Restricted Rotation in 9-Phenyl-anthracenes: A Prediction Fulfilled

The calculated phenyl rotation barrier in 9-phenylanthracene has been reported as ∼21 kcal mol−1, but experimental verification of this barrier is limited by its intrinsic symmetry. V-T NMR indicated the barrier to interconversion of the syn (C2v) and anti (C2h) rotamers of 9,10-bis(3-fluorophenyl)anthracene to be ∼21 kcal mol−1. Likewise, the V-T NMR spectra of 9-(1-naphthyl)-10-phenylanthracene reveal that the rotational barrier of the unsubstituted phenyl ring is at least 21 kcal mol−1.已有研究报道，9-苯基蒽（9-phenylanthracene）的计算苯基旋转势垒约为21 kcal mol⁻¹，但该势垒的实验验证受限于其本征对称性。变温核磁共振（Variable-Temperature NMR）测试表明，9,10-二(3-氟苯基)蒽的顺式（C₂ᵥ）与反式（C₂ₕ）旋转异构体之间的构象互变势垒约为21 kcal mol⁻¹。同样地，对9-(1-萘基)-10-苯基蒽进行的变温核磁共振光谱分析显示，其未取代苯基环的旋转势垒至少为21 kcal mol⁻¹。