Li Mingxue, Sun Qiaozhen, Bai Yan, Duan Chunying, Zhang Bingguang, Meng Qingjin
Coordination Chemistry Institute, State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing, 210093, PR China.
Dalton Trans. 2006 Jun 7(21):2572-8. doi: 10.1039/b514425f. Epub 2006 Mar 6.
Chiral aggregation and spontaneous resolution of thiosemicarbazone metal complexes MnL2 (1 and 1') (HL = acetylpyrazine thiosemicarbazone) were achieved through cooperation of hydrogen bonding and pi-pi stacking interactions. Compound 1 crystallized in a chiral space group P4(1)2(1)2 and the molecules exhibited lambda-configuration. Head-to-tail pyrazine-amino hydrogen bonding linked the molecules together presenting a two-dimensional homochiral sheet. The interlayer pi-pi stacking interactions linked the layers in a homochiral array and extended the 2D homochirality to a three-dimensional network. Compound 1 crystallized in space group P4(3)2(1)2, the opposite handedness of P4(1)2(1)2. The molecules, the two-dimensional hydrogen-bonded sheets and the three-dimensional network all exhibited the opposite chiralities to those of 1. Solid state CD spectra measurements confirmed the occurrence of spontaneous resolution of MnL2 and demonstrated that one of the enantiomers of the compound was always in excess. The zinc complexes (2 and 3) and nickel complex 4 crystallized in the chiral space group P4(3)2(1)2. Similar two-dimensional pyrazine-amine hydrogen bonded chiral sheets and three-dimensional networks were found in the crystal packing patterns. The cadmium complex 5 crystallized in a chiral space group P2(1)2(1)2(1), however, it exhibited a similar chiral packing pattern. The only difference was that enlarged Cd-S and Cd-N bond lengths induced the potential 4(1) symmetry. All results indicated that the supramolecular synthon, the cooperation of the pyrazine-amino hydrogen bonding and the pi-pi stacking interactions, were robust enough so that the orientation of the molecules in the solid state could be predicted to a reasonable degree of accuracy.
通过氢键和π-π堆积相互作用的协同作用，实现了硫代碳酰腙金属配合物MnL2（1和1'）（HL = 乙酰基吡嗪硫代碳酰腙）的手性聚集和自发拆分。化合物1结晶于手性空间群P4(1)2(1)2中，分子呈现λ-构型。头对头的吡嗪-氨基氢键将分子连接在一起，形成二维同手性片层。层间π-π堆积相互作用以同手性阵列连接各层，并将二维同手性扩展为三维网络。化合物1结晶于空间群P4(3)2(1)2中，与P4(1)2(1)2相反的手性。分子、二维氢键片层和三维网络均呈现出与1相反的手性。固态圆二色光谱测量证实了MnL2的自发拆分的发生，并表明该化合物的一种对映体总是过量的。锌配合物（2和3）和镍配合物4结晶于手性空间群P4(3)2(1)2中。在晶体堆积模式中发现了类似的二维吡嗪-胺氢键手性片层和三维网络。镉配合物5结晶于手性空间群P2(1)2(1)2(1)中，然而，它呈现出类似的手性堆积模式。唯一的区别是，增大的Cd-S和Cd-N键长诱导了潜在的4(1)对称性。所有结果表明，超分子合成子，即吡嗪-氨基氢键和π-π堆积相互作用的协同作用，足够强大，以至于可以在合理的精度范围内预测分子在固态中的取向。
