The Stability and Aromaticity of Metallasilapentalynes ： A DFT S tudy

1. The Stability and Aromaticity of Metallasilapentalynes ：A DFT Study Speaker: Xuerui Wang Advisor : Jun Zhu Wang, X.; Zhu, C.; Xia, H.; Zhu, J. Organometallics10.1021/om500170w.

2. Outline 1 1 Background Results and Discussion 2 Summary 3 3

3. Background In 1979 ,Thorn and Hoffmann predicted the three classes of stable metallabenzenes Thorn, D. L.; Hoffman, R. Nouv. J. Chim, 1979, 3, 39 In 1982, the first metallabenzene In 2001, the first metallabenzyne W. R. Roper, J. M. Waters, J. Chem. Soc. Chem.Commun, 1982, 811 T. Wen, G. Jia, Angew. Chem. Int. Ed, 2001, 40, 1951

4. Background Only a few examples of aromatic metallabicycles complex silicon atom is reluctant to participate in  bonding Zhu, C.; Li, S.; Luo, M.; Zhou, X.; Niu, Y.; Lin, M.; Zhu, J.; Cao, Z.; Lu, X.; Wen, T. B; Xie, Z.; Schleyer, P. v. R.; Xia, H. Nat. Chem. 2013, 5, 698. Zhu, C.; Luo, M.; Zhu, Q.; Zhu, J.; Schleyer, P. v. R.; Wu, J.; Lu, X.; Xia, H. Nat. Commun. 2014, 5, 3265. Kutzelnigg, W. Angew. Chem., Int. Ed. Engl. 1984 , 23 , 272. Wang, X.; Zhu, C.; Xia, H.; Zhu, J. Organometallics10.1021/om500170w.

5. 2. Computational Method Package : Gaussian 03 Method: DFT(B3LYP) Basis sets : C, H, O, N : 6-311++G ** LanL2DZ: P(ζ(d) = 0.340), Cl(ζ(d) = 0.514), Si (ζ(d) = 0.262) Fe(ζ(f) = 2.462, Ru(ζ(f) = 1.235), Os(ζ(f) = 0.886) 1. Ehlers, A. W.; Böhme, M.; Dapprich, S.; Gobbi, A.; Höllwarth, A.; Jonas, V.; Köhler, K. F.; Stegmann, R.; Veldkamp, A.; G., F. Chemical Physics Letters 1993, 208, 111. 2. Check, C. E.; Faust, T. O.; Bailey, J. M.; Wright, B. J. J. Phys. Chem. A. 2001, 105, 8111.

6. Results and Discussion Geometry and Stability of Metallasilapentalyne. most stable diffuse d-orbitals second most stable Figure 1. Relative stability of the isomers of metallasilapentalynes with the silicon atom at different positions.

7. Results and Discussion ♦ 2.325 Å in the first osmium silylene ♦2.176 Å in the first osmium silylyne Figure 2. The optimized structure with selected bond lengths (Å) and bond angles () in osmasilapentalyne 1b.

8. Results and Discussion Table 1. The bond lengths (Å), Wiberg bond indices and charges of Os≡E triple bonds (E = C or Si) in 1a and 1b. highly polarized OsSi triple bond OsSi  bond : 27% Os 73% Si Si :components of s and p orbitals are 56% and 44% Figure 3. A. The resonance structures of osmasilapentalyne 1b. B. Electron localization function (ELF) calculations with isovalue of 0.85 on osmasilapentalyne 1b and osmapentalyne 1a.

9. Results and Discussion Ring Strain Figure 4. The calculated strain energy of osmasilapentalyne 1b based on acyclic reference compounds. The correction of the zero-point energy is included in kcal mol-1.

10. Results and Discussion The Aromaticity of Metallasilapentalynes Figure 7. The NICS(1)zz values (ppm) for rings A and B in metallasilapentalynes. Figure 8. “isomerization stabilization energy” (ISE) of metallasilapentalyne.

11. Results and Discussion The Aromaticity of Osmasilapentalynes three Hückel-type MOs HOMO, HOMO-2, and HOMO-12 two Möbius-type MOs HOMO-3 and HOMO-8 mixed aromaticity with Möbius aromaticity dominated

12. Effect of the Phosphonium Substituent on the Aromaticity in Osmasilapentalynes: Ligand Effects on the Structure for Osmasilapentalynes Effect of Lewis Base on the Stabilization for Osmasilapentalyne:

13. Summary • The computed negative ISE and NICS(1)zz values reveal aromatic character of osmasilapentalyne. • Aromaticity in osmasilapentalyne is reduced in comparison with osmapentalyne. • The phosphonium substituent, -donor ligands and Lewis base can enhance the aromaticity or stability of osmasilapentalynes. • All these findings could be helpful for the synsthesis of the first metallasilapentalyne.

14. Future work • Geometry and stability of metallasilapentalene • The aromaticity of metallasilapentalynes • Effect of the substituent on the aromaticity in osmasilapentalenes • Ligand effects on the structure for osmasilapentalenes

15. Thank you for your attention