"Fotoquímica “verde”: desenvolvimento de complexos de metais de transição luminescentes para ativação de oxigênio singleto e a sua aplicação na desinfecção de água contaminada com microorganismos patogênicos (Escherichia Coli e Enterococcus Faecalis)”
Resumen
Green Photochemistry: Development of transition metal complexes for
activation of luminescent singlet oxygen and its application in the disinfection of
wastewaters contaminated with pathogenic microorganisms (Escherichia coli
and Enterococcus faecalis).
The development of the perylenes derivatives complexes Ru (II) and Re (I) has
received increasing attention in energy transfer. Here in we investigated, the
synthesis, characterization, energy transfer studies and biological testing of
three complexes of Ru (II) and Re (I) cis-RuCl2(PDI1)2, cis-RuCl2(1,10-
phen)(PDI1 ), fac-[Re(CO)3(PDI1)Br] and [Ru(1,10-phen)2(PDI2)]2+. The
complexes are simple and stable preparation of both solid as well as DMSO
solution (in the absence and presence of light) and are resistant to hydrolysis at
pH 4 to 8. All compounds were characterized by 1H NMR, IV, elemental
analysis and theoretical calculations whose results were consistent with the
proposed structural. The complexes exhibit intense absorption in the visible
region (500 nm, ε = 20,000 mol-1Lcm-1) and an intense band emission around
600nm, long emission lifetime 500 nsec and a small Stokes shift (600 cm-1),
consistent with the rigid structure of the perylene chromophore. We observed
that some complexes have paramagnetism ability in the ground state and both
solution and on solid medium which was confirmed by RPE and theoretical
calculation. These complexes were not able to produce photochemical 1O2.
However, [Ru(1,10-phen)2(PDI2)]2+ presented photochemical generation of 1O2
dissolved in methanol, ethanol, acetone and acetonitrile and quantum yield of
the formation of this species (Φ1O2) in order 0.30. Thus, we immobilize this
complex on silica gel functionalized with aminopropyl group and it produced 1O2
with Φ1O2 around 0.20. The ability microbicide of these complexes were tested
against the yeast Candida and values obtained show they are toxic for these
microorganisms. These results lead us to believe that the complex can act on
wastewater treatment.