ELECTRONIC-STRUCTURE OF NITROGEN SQUARE-PLANAR COPPER-COMPLEXES IN LANGMUIR-BLODGETT-FILMS

The Cu 2p and N 1s X-ray photoelectron spectra of nitrogen square planar copper(II) complex, derived from copper phthalocyanine and especially substituted to produce Langmuir-Blodgett (LB) films, are reported and compared with those of commercial copper phthalocyanine (CuPc) and selected porphyrin compounds. Although the copper atom is found primarily in the Cu(II) state, we observe the presence of the reduced Cu(I) form, with a great variety of relative intensities, because of a concomitant ability to reduction. In contrast, in the LB films, the copper atom remains in the Cu(II) state. We discuss this different behavior in terms of the reduction degree of the molecule, the localization of the additional electrons on the metal or the macrocycle, and a different nitrogen geometry around copper.