Preparation and Control of Functional Thin Films, Built-up Films of N, N'-Disubstituted Dithiooxamidatocopper (II) Coordination Polymer

Abstract

For the reproducible built-up of stable monolayers of catena-μ-N, N'-bis(dodecyloxycarbonylmethyl)dithiooxamidatocopper(II) on a solid substrate from air-water interface, optimum conditions of the copper concentration in the aqueous substrate, of the piston-oil pressure, and of the dipping rate were determined by elemental analyses and the observation of interference colors of the films. In order to obtain the built-up films composed of equimolecular amounts of the ligand and copper (Table 1), and to reduce the amount of adsorbed copper ions beneath the monolayer, the appropriate copper concentration was found to be 1×10^-4 mol⋅dm^-3. Uniform films with a constant interference color were obtained when the piston -oil was adjusted to 20 mN⋅m^-1 and the dipping rate was controlled within a range of 35-700 mm⋅min^-1.
Anisotropy of the built-up film was examined by means of the polarized infrared spectra (Fig.3) and the electron diffraction patterns (Fig.5, Table 2). These data show that the framework of dithiooxamidatocopper(II) was oriented in the built-up films in parallel to the dipping direction in the film plane. This orientation may arise- from the relative flow of adjacent molecules so as to fill up the vacant due to the consumption of molecules induced by the transfer to the dipping plate. To elucidate the orientation a one-dimensional molecular model is recommended rather than a. two-dimensional model previously proposed.