Crystalline Inclusion Compounds Constructed through Self-Assembly of Isonicotinic Acid and Thiocyanato Coordination Bridges

The synthesis, crystal structures, inclusion ability, and structural robustness of novel crystalline
inclusion compounds of [Ni(SCN)2(isoH)2]·xG (isoH = isonicotinic acid; G = aromatic guest) are described.
The inclusion compounds are constructed by stacking identical 2D host layers that consist of SCN-, isoH,
and Ni2+ with van der Waals contact separation. In the layer, two types of rectangular cavities (A-type and
B-type) are formed, and the guests are included in the former cavity. The inclusion compounds were
categorized into four stacking modes according to the difference in the stacking mode of the layers. A
systematic investigation of the crystal structures of the 21 inclusion compounds clarified the close relationship
between the molecular structure of the guest and the resultant stacking mode of the layers.

本文报道了[Ni(SCN)₂(isoH)₂]·xG（其中isoH为异烟酸(isonicotinic acid)，G为芳香客体(aromatic guest)）这类新型结晶包合化合物的合成、晶体结构、包合能力与结构稳定性。该类包合化合物由完全相同的二维主体层(2D host layers)堆叠构筑而成，主体层由硫氰根离子(SCN⁻)、异烟酸与镍(II)离子(Ni²⁺)构成，层间以范德华接触间距(van der Waals contact separation)实现相互作用。在单一层结构内，会形成两种矩形空腔(rectangular cavities)，分别为A型与B型，客体分子被包合于A型空腔中。研究人员根据层间堆积模式的差异，将该类包合化合物划分为四种堆积类型。对21种包合化合物晶体结构的系统性研究，阐明了客体分子结构与最终层间堆积模式之间的紧密关联。