The Physical And Chemical Properties Of Tetra-nickel Complexes And Fullerenes

Electron Paramagnetic Resonance(EPR)spectroscopy is a powerful method for s-tudying materials with unpaired electron,such as free radicals,metal complexes,irradi-ated samples,doped samples.With the advantage of rapid,trace and non-destructive de-tection,EPR techniques could precisely probe the unpaired electron structure in metallic oxides and free radicals,detecting the electron transitions in free radical reactions,for understanding the reaction mechanism.Here,we use EPR techniques to explore the non-zero nuclear spin determined chemical reaction in Molybdenum and Nickel iso-topes,meanwhile EPR simulation and ICP-MS techniques were used to verify these re-sults.Besides,the thermodynamic property of a singly intercage C-C bond in fullerene dimer was studied.Then,we focus on the laccase-catalyzed catechol oxidation reaction.This paper mainly introduce the following three works:1.we use EPR and ICP-MS techniques to explore the non-zero nuclear spin de-termined chemical reaction in Molybdenum and Nickel isotopes.The experimental re-sults shown that all the formed Mov ions during MoⅥ→MoⅤ reduction are composed solely of the magnetic isotopic 95,97Mov ions,while all the formed NiⅣ ions during NiⅡNi→Ⅲ oxidation are composed solely of the magnetic isotopic 61NiⅢ ions.We try to explain this new phenomenon in Molybdenum and Nickel isotopes,thus it could be a new way for isotopes fractionation distinguished from the traditional MDF.2.By using the in situ variable-temperature EPR technique,a rather small value of bond dissociation enthalpy(BDE)of 72.4 kJ·mol-1(17.3 kcal mol-1)for the singly C-C bond was estimated.The value was only about twice the typical hydrogen bonds,or one fifth of those in the diamond or the saturated hydrocarbons.The application of the pre-synthesized dimer for obtaining the aligned fullerene molecular devices was discussed.3.The aromatic hydrocarbon ring-opening occurred in laccase-catalyzed catechol and its derivatives oxidation reaction.With EPR spectroscopy,we analyse the selec-tively activation and ring-opening mechanism at C4-C5 site in catechol.These results could be helpful for improving the effects of the laccase-catalyzed catechol oxidation and shed light on the usage of protein modification.