Theoretical Study on the silaaromatics Speaker: Xuerui Wang Advisor : Jun Zhu Dec

Outline [1,3]- substituent Shift for the Formation of the Silabenzenes Summary and Future work The aromaticity of metallasilapentalynes

3 driving force Aromaticity silicon atom is reluctant to participate in  bonding Kutzelnigg, W. Angew. Chem., Int. Ed. Engl. 1984, 23, 272. Background

4 Bent’s rule : atomic s character tends to concentrate in orbitals that are directed toward electropositive groups and atomic p character tends to concentrate in orbitals that are directed toward electronegative groups. (a) Bent, H. A. Chem. Rec.1961, 61, 275. (b) Zhu, J.; Lin, Z.; Marder, T. B. Inorg.Chem. 2005, 44, silicon atom is reluctant to participate in  bonding sp 3 Results and Discussion

5 Figure 3. [1,3]-substituent shift for the formation of silabenzenes with various substituents. NICS(0)zz (X = H) (X=NMe 2 ) Evaluate Aromaticity : ISE(isomerization stabilization energy) method and NICS( nucleus independent chemical shift) calculations

6 Figure 4.Plot of reaction free energies (ΔG) against the percentage of the s character of Si in the Si-X bonds. Results and Discussion

7 Figure 5. The plot of s character of Si to the Si-X σ bond vs reaction barriers (ΔG  )

8 Results and Discussion Figure 6. Plot of reaction free energies (ΔG) against the percentage of the s character of Si in the Si-X bonds by replacing the acyl group with methylene group in acylsilane..

9 Silabenzene (X)ΔGΔG'ΔG'-ΔG A1 ' (H) A2 ' (NMe 2 ) A3 ' (Me) A4 ' (SMe) A5 ' (Cl) A6 ' (OMe) A7 ' (F) A8 ' (GeH 3 ) A9 ' (SiH 3 ) A10 ' (AlH 2 ) B1 ' (H) B2 ' (NMe 2 ) B3 ' (Me) B4 ' (SMe) B5 ' (Cl) B6 ' (OMe) B7 ' (F) B8 ' (GeH 3 ) B9 ' (SiH 3 ) B10 ' (AlH 2 ) Results and Discussion Figure 7. Plot of reaction free energies (ΔG) against the percentage of the s character of Si in the Si-X bonds in nonaromatic system.

10 Figure 8. Plot of reaction free energies (ΔG) against the percentage of the s character of Si in the Si-X bonds in the osmasilabenznes. Results and Discussion

11 1. The contribution from aromaticity can be evaluated quantitatively (ca. 30 kcal/mol) in such rearrangement. 2. Bent's rule plays an important role in both the thermodynamics and kinetics of the rearrangement. 3. Our findings could be a useful guide to the synthesis of silabenzenes. Summary

12 Outline [1,3]- substituent Shift for the Formation of the Silabenzenes 2 3 Future work The aromaticity of metallasilapentalynes

13 8e 116 ° 10e ° distorted triple bond extremely strained reduce the ring strain significantly Introduce a metal silicon atom is reluctant to participate in  bonding Kutzelnigg, W. Angew. Chem., Int. Ed. Engl. 1984, 23, 272. Zhu, C.; Li, S.; Luo, M.; Zhou, X.; Niu, Y.; Lin, M.; Zhu, J.; Cao, Z.; Lu, X.; Wen, T.; Xie, Z.; Schleyer, P. v. R.; Xia, H. Nat. Chem. 2013, 5, 698. Background

14 Ring A; NICS(0) = NICS(1) = NICS(2) = NICS(-1) = NICS(-2) = NICS(1)zz = Ring B: NICS(0) = NICS(1) = NICS(2) = NICS(-1) = NICS(-2) = NICS(1)zz = Results and Discussion The aromaticity of metallasilapentalynes Figure 9. The optimized structure 、 the ISEs values of the osmasilapentalynes and the NICS values of the each ring

The effect of ligand 15 The effect of base The ring strain

16 1.From the view of negative ISEs and negative NICS values compared to benzene both reveal aromaticity in osmasilapentalyne. 2.osmasilapentalyne prefer  -donor ligands than  - accepter ligands. Summary

17 Outline 1 3 [1,3]- substituent Shift for the Formation of the Silabenzenes 2 3 Future work The aromaticity of metallasilapentalynes

18 Future work 1. Theoretical study on the [1,3]- substituent shift for the formation of the stannumbenzenes and germaniumbenzene. 2. Tune the metal center by other transition metals.

19 Organophosphorus compounds 19 pesticide flame retardant medicine antibacterial agents enzyme inhibitors anti HIV agents

？ 20 Entryinitiator eq solventT( o C)t[h] NMR yield [%] 1 Mn(OAc) 3 2.2HOAc Mn(OAc) 3 2.2DMF Mn(OAc) 3 2.2THF8012trace 4 AgNO 3 0.5DMF8012trace 5 AIBN1.2THF8012trace Condition Optimization

21 致谢 感谢朱军老师在学习、生活等各方面给予的关心与指导 ! 感谢赵玉芬老师、特别要感谢唐果老师、高玉珍师姐、许 健师兄、张鹏波、吴巨在实验上的悉心指导和帮助 ! 感谢实验室的范景兰师姐、黄莹师姐以及其他同学的热心 帮助！

22 Thank you for your attention ！