pH dependent molecular self-assembly of octaphosphonate porphyrin of nanosale dimensions: sperical and tubular aggregates

Self-assembled nanostructures of zwitterionic octaphosphanatoporphyrin 1, of either nanoparticles or nanorods, depending on small changes in the pH, is demonstrated based on the J-aggregates. Porphyrin 1 self- assembled into nanosphere aggregates with a diameter of about 70-80 nm in the pH range 5-7, and nanorod aggregates were observed at pH 8.5. Hydrogen bonding, pi-pi stacking and hydrophilic interactions play important roles in the formation of this nanostructure morphology. Nanostructures were characterized by UV/Vis absorbance, fluorescence, atomic force microscopy (AFM) and transmission electron microscopy (TEM). This interesting pH dependent self-assembly phenomenon could provide a basis for development of novel biomaterials

Revisit: Eaton's reagent catalyzed synthesis of mono and bis-chalcone derivatives

Eaton's reagent efficiently catalyzed the Claisen-Schmidt condensation reaction of aryl aldehydes with aromatic and cyclic ketones under solvent free microwave irradiation conditions to afford mono and bis-chalcone derivatives. The present approach offers several advantages such as shorter reaction times, cleaner reactions, good yields, inexpensive reagent and mild reaction condition

Corrosion studies of PPy/Ni organic–inorganic hybrid bilayer coatings on commercial carbon steel

© 2014, Springer-Verlag Berlin Heidelberg. Electrodeposition of polypyrrole (PPy) was achieved on AISI 1018 carbon steel (CS) using a constant potential regime and cyclic voltammetry techniques evaluating different synthesis parameters, in monomer-containing oxalic acid solutions. Thereafter, CS PPy/Ni bilayer films were produced by Ni deposition onto PPy films using a potentiostatic method. The electrochemical performance of PPy/Ni-coated carbon steel systems was investigated in 3.0 wt% NaCl solutions. For this purpose, scanning Kelvin probe (SKP), open-circuit potential (Eocp), polarization curves, and cyclic voltammetry techniques were used. The influence of electro-synthesis method and parameters were analyzed. It was found that the deviation in the Volta potentials is correlated to the interfacial interaction between the PPy/Ni bilayer coating and substrate. Considering both experimental methods to obtain PPy/Ni coatings, a more effective protection against corrosion can be formed when potentiodynamic (cyclic voltammetry) and potentiostatic techniques are combined.Peer Reviewe