Spectral shift of porphyrin on Montmorillonite clay

F. DALMATI LIMA; E. DÍAZ SUÁREZ; VERA CONSTANTINO; A.V. GIL REBAZA; H.M. PETRILLI

Gramado

Encuentro; XVI Brazilian Materials Research Society Annual Meeting ? XVI SBPMat; 2017

The electronic spectra shift of tetracationic 5,10,15,20-tetrakis(1- methyl4-pyridyl)- 21H,23H-porphyrin (TMPyP) upon adsorption on a clay surface is hereinvestigated using ab-initio electronic structure calculations performed in theframework of the Density Functional Theory (DFT). Porphyrins are heterocyclicmacrocycle organic compounds with many applications such as photosensitizersfor light harvesting and chemical reactions, molecular electronics and enzymaticcatalysis. They can be found in biological systems like photosynthesis of light,enzymes, and transport proteins. The porphyrins optical spectra can becharacterized by the presence of a dominant so called Soret band plus a Q-bandstructure, whose positions and shapes offer a method to characterize porphyrinsin various environments. The influences of the environment and DFT exchangecorrelation functional on the UV-vis spectra of the model systems, hereconsidered, are investigated. With this aim, the TMPyP/Montmorillonite interfaceis studied and these results are further discussed to tentative address theobserved electronic spectral shift on TMPyP upon the TMPyP/Clay interaction.The results suggest that the mechanism is still controversial.