Mendo, AS, Figueiredo S, Roma-Rodrigues C, Videira PA, Ma Z, Diniz M, Larguinho M, Costa PM, Lima JC, Pombeiro AJL, Baptista PV, Fernandes AR.
2015.
Characterization of antiproliferative potential and biological targets of a copper compound containing 4'-phenyl terpyridine. Journal of Biological Inorganic Chemistry. 20:935-948., Number 6
Abstractn/a
Mendo, AS, Figueiredo S, Roma-Rodrigues C, Videira PA, Ma Z, Diniz M, Larguinho M, Costa PM, Lima JC, Pombeiro AJL, Baptista PV, Fernandes AR.
2015.
Characterization of antiproliferative potential and biological targets of a copper compound containing 4'-phenyl terpyridine, 2015. Journal of Biological Inorganic Chemistry. 20(6):935-948.
Abstractn/a
Pina, F, Parola AJ, Bencini A, Micheloni M, Manfrin MF, Moggi L.
1992.
CHARGE EFFECTS ON THE PHOTOCHEMISTRY OF THE CO(EDTA) .1. SYSTEM IN THE PRESENCE OF POLYAMMONIUM MACROCYCLIC RECEPTORS, 1992. Inorganica Chimica Acta. 195:139-143.
AbstractThe effects of polyammonium macrocycles on the spectroscopic and photochemical properties of the Co(EDTA)- . I- ion-pair have been investigated. The addition of a macrocycle to aqueous solutions containing Co(EDTA)- and I- causes an increase of the absorbance in the region of the ion-pair charge-transfer band, as well as an increase of the quantum yield for the intramolecular photooxidation reduction of the ion-pair. Both these effects are mainly, if not only, due to an increase of the association constant between Co(EDTA)- and I-, caused by the positive charge of the macrocycle bound to the complex. On the contrary no change was observed on the intrinsic photoreactivity of the excited ion-pair. This last result is discussed in comparison with the effects already observed on the ligand photodissociation of MC excited states of Co(III) cyanide complexes.
Oliveira, J, Petrov V, Parola AJ, Pina F, Azevedo J, Teixeira N, Bras NF, Fernandes PA, Mateus N, Ramos MJ, de Freitas V.
2011.
Chemical Behavior of Methylpyranomalvidin-3-O-glucoside in Aqueous Solution Studied by NMR and UV-Visible Spectroscopy, 2011. Journal of Physical Chemistry B. 115:1538-1545.
AbstractIn the present work, the proton-transfer reactions of the methylpyranomalvidin-3-O-glucoside pigment in water with different pH values was studied by NMR and UV-visible spectroscopies. The results showed four equilibrium forms: the methylpyranomalvidin-3-O-glucoside cation, the neutral quinoidal base, the respective anionic quinoidal base, and a dianionic base unprotonated at the methyl group. According to the NMR data, it seems that for methylpyranomalvidin-3-O-glucoside besides the acid base equilibrium between the pyranoflavylium cation and the neutral quinoidal base, a new species is formed at pD 4.88-6.10. This is corroborated by the appearance of a new set of signals in the NMR spectrum that may be assigned to the formation of hemiketal/cis-chalcone species to a small extent. The two ionization constants (pK(a1) and pK(a2)) obtained by both methods (NMR and UV-visible) for methylpyranomalvidin-3-O-glucoside are in agreement (pK(a1) = 5.17 +/- 0.03; pK(a2) = 8.85 +/- 0.08; and pK(a1) = 4.57 +/- 0.07; pK(a2) = 8.23 +/- 0.04 obtained by NMR and UV-visible spectroscopies, respectively). Moreover, the fully dianionic unprotonated form (at the methyl group) of the methylpyranomalvidin-3-O-glucoside is converted slowly into a new structure that displays a yellow color at basic pH. On the basis of the results obtained through LC-MS and NMR, the proposed structure was found to correspond to the flavonol syringetin-3-glucoside.
Oliveira, J, Petrov V, Parola JA, Pina F, Azevedo J, Teixeira N, Bras NF, Fernandes PA, Mateus N, Ramos MJ, de Freitas V.
2011.
Chemical Behavior of Methylpyranomalvidin-3-O-glucoside in Aqueous Solution Studied by NMR and UV-Visible Spectroscopy. Journal of Physical Chemistry B. 115:1538-1545., Number 6
Abstractn/a
Moro, AJ, Pana A-M, Cseh L, Costisor O, Parola J, Cunha-Silva L, Puttreddy R, Rissanen K, Pina F.
2014.
Chemistry and Photochemistry of 2,6-Bis(2-hydroxybenzilidene)cyclohexanone. An Example of a Compound Following the Anthocyanins Network of Chemical Reactions. Journal of Physical Chemistry A. 118:6208-6215., Number 32
Abstractn/a
Jimenez, A, Pinheiro C, Parola AJ, Maestri M, Pina F.
2007.
The chemistry of 6-hydroxyflavylium: zwitterionic base and p-quinoidal chalcones. A multiswitchable system operated by proton, electron and photon inputs, 2007. Photochemical & Photobiological Sciences. 6:372-380.
AbstractThe complex network of chemical reactions of the compound 6-hydroxyflavylium perchlorate was studied by different techniques including UV-vis absorption spectrophotometry, stopped-flow, electrochemistry, and photochemistry. The network is characterized by the formation of a very reactive zwitterionic base as well as by p-quinoidal chalcones. The trans-chalcone is metastable in very acidic solutions and exhibits reversible redox reactions, allowing to introduce for the first time in the flavylium network an electrochemical input.
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