Department of Chemistry, University of Wisconsin-Stevens Point, 2101 South Avenue, Stevens Point, WI 54481, USA.
Chemistry Department, Missouri State University, 901 South National Avenue, Springfield, MO 65897, USA.
Molecules. 2022 Feb 24;27(5):1527. doi: 10.3390/molecules27051527.
This study expands and combines concepts from two of our earlier studies. One study reported the complementary halogen bonding and π-π charge transfer complexation observed between isomeric electron rich 4-,-dimethylaminophenylethynylpyridines and the electron poor halogen bond donor, 1-(3,5-dinitrophenylethynyl)-2,3,5,6-tetrafluoro-4-iodobenzene while the second study elaborated the ditopic halogen bonding of activated pyrimidines. Leveraging our understanding on the combination of these non-covalent interactions, we describe cocrystallization featuring ditopic halogen bonding and π-stacking. Specifically, red cocrystals are formed between the ditopic electron poor halogen bond donor 1-(3,5-dinitrophenylethynyl)-2,4,6-triflouro-3,5-diiodobenzene and each of electron rich pyrimidines 2- and 5-(4-,-dimethyl-aminophenylethynyl)pyrimidine. The X-ray single crystal structures of these cocrystals are described in terms of halogen bonding and electron donor-acceptor π-complexation. Computations confirm that the donor-acceptor π-stacking interactions are consistently stronger than the halogen bonding interactions and that there is cooperativity between π-stacking and halogen bonding in the crystals.
本研究扩展并结合了我们之前两项研究的概念。一项研究报告了电子给体异构 4-，-二甲氨基苯乙炔基吡啶与电子受体卤键供体 1-（3,5-二硝基苯乙炔基）-2,3,5,6-四氟-4-碘苯之间观察到的互补卤键和 π-π电荷转移络合，而第二项研究则详细阐述了活化嘧啶的双位点卤键。利用我们对这些非共价相互作用的组合的理解，我们描述了具有双位点卤键和 π-堆积的共结晶。具体来说，电子受体卤键供体 1-（3,5-二硝基苯乙炔基）-2,4,6-三氟-3,5-二碘苯与电子给体富嘧啶 2-和 5-（4-，-二甲氨基苯乙炔基）嘧啶之间形成红色共晶。这些共晶的 X 射线单晶结构根据卤键和电子给体-受体 π-络合进行了描述。计算证实，供体-受体 π-堆积相互作用始终强于卤键相互作用，并且在晶体中存在 π-堆积和卤键之间的协同作用。
