Two crystals of quinolizidine compounds; systematic name: (rac)-(7,8,9,9a)-tetrahydro-4H-thieno[2,3-b]quinolizine-6,10-dione, (I), and (rac)-(9a,10)-10-hydroxy-8,9,9a,10-tetrahydro-4H-thieno[2,3-b]quinolizin-6(7H)-one, (II), have been compared and characterized by single-crystal X-ray diffraction and electronic analysis. N-heterocyclic rings in both structures are not planar and adopt a half-chair conformation. The molecules of (I) are linked via weak C–H···O hydrogen bonds into chains along c axis. While the crystal stacks in compound (II) are formed by strong O–H···O hydrogen bonds the molecules link into infinite zig-zag chains along the b axis. In both crystal structures, π–π stacking and C–H···π interactions are also observed. Calculation of the net atomic charges shows that O atoms in both compounds carry a relatively large negative charges, in comparison with the corresponding H atoms. Crystal, molecular and electronic structures of these compounds, which are influenced by hydrogen-bonded assemblies in the molecular crystals, are discussed in detail.Graphical AbstractCrystal, molecular and electronic structures of two related tricyclic compounds containing thienoquinolizidine ring skeleton, both structures have similar quinolizine ring moieties assuming conformations resembling half-chair.

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两种相关的噻吩并喹唑啉及其晶体、分子结构和电子性质

喹唑啉化合物的两个晶体；系统名称：(rac)-(7,8,9,9a)-tetrahydro-4H-thieno[2,3-b]quinolizine-6,10-dione, (I), and (rac)-(9a,10) )-10-羟基-8,9,9a,10-四氢-4H-thieno[2,3-b]quinolizin-6(7H)-one，(II)，已通过单晶X-射线衍射和电子分析。两种结构中的 N-杂环都不是平面的，而是采用半椅式构象。(I) 的分子通过弱的 C-H···O 氢键连接成沿 c 轴的链。虽然化合物 (II) 中的晶体堆叠是由强 O-H···O 氢键形成的，但分子沿 b 轴连接成无限的锯齿形链。在这两种晶体结构中，还观察到 π-π 堆积和 C-H……π 相互作用。净原子电荷的计算表明，两种化合物中的 O 原子都带有较大的负电荷，与相应的 H 原子进行比较。详细讨论了这些化合物的晶体、分子和电子结构，这些结构受分子晶体中氢键组装的影响。 图文摘要 含有噻吩并喹唑啉环骨架的两种相关三环化合物的晶体、分子和电子结构，两种结构都具有相似的喹啉环部分呈现类似于半椅的构象。