Study On DNA-binding Modes And Ion Recognition Properties Of Xanthone Derivatives Complexes

In this paper,we have reported synthesis,characterization and activity studies of the xanthone derivatives and their metal complexes.The thesis is included two parts: 1.A series of simple xanthones(L¹-L¹⁵)and novel transition metal complexes(M-Lⁿ) of L¹-L¹⁵have been synthesized and characterized.The interactions of M-Lⁿ with calf thymus DNA(ct-DNA)have been investigated by spectrophotometric methods and viscosity measurements.2.The xanthone-crown ether(L¹⁶),xanthone-[2,2]cryptand (L¹⁷)and novel metal complexes(M-L¹⁶)of L¹⁶have been synthesized and characterized.The ion recognition of L¹⁶and M-L¹⁶has been investigated by crystal structure analyses and spectra methods.The full text consists of five chapters.In chapter one,the background of this text is concisely introduced with the emphasis on the development of the interaction between small molecule and nucleic acid and the molecule recognition in supermolecule chemistry.Moreover,the aim as well as the progress of this thesis has been outlined.In chapter two,a series of simple xanthones(L¹-L¹⁵)and novel transition metal complexes(M-Lⁿ)of L¹-L¹⁵have been synthesized and characterized by mass spectra (MS),¹H NMR spectra,elementary analyses,molar conductivity and infrared spectra (IR).The possible structure of the complexes is M·(Lⁿ)₂·(H₂O)₂.In chapter three,the interactions of M-Lⁿ with calf thymus DNA(ct-DNA)have been investigated by spectrophotometric methods and viscosity measurements.The results demonstrate that the complexes can bind to DNA by intercalative mode,and the different substituent can influence the bond affinity.The scavenging abilities on the hydroxyl free radicals(·OH)of M-Lⁿ have been studied by spectrophotometry.The results show that the scavenging activity of the complexes is better than that of ligand.In chapter four,the xanthone-crown ether(L¹⁶),xanthone-[2,2]cryptand(L¹⁷)and novel metal complexes(M-L¹⁶)of L¹⁶have been synthesized and characterized by electrospray mass spectra(ESI-MS),¹H NMR spectra,elementary analyses and infrared spectra(IR).The structure characteristics of complexes(M-L¹⁶)have been discussed by crystal structure and bond valence sum(BVS)analyses.In chapter five,the ion recognition of xanthone-crown ether(L¹⁶)and metal complexes(M-L¹⁶)has been investigated by spectra methods and crystal structure analyses.The results indicate that L¹⁶is a good chemsensor for alkali earth metal and M-L¹⁶is a good detector for HSO₄^- with high sensitivity and selectivity.