EFFECT OF THE METAL ON THE ORGANIZATION OF TETRAAMIDOMETALLOPHTHALOCYANINES IN LANGMUIR-BLODGETT-FILMS

Metallophthalocyanines (MPc's) [M being one of the following metal ion s: Co(II), Ni(II), Cu(II), or Zn(TT)], bearing amide side chains and b eing highly soluble in organic solvents, have been synthesized by star ting from the corresponding phthalonitrile. All four compounds can for m Langmuir and Langmuir-Blodgett films, but interestingly, their behav ior as monolayers was shown to be very much dependent on the central m etal ion. The study of Pi-A isotherms, low-angle X-ray diffraction pat terns, and IR dichroism allowed us to elucidate these behaviors, Cobal t and zinc phthalocyanines are coordinated with water molecules and th erefore orient with art angle of around 60 degrees with the normal to the air-water interface or to the substrate. On the other hand, nickel phthalocyanine is not coordinated with water; Pi-Pi interactions beco me possible, and the molecules can orient more vertically at the air-w ater interface; they form columns that orient in the transfer directio n during the deposition process. Finally, the copper phthalocyanine is an intermediate ease. For low surface pressures, it behaves like Co a nd Zn compounds: the square planar copper(II) is certainly liganded wi th water molecules. At higher surface pressures, the water molecules a re ejected and the macrocycles can orient more vertically (angle of ar ound 30 degrees between macrocycle and normal to the air-water interfa ce) and form oriented columnar structures when deposited onto substrat es.