title: Classical Characterization Techniques to Reveal the Structural Model of Nanocomposites with Bimetallic Monolayers of Porphyrins.
abstract: Nanocomposites with bimetallic monolayers of porphyrins were prepared. The well-ordered metalloporphyrin monolayers covalently linked to the gold surface produce an important increase of the B band (∼400 nm) shifted 20 nm relative to that of the related high-spin iron(III) complexes in solution. The position of the B band in the bimetallic architectures is highly dependent on the relative amount of the two porphyrins, showing the most significant shift for the SiO2/APTES/AuNp/Fe-TPyP&M-TPyP (1:1) (30 nm, M = Ni(II) or Cu(II)). Resonance Raman based on the oxidation state marker bands (1553, 1354, and 390 cm(-1)) indicates that Fe-TPyP attached on gold nanoparticles adopts a low-spin Fe(II) conformation, which changes to Fe(II) intermediate spin or a low-spin Fe(III) in the presence of Cu-TPyP or Ni-TPyP. Surface-enhanced Raman scattering studies confirmed the hypothesis. MALDI-TOF analysis of the composites on gold nanoparticles was very useful in the detection of oxygenated forms of the metal complexes.
authors.affiliation: Universidad de Buenos Aires , Facultad de Farmacia y Bioquı́mica, CONICET-IQUIFIB, Junin 956, CP 1113 Buenos Aires, Argentina.
authors.forename: Mariana
authors.initials: M
authors.lastname: Hamer
authors.affiliation: Universidad de Buenos Aires , Facultad de Farmacia y Bioquı́mica, CONICET-IQUIFIB, Junin 956, CP 1113 Buenos Aires, Argentina.
authors.forename: Irene N
authors.initials: IN
authors.lastname: Rezzano