Synthesis,Separation And Derivatization Of Lutecium-based Endohedral Fullerenes

Fullerenes,as one of the novel carbon allotropes,are attracting more and more concerns during recent years.Interestingly the fullerene interior can dope various atoms,molecules and metal clusters,forming a unique hybrid structure endohedral metallofullerenes?EMFs?.Such unique molecular structures and chemical properties have successfully applied various fields such as polymer solar cells,biomedicine,semiconductor materials and so on.Among them,metallofullerenes containing scandium or lanthanum have been studied widely.However,the lutecium-based endohedral fullerenes,having similar ionic radii with scandium,are rarely studied.Therefore,this dissertation focuses on the synthesis,separation and derivatization of lutecium-based endohedral fullerenes,especially the characterization of their crystal structures.The corresponding works and results are summarized as follows:?1?Study the optimal synthesis and extraction conditions of Lu-EMFs.The arc-discharge method was used to obtain Lu-EMFs ash,and by changing the molar ratio of Lu/C and the pressure conditions and current conditions during the discharge process,the conditions for the optimal synthesis of Lu-EMFs were explored as follows:Lu/C molar ratio was 1:10,100 A,H₂:N₂=1:5.After the raw ash is obtained,the original ash is extracted using CS₂,N,N-dimethylformamide?DMF?and 1,2,4-trichlorobenzene?TCB?.By comparing the relative content of extracted metal fullerenes,we believe that the extraction of Lu-EMFs using CS₂ is the simplest and most effective.?2?Synthesis,extraction and characterization of a series of lutecium-containing dimetallofullerenes(Lu₂@C_82-86).Lu-EMFs were prepared using optimized synthesis conditions.A series of pure fullerene samples Lu₂@C_2n?2n=82,84,86?were prepared by multi-step high performance liquid chromatography.The single crystal X-ray diffraction results showed that these metallofullerenes aredimetallofullerenes.Our experimental and theoretical results revealed that a Lu-Lu single bond is formed between the two lutetium ions which transfer four electrons in total to the fullerene cages,thus resulting in a formal divalent state for each Lu ion.?3?We obtained mono-addition products with high reactivity and high regioselectivity,with the reaction of 1,3-dimesityl imidazole-2-ylidene 1 and Lu₃N@I_h?7?-C₈₀,Lu₂@C_3v?8?-C₈₂,Lu₂@C_2v?9?-C₈₂2 respectively,By changing the reaction conditions,we found that the reaction of Lu₃N@I_h?7?-C₈₀0 with 1 can give different addition products under different reaction conditions.While The reaction products between Lu₂@C_3v?8?-C₈₂2 and Lu₂@C_2v?9?-C₈₂2 and 1 did not change with the reaction conditions.The single crystal X-ray diffraction results indicated that all these reaction products were monoaddition products,and through further theoretical calculations,it was proved that the formation of these highly reactive and highly regioselective monoaddition products was caused by the LUMO distribution of the alkene and the molecular electrostatic potential distributionthese of the metal fullerene.