Fernando Roberto Secco

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The synthesis of the Fe(III), Co(II), Mn(II), and Ru(III) complexes with two polyamine-polycarboxylate ligands, N-(2-hydroxyethyl)ethylenediamine-N, N', N'-triacetic acid (H3L1) and ethylene bisglycol tetraacetic acid (H4L2) is reported. Potentiometric studies showed that these ligands form stable complexes in aqueous solution and no metal release occurs,(More)
Kinetics and equilibria of cyanine dyes thiazole orange (TO) and benzothiazole orange (BO) self-aggregation and binding to CT-DNA are investigated in aqueous solution at 25 degrees C and pH 7. Absorbance spectra and T-jump experiments reveal that BO forms J-aggregates while TO forms more stable H-aggregates. Fluorescence and absorbance titrations show that(More)
A study has been performed of the kinetics and equilibria involved in complex formation between the macrocyclic polyamine 2,5,8,11-tetraaza[12]-[12](2,9)[1,10]-phenanthrolinophane (Neotrien) and Cu(II) in acidic aqueous solution and ionic strength 0.5 M (NaCl), by means of the stopped-flow method and UV spectrophotometry. Spectrophotometric titrations and(More)
The binding of Ru(phen)(2)dppz(2+) (dppz=dipyrido[3,2-a:2',3'-c]phenazine) to DNA was investigated at pH 7.0 and 25 degrees C using stopped-flow and spectrophotometric methods. Equilibrium measurements show that two modes of binding, whose characteristics depend on the polymer to dye ratio (C(P)/C(D)), are operative. The binding mode occurring for values of(More)
The equilibria and kinetics of the complex formation and dissociation reaction between gallium(III) and PAR [4-(2-pyridylazo)resorcinol] have been investigated in water and in the presence of SDS micelles. The reactive form of Ga(III) is GaOH2+ in both cases. The addition of SDS results in an increase of both the binding affinity and velocity, the maximum(More)
The interaction of coralyne with poly(A)*poly(U), poly(A)*2poly(U), poly(A) and poly(A)*poly(A) is analysed using spectrophotometric, spectrofluorometric, circular dichroism (CD), viscometric, stopped-flow and temperature-jump techniques. It is shown for the first time that coralyne induces disproportionation of poly(A)*poly(U) to triplex poly(A)*2poly(U)(More)
The binding of proflavine (D) to single stranded poly(A) (P) was investigated at pH 7.0 and 25 degrees C using T-jump, stopped-flow and spectrophotometric methods. Equilibrium measurements show that an external complex PD(I) and an internal complex PD(II) form upon reaction between P and D and that their concentrations depend on the polymer/dye(More)
The role of solvent effects on the thermodynamics and kinetics of the coralyne self-aggregation process has been investigated in ethanol-water mixtures of different compositions. The changes in the UV/visible spectra of coralyne and FAB/LSIMS mass spectrometry agreed well with the formation of a dimer species. 1D and 2D 1H experiments have allowed one to(More)
The interactions of Poly(A).Poly(U) with the cis-platinum derivative of proflavine [{PtCl(tmen)}(2){HNC(13)H(7)(NHCH(2)CH(2))(2)}](+) (PRPt) and proflavine (PR) are investigated by spectrophotometry, spectrofluorimetry and T-jump relaxation at I=0.2M, pH 7.0, and T=25 degrees C. Base-dye interactions prevail at high RNA/dye ratio and binding isotherms(More)
The interaction of cyanines with nucleic acids is accompanied by intense changes of their optical properties. Consequently these molecules find numerous applications in biology and medicine. Since no detailed information on the binding mechanism of DNA/cyanine systems is available, a T-jump investigation of the kinetics and equilibria of binding of the(More)