Fuhrer Timothy J, Houck Matthew, Iacono Scott T
Department of Chemistry, Radford University, Box 6949 Radford, Virginia 24142, United States.
Department of Chemistry & Chemistry Research Center, United States Air Force Academy, Colorado Springs, Colorado 80840, United States.
ACS Omega. 2021 Nov 23;6(48):32607-32617. doi: 10.1021/acsomega.1c04175. eCollection 2021 Dec 7.
The addition of fluorine atoms to an aromatic ring brings about an additional set of π-bonding and antibonding orbitals culminating after the addition of the sixth fluorine with a new set of π-aromatic-like orbitals that affect the molecule in a way that we will refer to hereafter as "fluoromaticity". Depending on the number and position of the fluorine atoms, the contributed π-orbitals can even further stabilize the ring leading to smaller bond lengths within the ring and higher resistance to addition reactions. This added ring stability partially explains the high thermostability and chemical resistance found in polymers containing fluorinated aromatics in their architecture. A similar molecular orbital effect is seen with the addition of other halogen atoms to aromatic rings, though to a much smaller degree and not resulting in the additional ring stability.
在芳环上添加氟原子会产生一组额外的π键和反键轨道，在添加第六个氟原子后，会形成一组新的类似π芳香性的轨道，这种轨道以一种我们下文将称为“氟芳香性”的方式影响分子。根据氟原子的数量和位置，贡献的π轨道甚至可以进一步稳定环，导致环内键长更短，对加成反应的抗性更高。这种增加的环稳定性部分解释了在其结构中含有氟化芳烃的聚合物中发现的高热稳定性和耐化学性。在芳环上添加其他卤素原子时也会观察到类似的分子轨道效应，不过程度要小得多，并且不会导致额外的环稳定性。
