Structural, Hirshfeld surface and spectroscopic studies of the noncentrosymmetric 1-ethylpiperazinediium pentachloroantimonate (III) monohydrate

• A new organic-inorganic material, C6H18N2SbCl5·H2O, was synthesized.
• The new compound consists of isolated [C6H14N2]2+ cations, square pyramidal [SbCl5]2− anions and lattice water molecules.
• The crystal packing is ensured by hydrogen bonds.
• The Hirshfeld surface analysis reveals the percentage of intermolecular contacts of the title compound.
• This material was also investigated by IR, and CP-MAS NMR spectroscopy.

1-Ethylpiperazinediium pentachloroantimonate (III) monohydrate, C6H16N2SbCl5·H2O, has been synthesized by the reaction of antimony trioxide (Sb2O3) and 1-ethylpiperazine in an aqueous solution of hydrochloric acid. The structure crystallizes in orthorhombic system, in the non-centrosymmetric space group Pca21 and consists of isolated [C6H16N2]2+ cations, square pyramidal [SbCl5]2− anions and lattice water molecules. OH⋯Cl hydrogen bonds link the [SbCl5]2− anions and water molecules to form double chains stretching along the [101] direction. The chains in turn are linked to the organic cations via NH⋯Cl, CH⋯Cl, CH⋯O and NH⋯O hydrogen bonds to form a three-dimensional network. This structure presents an example of a general square pyramidal complex ion containing a stereo-chemically active lone pair of electrons. Solid state 13C and 15N CP-MAS NMR spectra are in agreement with the X-ray structure, and vibrational absorption bands were identified by infrared spectroscopy. DFT calculations allowed the attribution of the NMR peaks and IR absorption bands. The interactions variability of the two independent cations and ten chloride atoms is analyzed via Hirshfeld surface analysis.

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