Crystal structure and Hirshfeld surface analysis of bis{( Z )- N 000 -[( E )-(furan-2-yl)methylidene]carbamo-hydrazonothioato}nickel(II) methanol disolvate

In the title complex, [Ni(C6H6N3OS)2]·2CH3OH, the NiII atom is coordinated by the S and N atoms of two N′-[(Z)-(furan-2-yl)methylidene]carbamohydrazonothioic acid ligands in a distorted square-planar geometry. The two mutual ligands bound to NiII are also connected by C—H...S interactions, while the H atoms of the NH2 group of the ligands form R
 4
 4(8) motifs with the O atoms of the solvent ethyl alcohol molecules. At the same time, the OH groups of the solvent ethyl alcohol molecules form parallel layers to the (011) plane by the O—H...N interactions with the ligand N atom that is not bonded to the NiII atom.. The layers are connected by van der Waals interactions. A Hirshfeld surface analysis indicates that the most important contacts are H...H (37.7%), C...H/H...C (14.6%), O...H/H...O (11.5%) and S...H/H...S (10.6%).


Chemical context
Hydrazones have been used extensively as substrates in organic synthesis (Polyanskii et al., 2019;Shikhaliyev et al., 2019;Safavora et al., 2019;Zubkov et al., 2018) and multidentate ligands (Gurbanov et al., 2020a,b;Gurbanov et al., 2022) while their complexes have been found to possess a wide variety of useful properties. Thus, they can be used as sensor or analytical reagents, catalysts and building blocks in crystal engineering (Ma et al., 2021;Mahmudov et al., 2010;Mahmoudi et al., 2017a,b). Not only because of their coordination ability, but also the attached substituents, the intermolecular non-covalent interactions direct the functional properties as well as the supramolecular chemistry of hydrazones (Abdelhamid et al., 2011;Khalilov et al., 2021;Kopylovich et al., 2011;Mahmudov et al., 2015;). In fact, hydrogen and chalcogen bonds and other types of weak interactions have been well employed in the decoration of the secondary coordination sphere of transition-metal complexes (Mahmoudi et al., 2019;Mahmudov et al., 2012Mahmudov et al., , 2022. We have synthesized a new Ni II complex of a (E)-2-(furan-2-ylmethylene)hydrazine-1-carbothioamide ligand and studied its crystal structure. Fig. 1 shows the arrangement of the complex molecules in the unit cell. The Ni II atom is coordinated by the S and N atoms of two N 0 -[(Z)-(furan-2-yl)methylidene]carbamohydrazonothioic acid ligands in a distorted square-planar geometry. The ligands assume a trans arrangement with respect to each other around the Ni II ion, which lies on a crystallographic inversion centre at (Àx + 1, Ày, Àz + 1). The Ni-S [2.1818 (6) Å ] and Ni-N [1.9055 (17) Å ] bond lengths lie within the range of those found in related structures.

Supramolecular features and Hirshfeld surface analysis
In the crystal, the two mutual ligands bound to Ni II are also linked by C-HÁ Á ÁS interactions, while the H atoms of the NH 2 group of the ligands form R 4 4 (8) motifs (Bernstein et al., 1995; Tables 1 and 2; Fig. 2) with the O atoms of the solvent ethyl alcohol molecules. At the same time, the OH groups of the solvent ethyl alcohol molecules form parallel layers to the (011) plane by the O-HÁ Á ÁN interactions with the ligand N atom that is not bonded to the Ni II atom (Figs. 2, 3 and 4). These layers are connected by van der Waals interactions.
A Hirshfeld surface analysis was carried out using Crystal-Explorer 17.5 (Spackman et al., 2021) to analyse the intermolecular interactions. The three-dimensional Hirshfeld surface mapped over the normalized contact distance (d norm ) is shown in Fig. 5. The bright-red spots indicate shortened contacts, and correspond to the O-HÁ Á ÁN and N-HÁ Á ÁO intermolecular hydrogen bonds.

Figure 2
A view along the a axis of the crystal packing of the title compound. The O-HÁ Á ÁN, N-HÁ Á ÁO and C-HÁ Á ÁS hydrogen bonds are shown as dashed lines.

Figure 3
A view along the b axis of the crystal packing of the title compound, with hydrogen bonds indicated by dashed lines.

Database survey
A search of the Cambridge Structural Database (ConQUEST version 2022 3.0; Groom et al., 2016) for one of the Ni atoms plus ligands in the title compound yielded 14 structures that have the same framework as the title compound. FUTRAN (Puranik et al., 1987) appears to be the same structure, without any solvent, and NOQCUS (Rodríguez-Argü elles et al., 2009) is the same with a dimethyl sulfoxide solvent molecule; the other 12 have alkyl or phenyl groups attached.
In the crystal of FUTRAN, Ni II is in the distorted square planar ligand field of the N 2 S 2 chromophore. The thiosemicarbazonato group is planar with Ni-S = 2.149 (1) Å and Ni-N(2) = 1.921 (2) Å . The coordination around Ni is trans planar with respect to the two S and two N atoms. The furan ring plane is at an angle of 3(1) to the coordination plane. In the crystal of NOQCUS, the coordination environment around the nickel(II) ion is totally planar, as the NiN 2 S 2      Table 2 Summary of short interatomic contacts (Å ) in the title compound.

Figure 4
A view along the c axis of the crystal packing of the title compound, with hydrogen bonds indicated by dashed lines. chromophore lies on its least-squares calculated plane and the four angles formed by the metal centre with the four donor atoms add up to exactly 360 . The Ni-N and Ni-S distances are within the usual range. This plane forms a 18 angle with the uncoordinated furan ring, which is also highly planar.

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 3. C-bound H atoms were positioned geometrically (C-H = 0.93 and 0.96 Å ) and refined using a riding model with U iso (H) = 1.2 or 1.5U eq (C). O-and N-bound H atoms were located in difference Fourier maps [O2-H2O = 0.90 Å , N3-H3A = 0.90 Å , N3-H3B = 0.90 Å ] and refined with U iso (H) = 1.2U eq (N) and 1.5U eq (O), with their positions fixed. Two reflections (001) and (010)   Special details Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.