PHOTOACCELERATED COMPLEX-FORMATION OF A NOVEL LANGMUIR-BLODGETT-FILM WITH TRANSITION-METAL IONS AND ITS ION SELECTIVITY

The complex formation of an organized Langmuir-Blodgett (LB) film with transition metal ions in aqueous solutions was observed. The LB film of 5-(octadecyloxy)-2-(2-thiazolylazo)phenol (TARC18)) complexes with transition metal ions such as Ni(II), Cu(II), and Zn(II) in aqueous so lutions, and the reaction was accelerated by photoillumination. The me asurement of optical absorption spectra revealed that two kinds of com plexes with the ligand to center metal ion ratios of stoichiometric 2: 1 and 1:1 were formed in CuCl2 solution, while stoichiometric 1:1 comp lexes were formed in aqueous NiCl2 and ZnCl2 solutions. The X-ray diff raction and ESR measurements of the LB films confirmed that the regula r arrangements of the LB films were retained even after the complex wa s formed with the metal ion. The optical absorption measurement and an inductively coupled plasma analysis of the metal ion complexed LB fil m showed that the LB film had a selective binding ability to Cu(II) io n when all the above metal ions were present in the solution.