Supramolecular and heterometallic architectures based on [Fe(CN)6]3− metallotectons and diverse organic cations: Crystal structure, Hirshfeld surface analysis, spectroscopic and thermal properties
Résumé
An assembly involving [Fe(CN)6]3− metallotectons as building units and organic cations of different geometry has been envisioned in order to elaborate three hybrid supramolecules based on ionic H-bonds with the formula {(H-pip)(H2-pip)[Fe(CN)6]}∙5H2O (1)SPS:refid::e1, {(H-amtaz)3[Fe(CN)6]}∙2H2O (2), {(H-mel)4[Fe(CN)6]F}∙H2O (3) ([H-pip]+ = H-piperazine; [H2-pip]2+ = H2-piperazine; [H-amtaz]+ = H-4-amino-1.2.4-triazole; [H-mel]+: H-melamine and [H-gua]+ = H-guanidine) and one three-dimensional heterometallic network {(H-gua)2K[Fe(CN)6]} (4). The compounds have been prepared by the slow evaporation method and characterized by single-crystal X-ray diffraction, Energy Dispersive X-ray Spectroscopy analysis (EDX), and Raman IR spectroscopy with assignment from ab initio calculations. Single crystal X-ray diffraction reveals that 1–3 present supramolecular networks, while 4 belongs to the 3D heterometallic polymers group characterized by continuous tunnels containing [H-gua]+ cations. Based on different intermolecular hydrogen bonding (simple and charge-supported) and π-stacking interactions, compounds 1–3 further assembled into 2D and 3D supramolecular frameworks. Water molecules in compounds 1 and 2 are encapsulated in nearly closed cavities while compound 3 is practically non-porous. The thermogravimetric analyses (TGA) show that these complexes possess appreciable thermal stability.