DFT Study on the Structure and Racemization Mechanism of 1,1 ＇- Bina phthalene-8,8 ＇-diol

密度功能的理论(DFT ) 被使用学习扎根的州的几何学和 1,1'-binaphthalene-8,8'-diol 的异构化过程。三异构体，作为 ISO1， ISO2，和 ISO3 表示了，被发现，由 OH 组，和每 OH-orientational 异构体的不同取向区分了有 R-enantiomer 和 S-enantiomer。这些异构体的 conformational 稳定性被关于 ring-to-ring 扭转追踪精力变化调查。在三 OH-orientational S 异构体之间的互变现象被发现由于将近自由的旋转有相当低的障碍哦在 O-C 附近的组挑选契约。ISO1 和 ISO2 的 S-R enantiomerization 能在 C1 C1' 单个契约附近通过戒指戒指扭转发生，以反旋转方式或以 syn 旋转方式。反线路的障碍是比由 87.95 和 75.04 kJ/mol 的相应 syn 线路的那些低的。为 ISO3 的 S-R enantiomerization，仅仅反线路被发现。为 ISO1， ISO2，和 ISO3 的反线路 enantiomerizations 的障碍分别地是 119.61， 120.43，和 121.59 kJ/mol。经由三条反 enantiomerization 线路的平行反应机制为 1,1'-binaphthalene-8,8'-diol 的 racemization 被建议。

Density functional theory （DFT） was applied to study the ground state geometries and isomerization processes of 1,1＇-binaphthalene-8,8＇-diol. Three isomers, denoted as ISO1, ISO2, and ISO3, were found, distinguished by different orientations of the OH groups, and each OH-orientational isomer has R- and S-enantiomer. The conformational stabilities of these isomers were investigated by tracking the energy change with respect to the ring-to-ring torsion. The inter-conversions between the three OH-orientational S-isomers were found to have quite low barriers owing to the nearly free rotation of OH groups around the O-C single bonds. The S-R enantiomerization of ISO1 and ISO2 can take place through the ring-ring torsion around the C1-C1/ single bond, either in the anti-rotation manner or in the syn-rotation manner. The barriers of the anti routes are lower than those of the corresponding syn routes by 87.95 and 75.04 kJ/mol. For the S-R enantiomerization of ISO3, only the anti route was found. The barriers for the anti route enantiomerizations of ISO1, ISO2, and ISO3 are 119.61, 120.43, and 121.59 kJ/mol, respectively. A parallel reaction mechanism via three anti enantiomerization routes was proposed for the racemization of 1,1＇-binaphthalene-8,8＇-diol.