UROP Proceedings 2020-21

School of Science Department of Chemistry 4 Chemistry of Aromatic Metallacycles Supervisor: JIA Guocheng / CHEM Student: HO Hang Chi / SSCI Course: UROP1100, Summer Osmabenzynes are a family of organometallic complexes containing a benzyne ring with an osmium atom. Organic benzyne is a highly reactive species due to ring strain, which is why it has never been isolated. However, with the substitution of one of the carbons with an Os atom, the complex becomes much more stable. The osmaanthracyne complex (an organometallic analogue of anthracene), the synthesis and reactivity of which will be the focus of this report, is air stable and has been well-characterised. The remarkable stability of osmaanthracyne complex can be attributed to the very large size of the Os atom compared to C, and the steric hindrance caused by the large size of the trimethylsilyl group (TMS), thus protecting the electron-rich benzyne from electrophilic attack. The objective of this study is to study the similarities between anthracene and its organometallic analogue: osmaanthracyne complex. Chemistry of Aromatic Metallacycles Supervisor: JIA Guocheng / CHEM Student: YEUNG Tsz Ho / SSCI Course: UROP1100, Summer Metallabenzynes have much to be studied and discovered. The Jia group was the first to synthesize a metallabenzyne complex. With unsubstituted osmanaphthalynes and osmaanthracynes successfully synthesized by the group before, an unsubstituted osmabenzyne has yet to be synthesized. Taking part in synthesizing and characterizing an unsubstituted osmabenzyne in my UROP1100 project, I successfully synthesized the osmabenzyne 8 with a -TMS group independently. During my experiments, I am fortunate enough to take part in uncovering new discoveries about the synthetic route of the osmabenzyne 8. The following report documents my experimental results and data from my independent synthesis of osmabenzyne 8, as well as discussion on such results. Mentions on future works and the experimental information will also be included.