Sumanene-carbazole conjugate with push-pull structure and its chemoreceptor application

The first-of-its-kind tetra-substituted sumanene derivative, featuring the push-pull chromophore architecture, has been successfully designed. The inclusion of both strong electron-withdrawing (CF3) and electron-donating (carbazole) moieties in this buckybowl compound has enhanced the charge transfer characteristics of the molecule. This enhancement was supported by ultraviolet-visible (UV-Vis) and emission spectra analyses along with density functional theory (DFT) calculations. The application of the title sumanene-carbazole push-pull chromophore as a selective recognition material for cesium cations (Cs+) was also presented. The title compound exhibited effective and selective Cs+-trapping ability, characterized by a high apparent binding constant value (at the level of 105) and a low limit of detection (0.09-0.13 μM). Owing to the tuned optical properties of the title push-pull chromophore, this study marks the first time in sumanene-tethered chemoreceptor chemistry where efficient tracking of Cs+ binding was possible with both absorption and fluorescence spectroscopies. This work introduces a new approach toward tuning the structure of bowl-shaped optical chemoreceptors.

A novel amidine-based fluorescent probe TPE-4+ for rapid detection of anionic surfactant sodium dodecyl sulfate

An accurate, fast, and simple surfactant detection method is of great significance for monitoring surfactants pollution. Sodium dodecyl sulfate (SDS) is one of the most commonly used anionic surfactants and has been listed as an important monitoring pollutant for surfactant residues. Herein, a novel fluorescent probe named TPE-4+ with four amidines as the recognition functional group and tetraphenylethene as the fluorophore was fabricated. Due to the special intramolecular environment, the probe showed selectively identification towards SDS which made an aggregation induced fluorescence enhencement. Under the optimum conditions, the fluorescence enhencement of TPE-4+ is linearly related to the concentration of SDS in the range of 5.0-60.0 μM with limit of detection (LOD) of 0.010 μM and limit of quantification (LOQ) of 0.034 μM. Relative to the reported methods, the probe in our work showed better selectivity and sensitivity. The proposed method was successfully applied for the SDS determination of disinfecting bowls.

Multi-step Synthesis, Characterization and Photophysical Investigation of Novel Biologically Active Heterocyclic Chalcone (AECO)

Novel alkylated heterocyclic chalcone (E)-1-(2-(allyloxy)phenyl)-3-(9-ethyl-9H-carbazol-3-yl)prop-2-en-1-one (AECO) with extended π-bond was prepared by the multi-steps synthesis. The structure of the AECO was established by the spectroscopic technics and purity of the compound was confirmed by the elemental analysis. Physicochemical parameters of the AECO such as molar absorption coefficient, transition dipole moments, stokes shift, oscillator strength and fluorescence quantum yield were calculated in ten various solvents on the basis of polarity of the solvents to see the effect of the solvent with AECO. Interaction of the AECO chromophore with cationic CTAB and anionic SDS surfactants were determined by using the fluorescence spectroscopy techniques. The intensity of the florescence spectrum increase with increasing the concentrations of surfactants. This suggests that strong interaction occurs between AECO with surfactants and this interaction arise from electrostatic forces. So, AECO chromophore could be used as analysis to define the Critical Micelle Concentration (CMC) of the surfactants. In addition the in-vitro antibacterial active of novel heterocyclic chalcone agents four bacteria's strain were evaluated and result showed AECO is beater antibacterial agent against Gram-Negative Bacteria (E. coli and S. flexneri) as compare to the Gram Negative Bacteria with respected to the standard drug Tetracycline.

Self-assembly of silver nanoparticles through functionalization with coumarin-thiazole fused-ring thiol

Self-assembly of nanoscale building blocks plays a critical role for the edifice of functional nanomaterials. In this work coumarin based fused-ring heterocyclic thiol functionalized silver nanoparticle exhibiting large self-assembly is reported. The particles spontaneously self-organise towards the formation of larger superstructures, yet still retaining their individual particle morphology (~10nm). The π-stacking behaviour of coumarin based fused ring aromatic skeleton seems to play the key role for the induction of dense assembly in this hybrid nanoparticles. In the present work the anchoring group (thiol) is directly attached to the aromatic framework of the Coumarin-thiazole fused-ring, for easier electron flow between the metal and the aromatic ligand. The synthesized materials have been characterized by UV-Vis, Fluorescence, XRD, TEM, SAED, IR, 1H and 13C NMR. The synthesis of the ligand and process of functionalization is simple and easily reproducible.

A Fluorescent Turn-On Carbazole-Rhodanine Based Sensor for Detection of Ag+ Ions and Application in Ag+ Ions Imaging in Cancer Cells

Carbazole - Rhodanine conjugate is an effective fluorescent host for silver ions through fluorometric transformation from green to red color with a hyperchromic emission. An intramolecular charge transfer process derived from carbazole towards rhodanine favors interaction of thiocarbonyl S and carboxylic acid O of the rhodanine moiety towards Ag⁺ ion. Carbazole - rhodanine dyad accomplishes the lowest detection limit of 12.8 × 10^-9 M and high quantum efficiency. A fluorescence reversibility of the probe with I^- ion surges reutilization of sensor molecule as an Ag⁺ ion probe with minimal loss in the fluorescent efficiency. This fluorescent ligand is a biocompatible probe and is also a proficient candidate for fluorescent imaging of Ag⁺ ion in live cells.

Synthesis of a metal-coordinated N-substituted polybenzimidazole pyridine sulfone and method for the nondestructive analysis of thermal stability

N-substituted metal-coordinated cross-linking polybenzimidazole pyridine sulfone, as novel class of high-performance functional polymers, has been obtained by the coordination of N-substituted polybenzimidazole pyridine sulfone (Py-N-PBIS) ligand with varying content of metallic ion (Co2+, Ni2+, Zn2+). The structures of the polymers are characterized by means of fourier transform infrared spectroscopy (FT-IR) and 1H nuclear magnetic resonance (1H NMR) spectroscopy, the results show good agreement with the proposed structures. Thermogravimetric analysis measurements exhibit that the metal coordination polymers possess good thermal stability with high thermal decomposition temperature (thermally stable up to 405–510°C). More importantly, the thermal decomposition temperature of Py-N-PBIS-(Co2+, Ni2+, Zn2+) can be nondestructively detected by taking advantage of the fluorescence quenching effect of metal coordination to 2,6-Bis(2-benzimidazolyl)pyridine structure.