Advisor: Jun Zhu Speaker: Xuerui Wang

1. Theoretical study on the interconversion of silabenzenes and their non-aromatic isomers via the [1,3]-substituent shift: aromaticityvs Bent's rule Advisor: Jun Zhu Speaker: Xuerui Wang

2. Outline Background 1 2 Computational Method Results and Discussion 3 Conclusion 4

3. Background Text in here

4. Background driving force Aromaticity Rouf, A. M.; Jahn, B. O.; Ottosson, H. Organometallics.2013, 32, 16 silicon atom is reluctant to participate in  bonding Kutzelnigg, W. Angew. Chem., Int. Ed. Engl.1984, 23, 272.

5. Computational Method Package : Gaussian 09 M06-2X / B3LYP Method : basis sets : 6-311+G ** DFT • 1.(a) Becke, A. D. J. Chem. Phys. 1993, 98, 5648. (b) Miehlich, B.; Savin, A.; Stoll, H.; Preuss, H. Chem. Phys. Lett.1989, 157, 200. (c) Lee, C.; Yang, W.; Parr, G. Phys. ReV. B 1988, 37, 785. • 2. Zhao,Y.; Truhlar, D. G. Theor. Chem. Acc. 2008, 120, 215. • 3. Frisch, M. J. et al. Gaussian, Inc., Wallingford CT, 2010.

6. Results and Discussion Figure 4. The formation of silabenzenes through the [1,3]-Si→Osubstituent shift. reluctance sp3 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, 9384.

7. Results and Discussion Evaluate Aromaticity : ISE(isomerization stabilization energy) method and NICS( nucleus independent chemical shift) calculations • Figure 5. The calculated ISE values of A1' and A2'. NICS(0)zz -11.2 (X = H) -11.6 (X=NMe2) Figure 6. [1,3]-substituent shift for the formation of silabenzenes with various substituents.

8. Results and Discussion

9. Results and Discussion Figure 7. The plot of s character of Si to the Si-X σ bond vs ΔG

10. Results and Discussion • Figure 8. The plot of s character of Si to the Si-X σ bond vs reaction barriers (ΔG)

11. Results and Discussion Figure9. 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..

12. Results and Discussion Figure10. Plot of reaction free energies (ΔG) against the percentage of the s character of Si in the Si-X bonds in nonaromatic system.

13. Conclusion 1. Aromaticity is not the only driving force for the reaction. 2.Bent‘s rule plays an important role in formation of the silabenzene. 3. Our findings could be a useful guide to the synthesis of silabenzenes.

14. Thank You!