Syntheses And Reactivities And Preliminary Study On The Photocatalytic Performance Of Metal-Bridged Polycyclic Osma-and Iridacycles

Transition-metal-containing metallacycles with π-conjugated skeleton play an important role in organometallic chemistry,which are currently attracting widespread attention because of their novel structures,unique properties,and abundant chemical reactivities.In this dissertation,we focus on the construction of polycyclic metallacycles with π-conjugated skeleton,a series of metal-bridged osma-and iridacycles were synthesized and fully characterized based on the extension of synthesis methodologies and the development of new substrates.In addition,the preliminary photocatalytic performance of some iridacycles has been studied.The dissertation was divided into six parts as followings:In chapter 1,a brief summary was given for the syntheses and reactivities of fused-metallabenzenes and metallapentalynes,metallapentalenes as well as their derivatives.Besides,the properties of some representative metalla-aromatics were reviewed.The main ideas and purposes of this dissertation were also proposed.In chapter 2,the first metal-bridged osma-1,3-thiazine derivatives that contain two main-group heteroatoms(N and S)at ortho(for S)and para(for N)positions relative to metal center were synthesized by a formal[4+2]cyclization,which represents an important supplement to the rare metal-bridged metallacycles that contain main-group heteroatoms.In addition,the spectral and photothermal properties ware examined.In chapter 3,the iridapentalenes and its derivatives were realized in one pot with high efficiency by the introduction of new iridium starting material and "carbolong ligands".Interestingly,a rare type of π-conjugated iridapentalenes with four fused-carbon skeletons was also isolated in one pot.Morever,the mechanism was further studied by the isolation of key intermediates,and the reactivities of intermediates were also discussed.The spectral and photothermal properties of iridapentalenes and its derivatives suggest their potential applications in material science.In chapter 4,the effective synthesis of iridapentalenol with non-phosphonium substituent was realized.The functionalizations of iridapentalenol suggest the similar reactivities with phenol and metallaphenol,such as the weak acidity and the esterification.In addition,the iridapentalenol exhibited different reaction behavior.The realization of iridapentalenol provides new strategy for the construction of metallapentalynes and metallapentalenes with other non-phosphonium group,which enrich the "carbolong chemistry".In chapter 5,a preliminary photocatalytic performance of irida-aromatics and its derivatives was studied.The results showed that the iridaindene can be acted as photocatalyst to accelerate the oxidative coupling of benzylamine,which is the first application of metallaaromatics in the field of photocatalysis.Although the catalytic efficiency was low due to the insufficient photostability,the iridapentalene derivatives could actually promote the transformation of organic reactions.This work provides a new insight for further exploring the photocatalytic properties of metallaaromatics.In chapter 6,the conclusion of this dissertation was summarized and the outlook of this research is presented.