Chemical preparation, crystal structure, Hirshfeld surface analysis, spectroscopy, DFT studies, thermal decomposition and magnetic measurements of (C4H12N2)[FeCl3(H2O)3]Cl2

The title compound is an organic-inorganic hybrid material of formula (C4H12N2)[FeCl3(H2O)3]Cl2. The single crystal X-ray diffraction investigation reveals that the studied compound crystallizes in the monoclinic system, space group P21/m with the following unit cell dimensions: a = 6.8890(16) Å, b = 16.0298(38) Å, c = 7.0524(17) Å, β = 112.819(5)°, V = 717.8(3) Å3 and Z = 4. The crystal structure, refined down to R = 0.05, is composed of [FeCl3(H2O)3] octahedra, piperazinediium cations and chloride anions. The structure cohesion is achieved by hydrogen bonds established between the different entities. The 0D structure can be described as an alternation between organic and inorganic pseudo layers along the crystallographic b-axis. Raman and infrared spectra of the title compound were recorded in the range of 50–4000 and 400–4000 cm−1, respectively. For more reliability, Density Functional Theory calculations were performed in order to check the molecular structure and the vibrational spectra of the investigated molecule in the ground state. Good agreement between calculated structural parameters and single crystal XRD data leading to an appropriate assignment of the IR and Raman observed vibrational modes. The thermal behavior of the compound, studied by TG, showed that the successive decomposition stages of precursor lead to the formation of intermediate phases during heating giving rise to the iron oxide as a final product at 900 °C. The magnetic measurements show that the title compound is predominantly paramagnetic with antiferromagnetic interactions