L-lysine-L-tartaric acid: New molecular complex with nonlinear optical properties. Structure, vibrational spectra and phase transitions

International audienceThe first X-ray diffraction and vibrational spectroscopic analysis of a novel complex between L-lysine and L-tartaric acid is reported. The structure was solved in two temperatures (320 and 260 K) showing incommensurate phase between them. Room-temperature powder infrared and Raman measurements for the L-lysine-L-tartaric acid molecular complex (1: 1) were carried out. DSC measurements on powder samples indicate two phase transitions points at about 295, 300 and 293, 300K, for heating and cooling, respectively, with noticeable temperature interval between them. Second harmonic generation efficiency d(eff) = 0.35 d(eff) (KDP). (c) 2005 Elsevier Inc. All rights reserved

Corrosion control of aluminum surfaces by polypyrrole films: influence of electrolyte

Polypyrrole (PPy) films were galvanostatically deposited on 99.9 wt. (%) aluminum electrodes from aqueous solutions containing each carboxylic acid: tartaric, oxalic or citric. Scanning Electron Microscopy (SEM) was used to analyze the morphology of the aluminum surfaces coated with the polymeric films. It was observed that the films deposited from tartaric acid medium presented higher homogeneity than those deposited from oxalic and citric acid. Furthermore, the corrosion protection of aluminum surfaces by PPy films was also investigated by potentiodynamic polarization experiments