Roy Tarun, Thimmakondu Venkatesan S, Ghosal Subhas
Department of Chemistry, National Institute of Technology Durgapur, M G Avenue, Durgapur 713 209, India.
Department of Chemistry and Biochemistry, San Diego State University, San Diego, California 92182-1030, United States.
ACS Omega. 2022 Aug 19;7(34):30149-30160. doi: 10.1021/acsomega.2c03224. eCollection 2022 Aug 30.
1-Azulenylcarbene (; 0 kJ mol) is experimentally known as the key reactive intermediate for the rearrangement reactions of aryl carbenes in the laboratory. Here, using coupled-cluster methods up to the fc-CCSD(T)/cc-pVTZ//fc-CCSD(T)/cc-pVDZ level, thirteen new carbenes and one new cyclic allene are theoretically identified within the CH elemental composition that either energetically lie below or very close to . While the cyclic allene, bicyclo[5.4.0]undeca-2,3,5,7,9,11-hexene (; -166 kJ mol), is the experimentally known lowest energy isomer, three other cyclic allenes, bicyclo[5.4.0]undeca-1,2,4,6,8,10-hexene (; -100 kJ mol), bicyclo[5.4.0]undeca-1,3,4,6,8,10-hexene (; -97 kJ mol), and bicyclo[6.3.0]undeca-1,2,4,6,8,10-hexene (; -42 kJ mol), demand new experimental studies. In total, thirty-one isomers are studied in this work (within -166 to +15 kJ mol from ) and all are found to be polar (μ ≠ 0). Among these, 1H-benzo[7]annulen-1-ylidene (; -4 kJ mol; μ = 5.24 D), bicyclo[5.4.0]undeca-2,4,6,8,11-pentaene-10-ylidene (; 13 kJ mol; μ = 7.59 D), 5-methylene-naphthalen-1-ylidene (; 15 kJ mol; μ = 5.32 D), 6-methylene-naphthalen-2-ylidene (; -43 kJ mol; μ = 6.60 D), and 8-methylene-naphthalen-2-ylidene (; -39 kJ mol; μ = 5.55 D) are competitively polar compared to (μ = 5.39 D). Therefore, these carbene molecules are potential targets for rotational spectroscopists and radioastronomers. Considering the importance of naphthyl and azulenylcarbenes in reactive intermediate chemistry, mechanisms of different rearrangement reactions and plausible formation pathways of some of these new carbenes are studied in this work using density functional theory.
1-薁基卡宾（；0 kJ/mol）在实验室中是芳基卡宾重排反应的关键活性中间体，这是通过实验得知的。在此，使用高达fc-CCSD(T)/cc-pVTZ//fc-CCSD(T)/cc-pVDZ水平的耦合簇方法，在CH元素组成范围内理论上鉴定出了13种新的卡宾和1种新的环状丙二烯，它们在能量上要么低于，要么非常接近。虽然环状丙二烯双环[5.4.0]十一碳-2,3,5,7,9,11-己烯（；-166 kJ/mol）是实验上已知的能量最低的异构体，但另外三种环状丙二烯，双环[5.4.0]十一碳-1,2,4,6,8,10-己烯（；-100 kJ/mol）、双环[5.4.0]十一碳-1,3,4,6,8,10-己烯（；-97 kJ/mol）和双环[6.3.0]十一碳-1,2,4,6,8,10-己烯（；-42 kJ/mol），需要新的实验研究。在这项工作中总共研究了31种异构体（相对于能量在-166至+15 kJ/mol范围内），并且发现它们都是极性的（μ≠0）。其中，1H-苯并[7]轮烯-1-亚基（；-4 kJ/mol；μ = 5.24 D）、双环[5.4.0]十一碳-2,4,6,8,11-戊烯-10-亚基（；13 kJ/mol；μ = 7.59 D）、5-亚甲基萘-1-亚基（；15 kJ/mol；μ = 5.32 D）、6-亚甲基萘-2-亚基（；-43 kJ/mol；μ = 6.60 D）和8-亚甲基萘-2-亚基（；-39 kJ/mol；μ = 5.55 D）与（μ = 5.39 D）相比具有较强的极性。因此，这些卡宾分子是旋转光谱学家和射电天文学家的潜在研究目标。考虑到萘基和薁基卡宾在反应中间体化学中的重要性，本工作使用密度泛函理论研究了一些新卡宾的不同重排反应机理和可能的形成途径。
