Comprehensive structural studies of molecules and crystalline networks of new ferrocene-based thiosemicarbazones

Two newly Schiff base conjugates formulated as C22H25FeN3S (1) and C19H16Cl3FeN3S (2) were synthesized by the facile condensation method of acetylferrocene with appropriate acidic ethanolic solution of thiosemicarbazides used as catalyst which protonate the carbonyl group present on ferrocene. The structures of these conjugates were determined by spectroscopic techniques of Infrared, H-1 NMR, C-13 NMR, Mass spectrometry, and single crystal X-ray diffraction. The crystal packings are stabilized with the sparse network of hydrogen bonds and stacking interactions. DFT-D/B3LYP high level calculations confirmed the main role of N-H center dot center dot center dot S, C-H center dot center dot center dot N, and C-H center dot center dot center dot Cl non-conventional hydrogen bonds especially the first one in the stabilization of the pertaining 1-net and 2-net networks. The presence of big chlorine substituting atoms in 2, along with change of the spatial direction of the aryl ring plane relating to thioamide and ferrocenyl moieties, makes different C-H center dot center dot center dot Cl hydrogen bonds in 2-net. However, DFT-D and AIM computational results with the good consistency about measurement of binding energy interactions, show that hydrogen bonds especially N-H center dot center dot center dot S ones have the bigger contribution in the network construction than stacking interactions.

Automated summary

Two Schiff base conjugates (1 and 2) were synthesized by condensation method with acetylferrocene and acidic ethanolic solution of thiosemicarbazides. The structures of these conjugates were determined by spectroscopic techniques and X-ray diffraction. The hydrogen bonds and stacking interactions played important roles in the stabilization of crystal packings. N-H...S, C-H...N, and C-H...Cl hydrogen bonds were observed in the networks, with N-H...S ones having the bigger contribution than stacking interactions.