Reactions Of An ?-diimine-supported Dimagnesium(I) Compound With (iso)nitriles

Metal?metal bonded compounds have been a very important research direction owing to their unique bonding properties and electronic structures.In recent years,the synthesis and applications of metal?metal bonded compounds of main group elements have been studied because the low-valent,low-coordinate metal centers in these species may lead to novel reactivity.Especially there is much progress in the study of the group 2 Mg?Mg bonded compounds.In 2007,the first low-valent Mg?Mg bonded compounds[L¹MgMgL¹]?L¹={[?Ar?NC?Me?]₂CH}^?,[?Ar?NC?Ni Pr₂?N?Ar?]^?,Ar=Dip?were isolated and structurally characterized.Subsequently,our group synthesized the Mg????Mg???bonded compound containing?-diimine ligand,[K?THF?₃]₂[LMg?MgL](1,L=[?2,6-i Pr₂C₆H₃?NC?Me?]₂^2?)in2009.Recently,two Mg?Mg bonded compounds containing o-phenylene-diamino and N,N'-dipp-substituted phenanthrene-diamido ligands were reported by our group.In the current project,the?-diimine-supported compound 1 was used to activate unsaturated molecules such as nitriles,isonitriles and white phosphorous P₄.A series of products with different transformations of the small molecules have been obtained,and their structures were characterized by X-ray diffraction,NMR and elemental analysis,as well as density functional theory?DFT?study.This thesis consists of three parts:1.The development of metal–metal bonded compounds is reviewed.The synthesis and structures of magnesium?I?dimers that contain lower-valence metal ions stabilized by diferent ligands have been summarized,as well as some applications in activating small molecules and synthesis.2.Reactions of compound 1 with different nitriles and isonitriles were carried out.Complexes[L₄Mg₄??-CN?₄K₄?THF?₆]?2?and[L₄Mg₄??-CN?₄??Me?₃SiCN?₂K₄?THF?₄]?3?have been isolated when compound 1 was reacted with 2 and 3eq.of Me₃SiCN,respectively,in which CN^?ions bridge two Mg atoms or one Mg and one K atoms into a tetramer through reductive cleavage of Si–C bond.The cyanide-bridged tetranuclear complex[L₄Mg₄??-CN?₄??Me?₃CCN?₂K₄?THF?₄]?4?and tert-butyl magnesium complex?5?formed in the reaction of precursor 1 with Me₃CCN.Besides,[{K?THF?₂LMg?N=C=CMe₂?}₂]?6?and[{K?Tol?LMg(N=C=CC₅H₁₀)}₂]?7?were obtained by reductive deprotonation of?-H to give ketiniminate ligands bridging two Mg centers when precursor1 was reacted with Me₂CHCN and C₆H₁₁CN,respectively.The products were characterized by X-ray diffraction,IR,NMR and elemental analysis,as well as DFT studies.3.The reaction of compound 1 with 2 eq.of P₄ leads to the P?P bond cleavage and the rearrangement of P atoms,followed by the formation of a[P₇]^3?cage as bridging ligand,in which three types of phosphorus atoms were found.The interaction between solvated K⁺and[P₇]^3-cage and?-diimine ligand leads to dimerization of two[L₂Mg₂P₇K?THF?₂]moieties into compound 8,which was characterized by NMR,elemental analysis and DFT calculations.