X-ray photoelectron spectroscopy study of Langmuir-Blodgett films of N-octadecyl-8-hydroxy-2-quinoline carboxamide deposited from subphases containing metal ions

The Langmuir-Blodgett films of N-octadecyl-8-hydroxy-2-quinoline carboxamid e (HOQ) deposited from subphase containing metal ions were investigated by X-ray photoelectron spectroscopy (XPS). The amphiphilic HOQ with its comple xing head group in contact with the aqueous phase can form metal complexes with the metal ions present in the aqueous phase. The formation of HOQ-meta l complexes leads to the appearance of new XPS peaks assigned to the metal ions. The information on stoichiometry provided by XPS indicates that a met al ion is coordinated by one HOQ molecule for transition metal ions of the fourth period, but by two HOQ molecules for the metal ions after the fourth period. (C) 1999 Elsevier Science S.A. All rights reserved.