Monolayers and Langmuir-Blodgett Films of a Newly Synthesized Asymmetric Tetraazaporphyrin Derivative

Molecular assemblies such as monolayers at the water-air interface and Langmuir-Blodgett films of 2,3- bis(N-(3-thiopropy1)phtha1imido)-7,8,12,13,17,18-hexakis(octy1thio)-5,10,15,20-tetraazaporphyrinato ( TAP) copper(II) and nickel(II) derivatives were studied for the first time. Monolayers at the water-air interface both of the pure macrocyclic derivative and of its mixture with stearic acid were investigated. The degree of order within Langmuir-Blodgett films was established with the aid of UV-vis and ESR spectroscopies. The surface behavior of the above unsymmetrically substituted TAP, in the form of metal derivatives, has been compared with that of the corresponding symmetrically substituted compounds (Bonosi; et al. J. Phys. Chem. 1993, 97, 9181), which give disordered films. We report here on the improved ordering in the LB film fabrication reached with the unsymmetrical substitution as being due to the presence of the hydrophilic phthalimide moieties in two of the eight long chains around the TAP skeleton, which favor an edge-on orientation of the macrocycle at the air-water interface