Functionalization Of Osmapentalynes And Osmapentalenes

The combination of organometallic chemistry and aromatic chemistry generates metalla-aromatic chemistry.In the past 30 years,the development of this chemistry led to the isolation of many kinds of metalla-aromatic compounds,such as metallabenzenes,metallabenzynes,metallapyridines,and metallafurans.Since 2013,our group reported a series of metal-bridgeheaded aromatic metallapentalynes and metallapentalenes with novel structures and unique properties.Some of metallapentalynes and metallapentalenes can be used as near-infrared materials or biomedical materials.Aiming at materialization and polymerization of metallapentalynes or/and metallapentalenes,we studied their reactivitiesin this dissertation.As a result,a series of novel metallacycle compounds with functional groups are synthesized successfully.Some of them were also applied in the materialization or polymerization studies.The main contents of this dissertation are showed as following:In charpter 1,the classification and criteria of aromaticity are briefly introduced.The preparations,reactivities and properties of metallapentalynes and metallapentalenes are reviewed.In addition,metal-containing macromolecules are also summarized.The research objectives and plans of this dissertation are presented.In charpter 2,we report the construction of two new metalla-aromatic frameworks,a-metallapentalenofurans and lactone-fused metallapentalynes,by the reactions of osmapentalynes with aryl alkynes in the presence of water.DFT studies show that the a-metallapentalenofurans and lactone-fused metallapentalynes are mobius aromaticity essentially.18O-labeled experiments confirm that the newly introduced oxygen atom in a-metallapentalenofurans or lactone-fused metallapentalynes comes from water.In charpter 3,a series of osmapentalene derivatives with anchoring groups are synthesized for single molecular conductance measurement.It's the first time to study the charge transport properties of metalla-aromatic compounds at single molecule scale.When the phosphonium group is removed from the metallacycle,electron delocalizability is reduced along with the reduction of single molecular conductance with one order of magnitude,which indicates that the phosphonium group is important for charge transport in metallapentalynes and metallapentalenes.In charpter 4,halogenated osmapentalenofurans are synthesized by the electrophilic aromatic substitution reactions of osmapentalenofurans.These are the first examples of electrophilic aromatic substitution of mobius aromatic compound.The regioselectivity was studied by DFT calculations.In charpter 5,the[2+3]cycloaddition reactions of osmapentalenofurans with organic azides have been investigated.The first triaza-metallacycle with late transition metal is synthesized.It is the first metalla-aromatic compound with one metal center shared by four ?-aromatic rings.Further study shows that the osmapentalynofurans is the intermediate in the[2+3]cycloaddition reactions.In chapter 6,the synthesis of functionalized osmapentalynes and osmapentalenes with their model polymerization reactions are studied.We synthesize osmapentalynes and osmapentalenes with alkenyl,alkynyl or hydroxyl groups.A series of model compounds are achieved by their model polymerization reactions.This chapter creates the foundation for the polymerization and materialization of metallapentalynes,metallapentalenes.In chapter 7,the summary of this dissertation is presented along with outlook of this research.