Syntheses Of Multi-substituted Osmapentalynes And Reactions Involving Central Metal

As a kind of brand new metallaaromatics,osmapentalynes have unique properties.So far,the research of osmapentalynes mainly focus on the reactivities of metal carbyne,and there is little research on the ligand substitution reaction of osmapentalynes.At present,there are two main methods for the syntheses of osmapentalynes:a)Reaction of OSCl2(PPh3)3 with two alkynes via a two-step protocol to produce osmapentalynes;b)Reaction of OsCl2(PPh3)3 with polyacetylene compounds(which named“carbolong”in this dissertation)to afford osmapentalynes by one step.The one-step method can reduce the synthetic procedures and improve the synthetic efficiency.The“carbolong”can also be well extended.Thus,it is very valuable to develop the one-step method.In this dissertation,we devote to preparing multi-substituted osmapentalynes by treating multi-substituted“carbolong”with OsCl2(PPh3)3.Besides,the reaction involving central metal were studied.This dissertation was divided into the following five chapters:In chapter 1,the syntheses and reactivities of osmapentalynes are summarized.The properties of osmapentalynes and their derivatives are briefly introduced.In addition,research objectives and plan of this dissertation are stated.In chapter 2,the“carbolong”substituted with phenyl group and naphthyl were synthesized.Reaction of the“carbolong”with OsCl2(PPh3)3,several kinds of multi-substituted osmapentalynes were constructed.In addition,the transformation between the two kinds of osmapentalynes with different coordination environments were systemically studied.In this chapter,the method of intrducting substituent group to osmapentalynes through“carbolong”was expanded.Notably,we prepared a brand new fully substituted osmapentalynes.In chapter 3,we studied the ligand substitution reaction of several kinds of multi-substitutcd osmapentalynes with various N-donor ligands for the first time.This work provides new insights for further research on ligand substitution reaction of metallapentalynes and metallapentalenes.In chapter 4,the reaction of several kinds of multi-substituted osmapentalynes with coinage metal complexes were investigated and the related osmapentalyne-coinage metal adducts have been obtained,respectively.These adducts can readily dissociate to regenerate the precursor osmapentalyne with the addition of extra ligands.Notably,the osmapentalyne-silver(I)-phenanthroline adduct is the first example of cyclic metal carbyne-silver adduct.In chapter 5,the innovation of the dissertation is concluded and the outlook of this research is presented.