Structural characterization and Hirshfeld surface analysis of a CoII complex with imidazo[1,2-a]pyridine

Seth, S.K.

doi:10.1107/S2056989018003857

weak interactions in crystals

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ISSN: 2056-9890

Volume 74| Part 5| May 2018| Pages 600-606

https://doi.org/10.1107/S2056989018003857

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Structural characterization and Hirshfeld surface analysis of a Co^II complex with imidazo[1,2-a]pyridine

Saikat Kumar Seth ^a ^*

^aDepartment of Physics, Jadavpur University, Kolkata 700 032, India
^*Correspondence e-mail: skseth@phys.jdvu.ac.in

Edited by C. Massera, Università di Parma, Italy (Received 14 November 2017; accepted 5 March 2018; online 17 April 2018)

A new mononuclear tetrahedral Co^II complex, dichloridobis(imidazo[1,2-a]pyridine-κN¹)cobalt(II), [CoCl₂(C₇H₆N₂)₂], has been synthesized using a bioactive imidazopyridine ligand. X-ray crystallography reveals that the solid-state structure of the title complex exhibits both C—H⋯Cl and π–π stacking interactions in building supramolecular assemblies. Indeed, the molecules are linked by C—H⋯Cl interactions into a two-dimensional framework, with finite zero-dimensional dimeric units as building blocks, whereas π–π stacking plays a crucial role in building a supramolecular layered network. An exhaustive investigation of the diverse intermolecular interactions via Hirshfeld surface analysis enables contributions to the crystal packing of the title complex to be quantified. The fingerprint plots associated with the Hirshfeld surface clearly display each significant interaction involved in the structure, by quantifying them in an effective visual manner.

Keywords: crystal structure; Co^II complex with imidazopyridine; noncovalent interactions; supramolecular assembly; Hirshfeld surface; fingerprint plot.

CCDC reference: 1583014

1. Chemical context

In the realm of the synthesis of heterocyclic compounds, imidazopyridines have proven to be a most important class of molecules and have attracted significant interest because of their promising applications. They are biologically important and have shown a wide variety of pharmacological effects (Adib et al., 2011 ): anti-inflammatory (Rupert et al., 2003 ), antiviral (Puerstinger et al., 2007 ), antiulcer (Kaminski & Doweyko, 1997 ), antibacterial (Rival et al., 1992 ), antifungal (Rival et al., 1991 ), antiprotozoal (Biftu et al., 2006 ; Ismail et al. 2008 ), antiherpes (Gudmundsson & Johns, 2007 ; Véron et al., 2007 ), and for the treatment of hepatitis C (Bravi et al., 2007 ), and HIV (Gudmundsson & Boggs, 2007 ). These medically relevant compounds exhibit a wide range of activities including anti-herpes, antiapoptotic, sedative, anxiolytic, anticonvulsant, muscle relaxant, analgesic, antituberculosis and anticancer actions (Dymińska, 2015 ; Bagdi et al., 2015 ). The core structure of imidazo[1,2-a]pyridine is present in several drugs, such as zolpidem, alpidem, zolimidine, olprinone, GSK812397, saripidem, and necopidem (Gunja, 2013 ; Harrison & Keating, 2005 ; Bagdi et al., 2015). Besides, this heterocyclic scaffold has attracted tremendous attention from the synthetic community due to its prevalence in dyes, ligands for metal catalysts, and electronic materials (Enguehard-Gueiffier & Gueiffier, 2007 ; Prostota et al., 2013 ; Ke et al., 2013 ).

Inspired by the manifold potential applications of imidazo[1,2-a]pyridine, we focused our attention on its coordination behavior towards metal ions and to the structural features of the resulting complexes. Herein, the crystal and molecular structure of a new Co^II complex with imidazo[1,2-a]pyridine is described, along with an investigation of the intermolecular interactions via Hirshfeld surface analysis.

2. Structural commentary

The molecular structure of the title complex is shown in Fig. 1. The Co^II ion is located on a twofold axis, so that half of the complex is generated by symmetry. The metal center is coordinated to the nitrogen atoms of two imidazopyridine ligands and to two chlorine ions, and shows a tetrahedral geometry with angles ranging from 107.70 (5) to 112.44 (5)°. Selected geometric parameters around Co^II are reported in Table 1. The imidazopyridine moiety is planar, with a dihedral angle between the rings of 2.47 (3)°. In the imidazopyridine moiety, atoms C6 and C4 show the largest deviations in opposite directions [C6: +0.034 (1) and N1: −0.037 (1)] from the least-squares mean plane through the atoms N1/C6/C7/N2/C1–C5.

Table 1
Selected geometric parameters (Å, °)

Co1—N1	2.0168 (4)	Co1—Cl1	2.2556 (5)

N1—Co1—N1ⁱ	107.70 (5)	N1ⁱ—Co1—Cl1	112.44 (5)
N1—Co1—Cl1	106.83 (1)	Cl1—Co1—Cl1ⁱ	110.64 (4)
Symmetry code: (i) $[-x+{\script{1\over 2}}, y, -z+{\script{3\over 2}}]$ .

Figure 1
ORTEP view with atom-numbering scheme of the title complex with displacement ellipsoids drawn at the 30% probability level. The unlabeled counterpart is generated by the symmetry operation −x + $[{1\over 2}]$ , y, −z + $[{3\over 2}]$ .

3. Supramolecular features

The title structure exhibits intermolecular C—H⋯Cl and π–π stacking interactions; the details are included in Tables 2 and 3, respectively. It is convenient to consider the `substructures' generated by each interaction individually, and then combine these substructures to build up the supramolecular assembly. The first substructure is formed considering the pyridine ring carbon atom C5 in a general position, which acts as donor to the Cl1 atom at (−x, −y, 1 − z). This C5—H5⋯Cl1 interaction and its centrosymmetric analogue generate an R₂²(18) dimeric ring (M) centered at (0, 0, 1/2) (Fig. 2). A second substructure is formed via pairs of symmetry-related C7—H7⋯Cl1(x, −1 + y, z) interactions, which generate a dimeric R₂²(10) ring (N) (Fig. 2). The propagation of these dimers produces two infinite chains, the first running parallel to the ( $[\overline{1}]$ 01) plane and the second running parallel to the [010] direction. The interconnection of the two chains leads to the generation of another tetrameric R₄²(14) ring motif (P). Thus, the two types of R₂²(18) and R₄²(14) rings are alternately linked into infinite MPMP… chains along the [010] direction whereas the R₂²(10) and R₄²(14) rings are linked alternately into an infinite NPNP… chain parallel to the ( $[\overline{1}]$ 01) plane (Fig. 2).

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C5—H5⋯Cl1ⁱⁱ	0.93	2.89	3.663 (1)	141
C7—H7⋯Cl1ⁱⁱⁱ	0.93	2.88	3.734 (1)	153
Symmetry codes: (ii) -x, -y, -z+1; (iii) x, y-1, z.

Table 3
Geometrical parameters (Å, °) for π–π stacking

(a) Cg1 and Cg2 are the centroids of the (N1/C1/N2/C6/C7) and (N2/C1–C5) rings, respectively; (b) centroid–centroid distance between ring i and ring j; (c) vertical distance from ring centroid i to ring j; (d) vertical distance from ring centroid j to ring i; (e) dihedral angle between the first ring mean plane and the second ring mean plane of the partner molecule; (f) angle between the centroid of the first ring and the second ring; (g) angle between the centroid of the first ring and the normal to the mean plane of the second ring of the partner molecule.

Rings i–j^a	Rc^b	R1v^c	R2v^d	α^e	β^f	γ^g	Slippage
Cg1⋯Cg1ⁱⁱ	3.6414 (16)	−3.4980 (8)	−3.4980 (8)	0.0	16.13	16.13	1.012
Cg1⋯Cg2ⁱⁱ	3.9583 (16)	−3.5303 (9)	−3.5035 (9)	2.47	27.73	26.89	–
Cg1⋯Cg2^iv	3.8371 (16)	3.4625 (9)	3.4846 (9)	2.47	24.75	25.53	–
Cg2⋯Cg2^iv	3.5293 (16)	3.4671 (9)	3.4671 (9)	0.0	10.77	10.77	0.659
Symmetry codes: (ii) −x, −y, −z + 1; (iv) −x + 1, −y, −z + 1.

Figure 2
Formation of a two-dimensional supramolecular network generated through self-complementary C—H⋯Cl interactions.

Another substructure can be described considering that the molecules, because of their self-complementarity nature, are juxtaposed through π–π stacking interactions (Seth et al., 2011a , 2013 ; Manna et al., 2013 , 2014a ). The molecular packing of the complex is such that the π–π stacking interactions between the pyridine rings, as well as between the imidazo rings, are optimized. The pyridine rings of the molecules at (x, y, z) and (−x + 1, −y, −z + 1) are strictly parallel, with an interplanar spacing of 3.4671 (9) Å and a ring-centroid separation of 3.5293 (16) Å, corresponding to a ring offset of 0.659 Å. In addition, the imidazo rings at (x, y, z) and (−x, −y, −z + 1) are juxtaposed through face-to-face π-stacking with an inter-centroid separation of 3.6414 (16) Å. Moreover, the imidazo and pyridine rings of the parent molecules are also involved into multi π-stacking interactions with each other. In particular, the interplanar spacing between the imidazo ring in a general position and the pyridine rings at (−x, −y, −z + 1) and (−x + 1, −y, −z + 1) are of 3.5303 (9) and 3.4625 (9) Å, respectively, while the relative ring-centroid separations are 3.9583 (16) and 3.8371 (16) Å. These π–π stacking interactions result in a two-dimensional supramolecular layered assembly parallel to the (010) plane (Fig. 3).

Figure 3
Monomeric units linked through multi π–π stacking interactions leading to the formation of a supramolecular layered assembly. Color codes: the green and yellow dotted lines denote π–π stacking interactions between two pyridine rings and two imidazo rings, respectively, whereas π–π stacking interactions between pyridine and imidazo rings are represented by pink dotted lines.

4. Hirshfeld surface analysis

Molecular Hirshfeld surfaces (Spackman & McKinnon, 2002 ) in the crystal structure are constructed considering the electron distribution calculated as the sum of spherical atom electron densities (Spackman & Byrom, 1997 ; McKinnon et al., 1998 ). The normalized contact distance (d_norm) based on both d_e and d_i, and the van der Waals (vdw) radii of the atom, given by the equation

$[ d_{\rm norm} = {d_{\rm i} - r_{\rm i}^{\rm vdw} \over r_{\rm i}^{\rm vdw}} + {d_{\rm e} - r_{\rm i}^{\rm vdw} \over r_{\rm e}^{\rm vdw}}]$

enable the identification of the regions of particular importance to intermolecular interactions (McKinnon et al., 2007 ). The combination of d_e and d_i in the form of a two-dimensional fingerprint plot (Rohl et al., 2008 ) provides a summary of the intermolecular contacts in the crystal (Spackman & McKinnon, 2002). The Hirshfeld surfaces are mapped with d_norm, and the two-dimensional fingerprint plots presented in this work were generated using CrystalExplorer 3.1 (Wolff et al., 2012 ).

The pattern of the intermolecular interactions of the solid-state structure of the title complex prompted us to explore and quantify the contribution of the non-covalent interactions in the crystal packing, as well as the importance of the C—H⋯Cl bonding in directing the organization of the extended supramolecular network (Seth et al., 2011a,b , Manna et al., 2012 ; Seth, 2013 ; Mitra et al., 2014 ). In this present investigation, the contacts responsible for building the supramolecular assembly were evaluated with respect to their contribution to the overall stability of the crystal structure. In this context, the Hirshfeld surface analysis (Spackman & McKinnon, 2002; Seth et al., 2011a,b,c ,d ; Mitra et al., 2013 ) of the title complex was performed and the results are illustrated in Fig. 4. The surfaces represented were mapped over d_norm, d_e, shape-index and curvedness in the ranges −0.0620 to 0.9660 Å, 1.0626 to 2.4714 Å, −1.0000 to 1.0000 Å and −4.0000 to 0.4000 Å, respectively. The information regarding the intermolecular interactions summarized in Tables 2 and 3 are visible as spots on the Hirshfeld surfaces (Fig. 4). For instance, the distinct circular depressions (red spots) on the d_norm surface (Fig. 4a) are due to the C—H⋯Cl contacts, whereas other visible spots are due to H⋯H contacts. From the Hirshfeld surfaces, it is also evident that the molecules are related to one another by π–π stacking interactions, as can be inferred from inspection of the adjacent red and blue triangles (highlighted by yellow circles) on the shape-index surface (Fig. 4c). Indeed, the pattern of red and blue triangles in the same region of the shape-index surface is characteristic of π–π stacking interactions; the blue triangles represent convex regions resulting from the presence of ring carbon atoms of the molecule inside the surface, while the red triangles represent concave regions caused by carbon atoms of the π-stacked molecule above it. The presence of π–π stacking is also evident in the flat region toward the bottom of both sides of the molecules and is clearly visible on the curvedness surface (Fig. 4d): the shape of the blue outline on the curvedness surface unambiguously delineates the contacting patches of the molecules. On the d_e surface, this feature appears as a relatively flat green region where the contact distances are similar (Fig. 4b).

Figure 4
Hirshfeld surfaces of the title complex mapped with (a) d_norm, (b) d_e, (c) shape-index and (d) curvedness.

The intermolecular interactions present in the structure are also visible on the two-dimensional fingerprint plot (Rohl et al., 2008; Samanta et al., 2014 ; Seth, 2014a ,b ,c ), which can be decomposed to quantify the individual contributions of each intermolecular interaction involved in the structure (Manna et al., 2014b ). These complementary regions are visible in the fingerprint, where one molecule acts as donor (d_e > d_i) and the other as an acceptor (d_i > d_e). Table 4 contains the percentages of contributions for a variety of contacts in the crystal structure of the title compound.

Table 4
Percentage contributions of interatomic contacts to the Hirshfeld surface

Contact	% contribution	Contact	% contribution
Cl⋯H/H⋯Cl	30.0	Cl⋯Cl	0.4
N⋯H/H⋯N	4.1	N⋯N	0.9
C⋯H/H⋯C	12.1	C⋯C	7.9
Cl⋯C/C⋯Cl	0.5	H⋯H	38.4
N⋯C/C⋯N	5.7

The C—H⋯Cl interactions appear as two distinct spikes in the fingerprint plot (Fig. 5) of the title complex, where Cl⋯H interactions have a larger contribution (18.4%) than their H⋯Cl counterparts (11.6%). Thus, the sum of Cl⋯H/H⋯Cl interactions comprises 30.0% of the total Hirshfeld surface area of the molecule (Table 4). The Cl⋯H/H⋯Cl interactions represented by the spikes in the bottom right and left region (d_e + d_i ≃ 2.77 Å) indicate that the hydrogen atoms from the ligand moiety are in contact with the metal-coordinated Cl atoms to build the two-dimensional supramolecular framework. The spoon-like tips in the region (d_e + d_i ≃ 3.37 Å) of the fingerprint plot (Fig. 5) represent a significant N⋯H/H⋯N contribution, covering 4.1% of the total Hirshfeld surface of the molecules. The forceps-like tips in the region (d_e + d_i ≃ 3.12 Å) of the fingerprint plot (Fig. 5) represent the C⋯H/H⋯C contacts where the C⋯H counterpart shows a larger contribution (7.6%) than the H⋯C counterpart (4.5%). Overall, the C⋯H/H⋯C interactions account for 12.1% of the total Hirshfeld surface of the molecules (Table 4), and the carbon atoms of the imidazopyridine moiety mainly act as donors in building the molecular assembly. The scattered points in the breakdown of the fingerprint plot show that the π–π stacking interactions comprise 7.9% of the total Hirshfeld surface of the molecule (Table 5) displayed as a region of blue/green color on the diagonal at around d_e ≃ d_i ≃ 1.743 Å. Another contribution comes from H⋯H contacts (38.4%) represented by the scattered points in the fingerprint plots, and spread up only to d_i = d_e = 1.092 Å (Fig. 5).

Table 5
Summary of the short interatomic contacts (Å)

Contact	Distance	Contact	Distance
Cl1⋯H7^v	2.883	C2⋯H6^v	2.992
Cl1⋯C2ⁱ	3.613 (2)	C2⋯C5^iv	3.535 (3)
Cl1⋯H2ⁱ	2.932	C2⋯H3^vii	3.021
Cl1⋯H5ⁱⁱ	2.893	C4⋯C4^viii	3.525 (3)
Cl1⋯H3^vi	3.055	C4⋯H4^viii	2.834
N1⋯N1ⁱ	3.257 (2)	C6⋯H2ⁱⁱⁱ	3.050
C1⋯C4^iv	3.482 (3)	H2⋯H3^vii	2.416
C1⋯C5^iv	3.516 (3)	H4⋯H4^viii	2.309
C1⋯C6ⁱⁱ	3.518 (3)	H6⋯H2ⁱⁱⁱ	2.535
Symmetry codes: (i) −x + $[{1\over 2}]$ , y, −z + $[{3\over 2}]$ ; (ii) −x, −y, −z + 1; (iii) x, y − 1, z; (iv) −x + 1, −y, −z + 1; (v) x, y + 1, z; (vi) x − $[{1\over 2}]$ , −y + 1, z + $[{1\over 2}]$ ; (vii) −x + 1, −y + 1, −z + 1; (viii) −x + $[{1\over 2}]$ , y, −z + $[{1\over 2}]$ ;

Figure 5
Fingerprint plots: full (middle) and decomposed plots corresponding to all contacts involved in the structure [clockwise: from bottom left to bottom right]. The relative contributions of various intermolecular contacts to the Hirshfeld surface area of the title structure are displayed by the schematic illustration.

Finally, the short inter-atomic contacts of the structure (Table 5) of the type Cl⋯C/ C⋯Cl, N⋯C/ C⋯N, Cl⋯Cl and N⋯N are clearly visible as scattered points in the region d_e + d_i ≃ 4.07 Å, d_e + d_i ≃ 3.58 Å, d_e + d_i ≃ 4.11 Å and d_e + d_i ≃ 3.82 Å of the breakdown fingerprint plots (Fig. 5). They contribute 0.5%, 5.7%, 0.4% and 0.9%, respectively, to the total Hirshfeld area of the title complex (Table 4, see Fig. 6).

Figure 6
Perspective view of the decomposed d_norm surfaces of the title structure corresponding to (a) Cl⋯H/H⋯Cl; (b) N⋯H/H⋯N; (c) C⋯H/H⋯C; (d) Cl⋯C/C⋯Cl; (e) N⋯C/C⋯N; (f) Cl⋯Cl; (g) N⋯N; (h) C⋯C and (i) H⋯H contacts.

The individual intermolecular interactions described above and the quantitative contributions included in Table 4 can be also visualized by the different d_norm surfaces shown in Fig. 6, confirming that the Hirshfeld surface analysis provides a full understanding of the intermolecular interactions in a facile and immediate way.

5. Database survey

A search in the Cambridge Structural Database (Version 5.38, update May 2017; Groom et al., 2016 ) for structures of the general formula [ML₂X₂], where M is any transition metal, L is the ligand imidazo[1,2-a]pyridine, and X any halogen, yielded no results. However, two related complexes exist, with ruthenium and tin, respectively: (i) dichloro-[2,2′-(pyridine-2,6-diyl)bis(imidazo[1,2-a]pyridine)]triphenylphosphineruthenium(II) (GULNEI; Li et al., 2015 ); (ii) dibromo-bis(imidazo[1,2-a]pyridine)dimethyltin (NODREF; Agrawal et al., 2014 ). In both cases, the presence of the halogen atoms is relevant to the stabilization of the crystal structure. In the case of the ruthenium compound, the complex molecules are linked into discrete supramolecular dimers through pairs of C—H(imidazo)⋯Cl interactions. On the other hand, the tin complex forms undulating sheets parallel to the (100) plane by means of C—H(pyridine)⋯Br interactions in which both the Br ions and the ligands of one complex act as acceptor and donor, respectively.

6. Synthesis and crystallization

The title complex was prepared by simple hydrothermal reaction. CoCl₂·6H₂O (2.0 mmol, 0.476 g) was dissolved in water (20 ml) yielding a clear pink solution. A hot water–methanol (1:1) solution (20 ml) of imidazo[1,2-a]pyridine (1.0 mmol, 0.118 g) was added dropwise to the above solution under continuous stirring. The solution mixture thus obtained was further heated at 343 K for 2 h and then kept for crystallization at room temperature (303 K). The resulting solution was allowed to evaporate slowly at room temperature for several weeks, yielding testable dark-pink crystals, which were collected by filtration, washed with water and dried in air.

7. Refinement details

Crystal data, data collection and structure refinement details are summarized in Table 6. The hydrogen atoms were located in the difference-Fourier map and refined as riding atoms, with C—H = 0.93 Å and U_iso(H) = 1.2U_eq(C).

Table 6
Experimental details

Crystal data
Chemical formula	[CoCl₂(C₇H₆N₂)₂]
M_r	366.11
Crystal system, space group	Monoclinic, P2/n
Temperature (K)	293
a, b, c (Å)	7.712 (2), 6.7898 (18), 14.348 (4)
β (°)	98.533 (5)
V (Å³)	743.0 (4)
Z	2
Radiation type	Mo Kα
μ (mm⁻¹)	1.51
Crystal size (mm)	0.17 × 0.11 × 0.06

Data collection
Diffractometer	Bruker SMART APEXII CCD area-detector
Absorption correction	Multi-scan (SADABS; Bruker, 2007 )
T_min, T_max	0.82, 0.92
No. of measured, independent and observed [I > 2σ(I)] reflections	6663, 1307, 1241
R_int	0.023
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.024, 0.064, 1.06
No. of reflections	1307
No. of parameters	96
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.18, −0.32
Computer programs: APEX2 , SAINT and XPREP (Bruker, 2007), SHELXT2014 (Sheldrick, 2015a ), SHELXL2018 (Sheldrick, 2015b ), ORTEP-3 for Windows (Farrugia, 2012 ), DIAMOND (Brandenburg, 2006 ), Mercury (Macrae et al., 2006 ) and PLATON (Spek, 2009 ).

Supporting information

CCDC reference: 1583014

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2056989018003857/xi2004sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989018003857/xi2004Isup2.hkl

checkCIF report

Computing details top

Data collection: APEX2 (Bruker, 2007); cell refinement: APEX2 (Bruker, 2007) and SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007) and XPREP (Bruker, 2007); program(s) used to solve structure: SHELXT2014 (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2018 (Sheldrick, 2015b); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012), DIAMOND (Brandenburg, 2006) and Mercury (Macrae et al., 2006); software used to prepare material for publication: PLATON (Spek, 2009).

Dichloridobis(imidazo[1,2-a]pyridine-κN¹)cobalt(II) top

Crystal data top

[CoCl₂(C₇H₆N₂)₂]	F(000) = 370
M_r = 366.11	D_x = 1.636 Mg m⁻³
Monoclinic, P2/n	Mo Kα radiation, λ = 0.71073 Å
a = 7.712 (2) Å	Cell parameters from 647 reflections
b = 6.7898 (18) Å	θ = 1.5–25.0°
c = 14.348 (4) Å	µ = 1.51 mm⁻¹
β = 98.533 (5)°	T = 293 K
V = 743.0 (4) Å³	Block, pink
Z = 2	0.17 × 0.11 × 0.06 mm

Data collection top

Bruker SMART APEXII CCD area-detector diffractometer	1307 independent reflections
Radiation source: fine-focus sealed tube	1241 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.023
ω and φ scans	θ_max = 25.0°, θ_min = 2.8°
Absorption correction: multi-scan (SADABS; Bruker, 2007)	h = −8→9
T_min = 0.82, T_max = 0.92	k = −8→8
6663 measured reflections	l = −17→17

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.024	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.064	H-atom parameters constrained
S = 1.06	w = 1/[σ²(F_o²) + (0.0355P)² + 0.2499P] where P = (F_o² + 2F_c²)/3
1307 reflections	(Δ/σ)_max < 0.001
96 parameters	Δρ_max = 0.18 e Å⁻³
0 restraints	Δρ_min = −0.31 e Å⁻³

Special details top

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.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > 2sigma(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Co1	0.250000	0.21247 (5)	0.750000	0.03788 (13)
Cl1	0.00699 (6)	0.40150 (8)	0.73557 (4)	0.05261 (16)
N1	0.2270 (2)	0.0373 (2)	0.63532 (10)	0.0410 (3)
N2	0.2373 (2)	−0.0539 (2)	0.48712 (11)	0.0452 (4)
C2	0.3250 (3)	0.2781 (3)	0.52292 (15)	0.0513 (5)
H2	0.341071	0.383348	0.564797	0.062*
C1	0.2664 (2)	0.0958 (3)	0.55145 (12)	0.0386 (4)
C6	0.1741 (3)	−0.2106 (3)	0.53192 (17)	0.0554 (5)
H6	0.141218	−0.332623	0.505604	0.066*
C5	0.2770 (3)	−0.0324 (4)	0.39615 (14)	0.0635 (6)
H5	0.261300	−0.136802	0.353786	0.076*
C7	0.1689 (3)	−0.1537 (3)	0.62194 (16)	0.0503 (5)
H7	0.131285	−0.232355	0.668094	0.060*
C3	0.3582 (3)	0.2988 (4)	0.43289 (15)	0.0629 (6)
H3	0.394972	0.419967	0.412794	0.075*
C4	0.3379 (3)	0.1406 (5)	0.37060 (15)	0.0677 (7)
H4	0.367003	0.155512	0.310375	0.081*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Co1	0.0447 (2)	0.0343 (2)	0.0365 (2)	0.000	0.01225 (14)	0.000
Cl1	0.0507 (3)	0.0496 (3)	0.0578 (3)	0.0098 (2)	0.0093 (2)	0.0003 (2)
N1	0.0469 (8)	0.0342 (8)	0.0436 (8)	−0.0029 (6)	0.0121 (7)	−0.0024 (6)
N2	0.0415 (8)	0.0476 (9)	0.0451 (9)	0.0027 (7)	0.0022 (7)	−0.0107 (7)
C2	0.0594 (12)	0.0493 (11)	0.0442 (11)	−0.0098 (9)	0.0045 (9)	0.0033 (9)
C1	0.0383 (9)	0.0406 (10)	0.0367 (9)	0.0018 (7)	0.0049 (7)	−0.0037 (7)
C6	0.0561 (12)	0.0403 (11)	0.0677 (14)	−0.0017 (9)	0.0023 (10)	−0.0165 (9)
C5	0.0534 (12)	0.0963 (18)	0.0387 (11)	0.0085 (13)	−0.0003 (9)	−0.0252 (12)
C7	0.0520 (11)	0.0353 (9)	0.0644 (12)	−0.0050 (9)	0.0109 (9)	0.0038 (9)
C3	0.0607 (13)	0.0808 (16)	0.0454 (11)	−0.0161 (12)	0.0019 (10)	0.0154 (11)
C4	0.0540 (13)	0.111 (2)	0.0381 (11)	−0.0105 (14)	0.0054 (9)	0.0056 (13)

Geometric parameters (Å, º) top

Co1—N1	2.0168 (4)	C2—C1	1.400 (3)
Co1—N1ⁱ	2.0169 (15)	C2—H2	0.9300
Co1—Cl1	2.2556 (5)	C6—C7	1.355 (3)
Co1—Cl1ⁱ	2.2556 (7)	C6—H6	0.9300
N1—C1	1.344 (2)	C5—C4	1.337 (4)
N1—C7	1.376 (2)	C5—H5	0.9300
N2—C1	1.369 (2)	C7—H7	0.9300
N2—C6	1.370 (3)	C3—C4	1.391 (4)
N2—C5	1.392 (3)	C3—H3	0.9300
C2—C3	1.361 (3)	C4—H4	0.9300

N1—Co1—N1ⁱ	107.70 (5)	N2—C1—C2	119.15 (17)
N1—Co1—Cl1	106.83 (1)	C7—C6—N2	106.79 (17)
N1ⁱ—Co1—Cl1	112.44 (5)	C7—C6—H6	126.6
N1—Co1—Cl1ⁱ	112.44 (5)	N2—C6—H6	126.6
N1ⁱ—Co1—Cl1ⁱ	106.83 (5)	C4—C5—N2	119.0 (2)
Cl1—Co1—Cl1ⁱ	110.64 (4)	C4—C5—H5	120.5
C1—N1—C7	105.44 (16)	N2—C5—H5	120.5
C1—N1—Co1	123.48 (12)	C6—C7—N1	110.28 (19)
C7—N1—Co1	131.06 (14)	C6—C7—H7	124.9
C1—N2—C6	107.13 (16)	N1—C7—H7	124.9
C1—N2—C5	121.17 (19)	C2—C3—C4	120.7 (2)
C6—N2—C5	131.65 (19)	C2—C3—H3	119.6
C3—C2—C1	118.9 (2)	C4—C3—H3	119.6
C3—C2—H2	120.5	C5—C4—C3	120.9 (2)
C1—C2—H2	120.5	C5—C4—H4	119.6
N1—C1—N2	110.35 (16)	C3—C4—H4	119.6
N1—C1—C2	130.48 (17)

N1ⁱ—Co1—N1—C1	−157.31 (17)	C5—N2—C1—C2	4.7 (3)
Cl1ⁱ—Co1—N1—C1	−39.88 (15)	C3—C2—C1—N1	179.1 (2)
Cl1—Co1—N1—C1	81.68 (14)	C3—C2—C1—N2	−2.6 (3)
N1ⁱ—Co1—N1—C7	24.35 (15)	C1—N2—C6—C7	−0.9 (2)
Cl1ⁱ—Co1—N1—C7	141.78 (16)	C5—N2—C6—C7	176.8 (2)
Cl1—Co1—N1—C7	−96.66 (17)	C1—N2—C5—C4	−2.7 (3)
C7—N1—C1—N2	−1.1 (2)	C6—N2—C5—C4	180.0 (2)
Co1—N1—C1—N2	−179.77 (11)	N2—C6—C7—N1	0.2 (2)
C7—N1—C1—C2	177.4 (2)	C1—N1—C7—C6	0.5 (2)
Co1—N1—C1—C2	−1.3 (3)	Co1—N1—C7—C6	179.08 (14)
C6—N2—C1—N1	1.2 (2)	C1—C2—C3—C4	−1.3 (3)
C5—N2—C1—N1	−176.69 (16)	N2—C5—C4—C3	−1.3 (3)
C6—N2—C1—C2	−177.42 (18)	C2—C3—C4—C5	3.4 (4)

Symmetry code: (i) −x+1/2, y, −z+3/2.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
C5—H5···Cl1ⁱⁱ	0.93	2.89	3.663 (1)	141
C7—H7···Cl1ⁱⁱⁱ	0.93	2.88	3.734 (1)	153

Symmetry codes: (ii) −x, −y, −z+1; (iii) x, y−1, z.

Geometrical parameters (Å, °) for π–π stacking top

Rings i–j^a	Rc^b	R1v^c	R2v^d	α^e	β^f	γ^g	Slippage
Cg1···Cg1ⁱⁱ	3.6414 (16)	-3.4980 (8)	-3.4980 (8)	0.0	16.13	16.13	1.012
Cg1···Cg2ⁱⁱ	3.9583 (16)	-3.5303 (9)	-3.5035 (9)	2.47	27.73	26.89	–
Cg1···Cg2^iv	3.8371 (16)	3.4625 (9)	3.4846 (9)	2.47	24.75	25.53	–
Cg2···Cg2^iv	3.5293 (16)	3.4671 (9)	3.4671 (9)	0.0	10.77	10.77	0.659

Symmetry codes: (ii) -x, -y, -z + 1; (iv) -x + 1, -y, -z + 1.

Percentage contributions of interatomic contacts to the Hirshfeld surface top

Contact	% contribution	Contact	% contribution
Cl···H/H···Cl	30.0	Cl···Cl	0.4
N···H/H···N	4.1	N···N	0.9
C···H/H···C	12.1	C···C	7.9
Cl···C/C···Cl	0.5	H···H	38.4
N···C/C···N	5.7

Summary of the short interatomic contacts (Å) top

Contact	Distance	Contact	Distance
Cl1···H7^v	2.883	C2···H6^v	2.992
Cl1···C2ⁱ	3.613 (2)	C2···C5^iv	3.535 (3)
Cl1···H2ⁱ	2.932	C2···H3^vii	3.021
Cl1···H5ⁱⁱ	2.893	C4···C4^viii	3.525 (3)
Cl1···H3^vi	3.055	C4···H4^viii	2.834
N1···N1ⁱ	3.257 (2)	C6···H2ⁱⁱⁱ	3.050
C1···C4^iv	3.482 (3)	H2···H3^vii	2.416
C1···C5^iv	3.516 (3)	H4···H4^viii	2.309
C1···C6ⁱⁱ	3.518 (3)	H6···H2ⁱⁱⁱ	2.535

Symmetry codes: (i) -x + 1/2, y, -z + 3/2; (ii) -x, -y, -z + 1; (iii) x, y -1, z; (iv) -x + 1, -y, -z + 1; (v) x, y + 1, z; (vi) x - 1/2, -y + 1, z + 1/2; (vii) -x + 1, -y + 1, -z + 1; (viii) -x + 1/2, y, -z + 1/2;

Funding information

The author is grateful to the Science and Engineering Research Board (SERB) –Department of Science and Technology (DST), Govt. of India for a SERB Overseas Postdoctoral Fellowship (SB/OS/PDF-524/2015–16).

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