Crystal structure of fac-aqua[(E)-4-(benzo[d]thiazol-2-yl)-N-(pyridin-2-ylmethylidene)aniline-κ2 N,N′]tricarbonylrhenium(I) hexafluoridophosphate methanol monosolvate

A structural trans effect study and the packing arrangement of a fac-tricarbonyl ReI ‘2 + 1’ mixed-ligand complex are reported.


Structural commentary
The asymmetric unit of the title compound comprises one facaquatricarbonyl-(E)-4-(benzo[d]thiazol-2-yl)-N-(pyridin-2-ylmethylidene)aniline-rhenium(I) complex molecule, one PF 6 À counter-anion and one methanol solvent molecule (Fig. 1). Within the complex, the Re I atom presents a distorted octahedral C 3 N 2 O coordination set with the three tricarbonyl ligands in facial and the bidentate diimine (NNbz) and the monodentate water ligands in a cis arrangement (Fig. 1). The two coordinating nitrogen atoms N1 and N2 of the bidentate NNbz ligand together with two carbonyl carbon atoms define the equatorial plane with almost perfect planarity (deviation from the least-squares plane = 0.006 Å ). The Re-N1 and Re-N2 distances are 2.177 (2) and 2.194 (2) Å , respectively. The oxygen atom of the water molecule [Re-O1W = 2.189 (2) Å ] and the carbon atom from the third carbonyl ligand define the axial direction of the octahedron. Both the Re-N and the Re-O distances fall in the range of observed values in complexes with a diimine, aqua or tricarbonyl core (Mella et al., 2016;Connick et al., 1999;Schutte et al. 2011;Salignac et al., 2003;Knopf et al., 2017;Rillema et al., 2007;Barbazá n et al., 2009;Carrington et al., 2016;Tzeng et al., 2011;Grewe et al., 2003). The NNbz ligand deviates from planarity as the dihedral angle between the central phenyl ring and the benzothiazole group is 20.48 (8) , while the dihedral angle between the phenyl ring and the pyridine ring is 39.13 (8) .

Figure 1
Molecular structure and labeling scheme for the title Re I complex, the methanol solvent molecule and the PF 6 À counter-anion. Displacement ellipsoids are drawn at the 50% probability level. Cyan and dark-green dashed lines indicate the O1W-H101Á Á ÁO1M and O1W-H102Á Á ÁF1 hydrogen bonds, respectively. Table 1 Hydrogen-bond geometry (Å , ). ecules are centrosymetrically related and thus exhibit parallel phenyl rings of the NNbz ligand at a distance of 3.50 (1) Å . In addition, both the pyridine rings and the phenyl rings of the benzothiazole parts of neighbouring centrosymmetrically related NNbz ligands overlap with each other, with their respective centroids Cg1 and Cg2 lying at a distance of 3.8525 (1) Å and forming an angle of 18.67 (6) [Cg1 and Cg2 0 are the centroids of the N1, C4-C8 and C17 0 -C22 0 rings; symmetry code: ( 0 ) 1 À x, 1 À y, 1 À z; Fig. 2]. The dimers are stacked along the a-axis direction. Methanol solvent molecules are interleaved between adjacent dimers within the stacked molecules and are linked through intermolecular O1W-H101Á Á ÁO1M and O1M-H201Á Á ÁN3 interactions (Fig. 3). These stacks are extended into layers parallel to (011) through C5-H5Á Á ÁO2 hydrogen bonds and further O1W-H102Á Á ÁF1, C9-H9Á Á ÁF3 ii (Table 1) hydrogen bonds between the counteranions and the coordinating ligands result in the formation of a three-dimensional network structure (Fig. 4).

Hirshfeld surface study
The view of the Hirshfeld surface mapped with d norm (Fig. 5a) reveals almost all of the hydrogen-bonding interactions discussed above as intense red areas. The same view of the surface mapped with the curvedness property reveals the contact areas of the tricarbonyl part of the complex with the benzothiazole end of the coordinating ligand, as indicated by patches of the same shape (circled areas in Fig. 5b). Finally, the plot of the surface mapped with the shape-index property ( Layers of complexes parallel to (011). C5-H5Á Á ÁO2 hydrogen bonds are indicated by yellow dashed lines. For the atoms and the rest of the bonds, the colour code is as in Fig. 2.

Figure 4
Three-dimensional arrangement of layers. C9-H9Á Á ÁF3 ii hydrogen bonds are indicated by black dashed lines. For the atoms and the rest of the bonds, the colour code is as in previous figures. The cyan arrows indicate the position of the layers within the structure and the orange ones the areas where the complexes interact throughinteractions.

Figure 5
Views of the Hirshfeld surfaces mapped over (a) d norm , (b) curvedness and (c) shape-index, and (d) the fingerprint plot for the title complex. The red circles in (b) indicate patches of the same shape corresponding to contact areas of neighbouring complexes. The central ellipse in (c) indicates theoverlap of the central phenyl rings, and the two circles at both ends of the surface the overlap of the pyridine ring and the phenyl ring of the benzothiazol part of neighbouring centrosymmetrically related NNbz ligands. In ( (Table 2) are longer than those in most of the previously studied complexes, and close to the longer ones observed in the SEHGUK structure (Knopf et al., 2017) with the 4,7diphenyl-1,10-phenanthroline bidentate ligand. As can be seen in Table 2, the Re-N bond lengths fall in the range 2.142-2.210 Å . The corresponding range for the Re-O1W bond is 2.143-2.214 Å , with the value observed in the present study falling in the middle of this range. The values of the Re-C bond lengths are also given. In all cases, the Re-C bonds trans to water molecule are shorter than the Re-C bonds trans to N atoms, in accordance with the intensity of the trans effect of the coordinating ligands.

Synthesis and crystallization
A mixture of Re(CO) 5 Br (81 mg, 0.2 mmol) and the NNbz ligand (69 mg, 0.22 mmol) was suspended in 7 ml toluene and refluxed under an N 2 atmosphere for 4 h. The red suspension was then allowed to cool to room temperature. The red solid that formed was dissolved in acetonitrile (25 ml) and a batch of AgPF 6 (55 mg, 0.22 mmol) was added. The reaction mixture was refluxed for 18 h under an N 2 atmosphere. The round flask was covered with aluminium foil to avoid exposure to any ambient light. The reaction mixture was allowed to cool for 1 h to 273 K, and then the precipitate (AgBr) was filtered off through celite. The yellow-orange filtrate was evaporated to dryness under reduced pressure, and the residue was recrys-   (1) Notes: (a) 1,10-Phenanthroline (Connick et al., 1999) 9.15, 8.49, 8.45, 8.37, 8.21, 8.12, 7.98, 7.83, 7.78, 7.60, 7.52. Red-brown crystals suitable for X-ray analysis were obtained by slow evaporation from a methanol/water solution.

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 3. All H atoms were freely refined.

Computing details
Data collection: CrystalClear (Rigaku, 2005); cell refinement: CrystalClear (Rigaku, 2005); data reduction: CrystalClear (Rigaku, 2005); program(s) used to solve structure: SHELXS (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015b); molecular graphics: DIAMOND (Crystal Impact, 2012); software used to prepare material for publication: publCIF (Westrip, 2010). 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.