Mixed Lb Films Of Rare Earth Three Phthalocyanine Sandwich Compounds

Sandwich-type phthalocyaninato and / or porphyrinato rare earth complexes, possessing highly delocalized macrocycles, have attracted increasing interest in areas of semi- conductors, molecular metals, and molecular electronics due to their special optical and electronic properties. In particular, the bis(phthalo- cyaninato) rare earth compounds were noted for their sensitivity to such gases as NO2, SO2, CO, Br2, Cl2, and NH3. Because of the conjugated n molecular structure and the strong n-n interaction between the aromatic rings, phthalocyanine derivatives have been used as building blocks for ordered molecular systems. With the help of Langmuir-Blodgett technique, this kind of building block can be fabricated into well-ordered thin films. Preparing the monolayer and multilayers of different bis(phthalocyaninato) rare earth complexes by Langmuir-Blodgett mothod to meet the need of different applications attract many chemists. Naphthalocyanine possesses more extensive planar conjugated molecular structure and less HOMO-LUMO energy gap than phthalocyanine, therefore more unique spectroscopic, electrochemical, and physical-chemical properties have been expected for these naphthalocyanine derivatives.In this thesis, the ordered molecular assemblies of pure substituted triphthalocyaninesrare earth complexes and its mixture with stearic acid have been fabricated by Langmuir-Blodgett technique and characterized by surface pressure-area isotherms, electronic absorption spectra, polarized absorption spectra, low-angle X-ray diffraction patterns and Transmission Electron Microscope experiments. The results are briefly illustrated as follows:Monolayers and Langmuir-Blodgett(LB) films of the sandwich-type complex (Pc)M[Pc(OC8H17)8]M[Pc(OC8H17)g] (M=Gd,Dy,Er)and its mixture with stearic acid (SA) have been studied. Surface pressure-area isotherm indicates that stable monolayer was formed . The monolayer morphology was investigated by transmission electron microscopy (TEM). SA molecules effectively disperse the aggregates of the (Pc)M[Pc(OC8H17)8]M[Pc(OC8H17)8] (M=Gd,Dy,Er) molecules by the TEM observation .Columnar domains with the width of ca.40 nm and the length of several hundreds of nanometers appearing in the micrograph have ordered orientation .The monolayer of the complex mixed with SA was successfullydeposited on hydrophobic substrates by Langmuir-Blodgett method. The UV-vis absorption peaks of LB films are red shifted compared with those in solution, indicating the formation of J-aggregates. The orientation angle of the phthalocyanine ring with respect to the substrate was evaluated to be ca.52° according to the Polarized UV-vis spectra. The low-angle X-ray diffraction pattern showed a periodic distances for the mixed LB films of ca. 2.4 run. Based on all these considerations, a schematic arrangement of the complex molecules in LB films was suggested.