Di-μ-chlorido-bis[(2,2′:6′,2′′-terpyridine-κ3 N,N′,N′′)copper(II)] bis(trifluoromethanesulfonate)

The crystal structure of the centrosymmetric complex [Cu(terpy)2Cl2](OTF)2 consists of a CuII metal center in a distorted square-pyramidal geometry with π–π stacking interactions contributing to the crystal packing.


Structure description
Terpyridines are some of the most studied nitrogen-based tridentate ligands in coordination chemistry, and their metal complexes have found application in catalysis (Wei et al., 2019;Choroba et al., 2019), supramolecular chemistry (Wei et al., 2019), and medicinal chemistry (Glišić et al., 2018;Malarz et al., 2021;Li et al., 2020). Recently, copper(II) terpyridine complexes have received much attention due to their remarkable cytotoxicity and ability to interact with DNA (Karges et al., 2021); herein, we report the synthesis and structure of the title copper(II) terpyridine complex.
The asymmetric unit of the title compound, depicted in Fig. 1, consists of half of a centrosymmetric dication [Cu(terpy) 2 Cl 2 ] 2+ and one trifluoromethanesulfonate ion completing the outer coordination sphere. The Cu-N, and Cu-Cl distances, as well as, the Cl-Cu-Cl, N-Cu-Cl and N-Cu-N angles are in good agreement with the reported values in similar copper(II) terpyridine complexes currently available in the CSD (version 5.42 with update September 2021; Rojo et al., 1987;refcode FECJEC; data reports Valdé s-Martínez et al., 2002;refcode HULZAP;Gasser et al., 2004;refcode HULZAP01). All relevant bond lengths and angles involving the Cu atom are presented in Table 1.
In the crystal packing of the title compound,stacking interactions between the N1 and N3 pyridyl ring of adjacent molecules are observed, with a centroid-to-centroid (CgÁ Á ÁCg) distance of 3.658 (1) Å and an offset distance of 1.723 Å . No other supramolecuar interaction is present in the crystal packing of the title compound.

Figure 2
Perspective view of the packing structure of the title complex along the crystallographic a-axis; H atoms are omitted for clarity.

Figure 1
The molecular structure of the title compound with displacement ellipsoids drawn at the 50% probability level; H atoms are omitted for clarity. Symmetry operator for generating equivalent atoms: (i) 1 À x, 1 À y, 1 À z.
0.429 mmol) and filtration using a 0.45 mm PTFE syringe filter. Crystals suitable for X-ray diffraction of the title compound were obtained by vapor diffusion of diethyl ether over the resulting acetonitrile solution at 278 K.

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 2. H atoms were located in a difference map and refined in idealized positions using a riding model with atomic displacement parameters of U iso (H) = 1.2U eq (C) and with a C-H distance of 0.95 Å .

data-1
IUCrData (  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.

data-2
IUCrData (2021). 6, x211096 Refinement. H atoms were located in a difference map and refined in idealized positions using a riding model with atomic displacement parameters of U iso (H) = 1.2U eq (C) and with a C-H distance of 0.95 Å.