Formation of 2D supramolecular architectures at electrochemical solid/liquid interfaces

The controlled formation of supramolecular architectures on chloride pre-covered Cu(1 0 0) has been studied by means of in situ scanning tunneling microscopy (STM) in an electrochemical environment. On top of the c(2 × 2)-Cl layer, ordered arrays of supramolecular cavitand structures could be obtained either by a surface assisted assembly of monomer building-blocks (1,1′-dibenzyl-4,4′-bipyridinium molecules) or by a direct adsorption of supramolecular assemblies (metallo-supramolecular squares) from the solution phase. Besides the omnipresent van-der-Waals-like interactions additional electrostatic interactions between the anionic chloride layer and the positively charged (metallo)-organic molecules are supposed to have strong impact on the 2D phase behavior in both cases.The obtained supramolecular entities with their cavities oriented towards the solution phase can be regarded as potential host assemblies for the specific inclusion of guest molecules.     

INTEKFACIAL ACTIVITY OF 2-HYDH0XY-5-ALKYLBEKZALDEHYDE OXIMES AHD MECHANISM AND KINETICS OF COPPER EXTRACTION

Different adsorption isotherms such as the Gibbs, Szyszkowski,Frumkln and Temkin and polynomial were found as fits well to experimental interfacial tension isotherms for 2-hydroxy-5-alkylbenzaldehyde oximes at octane/water and xylene/water interfaces. The values of surface excess computed according to them increase as the length of the alkyl chain length increases for xylene/water system. Different behaviour was found at octane/water interface.

The interfacial activity data were used to predict reaction orders against hydroxyoxime for different proposed mechanisms of copper extraction from acid sulphate solution.It was shown that an interfacial mechanism is very probable for compounds with long alkyl chains. For these compounds the extraction limiting step is the reaction between hydroxyoxime molecules present near the interface and the intermediate 1:1 complex.