The Preparation and Structural Characteristics of Langmuir--Blodgett Films for Metal Complexes with Schiff Base

The complexes of Zn²+, Cd²⁺ with ligand containing Shiff base substituted by long hydrocarbon chain have been synthesized and confirmed by elementary analysis, IR and UV--Vis spectra. The monolayer properties of these compounds at the air/water interface was desdbed. The LB films were successfully deposited on various substrates by vertical lefting method. The pattens of low angle X-ray diffraction of the LB films showed that the multilayers occurs a well--defined layer structure. The H-aggregate state of the molecules in the LB films was approved by UV-Vis absorption spectra. The molecular orientation wasmeasured by use of UV--Vis transmission linear dichromic determinations. The tilt angle of longaxies of Shiff base group relative to the substrate plane was calculated. The molecules of complexes in the LB films performed an ultrafast proton transfer which may be followed by a slower inversion from enol to quinoid conformation by irradiating with 365nm UV light. The photoisometrization process may influence on the nonlinear optical properties of the thin films,exhibiting larger second order nonlinear hyperpolarizabilities.