Acrylonitrile adducts: design, synthesis and biological evaluation as antimicrobial, haemolytic and thrombolytic agent.

In this work, five acrylonitrile adducts were screened for antibacterial activity against Gram-positive Bacillus subtilis, Microbial Type Culture Collection and Gene Bank (MTCC 1305) and Gram-negative Escherichia coli (MTCC 443). Synthesis was followed by aza-Michael addition reaction, where the acrylonitrile accepts an electron pair from the respective amines and results in the formation of n-alkyliminobis-propionitrile and n-alkyliminopropionitrile under microwave irradiation. Characterization of the compounds were performed using Fourier Transform Infrared (FTIR), Proton Nuclear Magnetic Resonance (1H NMR) and Electrospray Ionisation Mass Spectrometry (ESI-MS). The particle size characterization was done by Dynamic Light Scattering (DLS) technique. The antibacterial study showed higher inhibition rate for both Gram-positive and Gram-negative bacteria. The antibacterial ability was found to be dose dependent. The minimum inhibitory concentration against both bacteria were found to be 1, 3, 0.4, 1, 3 µl/ml for E. coli and 6, 6, 0.9, 0.5, 5 µl/ml for B. subtilis. Time-kill kinetics evaluation showed that the adducts possess bacteriostatic action. Further it was evaluated for high-throughput in vitro assays to determine the compatibility of the adducts for drug delivery. The haemolytic and thrombolytic activity was analysed against normal mouse erythrocytes. The haemolytic activity showed prominent results, and thereby projecting this acrylonitrile adducts as potent antimicrobial and haemolytic agent.

Catalytic activity and mechanistic investigation of 1D 2-Picolinic acid based Cu(II) coordination polymer in the selective construction of 1,4-disubstituted triazoles.

The catalytic activity of 1D 2-Picolinic acid based Cu (II) coordination polymer (CP1) in click reaction was evaluated to generate 1,4-disubstituted 1,2,3-triazoles selectively. The CP1 catalyst loading of 2 mol% was applied successfully in the reaction for primary azides with diverse functionalities of terminal alkynes in green solvent (EG/H2O). Moreover, the one-pot, multicomponent click reaction involving benzyl bromide, sodium azide, and phenylacetylene was also catalyzed by CP1. The findings show that 1D 2-Picolinic acid based Cu (II) coordination polymer catalytic systems are highly efficient for green click triazoles synthesis. DFT calculation supported the plausible mechanism involved in the CP1 catalyzed click reaction.

Carbon nanotubes ornamented hollow polymethyl methacrylate microspheres for turbidity removal from water.

Novel materials with low density are being synthesized with great interest owing to their effectiveness in water purification systems. Materials of micro/nano-scale provide outstanding results in miniature point-of-use devices because of their high surface-to-volume ratio. In this study, we report the successful synthesis of hollow polymethyl methacrylate microspheres (HPM) coated with functionalized carbon nanotubes (f-CNTs) (CHPM) by employing solvent evaporation and in situ coating techniques. The surface coating of HPM with the f-CNTs was visually confirmed by the surface roughness recorded in scanning electron microscopy. Furthermore, characterization with Fourier transform infrared spectroscopy substantiated the presence of hydroxyl and carboxyl groups of f-CNTs on the CHPM. The efficiency of CHPM to remove the turbidity from surface water was evaluated. The CHPM was effective in bringing down the turbidity of the water from 500 NTU to <1 NTU (>97%) which was within the desirable limit of the Bureau of Indian Standards. The temperature and pH for maximum reduction in turbidity were optimized to 49.5 °C and 4.5, respectively. Moreover, kinetic studies of CHPM indicated that the material followed the Langmuir isotherm model with regeneration efficiency lasting more than 10 cycles. From the results, we propose a simple, facile, and cost-effective synthetic route for the synthesis of CHPM for water purification, especially for turbidity removal. The synthesized CHPM with low density and relatively large surface area offer huge potential in water treatment applications and related fields.

Smart pH-Responsive Polyaniline-Coated Hollow Polymethylmethacrylate Microspheres: A Potential pH Neutralizer for Water Purification Systems.

Smart materials with potential pH controllability are gaining widespread concern due to their versatile applicability in water purification systems. A study presented here demonstrates a successful synthesis of smart pH-responsive polyaniline (PANI)-coated hollow polymethylmethacrylate microspheres (PHPMs) using a combination of solvent evaporation and in situ coating techniques. The material was characterized by using conventional techniques. Images recorded by an optical microscope displayed clear evidence in support of the coating, which was further supported by the SEM images. Surface roughness due to the coating was distinct in the SEM images. The PANI coating has enabled the microsphere to effectively neutralize the pH of water in water purification systems, which is very important in tackling the excessive acidic or basic problem of water resources. This study introduces a simple, facile, and cost-effective synthetic route to develop polyaniline-coated hollow polymethylmethacrylate microspheres with high performance as a pH-responsive material for water purification. The low density of the material and relatively large surface area compared to conventionally used chemicals further enhance the application prospect of the material.

Iron oxide coated hollow poly(methylmethacrylate) as an efficient adsorption media for removal of arsenic from water.

Adsorption of arsenic onto iron-based adsorption media has been established as a convenient method for the removal of arsenic from contaminated water. The study describes the efficiency of iron oxide coated hollow poly(methyl methacrylate) microspheres (FHM) as an adsorptive media for the removal of arsenic from water. Hollow poly(methyl methacrylate) microspheres (HPMM) were synthesized by solvent evaporation and an electroless plating technique and the surface of the polymer was coated with iron oxide (FeO) particles. Structural characterization was performed using Optical Microscopy (OM), Scanning Electron Microscopy (SEM), Fourier Transform Infrared spectroscopy (FTIR), Energy Dispersive X-ray diffraction (EDAX), and Thermogravimetric Analysis (TGA). A study on the effect of the varying initial concentration of arsenic ions on percentage removal was performed in the laboratory and the adsorption capacity of the adsorbent was measured. Adsorption isotherm studies were carried out to evaluate the adsorption efficiency of FHM in removing arsenic from contaminated water. The Langmuir and Freundlich isotherm models were used to analyze the equilibrium experimental data. The isotherm study revealed that Langmuir adsorption data are well fitted and the maximum adsorption capacity of FHM in removing arsenic is 10.031 mg g-1. This high arsenic uptake capability combined with a low density of FHM makes it a potential material for arsenic removal particularly during the fabrication of lightweight portable water purification devices.

Fluorescent probe sensor based on (R)-(-)-4-phenyl-2-oxazolidone for effective detection of divalent cations.

Significant progress attained in sensor science in recent years has resulted in the development of highly efficient fluorescence probes for sensing metal ions. Fluorescent molecular probes based on (R)-(-)-4-phenyl-2-oxazolidone are reported here. Fluorescence studies indicated that the molecular probe could be used successfully to sense divalent metal cations such as Cu2+ , Co2+ , Pb2+ , and Zn2+ . The addition of divalent metal cations to the molecular probe produced a specific interaction pattern under UV-visible and fluorescence spectroscopy. These molecules could detect metal cations using fluorescence quenching. Stern-Volmer plots were used to determine quenching rate coefficients, which were calculated to be 2 × 101 , 1.06 × 103 and 7.39 × 102 M-1 s-1 for copper, cobalt, and zinc respectively. Calculation of limit of detection for heavy metal cations revealed that the reported molecular probes improved the limit of detection compared with available standard data. Limit of quantitation values were also well within the permissible range. The frontier energy gap of highest occupied molecular orbital to the lowest unoccupied molecular orbital was evaluated using the density functional theory approach and Gaussian 09 W software, which complemented the coordination of azetidinones with divalent metal ions.