Molecular interactions of ferrocenyl hydrazones (FcHZ) inclusion complexes with β-cyclodextrin (BCD), methyl-β-cyclodextrin (MEB), 2,6-di-O-methyl-β-cyclodextrin (DIMEB) and 2,3,6-tri-O-methyl-β-cyclodextrin (TRIMEB) in order to enhance their aqueous solubility and anti-mycobacterial efficiency were investigated by semi-empirical PM7 method and B3LYP/m6-31G* calculations. Simulation results suggest the complex formations of FcHZ with BCD, MEB, DIMEB and TRIMEB are possible with 1:1 host–guest molecular ratio. Two different binding modes of the FcHZ inside the BCD and MEB cavities were found. The ferrocene fragment of FcHZ molecule was entrapped in the cavity, located near the wider rim of BCD and MEB in both orientations (A and B). The hydrazone aromatic fragment of FcHZ cannot be completely embedded inside the hydrophobic cavity of BCD. It points downward from the narrower rim of BCD in orientation A and point upward from the wider rim of BCD in orientation B. Only orientation B was found in 1:1 inclusion complex of FcHZ agents with DIMEB and TRIMEB due to the effect of methyl group substitutions at the primary hydroxyl groups, which located at the narrower rim of cyclodextrins. The entering pathways of the FcHZ molecule into the molecular cavity of the BCD, MEB, DIMEB and TRIMEB were also discussed.

中文翻译：

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二茂铁腙与β-环糊精及其三个甲基化衍生物包合物的理论研究

二茂铁腙 (FcHZ) 包合物与 β-环糊精 (BCD)、甲基-β-环糊精 (MEB)、2,6-二-O-甲基-β-环糊精 (DIMEB) 和 2,3,6- 的分子相互作用为了提高其水溶性和抗分枝杆菌效率，通过半经验 PM7 方法和 B3LYP/m6-31G* 计算研究了三-O-甲基-β-环糊精（TRIMEB）。模拟结果表明 FcHZ 与 BCD、MEB、DIMEB 和 TRIMEB 的复杂形成是可能的，主客体分子比为 1:1。发现 BCD 和 MEB 腔内 FcHZ 的两种不同结合模式。FcHZ 分子的二茂铁片段被困在空腔中，位于两个方向（A 和 B）上 BCD 和 MEB 的较宽边缘附近。FcHZ 的腙芳香族片段不能完全嵌入 BCD 的疏水腔内。它在方向 A 从 BCD 较窄的边缘向下指向，在方向 B 从 BCD 的较宽边缘向上指向。 由于甲基的影响，在 FcHZ 试剂与 DIMEB 和 TRIMEB 的 1:1 包合物中仅发现方向 B位于环糊精较窄边缘的伯羟基上的取代。还讨论了FcHZ分子进入BCD、MEB、DIMEB和TRIMEB分子腔的途径。