Insights on the synthesis and organisational phenomena of twisted pyrazine–pyridine hybrids
作者:Fenton Heirtzler、Markus Neuburger、Klaus Kulike
DOI:10.1039/b107751a
日期:2002.3.8
Pyrazineâpyridine hybrids containing two different oligopyridyl chains, 2,3-disubstituted onto the pyrazine ring nucleus are prepared from appropriate mixed α-diketone precursors. The latter were obtained by epoxidation of the enols of corresponding 1,2-disubstituted ethanones. The structures of the pyrazine derivatives were investigated by detailed proton NMR spectroscopic and X-ray crystallographic methods. These indicated a twisting of the oligopyridyl chains about one another to result in a pre-double helical topology. This phenomenon occurred up to two pyridin-2,6-diyl groupings from the pyrazine ring and is accompanied by edge-on-face stacking of spatially proximate pyridyl rings. Parallel stacking of pyrazine and weak CâHâ¯N acid interactions are significant in their crystal lattices and may also figure in their metallosupramolecular self-assembly behaviour patterns.
通过适当的混合α-二酮前体,制备了含有两种不同寡吡啶链的吡嗪-吡啶杂化物,这些杂化物在吡嗪环核上进行2,3-二取代。后者是通过相应1,2-二取代乙酮的烯醇的环氧化反应获得的。通过详细的质子核磁共振光谱学和X射线晶体学方法研究吡嗪衍生物的结构。这些研究表明寡吡啶链相互扭曲,形成预双螺旋拓扑结构。这种现象发生在距离吡嗪环最多两个吡啶-2,6-二基基团处,并伴随着空间上接近的吡啶环的边缘面对堆积。吡嗪的平行堆积和弱的C-H…N酸性相互作用在其晶格中具有重要意义,并可能在其金属超分子自组装行为模式中发挥作用。