, the interaction mechanism of the probes with CN- was further investigated by using the 1H NMR technique. Collectively, these findings suggest that 5-arylRh, N-arylRh, and 5-arylRh-CN- hold promise as selective and sensitive candidate sensors for CN-, Hg2+, and Al3+ ions.

A Novel Rhodamine-Phenolphthalein Architecture for Selective Mercury Ion Detection in Aqueous Media.

In this study, the primary objective is to synthesize a novel fluorescent Rh-PP-Rh compound and explore its extensive range of photochemical behaviors. Initially, the synthesis of the novel Rh-PP-Rh was carried out for this purpose. Subsequently, UV-Vis and fluorescence spectroscopy were employed to investigate the interactions between Rh-PP-Rh and a diverse array of ions in aqueous solvent systems. Through fluorescence and UV-Vis studies, it was observed that Rh-PP-Rh demonstrated turn-on sensor properties in the presence of Hg2+ ions. Furthermore, the limits of detection (LOD) and association constant (Ka) values for Rh-PP-Rh/Hg2+ were determined as 334 nM and 9.13×1011 M-2, respectively. Additionally, the reversible studies demonstrated a switchable on/off response upon alternate addition of HgCl2 and [Bu4N]F to Rh-PP-Rh. These findings suggest that the probe Rh-PP-Rh also possesses specific sensor properties for F- ions in the presence of mercury. In addition, the investigation encompassed an assessment of the visual analysis of the color alterations of Rh-PP-Rh both on filter paper and in an EtOH/H2O solution. The findings demonstrated that Rh-PP-Rh can be successfully utilized in solutions containing mercury, as it generates significant color transformations.

Preparation of chiral monoliths with new modulation of the monolith surface chemistry for the enantioseparation of chiral drugs by nano-liquid chromatography.

Here, we report the preparation and application of two new chiral monoliths for the enantioseparation of chiral drugs in nano-LC. Using 3­chloro-2-hydroxypropylmethacrylate (HPMA-Cl, 2) as a precursor monomer, two different chiral monomers namely, Nα-Boc-Lys-HPMA (3A) and Nα-Fmoc-Lys-HPMA (3B) were synthesized and used for the preparation of chiral polymer monoliths. The first monolithic column (referred to as monolith I) was prepared by an in-situ polymerization of Nα-Boc-Lys-HPMA as the chiral monomer and ethylene dimethacrylate while the second monolithic column (referred to as monolith II) was prepared by an in-situ polymerization of Nα-Fmoc-Lys-HPMA as the chiral monomer and ethylene dimethacrylate as the crosslinker. Methanol and 1-propanol were used as the porogenic solvents. The prepared chiral monoliths were investigated for the enantioseparation of chiral drugs, including ß-blockers (e.g., atenolol, propranolol, metoprolol) and anti-inflammatory drugs (e.g., ketoprofen, ibuprofen, flurbiprofen, naproxen, etodolac). The enantioseparation could be achieved via the formation of π-π interactions on the aromate-rich and aromate-poor chiral molecules while enantioseparation mechanism of chiral drugs included mostly π-π interactions and hydrogen bonding. Monolith II showed better enantioselectivity than Monolith I and the resolution values up to 2.12 were successfully achieved.

Synthesis of Bis-tetraphenylethene as a Novel Turn-On Selective Zinc Sensor.

The main purpose of this study is the synthesis of novel fluorescent Bis-TPE and the investigation of its wide range of photochemical behaviors. For this purpose, initially, Bis-TPE was synthesized. Following this, the interactions of Bis-TPE with a wide range of ions were studied in EtOH using ultraviolet-visible (UV-vis) and fluorescence spectroscopy. As a result of all UV-vis and fluorescence studies, it was determined that Bis-TPE showed turn-on sensor features against Zn2+ ions. Moreover, the limit of detection (LOD) and Ka values of Bis-TPE/Zn2+ were calculated as 0.97 µM (970 nM) and 3.76 × 105 M-1, respectively. Moreover, all reversal studies resulted in switchable on/off variation of the alternative addition of ZnCl2 and [Bu4N]OH to Bis-TPE. This result also implies that the probe Bis-TPE also exhibits specific OH- sensor properties in the presence of zinc.

The isolation of secondary metabolites from Rheum ribes L. and the synthesis of new semi-synthetic anthraquinones: Isolation, synthesis and biological activity.

Rheum ribes L. (Rhubarb) is one of the most important edible medicinal plants in the Eastern Anatolia region and is called "Iskin" by local people. Resveratrol and 6-O-methylalaternin were isolated from the Rhubarb for the first time in addition to well-known secondary metabolites including emodin, aloe-emodin, ß-sitosterol and rutin. The new semi-synthetic anthraquinone derivatives with the NαFmoc-l-Lys and ethynyl group were synthesized from the isolated anthraquinones emodin and aloe-emodin of Rhubarb to increase the bioactivities. Aloe-emodin derivative with NαFmoc-l-Lys shows the highest inhibition values by 94.11 ± 0.12 and 82.38 ± 0.00% against HT-29 and HeLa cell lines, respectively, at 25 µg/mL. Further, modification of the aloe-emodin with both the ethynyl and the NαFmoc-l-Lys groups showed an antioxidant activity-enhancing effect. From molecular docking studies, the relative binding energies of the emodin and aloe-emodin derivatives to human serum albumin ranged from -7.30 and -10.62 kcal/mol.

The impact of metal coordination on the assembly of bis(indolyl)methane-naphthalene-diimide amphiphiles.

The self-assembly and coordination of amphiphiles comprised of naphthalenediimide (NDI) and bis(indolyl)methane (BIM) chromophores were investigated as a function of pH and metal. As observed by TEM, SEM and AFM imaging, the self-assembly of NDI-BIM 1 produced irregular nanostructures at neutral pH in CH3CN-H2O (1 : 1); whereas, well-defined nanotubes were observed at pH 2. Conversely, Fmoc-protected, NDI-BIM 2 formed nanotubes at neutral pH and nonspecific aggregates at pH 2. Upon coordination of Cu2+ ions to the bis(indoyl)methane moiety, a reorganization from nanotubes to vesicular structures was observed.

The green synthesis and molecular docking of novel N-substituted rhodanines as effective inhibitors for carbonic anhydrase and acetylcholinesterase enzymes.

Recently, inhibition effects of enzymes such as acetylcholinesterase (AChE) and carbonic anhydrase (CA) has appeared as a promising approach for pharmacological intervention in a variety of disorders such as epilepsy, Alzheimer's disease and obesity. For this purpose, novel N-substituted rhodanine derivatives (RhAs) were synthesized by a green synthetic approach over one-pot reaction. Following synthesis the novel compounds, RhAs derivatives were tested against AChE and cytosolic carbonic anhydrase I, and II (hCAs I, and II) isoforms. As a result of this study, inhibition constant (Ki) were found in the range of 66.35 ±â€¯8.35 to 141.92 ±â€¯12.63 nM for AChE, 43.55 ±â€¯14.20 to 89.44 ±â€¯24.77 nM for hCA I, and 16.97 ±â€¯1.42 to 64.57 ±â€¯13.27 nM for hCA II, respectively. Binding energies were calculated with docking studies as -5.969, -5.981, and -9.121 kcal/mol for hCA I, hCA II, and AChE, respectively.

A novel pyrene-based selective colorimetric and ratiometric turn-on sensing for copper.

Detection of copper attracts important in most environmental and biological systems. In this study, a simple probe BisPyTSC containing bis-pyrene core was synthesized, and cation binding and sensing properties were studied using colorimetric and fluorometric detection. The research indicated that the specific ligand affinity for Cu2+ ions results in drastic color and spectral changes. According to the data obtained, while the peak intensity increases at 376 nm, the peak intensity decreased at 280 nm in the absorption spectrum of BisPyTSC and an increase in fluorescence intensity of BisPyTSC was observed in the presence of Cu2+ ions. The binding ratio of BisPyTSC to Cu2+ was found to be 1:1 according to Job's plot experiments. The binding constant was calculated using the Benesi-Hildebrand equation and found to be 3.26 × 104 M-1. Based on these concentration dependent fluorescence changes, the limit of detection (LOD) value was calculated to be 14.5 µM for Cu2+, which is the range of copper that should be in the blood (11.8-23.6 µM). As a result of all these studies, we can understand that BisPyTSC is a good selective candidate turn-on sensor that can be used for Cu2+ detection.

The synthesis of N-benzoylindoles as inhibitors of rat erythrocyte glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase.

Glucose-6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6PGD) play an important function in various biochemical processes as they generate reducing power of the cell. Thus, metabolic reprogramming of reduced nicotinamide adenine dinucleotide phosphate (NADPH) homeostasis is reported to be a vital step in cancer progression as well as in combinational therapeutic approaches. In this study, N-benzoylindoles 9a--9d, which form the main framework of many natural indole derivatives such as indomethacin and N-benzoylindoylbarbituric acid, were synthesized through three easy and effective steps as an in vitro inhibitor effect of G6PD and 6PGD. The N-benzoylindoles inhibited the enzymatic activity with IC50 in the range of 3.391505 µM for G6PD and 2.19-990 µM for 6PGD.