Synthesis And Reactivity Of Metal-Metal-Bonded Compounds With An O-Phenylene-diamino Ligand

The dimeric Mg-Mg-bonded compounds,which feature a low-valent[Mg^I]₂ core stabilized by sterically demanding ligands,are of great significance because of their novel bonding and reactivity.Herein we report on the synthesis of the Mg-Mg-bonded compound[K（THF）₃]₂[L²MgMgL²]（2）with the dipp derivative of the well-known pda,N,N’-bis（dipp）-o-phenylenediamine（H₂L²;dipp=2,6-diisopropylphenyl）,as the ligand.The new dimagnesium（I）compound has been characterized by crystal structure,NMR,UV-vis absorption and fluorescence spectroscopy and DFT computations.The reactions of 2with a series of unsaturated organic molecules were tested,and two products,[L²Mg（THF）₂K（THF）（μ-N₃）₂K（THF）Mg（THF）₂L²]（3）and[Li（THF）₄]₂[（L²Mg）₂（tBuNCO）₂]（4）were obtained in the case of reaction with Me₃SiN₃ and tBuNCO,respectively.Moreover,the dinuclear compound[L²GaGaL²]（5）was obtained by the reaction between N,N’-bis（dipp）-o-phenylenediamine and GaCl₃.This thesis consists of three sections:In the first section,the history of metal-metal bonds including transition metal-metal bond chemistry and main group metal-metal bond chemistry is briefly summarized,followed by a discussion of the reactivities of these compounds.Non-innocent ligands and complexes with the ortho-phenylene diamine ligands are also described.In the second section,the synthesis,characterization,and reactivity of[K（THF）₃]₂[L²MgMgL²]（2）was discussed.Compound 2 was obtained from the reaction of MgCl₂ with H₂L²,after deprotonation,and then reduction by KC₈.The compound 2 can act as a two-electron reductant towards unsaturated organic molecules.For Me₃SiN₃,cleavage of the Si-N bond occurred to elimination the Me₃Si-group and the remaining N₃^-bridges thetwoL²Mg（THF）₂K（THF）sectionstoformtheproduct[L²Mg（THF）₂K（THF）（μ-N₃）₂K（THF）Mg（THF）₂L²]（3）.For tBuNCO,there is a coupling of C-C single bond.The structures of 2-4 were investigated by NMR and X-ray diffraction.DFT calculations elucidate the electronic characters of 2-4.Meanwhile,UV-vis spectroscopy,fluorescence spectroscopy and TD-DFT calculations were used to investigate the electronic transition of 2.In the third section,the synthesis of[L²GaGaL²]（5）by deprotonation and reduction process from H₂L²,PhCH₂K,and KC₈.The structure of 5 was detected by NMR and X-ray diffraction.