1. Cross-Aromaticity in annulated benzene and analogs Advisor: Jun Zhu Reporter: Yulei.Hao Date: 2014.3.14 2016-1-311

2. Results and Discussion Futher Work Background Computational Methods 2016-1-312

3. Background α β Mills–Nixon effect ： Geometric changes of the benzene ring due to annulation by small, strained rings. in terms of the stability of the Kekulé resonance structures, it favor the resonance structure with the double bonds exo to the strained annulated ring. α=360 。 -2β Mills, W.H.; Nixon, I.G. J.Chem.Soc. 1930, 2510 2016-1-313

4. Background Coupling of diazo-compounds and Bromination Fuller, F. J.; Valente, J. E. J.Chem.Cryst. 1996, 26, 815. Mills, W.H.; Nixon, I.G. J.Chem.Soc. 1930, 2510 2016-1-314

5. Background “The field of the cycloproparene chemistry can be aptly regarded as something of a Cinderella area since the simple beginnings have led to a wealth of fascinating and fruitful chemistry far beyond expectation in 1960s.” ----Brian Halton Chem. Rev. 2003, 103, 1327-1369 [1] Vogel, E.; Grimme, W.; Korte, S. Tetrahedron Lett. 1965, 6, 3625. The synthesis some of cycloproparens: TM.1 2016-1-315

6. [2] [3] [4] TM.2 TM.3 TM.4 2016-1-316

7. Computational Methods G03 program OPT ： B3LYP/6-311++G* NICS: B3LYP/6-311++G* 2016-1-317

8. Results and Discussion Figure 1. Monomers of annulated rings in calculation. Figure 2. Combination of non-π aromatic monomers. CompoundsNICS(0)NICS(1)zz cyclopropane-42.73-24.16 3-47.57 -21.40(-23.53) a 4-41.96 -18.26(-26.20) cyclopropene-28.49-16.17 1-36.961.8 2-40.57 -27.97(-7.52) cyclobutane3.115.54 4-6.74 0.59(3.43) Table 2. Comparing NICS values(ppm) of 1, 2, 3 and 4 with their monomers. a Numbers in the brackets are NICS(1)zz opposite the dihedral. 2016-1-318

9. Results and Discussion Figure 3. Selected bond distances(Å) for 5-15. Figure 4. Selected bond distances(Å) for 16-22. 2016-1-319

10. Results and Discussion Compounds aΔRaΔR ΔRΔR 50.034160.073 60.040170.012 7-0.051 8-0.027180.069 190.069 90.01620-0.004 10-0.006210.029 11-0.020220.072 12-0.024 130.039 140.036 15-0.041 Table 3. ΔR(Å) for compounds 5-22. R defined as the endo distance minus the exo distance. The bond between the two rings is used as the exo bond, and the maximum of the difference is used for the asymmetric compounds. We can conclude that the bond length in benzene and naphthalene of these compounds change slightly after fused by small strained rings, impling the retained π aromaticity. 2016-1-3110

11. compounds3- /4-membered rings6-membered rings NICS(0)NICS(1)zz NICS(0)NICS(1)zz monomers -28.49-16.17-8.02-29.25 5-21.10-14.48-7.98-27.55 6-20.91-6.69-7.56-25.85 7-18.29-14.18-7.79-26.59 8-15.99-14.72-11.19-29.20 -28.49-16.17-8.41-29.05 9-3.523.04-8.40-27.77 102.852.80-8.90-26.20 113.303.12-8.65-26.39 123.403.45-9.37-25.23 13 -20.99/ 4.46 -14.20/ 3.11-8.26-26.20 14 -21.56/ 2.55 -14.34/ 2.11-8.49-26.21 15 -20.96/4.91 -13.83/ 3.53-8.89-25.02 16-22.29-13.14 -8.95/ -7.95 -26.88/ -27.87 17-19.85-13.55 -8.10/ -8.40 -26.60/ -29.00 18-19.51-12.80 -9.33/ -6.72 -29.56/ -26.53 19-22.12-13.01-8.02-27.54 20-20.65-13.54-7.89-26.40 21 -20.19/ -22.49 -13.56/ -25.26 -7.39/ -8.80 -25.26/ -28.66 22-21.93-12.99-8.24-27.81 compounds3- /4-membered rings6-membered rings NICS(0)NICS(1)zz NICS(0) NICS(1)zz monomers -28.49-16.17-8.02-29.25 5-21.10-14.48-7.98-27.55 6-20.91-6.69-7.56-25.85 7-18.29-14.18-7.79-26.59 8 -15.99-14.72-11.19-29.20 monomers 1.430.14-8.41-29.05 9-3.523.04-8.40-27.77 102.852.80-8.90-26.20 113.303.12-8.65-26.39 123.403.45-9.37-25.23 13 -20.99/ 4.46 -14.20/ 3.11-8.26-26.20 14 -21.56/ 2.55 -14.34/ 2.11-8.49-26.21 15 -20.96/4.91 -13.83/ 3.53-8.89-25.02 16-22.29-13.14 -8.95/ -7.95 -26.88/ -27.87 17-19.85-13.55 -8.10/ -8.40 -26.60/ -29.00 18-19.51-12.80 -9.33/ -6.72 -29.56/ -26.53 19-22.12-13.01-8.02-27.54 20-20.65-13.54-7.89-26.40 21 -20.19/ -22.49 -13.56/ -25.26 -7.39/ -8.80 -25.26/ -28.66 22-21.93-12.99-8.24-27.81 Table 4. NICS(0) and NICS(1)zz of computed compounds The aromaticity of both are not destroyed. 2016-1-3111

12. Results and Discussion Table 3. Smooth line of NICS(0) vs exo bond distance of compounds 5-22. We can conclude that the π- aromaticity in benzene and naphthalene weaken the σ- aromaticity in cyclopropene, and strengthen the σ- antiaromaticity in cyclobutene. 2016-1-3112

13. Figure 5. The Gibbs Free Energy(in kcal.mol -1 ) of some compounds to their isomers. We can conclude that those compounds with higher symmetry are more stable. Results and Discussion 2016-1-3113

14. Futher Work …… 2016-1-3114

15. Thank you for listening! 2016-1-3115