Studies On The Synthesis,Charaterization And Binding Mechanism With DNA Of Electroactive Metal Complexes Of Copper, Cobalt, Nickel And Manganese

Deoxyribonucleic acid (DNA) is an important genetic substance in organism. As the basis of genetic expression, it plays an important role in the process of storing, copying and transmitting germ messages. Serving as a target molecule, the recognition of DNA for natural and artificial molecules in the inhibition of cellular disorders and in therapy of certain diseases is of paramount importance in inorganic biochemistry. The binding of small molecules, especially transition metal complexes, to DNA and molecular identification are very important in life science. It is generally accepted that there are three kinds of binding modes for small molecules to DNA, which refer to intercalative binding, groove binding and electrostatic force. Of the three binding modes, the intercalative binding is thought to be the strongest binding because it is a type of binding caused by the intercalative molecule plane sandwiched between the aromatic heterocycle and base group pairs of DNA. For a small molecule, what part intercalates into DNA strand is of vital importance because it can provide useful information to design novel and efficient drugs for disease diagnosis and chemotherapeutic agents. At the same time, it can provide a theoretical basis for the selection of novel hybridization indicators in DNA electrochemical sensors.In this paper, with 5,7,7,12,14,14-hexad-methyl-l,4,8,ll-tetranitrogen macrocyclic fourteen - 4,11 - dialkene diiodid, imidazole and 1,10-phenanthroline as ligends, Cu(Ⅱ), Co(Ⅱ), Ni(Ⅱ) and Mn(Ⅱ) as central ion, respectively, the corresponding mental complexes have been synthesized successfully. The structures nine novel complexes with three structure types have been determined by means of crystalline structure determination, IR, EA and TG Reaction conditions, interaction modes, binding ratios and binding constants between metal complexes anddeoxyribonucleic acid(DNA) have been determined by means of electrochemical and spectroscopic methods. With [Co(phen)2(Cl)(H2O)]Cl and [Mn(Im)6](teph)-2H2O as hybridization indicator, the DNA electrochemical sensor via thiohydroxy self-assembly modified gold electrode and DNA electrochemical sensor via covalently immobilized DNA modified glassy carbon electrod have been prepared, respectively.(1) Three novel complexes of macrocyclic copper(II), cobalt( II )and nickel(II) have been designed and synthesized, and their structures have been determined by means of crystalline structure determination, IR, EA and TG. The interactions between metal complexes and DNA have been studied by means of electrochemical and spectroscopic methods. The results show that the compound formulas are Cu(C16H32N4)I2·2H2O,Co(C16H32N4)·(CH3COO)2·I3 and Ni(C16H32N4)·I2, respectively. The interaction mode between metal-complexes and deoxyribonucleic acid is electrostatic force. The binding ratios are 1:1 and the binding constants are 1.02 × 104 L·mol-1, 4.00×104L·mol-1, 3.64× 102 L·mol-1, respectively.(2) Four novel complexes of tetraploid(imidazole) copper(II), hexakis(imidazole) cobalt(II), hexakis(imidazole)nickel(II) and hexakis(imidazole) manganese(II) have been designed and synthesized and their structures have been determined by means of crystalline structure determination, IR, EA and TG. The interactions between metal complexes and DNA have been studied by means of electrochemical and spectroscopic methods. The results show that the compound formulas are [C12H16N8Cu](teph), [C18H24N12Co]Cl·2·2H2O·2HCl, [C18H24N12Ni]Cl2·4H2O and C18H24N12Mn](teph)·2H2O(teph, Tere- phthalate), respectively. The interaction modes between metal complexes and deoxyribonucleic acid are intercalation, and binding ratios of tetraploid(imidazole) copper(II), hexakis(imidazole) cobalt(II), and hexakis(imidazole) manganese(II) with DNA are 1:1 and binding constants of hexakis(imidazole) cobalt(II), and hexakis(imidazole) manganese(II) with DNA are 5.94× 105 L·mol-1 and 4.44× 103 L·mol-1, respectively.(3) Two complexes of 1,10-phenanthroline cobalt(II), 1,10-phenanthroline nickel(II) have been designed and synthesized and their structures have been determined by means of crystalline structure determination, IR, EA and TG. The interactions between metal complexes and DNA have been studied by means of electrochemical and spectroscopic methods. The results show that the compound formulas are [Co(phen)2(Cl)(H2O)]Cl-2H2O, [Ni(phen)(C8H4O4)(H2O)3]·H2O (phen, 1,10-phenan -throline), respectively. The interaction modes between metal complexes and deoxyribonucleic acid are intercalation, and binding ratios are 1:1 and bindingconstants are 6.35 × 105 L·mol-1 and 8.28 × 102 L·mol-1, respectively.(4) Thiohydroxy-modified ss-DNA has been fixed on the surface of gold electrode using self-assemble film method and the modified electrode has been characterized by electrochemical method. Using [Co(phen)2(Cl)(H2O)]Cl as the hybridization indicator, the DNA electrochemical sensor with thiohydroxy self-assembly gold electrode has been prepared. By comparing the differential pulse voltammetric curves of the indicator on bare gold electrode, ss-DNA modified gold electrode, ss-DNA modified gold electrode hybrizated with complementary ss-DNA (that is, ds-DNA modified glassy carbon electrode), ss-DNA modified gold electrode hybrizated with noncomplementary ss-DNA modified gold electrode, the DNA electrochemical sensor based on the electrochemical reaction of [Co(phen)2(Cl)(H2O)]Cl with a DNA probe immobilized electrode can be used to the recognition of specific DNA with good selectivity. DNA electrochemical sensor with covalently immobilized DNA modified glassy carbon electrode, in which [Mn(Im)6](teph)·2H2O is used as the hybridization indicator, has been also prepared. And the modified electrode was characterized by electrochemical method. By comparing the differential pulse voltammetric curves of the indicator on bare glassy carbon electrode, ss-DNA modified glassy carbon electrode, ss-DNA modified glassy carbon electrode hybrizated with complementary ss-DNA (that is, ds-DNA modified glassy carbon electrode), ss-DNA modified glassy carbon electrode hybrizated with noncomplementary ss-DNA modified glassy carbon electrode, the DNA electrochemical sensor based on the electrochemical reaction of [Mn(Im)6](teph)·2H2O with a DNA modified glassy carbon electrode can be used to the analysis of sample, which is of good selectivity.