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In this paper , vanillin and L-tryptophan for the synthesis of the Schiff base with the body ( K [ HL ] ) select samarium , europium, magnesium, nickel, zinc, as the center of the complex , were designed and synthesized a series of complexes , and the use of infrared and UV spectra , fluorescence spectroscopy and other analytical tools to characterize the structure . Using ultraviolet spectroscopy , fluorescence spectroscopy , electrochemistry, circular dichroism and viscosity measurement method , the study of this amino acid Schiff base and its complexes with DNA interaction . Calculation of the ratio of the combination of the interaction , combined with constant thermodynamic functions and parameters . Under physiological conditions (pH = 7.40) were studied K [HL ] , Sm (III) L , Eu ( III) L , Mg (II ) L , Ni (II ) L , Zn (II ) L of DNA interactions ratio of 5 : 1 , the calculation of K [HL] and its complexes with DNA combine calculable combination of constants were K the B θ 28 ° CK [ HL] = 1.94 × 10 5 L · mol -1 , K B θ 25 ° C Sm (Ⅲ ) L = 1.19 × 10 5 L · mol -1 , K B θ 22 ° C Eu (Ⅲ ) L = 2.29 × 10 5 L · mol -1 , K B θ 13 ° C Mg (Ⅱ ) L = 4.32 × 10 4 L · mol -1 , K B θ 13 ° C Ni (Ⅱ ) L = 9.90 × 10 4 L · mol -1 , K B θ 13 ° C Zn (Ⅱ ) L = 1.43 × 10 4 L · mol -1 . Fluorescence spectrometry Scatchard method, circular dichroism spectroscopy , cyclic voltammetry and viscosity method that K [HL ] , the main mode of action between the Sm (III) L DNA intercalation and ditches role ; Eu ( III) L , Mg (II ) L , Ni (II ) L , Zn (II ) L with DNA intercalation and electrostatic interaction between . Tryptophan in the molecular structure containing a fused ring aromatic planar indole ring , which may be a K [HL] and its complex with DNA intercalation internal structural reasons .
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