Synthesis and characterization of pentafluorophenil-pyridil-porphyrins substituted with ruthenium complex.

Author(s)

Emmanuel Zimmermann Moreira

• Document type: Master's Dissertation
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (PCARP/BC)
• Defense date: 2007-08-10

Examining board members

Yassuko Iamamoto; Ana Maria da Costa Ferreira; Herenilton Paulino Oliveira

• Advisor: Yassuko Iamamoto

Abstract

This work reports the synthesis and characterization of free base pentafluorophenylpyridilporphyrins as well as the synthesis and characterization of these compounds coordinated with ruthenium complexes. We have investigated how the insertion of pentafluorophenyl groups (electronwithdrawing groups) interferes with the eletrochemical, spectroscopic and photophysical properties of the compounds. The dyads models [M(4-N-Py)TFFPH2{Ru3O(Ac)6(py)2}]PF6 and [M(4-N-Py)TFFPH2{Ru(bpy)2Cl}] PF6 were constructed using the [Ru(bpy)2Cl]+ complex, the trinuclear ruthenium cluster [Ru3O(Ac)6(py)2]+, and the free base porphyrin M(4-N-Py)TFPPH2. These dyads were characterized by the same techniques used to characterize the isolated porphyrins. The assimetric triads cis- and trans-[B(4-N-Py)BFFPH2{Ru3O(Ac)6(py)2} {Ru(bpy)2Cl}](PF6)2 were also synthesized, through coordination of the [Ru(bpy)2Cl]+ complex with the [Ru3O(Ac)6(py)2]+ trinuclear ruthenium complex and the cis- and trans isomers of the B(4-N-Py)BFFPH2 porphyrin. These molecules were characterized by ESI MS and ESI MSMS mass analyses and UV-Visible spectroscopy. The UV-Visible spectra were a sum of the spectral profile of the isolated components, suggesting a lack of eletronic communication between the units. However, electrochemical studies of the [M(4-N-Py)TFFPH2{Ru3O(Ac)6(py)2}]PF6 and [M(4-N-Py)TFFPH2{Ru(bpy)2Cl}]PF6 dyads denoted this communication exists. So, despite being low, it must not be disregarded. ESI MS and ESI MSMS mass analyses of the porphyrins, the complex [Ru(bpy)2Cl]+, the trinuclear ruthenium cluster [Ru3O(Ac)6(py)2]+, the dyads model [M(4-N-Py)TFFPH2 {Ru3O(Ac)6(py)2}]PF6, and [M(4-N-Py)TFFPH2{Ru(bpy)2Cl}]PF6 and the assimetric triads cis- and trans-[B(4-N-Py)BFFPH2{Ru3O(Ac)6(py)2}{Ru(bpy)2Cl}](PF6)2 were carried out. The structures of the compounds were confirmed by ESI MS. The ESI MSMS experiments for the cis- and trans-[B(4-N-Py)BFFPH2{Ru3O(Ac)6(py)2} {Ru(bpy)2Cl}](PF6)2 triads allow us to verify that the fragmentation of the compounds results in the monosubstituted units [B(4-N-Py)BFFPH2{Ru3O(Ac)6(py)2}]+ and [B(4-N-Py)BPFPH2{Ru(bpy)2Cl}]+, and the substituents units [Ru(bpy)2Cl]+ and [Ru3O(Ac)6(py)2]+. No difference in the fragmentation of the cis- and trans-isomers of the supermolecules was detected. The luminescence experiments showed that the porphyrin emission is almost totally quenched because of the binding of the groups [Ru(bpy)2Cl]+ and [Ru3O(Ac)6(py)2]+. Photophysics results shows that these two units bounded to porhyrins M(4-N-Py)TFPPH2, cis- and trans- B(4-N-Py)BFPPH2 act as charge receptors. (AU)