Studies On The Application Of Low-Valent Aluminum Compounds In The Activation Of Aromatic Small Molecules And Aliphatic Nitriles

Main group metal-metal(multiple)bond compounds and main group metal carbene compounds have unique advantages in the field of small molecule activation and organic catalysis,and have attracted the attention of chemists in recent years.As an atypical ligand,?-diimine can participate in the electron transfer process of the metal center when the redox ligand is coordinated with the metal center,effectively stabilizing low-valent metal compounds.Based on the aluminum-aluminum bond compound stabilized by the?-diimine ligand,this thesis studied its reactivity with aromatic pyridine,picoline and aliphatic nitrile,and initially explored the potential laws of activating such small molecules.Synthesized and characterized 13 cases of aluminum-containing metal organic compounds with novel structures.The crystal structure and electronic configuration of the above compounds were studied by X-ray single crystal diffraction,nuclear magnetic/electron paramagnetic resonance and DFT theoretical calculations,etc.1.The development history of the low-valence metal aluminum compounds of the third main group and the research progress of low-valence aluminum compounds in the activation of small molecules are introduced.2.The Al-Al bond compound stabilized by?-diimine ligand[L^2-(THF)Al^II-Al^II()THFL^2-](L=[(2,6-i Pr₂C₆H₃)NC(Me)]₂)(1)was used as a precursor to react with pyridine and picoline to form a searies of coordination adducts[L(Py)Al]₂·toluene(2),[L(4-Me-Py)Al]₂·toluene(4a),[L(4-Me-Py)Al]₂(4b)and[L(2-Me-Py)Al-Al L]·toluene(4c),Interestingly,the solution of 1 and pyridine was treated at high temperature to obtain the unique macrocyclic hexanuclear Al(III)compound[{LAl(pyridyl)}₆]·7toluene(3),which was accompanied by regioselective reductive dehydrogenation with pyridine.3.The reactivity of 1 and its reduction products(?dialuminene?,[LAl=Al L]^2–and?radical monoanionic dialuminum species?,[Al Al]^–)with aliphatic nitriles were studied.This low-valence Al metal compound has high reactivity.The activation of such small molecules can cause C-H bond activation,C-C/C-N coupling and cycloaddition reaction.The activated product was separated and its structure was characterized in more detail.