Influence of the Central Metal Ion on the Physicochemical Properties of a Water Soluble Series of Silver Nanoparticles/Metallophthalocyanines (Fe, Co, Ni, Cu) Hybrids

This work reports the synthesis and characterization of nanostructured hybrid systems based on the combination of water soluble transition-metal phthalocyanines of a Fe, Co, Ni, and Cu, and silver nanoparticles (AgNPs). Transmission electron microscopy reveals images of the hybrid compounds, which are approximately 20 nm in size. The bathochromic shift and the broadening of the plasmon band characteristic of AgNPs, observed in the UV-Vis spectra of the nanostructured hybrid systems, indicate the coordination of the complexes on the nanoparticle surface. Infrared and Raman spectra confirmed an effective interaction between the complexes, and the nanoparticles, marked in particular by a modulation of intensities and shifts in characteristic frequencies. Raman spectroscopy identified a SERS (surface-enhanced Raman scattering) effect due to the plasmonic resonance properties of the AgNPs. The shifts observed for the C-N-C bond follow a clear trend related to the ionic radius and the polarizing power of the metals. Solid-state NMR 13 C CP-MAS, an innovative tool for these types of compounds, yields results consistent with those obtained for nanohybrids systems comprising Zn phthalocyanine complexes. All these results indicate the formation of nanohybrid species, and suggest that they may be good candidates for various applications, such as photocatalysis.