Microwave assisted one-pot synthesis, photophysical and physicochemical studies of novel biologically active heterocyclic Donor (D)-π-Acceptor (A) chromophore.

A donor-π-acceptor (D-π-A) chromophore, 2-amino-4-(9-ethyl-9H-carbazol-3-yl)-8-methoxy-5,6-dihydrobenzo[h]quinoline-3-carbonitrile (AEDQ) was synthesized from the condensation of 6-methoxy-3,4-dihydronaphthalen-1(2H)-one, 9-ethyl-9H-carbazole-3-carbaldehyde, malononitrile and NH4OAc in ethanol. Spectroscopic techniques and elemental analysis were employed to establish the structure of AEDQ. Photophysical parameters and fluorescence quantum yield were calculated in the different polarity solvents to evaluate the interactions of the solvent with AEDQ chromophore. Further, the interaction of the AEDQ with cationic and anionic surfactants (CTAB, SDS) were also evaluated by using fluorescence spectroscopy techniques. The intensity of the fluorescence spectrum increased as the concentration of surfactants increased, suggesting that strong interaction occurs between AEDQ with surfactants, and this interaction arises from electrostatic forces. As a result, the AEDQ chromophore could be used to determine the CMC of surfactants. The disc diffusion and minimal inhibitory concentration (MIC) technique were used to test in-vitro antibacterial activity against Gram +ve and Gram -ve bacteria, and the results are compared with the standard drug, tetracycline. AEDQ also showed good ADMET, pharmacokinetics and drug-likeness properties, which are desirable for a good drug candidate. The molecule also fits well in the DNA gyrase A active pocket site with the binding free energy of -17.92 kcal/mol, which testifies its good antibacterial activity.

Fabrication of Novel and Potential Selective 4-Cyanophenol Chemical Sensor Probe Based on Cu-Doped Gd2O3 Nanofiber Materials Modified PEDOT:PSS Polymer Mixtures with Au/µ-Chip for Effective Monitoring of Environmental Contaminants from Various Water Samples.

Herein, a novel copper-doped gadolinium oxide (Cu-doped Gd2O3; CGO) nanofiber was synthesized by a simple solution method in the basic phase and successfully characterized. We have used Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), Field Emission Scanning Electron Microscope (FESEM) and Energy-Dispersive Spectroscopy (EDS) techniques for characterization of the CGO nanofiber. The CGO nanofiber was used later to modify Au-coated µ-Chips with poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) polymer mixtures (coating binder) to selectively detect 4-cyanophenol (4-CP) in an aqueous medium. Notable sensing performance was achieved with excellent sensitivity (2.4214 µAµM-1 cm-2), fast response time (~12 s), wide linear dynamic range (LDR = 1.0 nM-1.0 mM: R2 = 0.9992), ultra-low detection limit (LoD; 1.3 ± 0.1 pM at S/N = 3), limit of quantification (LoQ; 4.33 pM), and excellent reproducibility and repeatability for CGO/Au/µ-Chip sensor. This CGO modified Au/µ-chip was further applied with appropriate quantification and determination results in real environmental sample analyses.