Speaker: Ke An Advisor: Jun Zhu A Brief Insight into the Bridged- and Non-bridged Osmanaphthalene and the Osmaazulene Isomers

Conclusion Results and Discussion Introduction Motivation

Introduction 1. C. Zhu; S. Li; M. Luo; X. Zhou; Y. Niu; M. Lin; J. Zhu; Z. Cao; X. Lu; T. Wen; Z. Xie; P. v. R. Schleyer; H. Xia. Nat. Chem accepted. 1. The first metallapentalyne has been successfully synthesized. 1

Introduction 2. In 2003, the first non-bridged-iridanaphthalene was reported. 2,3 2. J. Chen, G. Jia, Coord. Chem. Rev. (2013), 3. M. Paneque, C. M. Posadas, M. L. Poveda, N. Rendón, V. Salazar, E. O˜nate, K. Mereiter, J. Am. Chem. Soc. 2003, 125, 9898.

Introduction 3. In 2007, the first non-bridged-osmanaphthalyne from zinc reduction of vinylcarbyne complex. 4. In 2009, selective synthesis of osmanaphthalene and osmanaphthalyne by C-H activation. Z. Lin and G. Jia, Angew. Chem., Int. Ed. 2007, 46, Z. Cao and H. Xia, Angew. Chem., Int. Ed. 2009, 48, 5461.

Motivation

Results and Discussion The ISE value shows that naphthalene is more stable than azulene. All energies(kcal/mol) were calculated at B3LYP/6-31G* level, zero-point energy were applied. 1. The comparison between azulene( 薁 ) and naphthalene.

Results and Discussion 1. The comparison between azulene and naphthalene. NICS 4 (0) NICS(1) NICS(-1) BLA(Angstrom) Ring A Ring B 4. P. v. R. Schleyer; C. Maerker; A. Dransfeld; H. Jiao; N. J. R. v. E. Hommes. J. Am. Chem. Soc. 1996, 118, Result 1: Azulene and naphthalene are both aromatic, which can be reflected by the negative NICS values and the BLA result. NICS: Nucleus Independent Chemical Shift. BLA: Bond Length Alternation

Results and Discussion 2. The comparison between bridged-osmaazulene and osmanaphthalene. (1). [Os] = OsCl(PH 3 ) 2 NICS(0) NICS(1) NICS(-1) BLA(C-C) Dihedral Angel Ring ARing B Ring A Ring B Result 2: The NICS values indicate the nonaromaticity of both molecules, which means the transition metal destroys the aromaticity of azulene and naphthalene.

Results and Discussion (2). [Os] = OsCO(PH 3 ) 2 NICS(0) NICS(1) NICS(-1) BLA(C-C) Dihedral Angel Ring A Ring B Ring A Ring B 2. The comparison between bridged-osmaazulene and osmanaphthalene. Result 3: The NICS values indicate the antiaromaticity of both molecules, which means the transition metal reverses the aromaticity of azulene and naphthalene with the ligand influence.

Results and Discussion 3. The comparison between bridged-osmaazulene and osmanaphthalene in T1 state. NICS(0) NICS(1) NICS(-1) BLA(C-C) Dihedral Angel Ring A Ring B Ring A Ring B (1). [Os] = OsCl(PH 3 ) 2 Result 4: In T1 state, bridged-osmanaphthalene is more stable. And the NICS values indicate the nonaromaticity of both compounds.

Results and Discussion 3. The comparison between bridged-osmaazulene and osmanaphthalene in T1 state. (2). [Os] = OsCO(PH 3 ) 2 NICS(0) NICS(1) NICS(-1) BLA(C-C) Dihedral Angel Ring A Ring B Ring A Ring B Result 5: The NICS values indicate the aromaticity of both molecules, which is just another demonstration of the antiaromaticity of the ground state.

Results and Discussion 4.The comparison between bridged-osmaazulene and non-bridged- osmaazulene. (1). [Os] = OsCl(PH 3 ) 2 / OsCl(PH 3 ) 2 H E(kcal/mol) Result 6: Non-bridged-osmaazulene with chloride ligand is more stable than bridged- osmaazulene. The isomer of 6-CH group substituted by osmium fragment has the most negative values.

Results and Discussion 4.The comparison between bridged-osmaazulene and non-bridged- osmaazulene. (1). [Os] = OsCl(PH 3 ) 2 H NICS(0) NICS(1) NICS(-1) BLA(C-C) Dihedral Explanation: The BLA result of the 6-subtituted isomer indicates result 6 again. The NICS values demonstrate the aromaticity of the non-bridged-osmaazulene isomers, except the seven-membered ring of the 2-substituted isomer.

Results and Discussion 4.The comparison between bridged-osmaazulene and non-bridged- osmaazulene. (2). [Os] = OsCO(PH 3 ) 2 / OsCO(PH 3 ) 2 H E(kcal/mol) Result 7: Non-bridged-osmaazulene with CO ligand is more stable than bridged- osmaazulene except for 5- and 7-substituted isomers. The isomer of 1-CH group substituted by osmium fragment has the most negative values.

Results and Discussion 4.The comparison between bridged-osmaazulene and non-bridged- osmaazulene. (2). [Os] = OsCO(PH 3 ) 2 H NICS(0) NICS(1) NICS(-1) BLA(C-C) Dihedral Explanation: The BLA result of the 1-subtituted isomer and the larger BLAs of 5- and 7-substituted indicate result 7 again. The NICS values demonstrate the aromaticity of the 1- and 6-substituted isomers, except the seven-membered ring of the 2- and 5- substituted isomers and the five-membered ring of 7-substituted isomer.

Results and Discussion 4.The comparison between bridged-osmanaphthalene and non- bridged-osmanaphthalene. (1). [Os] = OsCl(PH 3 ) 2 / OsCl(PH 3 ) 2 H(2). [Os] = OsCO(PH 3 ) 2 / OsCO(PH 3 ) 2 H E(kcal/mol) E(kcal/mol) Result 8: Non-bridged-osmanaphthalene is more stable than bridged-osmaazulene. The isomer of 1-CH group substituted by osmium fragment with CO ligand has the most negative values.

Results and Discussion 4.The comparison between bridged-osmanaphthalene and non- bridged-osmanaphthalene. NICS(0) NICS(1) NICS(-1) BLA(C-C) Dihedral (1). OsCl(PH 3 ) 2 H (2). OsCO(PH 3 ) 2 H NICS(0) NICS(1) NICS(-1) BLA(C-C) Dihedral Explanation: The BLA results indicate result 8 again. The NICS values demonstrate the aromaticity and stabilization of the non-bridged-osmanaphthalene isomers.

Conclusion 1. Azulene and naphthalene are both aromatic, and naphthalene is more stable than azulene. 2.Bridged-transition metal destroys the aromaticity of azulene and naphthalene. It’s nonaromatic with a chloride ligand and antiaromatic with CO ligand.

Conclusion 3. In T1 state, bridged-osmaazulene and osmanaphthalene are nonaromatic with a chloride ligand and aromatic with CO ligand. 4. Non-bridged-osmaazulene and osmanaphthalene are more stable than bridged one. Due to the influence of the ligand, here are the most stable structures of osmaazulene and osmanaphthalene.