Synthesis Of Multi-benzimidazole Complexes And Its Superoxide Dismutase Mimic Activities

Multi-benzimidazole compounds have attracted great attention by their mimic enzyme activities, such as superoxide dismutase activity, catalase activity, and their coordination chemistry. In this dissertation, we selected multi-benzimidazole compounds as a main ligand to study the structure characteristic of its complexes and their influence on the activity of eliminating active oxygen by means of X-ray single crystal diffractometer, Here are the results.(i) We designed and synthesized multi-benzimidazole compounds, and obtained three single crystals, by means of X-ray single crystal diffraction method, among which three were characterized and two were novel. The novel compound is C34H32N10 2C2H6O2 and C38H44N10O2 2C1O4-2Cl-2CH3OH, i.e. EDTB-2C2H6O2 (EDTB = N,N,N',N'-tetrakis-(2'-benzimidazolylmethyl)-l,2-ethanediamine), and (EGTBH4)-2C1O4-2C1-2CH3OH, (EGTB= N,N,N',N'-tetrakis-(2-benzimidazolyl methyl-1,4-di-ethylene amino) glycol ether).(ii) We designed and synthesized seven metal-containing multi-benzimidazole complexes. All of them were analyzed by X-ray single crystal diffraction method. Crystal structure showed that: (1) NTB metal complexes which contained three benzimidazole group have different coordination geometry according to central metal ion, such as octahedron structure, formed butterfly-like shape complex, and triangle bipyramid structure, gear-like shape compound, respectively. (2) EDTB metal complexes in which contained four benzimidazole groups have distorted octahedron geometry structure because of rigidity of EDTB. (3) EGTB metal complexes in which included four benzimidazole groups and an intra-ligand (-OCH2CH2O-) group have slightly distorted octahedron structure.The structure of [Fe(NTB)Cl2]Cl-CH3OH-2H2O and [Co(NTB)Cl](CoCl4)-CH3OH were confirmed by means of X-ray single crystal diffraction method, IR and UV. Crystal structure showed that [Fe(NTB)Cl2]+ moiety has octahedron geometry and [Co(NTB)Cl]+ moiety has triangle bipyramid configuration. The dihedral angel between the benzimidazole rings is different in the two complexes, in [Fe(NTB)Cl2]+ moiety, the angelbetween the two benzimidazole rings including N2 and N4 is 9.41(0.11)° and the two benzimidazole rings is nearly on a plane, butterfly shape complex formed. But in the [Co(NTB)Cl]+ moiety, the three benzimidazole rings shared the whole space equally, the dihedral angel among them is about 120°, just like three fan blades of an airscrew, the molecular structure appear gear-like shape.Four single crystal of metal-containing EDTB complexes were characterized by X-Ray single diffraction method, and crystal structure show that Cu(EDTB)CdBr4-3H2O or Cu(EDTB)ZnCl4-4CH3OH is combined [CuEDTB]2+ cation with large counter ion [CdBr4]2 " or [ZnCl4]2 " , but in the complex Ni(EDTB)Cl2-CH3OH-C2H5OH or Ni(EDTB)(NO3)2-C2H5OH the counter ion is simple ion Cl" or NO3". In the four EDTB metal complexes the central ion is coordinated by four benzimidazole N atoms and two amine N atoms. The coordination geometry around the central ion can be described as distorted octahedron. Anyway, the four complexes are novel compound.The novel dinuclear Ni2+ complex [Ni2(yu-Cl)(//-0Ac)(EGTB)]-Cl-C104-2CH30H is bridged triply bridging agents of a chloride ion, an acetate and an intra-ligand (-OCH2CH2O-) group. The nickel coordination geometry is that of a slightly distorted octahedron with a NiN3O2Cl arrangement of the ligand donor atoms. Each identical Ni(II) cation is coordinated by a chloride ion, an oxygen atom from the acetate, an ether oxygen atom from the ligand and three nitrogen atoms from two benzimidazole groups and an aliphatic amine group of the same ligand. Because of flexibility of EGTB, each identical Ni(II) geometry is slightly distorted octahedron. Whole molecular is highly symmetrical and has particular nest-shape structure.Common ground of multi-benzimidazole metal complex is that the bond distance between benzimidazole N atoms and metal is shorter than the distance between amine group N atom and metal. The different metal-N bond length is likely due to benzimidazole N atoms can provide better o and 71 electron donor than amine group N atom, naturally, the metal ion bond more tightly.(iv) The pyrogallol UV-VIS spectrophotometeric method was performed to study the activity of SOD mimics at 320nm. The Ni(II)(EDTB) cationic species exhibit a high SOD mimic activity, but Cu(II)(EDTB) and [Ni2(EGTB)Cl(OAc)] cationic species do not have SOD mimic activity.