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

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Presentation on theme: "Advisor: Jun Zhu Speaker: Xuerui Wang Theoretical study on the interconversion of silabenzenes and their non-aromatic isomers via the [1,3]-substituent."— Presentation transcript:

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

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 G ** 1.(a) Becke, A. D. J. Chem. Phys. 1993, 98, (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, Zhao,Y.; Truhlar, D. G. Theor. Chem. Acc. 2008, 120, Frisch, M. J. et al. Gaussian, Inc., Wallingford CT, 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, 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 (X = H) (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) b(OMe) c(Cl) d(NMe 2 ) e(SMe) f(Me) g(H) h(GeH 3 ) i(SiH 3 ) j(AlH 2 ) a(F) b(OMe) c(Cl) d(NMe 2 ) e(SMe) f(Me) g(H) h(GeH 3 ) i(SiH 3 ) j(AlH 2 )

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 ) 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 )

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!


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