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.

Zinc porphyrin/mesoporous titania thin film electrodes: a hybrid material nanoarchitecture for photocatalytic reduction

“…37 It is noteworthy that no new absorption bands are observed, reecting that ZnP does not self-assemble or aggregate on the surface. 22,38,39 Likewise, ZnP emission properties in solution are retained aer its attachment to the surface, with a change in emission intensity ratio of the bands (Fig. 2D).…”

“…This means porphyrin stacking would occur, since ZnP specic area is $4 nm 2 per molecule, and agglomerates should be observed on the surface. Stacking would lead to the appearance of characteristic porphyrinic aggregation bands in the UV-Vis spectrum, 22,38,39 which is not the case for ZnP@MTTF.…”

Metalloporphyrin nanoparticles: Coordinating diverse theranostic functions

“…This approach shows not only that can PET imaging non-invasively assess pharmacokinetic and time-dependent biodistribution, but the use of porphyrin nanoparticles has the advantage of having the option to use 64 Cu to conveniently gain critical information about pharmacological behavior. [120][121][122][123]. By analyzing Raman signatures, highly multiplexed analysis of nanoparticles is possible.…”

“…SERS analysis can be used to understand how various metalloporphyrins (e.g. Fe, Ni, Cu) interact on the surface of AuNPs [122]. 5,10,15,20-Tetra(4-pyridyl)-21H,23H-porphine metallocomplexes (M-TPyP, M=Cu, Fe.…”

Fe–Ni porphyrin/mesoporous titania thin film electrodes: a bioinspired nanoarchitecture for photoelectrocatalysis

“…These include bimetallic interactions, where the combination of two metalloporphyrins has a synergistic effect. [5][6][7] Furthermore, porphyrins can be immobilized on solid supports, such as zeolites or metal oxides. The combination of porphyrins and materials with an organized structure further extends the possibilities for application.…”