Floating layers and thin films of mesogenic mix-substituted phthalocyanine holmium complex

The supramolecular organization of the A(3)B-type phthalocyanine holmium complex (A(3)B-Ho) was investigated in floating layers at the air-water interface and in Langmuir-Schaefer thin films at the air-solid interface. The floating layers formed under different experimental conditions on the water subphase using the Langmuir technique. They were studied by Brewster angle microscopy, grazing incidence X-ray diffraction and X-ray reflectometry. It was established that molecules of A(3)B-Ho form stable ordered floating monolayer on the water surface. Experimental conditions required for this monolayer formation were determined as following: the initial degree of coating of the water surface was 18%, the compression rate of barriers was 6 cm(2)/min and the surface pressure was 0.4 mN/m. Under these conditions a stable crystalline monolayer structure was obtained with an area per one molecule 3.9 nm(2). It has a two-dimensional face-on packing with the intralayer period of 2.06 nm. The Langmuir-Schaefer thin film was obtained on the basis of the above mentioned monomolecular floating layer. The film possesses a single two-dimensional structure with the packing of the molecules parralel to the substrate surface that was revealed by electron diffraction. The lattice parameters of the monomolecular film were a = 1.65 nm, b = 1.92 nm, gamma(1) = 75. It was shown that the film preserves the structure of the floating monolayer.