Synthesis, Characterization And Bioactivity Of Nitrogen-containing Heterocyclic Ligands And Their Complexes

In this paper, eight derivatives of five-or six-membered nitrogen-containing heterocyclic compounds of 1-phenyl-3-methyl-2-pyrazolin-5-one (namely PMP),1-(2-aminoethyl)-piperazine (namely AEP) and 1,4-bis(3-aminopropyl)piperazine (namely BAPP) were synthesized. And with these derivatives used as ligands, nine transition metal complexes were synthesized by classical solution method or solvothermal method. These compounds were characterized by elemental analysis, IR,'H NMR,13C NMR, UV-vis and fluorescent spectrum. The crystal structures of fifteen compounds were determined by single-crystal X-ray diffraction. The thermal stabilities of some compounds were studied by TG-DTA method and their electrochemical properties were also investigated by cyclic voltammetry. Furthermore, the biological activities such as antibacterial activity, interaction with Bovine Serum Albumin (BSA) and calf thymus DNA (CT-DNA) for some compounds were investigated preliminary by the agar diffusion method, electronic absorption spectroscopy and viscometry, respectively.Five-membered azaheterocyclic ligand PMP was synthesized by the reaction of acetylacetic ester with phenylhydrazine. With PMP used as reactant, two compounds, PMP (1) in enol form and 4,4'-methenyl-bis(1-phenyl-3-methyl-2-pyrazolin-5-one) (2), were obtained respectively under solvothermal condition in the presence of different volume of acetonitrile. Another new compound, Ethylenediammonium bis(5-methyl-3-oxo-2-phenyl-2,3-dihydro-pyrazol-1-ide) (3), was prepared by the reaction of PMP with ethylenediamine in methanol solution. Their structures were confirmed by elemental analysis, IR,'H NMR,13C NMR spectrum, TG-DTA and single-crystal X-ray diffraction analysis.Four transition metal complexes of PMP were prepared by the reaction of PMP with zinc chloride, zinc acetate hydrate, cadmium chloride hydrate and cadmium acetate hydrate in methanol solution, respectively. And three single crystals of these complexes, [Zn(PMP)2Cl]n (4),[Cd(PMP)2]n (6) and [Cd2(PMP)2Cl4]n (7), were also obtained. These complexes were characterized by spectral analysis. Their thermal stabilities were studied by TG-DTA method and their electrochemical properties were also investigated by cyclic voltammetry. The biological activities for some PMP complexes were also preliminary studied. The single-crystal X-ray diffraction revealed that complex (4) is 1-D chain coordination polymer, complex (6) 3-D coordination polymer and complex (7) 2-D ladder coordination polymer.Two complexes, [Zn2(dien)2Cl4] (8) and{[Cu(dien)NO3]NO3}_n(9), were obtained by the reaction of diethylenetriamine with zinc chloride or copper nitrate hydrate, respectively, in the presence of PMP in methanol solution. The structures of the two complexes were confirmed by elemental analysis, IR spectrum and single-crystal X-ray diffraction. Furthermore, their thermal stabilities were studied by TG-DTA method and their electrochemical properties were investigated by cyclic voltammetry.The solvothermal treatment of the mixture of copper chloride dihydrate and acetonitrile in the presence of 5,5-dimethyl-imidazolidine-2,4-dione (namely DMH) resulted in the formation of a new acetate-bridged dinuclear copper complex, [Cu2Cl2(μ-Ac)4](H3C2ONH)2 (10). The complex was characterized by elemental analysis, IR spectrum and single-crystal X-ray diffraction, and its electrochemical property was also studied by cyclic voltammetry.A novel polynitrile containing piperazine ring, N,N,N',N'-tetra(2-cyanoethyl)-1,4-bis-(3-aminopropyl)piperazine (11), was synthesized by the nucleophilic addition reaction of BAPP and acrylonitrile for the first time. Compound (11) was characterized by elemental analysis, IR,~1H NMR spectrum and TG-DTA analysis, and its crystal structure was determined by single-crystal X-ray diffraction.Five Schiff base compounds, bis(p-hydroxylbenzaldehyde)-BAPP (12), bis(salicylal)-BAPP (13), bis(p-dimethylaminobenzaldehyde)-BAPP (14) and bis(paeonol)-BAPP (15), were synthesized by condensation of BAPP with p-hydroxylbenzaldehyde, salicylal, p-dimethylaminobenzaldehyde and paeonol, respectively. And two complexes, copper paeonol-AEP Schiff base complex (16) and dinuclear zinc bis(salicyal)-BAPP Schiff base complex (17), were obtained by the reaction of AEP, paeonol and copper nitrate dihydrate or by the reaction of salicyal, BAPP and zinc chloride, respectively. These compounds were characterized by elemental analysis, spectral analysis and TG-DTA method, and the crystal structures of six compounds were determined by single-crystal X-ray diffraction. The electrochemical behavior of complex (16) was studied by cyclic voltammetry. Moreover, antibacterial activities and interaction with BSA and CT-DNA for some compounds containing piperazine ring were also investigated.