Synthesis,Crystal Structure And Catalytic Activity Of Transition Metal Complexes With Bis(2-hydroxynaphthalen-1-yl)-1,2-Diaminocyclohexane Ligands

Superoxide dismutase(SOD),a type of metalloproteinases that own some certain biocatalytic function,can eliminate residual free radicals(mainly O2·),and the turnover number is high.However,there are some drawbacks when SOD is used as a medicine,such as high molecular weight,weak tissue permeability,short half-life and so on.So its application was restricted.Hence,many efforts have been devoted to synthesize small molecular compounds to mimic the functionality of natural SOD.On the other hand,higher solubility in aqueous can limit hybridization between these compounds with albumen.So the activity of SOD is affected by this factor.Therefore,we have synthesized some metal complexs with worse solubility in aqueous for mimicking the activity of SOD.Now synthesizing chiral sulfoxide by asymmetric oxidation of thioether is a hot research topic.Especially,the use of chiral metal catalysts in the reaction process is the most effective way to prepare optical pure sulfoxide.In this paper,2-hydroxynaphthalen-1-naphthaldehyde and cyclohexanediamine acid were used to synthesize the chiral schiff ligand and their transition metal complexes were also synthesized.We have synthesized 10 hybrid proteins through the interaction with HSA and SOD-like activity of transition metal complexes.The structure of these compounds have been determined by X-ray crystallographic methods,FT-IR,elemental analysis,MS and VIS-UV.These complexes SOD-like activity were also tested by xanthine/xanth:ine oxidase method.This 1s of importance for theoretical research of SOD mimics.In this paper,we also studied the catalytic activity of these complexes and their hybrid proteins.Studying shows that there are powerful binding force between these complexes and HSA.We obtained the quenching constants KSV,binding constants K,binding modes.The binding compounds to BSA were static quenching.The competitive experiment of these complexes with hemin,ibuprofen,thyroxine,showed that the binding site of complexes is site 1.Additionaly,the secondary structure of HSA,the micro-environment of tyrosine residue and tryptophan residue were changed in the presence of these compounds.Through the SOD activity tests of the SODm we know that Mn-3?HSA-Mn-3?Mn-8?HSA-Mn-8?Co-5?HSA-Co-5?Co-10?HSA-Co-10 have high SOD-like activity The values of IC50 and Kcat have been obtained.The result shows that with the presence of HSA,the SOD activity of these compounds all improved.The metal ion of compounds and natural SOD are consistent,HSA-Mn-3 shows higher SOD activity than others.The research about synthesizing chiral sulfoxide by asymmetric oxidation of thioether shows that the yield of hybrid proteins is approximately twice than that of other complexes.The enantioselectivity(ee)values of V-1,Cr-2,HSA-Cr-2 are higher.