A two-dimensional copper(I) coordination polymer based on 1-[2-(cyclohexylsulfanyl)ethyl]pyridin-2(1H)-one

The structure of the title copper(I) coordination polymer is reported. One CuI atom is surrounded by three μ3-iodide anions and one S atom, while the other is coordinated by three μ3-iodide ions an O atom. In the crystal, there are intermolecular C—H⋯I hydrogen bonds and C—H⋯π interactions between ligands. The packing generates a two-dimensional brick-wall structure.


Chemical context
Copper(I) complexes have been studied continuously over several decades because of their potential applications as sensors, catalysts, and gas storage materials (Lin et al., 2016;Ananthnag et al., 2015;Pal et al., 2015). They exhibit a variety of structures, photoluminescence, and other physical properties as a result of the d 10 electron configuration of Cu I (Peng et al., 2010;Ford et al., 1999;Kobayashi & Kato, 2017). In addition, the arrangement of donor atoms in the ligands may affect both the structures of the complexes and their physical properties. Copper(I) complexes of flexible ligands with N/S donor atoms have been studied (Jeon et al., 2014;Cho et al., 2015). Mechanochromism, vapochromism and solvatochromism of such complexes have also been reported Kang et al., 2015;Kim et al., 2013). Herein we describe the synthesis and crystal structure of a copper(I) complex [Cu 4 I 4 L 2 ] n of L (C 13 H 19 NOS) with O/S donor atoms. Cu I -O bonds have been reported previously in copper(I) coordination polymers with phosphine ligands (Darensbourg et al., 1998) but those with an O/S donor ligand set are unique as far as we know.

Database survey
Syntheses and properties of the copper(I) complexes of N/S mixed donor atom ligands have been reported (Jeon et al., 2014;Cho et al., 2015). Copper(I) complexes of N/S mixeddonor atom ligands with cyclohexyl group have also been reported (Park et al., 2016(Park et al., , 2017. In addition, a database search (CSD Version 5.27, last update February 2017; Groom et al., 2016) showed the crystal structures of three complexes with infinite stair-step (CuI) n cluster units (Jess et al., 2007;Jess & Nä ther, 2004;Graham et al., 2000).

Figure 1
The molecular structure of the title compound, with the atom labelling and displacement ellipsoids drawn at the 50% probability level. H atoms are shown as small spheres of arbitrary radius.
Cg1 is the centroid of the N2/C22-C26 ring ethylcyclohexylsulfide. 2-Hydroxypyridine (1.90 g, 20 mmol) and potassium hydroxide (1.12 g, 20 mmol) were dissolved in 10 ml of tetrahydrofuran and 5 ml of water, and then the solution was added dropwise to the crude chloride. The solution was refluxed for 24 h and cooled. The crude product was extracted by dichloromethane. The dichloromethane layer was dried with anhydrous Na 2 SO 4 , and evaporated to give a crude oil. Column chromatography (silica gel, MeCOOEt/n- The two-dimensional brick-wall networks are stacked in an Á Á ÁabababÁ Á Á fashion along [001]. All H atoms have been omitted for clarity.

Figure 2
A packing diagram showing the intermolecular C-HÁ Á ÁI hydrogen bonds (yellow dashed lines) and C-HÁ Á Á interactions (red dashed lines) between ligands. H atoms have been omitted for clarity.
Preparation of [Cu 4 I 4 L 2 ] n A dichloromethane (5 ml) solution of L (0.006 g, 0.025 mmol) was allowed to mix with an acetonitrile (5 ml) solution of CuI (0.010 g, 0.053 mmol). The colourless precipitate was filtered and washed with a diethyl ether/acetonitrile (5/1 v/v) solution. Single crystals suitable for X-ray analysis were obtained by slow evaporation of dichloromethane from the reaction mixture.

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 3. All H atoms were positioned geometrically and refined using a riding model, with C-H = 0.95 Å and U iso (H) = 1.2U eq (C) for aromatic C-H groups, C-H = 0.99 Å and U iso (H) = 1.2U eq (C) for CH 2 groups, and C-H = 1.00 Å and U iso (H) = 1.2U eq (C) for Csp 3 -H groups.

Poly[bis{µ 2 -1-[2-(cyclohexylsulfanyl)ethyl]pyridin-2(1H)-one}tetra-µ 3 -iodidotetracopper(I)]
Crystal data 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.