Vol.:(0123456789) 1 3 Journal of the Iranian Chemical Society https://doi.org/10.1007/s13738-018-1454-4 ORIGINAL PAPER Synthesis of [MnCl 3 (H 2 O) 2 (Hatz)]·H 2 O and investigation of its structure via X-ray diffraction, spectroscopic measurements and DFT calculations Sabri Hassen 1  · Hammouda Chebbi 2,3  · Mohamed Faouzi Zid 3  · Youssef Arfaoui 1 Received: 26 February 2018 / Accepted: 14 July 2018 © Iranian Chemical Society 2018 Abstract The 3-amino-1,2,4-triazole (atz)-based manganese complex was prepared and characterized through single-crystal X-ray diffraction, IR, EPR, and UV–visible spectroscopy. In the crystal structure, individual complex are interconnected through N(O)–H…Cl hydrogen bonds into 1D undulating chains running parallel to the [110] direction of the unit cell. Chains further grow into 2D supramolecular layers by way of the lattice water molecules of coordination and the chloride anions (O–H… Cl). Layers pack along the b-axis of the unit cell mediated by O–H…Cl(N) and N–H…O(Cl) hydrogen bonds forming a 3D supramolecular architecture. The theoretical calculations were also performed to optimize the structure of the complexes in the gas phase to confirm the structures proposed by X-ray crystallography. In addition, IR and UV–visible spectra of com- plex were calculated and compared with the corresponding experimental spectra to complete the experimental structural identification. The three-dimensional Hirshfeld surface (3D-HS) and their relative two-dimensional fingerprint plots (2D-FP) reveal that the structure is dominated by H…Cl/Cl…H (50.5%), H…O/O…H (11.3%) and N…O/O…N (10.2%) contacts. Keywords Manganese complex · Crystal structure · Infrared · DFT · Hirshfeld surface Introduction The rational strategy to design new coordination complexes, especially metal–organic frameworks (MOFs) or coordination networks, by self-assembly has received remarkable inter- est due to their fascinating structural features and potential to be applied as novel functional materials [1–3]. The final assembly can be influenced by numerous factors, such as geo- metric requirements of metal centers, shape and nature of the ligands, reaction routes, solvents, templates, pH of the reactive medium and counterions [4–6]. In particular, manganese-based complexes have been investigated for their biological, catalytic, magnetic, and electrochemical applications [7–11]. One fruitful selection of the organic building units relies on five-membered N-heterocycles, such as pyrazole, imida- zole, triazole, and tetrazole, which are good representatives for small and simple organic bridging ligands. 1,2,4-Tria- zole residues, presenting a hybrid of pyrazole and imida- zole, represent a class of ligands that can combine different substituent groups, thus constituting a good building block for the preparation of metal complexes and materials with structural, optical and magnetic properties [12–15]. Herein, 3-amino-1,2,4-triazole (atz), comprising a triazole ring with three N-donors, was chosen as the organic building unit. To the best of our knowledge, only a few 3-amino-1,2,4-triazole (atz) based Mn(II) complexes have been investigated [16–18]. In this study, we report the synthesis of a new Mn(II) coordination compound with the protonated 3-amino-1,2,4- triazole (Hatz) ligand, chloride ion and water molecules of coordination. The prepared compound was identified by IR, EPR, and UV–visible spectroscopy. The structure of [MnCl 3 (H 2 O) 2 (Hatz)]·H 2 O (I) was determined from X-ray crystallography. In addition, density functional the- ory (DFT) calculations were performed to optimize the * Hammouda Chebbi chebhamouda@yahoo.fr 1 Laboratory of Physical Chemistry of Condensed Materials, Faculty of Sciences of Tunis, University of Tunis El Manar, El Manar II, 2092 Tunis, Tunisia 2 Preparatory Institute for Engineering Studies of Tunis, University of Tunis, Street Jawaher Lel Nehru, Montfleury, 1089 Tunis, Tunisia 3 Laboratory of Materials, Crystal Chemistry and Applied Thermodynamics, Faculty of Sciences of Tunis, University of Tunis El Manar, El Manar II, 2092 Tunis, Tunisia