Inclusion phenomenon in mixed floating layers containing phthalocyanines

UV-vis absorption spectra of floating layers of octa-substituted metal-free phthalocyanines (AmPc) mixed with stearic acid or calix(4)-resorcinarene derivatives (CA) were studied during monolayer compression. Most of the mixed floating layers, as well as those of the pure AmPc compounds, show characteristic spectra typically attributed to the AmPc condensed state, even at zero surface pressure, These results indicate the formation of aggregates of AmPc molecules on the water surface immediately after spreading. However mixed AmPc/CA floating layers with the molar ratios less than 1:2 show some spectral transformation at high values of surface pressure, which can be interpreted in terms of molecular rearrangement. Isolated AmPc molecules are thought to have formed due to their inclusion within the CA matrix. (C) 1998 Elsevier Science S.A. All rights reserved.