Combination of “Buttressing” and “Clothespin” Effects for Reaching the Shortest NHN Hydrogen Bond in Proton Sponge Cations
作者:Valery A. Ozeryanskii、Andrey V. Marchenko、Alexander F. Pozharskii、Aleksander Filarowski、Darya V. Spiridonova
DOI:10.1021/acs.joc.0c03008
日期:2021.2.19
compression of the hydrogen bond. As a result, the previous record of the hydrogen bond shortness (N···N = 2.524 Å) has been surpassed in favor of 2.502 Å found for the tetrafluoroborate of 2,4,5,7-tetramethyl-1,8-bis(dimethylamino)naphthalene. The molecular structure of the latter differs by perfect symmetry and practically barrier-free proton transfer in the [NHN]+ bond. On the basis of the results
一系列先前未知的2,4,5-三和2,4,5,7-四取代的1,8-双(二甲基氨基)萘及其与HBF 4的盐,它们都包含大球形的取代基(Me,Br和SiMe 3)在萘环中已经合成。使用X射线衍射分析11个样品,研究了所谓的“支撑”和“衣夹”效应对其分子结构和固体阳离子中NHN氢键几何形状的影响。已显示两种作用的联合作用显着增加了氢键的压缩。结果,先前的氢键短度记录(N···N = 2.524Å)已被超过2.502Å,这是针对2,4,5,7-tetramethyl-1,8-bis的四氟硼酸盐发现的(二甲基氨基)萘。后者的分子结构因[NHN] +中的完美对称性和几乎无障碍的质子转移而有所不同键。根据量子化学计算的结果,建议值2.502Å可能代表或非常接近胺型氮原子之间短氢键的理论极限。