Noncovalent Interactions in Organic Radicals: Pancake, σ-Hole, and H-Bonding in F<sub>2</sub>HbimDTDA
作者:Michelle B. Mills、Harrison K. S. Young、Gabriele Wehrle、Willem R. Verduyn、Xibo Feng、Paul D. Boyle、Pierre Dechambenoit、Erin R. Johnson、Kathryn E. Preuss
DOI:10.1021/acs.cgd.1c00520
日期:2021.10.6
The solid-state structure of neutral thiazyl radical 4-[2′-(5,6-difluorobenzimidazolyl)]-1,2,3,5-dithiadiazolyl (F2HbimDTDA) is the result of a combination of structure-directing intermolecular interactions. Pancake bonding of radical molecules leads to stacks of [F2HbimDTDA]2 pairs along [100]. Polarization of the DTDA S atoms creates an area of positive electrostatic potential, forming contacts with electronegative F atoms of a neighboring molecule to define chains along [010]. Importantly, the first observation of H-bonding to DTDA N atoms is reported, with imidazolyl N-H donors. The variety of intermolecular interactions is similar to that observed in the related HbimDTDA, but the resulting solid-state structure of the F2HbimDTDA morphology reported here is quite different. Moreover, computational analysis of the two structures, using a combination of periodic-boundary and finite-molecule calculations, has allowed rationalization of the observed results, indicating that F2HbimDTDA is unlikely to occur in a morphology comparable to that reported for HbimDTDA and revealing σ-hole interactions as the determining factor in the packing of F2HbimDTDA.
中性噻唑基 4-[2′-(5,6-二氟苯并咪唑基)]-1,2,3,5-二噻二唑(F2HbimDTDA)的固态结构是结构引导分子间相互作用的综合结果。自由基分子的薄饼键导致[F2HbimDTDA]2 对沿[100]堆积。DTDA S 原子的极化产生了一个正静电势区域,与邻近分子的电负性 F 原子形成接触,从而沿着 [010] 形成链。重要的是,报告首次观察到了 DTDA N 原子与咪唑 N-H 给体之间的 H 键作用。分子间相互作用的种类与在相关的 HbimDTDA 中观察到的相似,但此处报告的 F2HbimDTDA 形态所产生的固态结构却截然不同。此外,利用周期边界计算和有限分子计算相结合的方法对这两种结构进行的计算分析使观察到的结果趋于合理,表明 F2HbimDTDA 不可能出现与 HbimDTDA 相似的形态,并揭示了 σ 孔相互作用是 F2HbimDTDA 堆积的决定性因素。