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

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

3. Background Text in here

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

5. Computational Method Package : Method : basis sets : Gaussian 09 M06-2X / B3LYP 6-311+G ** 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. DFT

6. Results and Discussion Figure 4. The formation of silabenzenes through the [1,3]-Si→O substituent shift. 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. reluctancesp 3

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

8. Results and Discussion SilabenzeneΔG(298k) (kcal/mol) ΔSiC(ring)ΔCC(ring)NICS(0)zzΣα(Si) 1a(F)117.80.0210.008-12.5360.0 1b(OMe)84.760.020.006-11.9360.0 1c(Cl)77.150.020.017-10.9359.2 1d(NMe 2 )46.760.020.005-11.6360.0 1e(SMe)38.130.0260.006-12.0360.0 1f(Me)17.830.0290.01-11.9360.0 1g(H)-0.330.0260.006-11.2360.0 1h(GeH 3 )-0.80.0330.004-11.5360.0 1i(SiH 3 )-16.080.0310.005-11.7359.9 1j(AlH 2 )-29.320.0260.005-11.3360.0 2a(F)122.20.0110.016-9.2360.0 2b(OMe)90.20.0240.009-12.3360.0 2c(Cl)81.450.0140.009-10.0359.8 2d(NMe 2 )54.480.0260.009-12.0360.0 2e(SMe)42.380.0290.012-11.6360.0 2f(Me)22.290.0310.003-12.3360.0 2g(H)2.320.0310.012-11.8360.0 2h(GeH 3 )0.110.0330.007-11.8360.0 2i(SiH 3 )-14.80.0310.008-11.9360.0 2j(AlH 2 )-28.480.0290.01-11.5360.0

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 Figure 9. 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 Figure 10. Plot of reaction free energies (ΔG) against the percentage of the s character of Si in the Si-X bonds in nonaromatic system. Silabenzene (X)ΔGΔG'ΔG'-ΔG A1 ' (H) A2 ' (NMe 2 ) -0.3 46.8 27.6 74.8 27.9 28.0 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 ) 17.8 38.1 77.2 84.8 117.8 -0.8 -16.1 -29.3 2.3 54.5 22.3 42.4 81.5 90.2 122.2 0.1 -14.8 -28.5 46.1 67.0 105.9 114.0 147.4 26.8 12.5 -2.2 32.9 83.9 51.1 73.3 114.1 121.8 153.8 30.0 15.6 -0.2 28.3 28.9 28.7 29.2 29.6 27.6 28.6 31.5 30.6 29.4 28.8 30.9 32.6 31.6 29.9 30.4 28.7

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!