Studies On Synthesis, Characterization Of New Schiff Base Complexes And Interaction With DNA

Three new Schiff base ligands which were derived from N,N'-bis(2-hydroxy-1-naphthaldehy-2,6-pyridinediamine(H₂L¹); N,N'-bis(o-vanillin) - 2,6-pyridinediamine(H₂L2) and N,N'-bis(2,4-Dihydroxyacetophenone) - 2,6-pyridine -diamine(H₄L₃) have been synthesized, and sixteen coordination compounds of lanthanide nitrates or transition metal with these ligands have been synthesized. All these complexes are first reported by author. These ligands and complexes were characterized by elemental analysis,IR spectra ,UV spectra, TG-DTG and molar conductance analysis. The action of some complexes with DNA has been studied.The complexes'compositions of the metal with Schiff base N,N'-bis- (2-hydroxy-1-naphthaldehyde)-2,6-pyridinediamine(H₂L¹) were confirmed to be [Cu(HL1) (CH₃COO)]·3H₂O;[M (HL1)(CH₃COO)]·CH₃CH₂OH·xH₂O (M=Zn,Cd,x=1);[Co(HL1)(CH₃COO)];[Ln(HL1)(NO₃)]NO₃·xH₂O(Ln=La(â…¢), x=2; Ln=Dy(â…¢), x=1:Ln=Sm(â…¢),x=1;Ln= Ce(III), x=1); [Gd(HL1)(NO₃)(H₂O)₂] NO₃·H₂O. The complexes'compositions of the metal with Schiff base N,N'-bis(o-vanillin)- 2,6-pyridinediamine(H₂L2) were confirmed to be [Ln(HL2)(NO₃)]NO₃·xH₂O (Ln=La(â…¢), x=2; Ln=Dy(â…¢) , x=3; Ln=Ce(â…¢), x=2; Ln=Sm(â…¢) ,x=3/2); [Gd(HL2)(NO₃)(H₂O)₂]NO₃·H₂O.The complexes'compositions of the lanthanide nitrates or transition metal with N,N'-bis(2,4-Dihydroxyacetophenone) 2,6-pyridinediamine(H₄L₃) were confirmed to be [Cu(H3L3) (CH₃COO)];[Ni(H3L3) (CH₃COO)]·2H₂O.The synthesis of ligands and complexes was in non-aqueous solvents. The complexes were all stable and could be preserved in the air for a long time. The complexes were colored and powered substances. The properties of the Ln(â…¢)complex with the same Schiff base are basically similar.The ligands synthesized are chelating agents. The nitrogen atom of Schiff base, oxygen atom of hydroxybenzene, methoxide were all coordinated to the metal ions. The nitrate ions are either within the coordination sphere or not coordinated. Carboxyl and nitrate ions are coordinated to the metal ions in a mondentate or bidentate fashion.Combinating Achar differential and Coats-Redfern integral method which fits the thirty kinetic equations, the calculating program was designed. The kinetic equations of thermal decomposition for complexes and the corresponding kinetic parameters were gained. The kinetic parameters include E, A, order of reaction and correlation coefficient, etc. The activation entropyâ–³S≠and activation free-energyâ–³G≠for some thermal decomposition stage were also gained.The thermal decomposition kinetic function of [La HL1(NO₃)] NO₃? 2H₂O in step(2) may be expressed as f(α)=1/4(1-α)[-ln(1-α)]-3, and the kinetic equation of thermal decomposition may be expressed as dα/dt=Αexp(-E/RT)f(α)=Αexp(-E/RT)1/4(1-α)[-ln(1-α)]-3,E = 448.69kJ/mol,lnA = 87.17, r = 0.9968,â–³S≠=474.40J/mol ,â–³G≠=177.33kJ/mol.The thermal decomposition kinetic function of [Sm(HL₂)(NO₃)] NO₃·3/2H₂O in step(2) may be expressed as f(α)=1/3(1-α)[-ln(1-α)]-2 , and the kinetic equation of thermal decomposition may be expressed as dα/dt =Αexp(-E/RT) f(α) =Αexp(-E/RT) 1/3(1-α) [-ln(1-α)]-2,E=386.06 kJ/mol,lnA= 76.34,r = 0.9958,â–³S≠=384.45J/mol?K,â–³G≠=169.24kJ/mol.A Schiff base compound C18H17N3O has been synthesized and characterized by IR, elemental analysis and X-ray diffraction single crystal analysis. The crystal belongs to monoclinic, space group P21/c with a = 13.046(3),b =6.9350(14),c = 17.266(3) ?,α= 89.91(3)o,β=91.07(3)o,γ= 90.08(3)o, V =1561.8(5) ?3,Z=4,Dc =1.239g·cm-3,F(000)=616 ,S = 1.036, R1 = 0.0891, wR2 = 0.1760,μ=0.079mm-1。Quantum chemistry calculation of the Schiff base compound was carried out by the density functional theory (DFT) B3LYP method. The geometrical structure of the compound was optimized at B3LYP/6-311G**level. The natural atomic charges distribution, molecular total energy, frontier molecular orbital energies and natural bond orbital analysis of the compound were discussed.Electron absorption spectrum analysis and ethidium bromide (EB) fluorescene spectrum analysis were used to determine the bioactivities of some complexes, respectively. The results show that some complexes present intercalation action with DNA and the positive correlation exists between the concentration and bioactivities of the complexes.