Monolayers and Langmuir–Blodgett films of (phthalocyaninato)(tetra-4-pyridylporphyrinato)cerium double-decker heterocomplex

Monolayers of a sandwich-type heterocomplex Ce(TPyP)(Pc) with porphyrin–phthalocyanine ligands and its mixtures with stearic acid (SA) have been investigated at the air–water interface. The limiting molecular area for the complex in mixed monolayers is almost independent on the molar fractions of SA. However, SA molecules effectively disperse the aggregates of the Ce(TPyP)(Pc) molecules according to the direct observation by Brewster angle microscopy, and the collapse processes are dependent on the molar ratios of the complex and SA. The monolayer of the complex mixed with SA was successfully deposited on hydrophobic substrates by Langmuir–Blodgett (LB) method. The UV-vis absorption peaks of LB films are red shifted compared with those in solution, indicating the formation of J-aggregates. The macrocycle rings of the complex in LB films were evaluated to be ca. 30° with respect to the substrate. A rather small distance between two layers was measured. Based on all these considerations, a schematic arrangement of molecules in LB films was suggested.