Reactions Of Organolithium Compounds With Small Molecules

The activation of small molecules has been one of the fastest developing fields in organometallic chemistry by using reactive metal complexes to activate these small molecules,and has been widely used in elementary reaction,organic transformations,new catalysts design,the metabolic processes of the organism,etc.Therefore,the researches on reactions of organometallics with small molecules and the exploration of activation law are very significant.In organometallic chemistry,lithium compounds based on amidines and?-diketimines with highly reactive have been frequently used as intermediates and transfer metal reagents in organic synthesis.However,the researches on the reactions between lithium compounds and small molecules?O₂,CO₂,CS₂?are few.Furthermore,small molecules are small but abundant,pervasive,and impactful.Efficient uses of small molecules are crucial to develop green economy.In view of the above contents,a series of related research work of this subject were conducted in this paper and were outlined as follows:Chapter 1,introducion of the research background of this subject:?1?small molecules?O₂,CO₂,CS₂?activating reactions;?2?the summary of amidinate ligands and their lithium compounds based on amidinate ligands;?3?the summary of?-diketiminato ligands and their lithium compounds based on(3-diketiminato ligands.Chapter 2,the reactions between lithium amidinates and small molecules were studied.Different lithium amidinates reacted with the small molecules?O₂,CO₂,CS₂?under the corresponding conditions,and the new lithium compounds[Li₂O₂·{Li?THF?}4{?3-CH₃C₆H₄?NC?H?N?3-CH₃C₆H₄?}₄]?2j?,[Li{O₂C?N?2,6-Me₂C₆H₃?C?H?N?2,6-Me₂C₆H₃??}-THF]₄?2k?and[Li{O₂C?N?4-CH₃C₆H₄?C?H?N?4-CH₃C_6H4??}·THF]₆?21?were achieved.Compounds 2j,2k and 21 were fully characterized by NMR spectroscopy and X-ray structural determinations.Compound 2j is lithium inverse crown ether complex with O₂^2- in central;compound 2k is a tetramer forming a cage structure;compound 21 is a hexamer forming a "wheel" cage structure in central.Compounds 2k and 21 indicate that CO₂ were successfully inserted into the pre-formed N-Li bonds.Chapter 3,the reactions between lithium?-diketiminates and small molecules were studied.Adopting the similar method of Chapter 2,different lithium?-diketiminates reacted with the small molecules?O₂,CO₂,CS₂?under the corresponding conditions.The new lithium compounds[Li{S₂C?C?CHN?2,6-ⁱPr₂C₆H₃??CHNH?C₆H₃ⁱPr₂-2,6??}·2THF]?3c?,[?C₆H₅?NCHC?CS₂Li?THF?₂?CHN?C₆H₅?CS₂Li?THF?₂]?3d?and[Li6{O₂C?C?CHN?2,6-ⁱPr₂C₆H₃??CHNH?C₆H₃ⁱPr₂-2,6??}₆·6THF]?3e?were achieved after the activation of small molecules.Compounds 3c,3d and 3e were characterized by X-ray single crystal diffraction and NMR.Compound 3c was a monolithium salt with CS₂-Li+ chelation;compound 3d was a dilithium salt with CS₂-Li+ chelation;compound 3e was a hexamer forming a "wheel" cage structure in center and was similar to compound 2k.Chapter 4,the experimental tests of catalytic oxidation of benzyl alcohol through organic lithium-peroxo compounds[Li₂O₂·{Li?THF?}₄{?C₆H₅?NC?H?N?C₆H₅?}₄]?2g?,[Li₂O₂,{Li?THF?}₄{?4-CH₃C₆H₄?NC?H?N?4-CH₃C₆H₄?}₄]?2h?and[Li₂O₂·{Li?THF?}₄{?3-CH₃C₆H₄?NC?H?N?3-CH-3C₆H₄?}₄]?2j?.Compound 2g as catalyst,was used to catalyze benzyl alcohol to benzoic acid in the presence of oxygen environment.The experimental results show that compound 2g has some catalytic activity,but the catalytic efficiencies are moderate?38.5%?.