Crystal structure and Hirshfeld surface analysis of trans-2,5-di­methyl­piperazine-1,4-diium tetra­chlorido­cobaltate(II)

Landolsi, M.; Abid, S.

doi:10.1107/S2056989021002954

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ISSN: 2056-9890

Volume 77| Part 4| April 2021| Pages 424-427

https://doi.org/10.1107/S2056989021002954

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Crystal structure and Hirshfeld surface analysis of trans-2,5-dimethylpiperazine-1,4-diium tetrachloridocobaltate(II)

Meriem Landolsi ^a and Sonia Abid ^a ^*

^aUniversité de Carthage, Faculté des Sciences de Bizerte, LR13ES08, Laboratoire de Chimie des Matériaux, 7021, Zarzouna Bizerte, Tunisia
^*Correspondence e-mail: landolsimeriem@gmail.com

Edited by W. T. A. Harrison, University of Aberdeen, Scotland (Received 10 March 2021; accepted 19 March 2021; online 26 March 2021)

In the title molecular salt, (C₆H₁₆N₂)[CoCl₄], the complete dication is generated by crystallographic inversion symmetry and the piperazine ring adopts a chair conformation with the pendant methyl groups in equatorial orientations. The complete dianion is generated by crystallographic twofold symmetry. In the crystal, the (C₆H₁₆N₂)²⁺ and [CoCl₄]²⁻ ions are linked by N—H⋯Cl and C—H⋯Cl hydrogen bonds, thereby forming a two-dimensional supramolecular network. The Hirshfeld surface analysis and fingerprint plots reveal that the largest contributions to the crystal stability come from H⋯Cl/Cl⋯H (68.4%) and H⋯H (27.4%) contacts.

Keywords: crystal structure; tetrachloridocobaltate(II) salt; Hirshfeld surface analysis.

CCDC reference: 1831453

1. Chemical context

Tetrachlorocobalt/copper (II) salts with organic cations, such as (C₆H₁₀N₃)₂[CoCl₄] (Titi et al. 2020 ), [(CH₃)₂NH₂]₂[CoCl₄] (Pietraszko et al. 2006 ) and (C₇H₇N₂S)₂[CuCl₄] (Vishwakarma et al. 2017 ) have received attention due to their potential applications in the electronic, magnetic, optical and antimicrobial fields. In these materials, the negative charge on the inorganic complex ion is balanced by the organic groups, which usually act as structure-directing agents by the formation of N—H⋯Cl hydrogen bonds and significantly affect the structure and dimensionality of the supramolecular network.

As an extension of these studies, we now describe the synthesis, structure and Hirshfeld surface analysis of the title molecular salt, (I).

2. Structural commentary

The asymmetric unit of (I) comprises half of a trans-2,5-dimethylpiperazine-1,4-dium cation and a half tetrachloridocobaltate anion (Fig. 1). The cation and anion are completed by crystallographic inversion and twofold symmetry, respectively. In the organic species, the N—C and C—C bond lengths vary from 1.490 (2) to 1.513 (2) Å and the angles C—C—C, N—C—C and C—N—C range from 109.15 (14) to 113.54 (15)°. These data are in agreement with those reported in other salts of the trans-2,5-dimethylpiperazine-1,4-diium cation (Gatfaoui et al., 2014 ; Ben Mleh et al., 2016 ). The Co²⁺ ion in (I) has a tetrahedral geometry, with Cl—Co—Cl angles ranging from 103.32 (2) to 116.57 (3)°. The average length of the Co—Cl bonds, 2.27 Å, is close to that observed in similar complexes (Tahenti et al., 2020 ; Zhang et al., 2005 ; Zeller et al., 2005 ).

Figure 1
The molecular structure of (I)

with displacement ellipsoids set to 50% probability and hydrogen bonds shown as dashed lines. Symmetry codes: (i) −x + 1, y, −z + $[{3\over 2}]$ ; (ii) −x + 2, −y + 1, −z + 1.

3. Supramolecular features

In the crystal of (I), adjacent anions are interconnected by the cations via N—H⋯Cl hydrogen bonds and C—H⋯Cl interactions (Table 1) to form a layer built up from the organic and inorganic species, lying parallel to (101) (Fig. 2). The hydrogen bonds engage the chloride ions of the [CoCl₄]^2– tetrahedron, producing four types of graph-set motifs on the basis of Etter's notation (Etter et al., 1990 ; Bernstein et al., 1995 ). The isolated molecules can be described by the elementary graph-set descriptors E^a_d (n) (Daszkiewicz, 2012 ). The graph-set descriptor of the pattern can be easily obtained by the summation of elementary E^a_d (n) graph-sets of isolated ions and molecules. In the case of (I), the elementary graph-sets can be collected (Fig. 3) as follows:

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1A⋯Cl1ⁱ	0.89	2.30	3.1777 (2)	171
N1—H1B⋯Cl1	0.89	2.65	3.2594 (2)	126
N1—H1B⋯Cl2	0.89	2.49	3.2631 (2)	145
C1—H1C⋯Cl2ⁱⁱ	0.97	2.82	3.7065 (2)	153
Symmetry codes: (i) $[-x+2, y, -z+{\script{3\over 2}}]$ ; (ii) .

Figure 2
(a) Crystal packing in the structure of (I)

along the crystallographic a axis. (b) View of a supramolecular layer along the b-axis direction.

Figure 3
Hydrogen-bonding interactions between cations and anions showing the ring patterns of weak interactions formed by N—H⋯Cl/C—H⋯Cl links.

E⁰₁ (1) + E²₀ (3) = R₁² (4)

2E⁰₂ (3) + 2E¹₀ (1) = R₄² (8)

E⁰₂ (3) + E²₀ (5) = R₂² (8)

2E¹₀ (1) + 2E⁰₂ (4) = R₄² (10).

4. Hirshfeld surface analysis

To further understand the different interactions and contacts in the crystal of (I), its Hirshfeld surface (HS) (McKinnon et al., 2004 ) was calculated. The d_norm surface (Fig. 4) and the associated two-dimensional fingerprint plots (see supporting information) were calculated using CrystalExplorer 3.1 (Wolff et al., 2013 ; Spackman & Jayatilaka, 2009 ). This figure shows the areas mapped in the range from −0.480 to 1.048 of the asymmetric ion-pair surrounded by neighboring ions where we can see some of the closest intermolecular contacts. The large dark-red spots on the HS indicate close contact interactions, which are primarily responsible for significant hydrogen-bond contacts. The fingerprint plots indicate that the most important interactions are H⋯Cl/Cl⋯H, which cover a HS range of 68.4% and appear as two shape-symmetric spikes in the two-dimensional fingerprint maps (where d_i ∼d_e ∼1.4 Å). It should be also noted that the the van der Waals radii of the hydrogen and chlorine atoms are 1.20 and 1.75 Å, respectively. The H⋯H contacts represent the second most abundant interactions with 27.4% of the total Hirshfeld surface, including a short H⋯H contact near 2.4 Å (where d_i ∼d_e ∼1.2 Å), represented by a cluster of points accumulated on the diagonal of the graph. Other contacts including Cl⋯Cl and Co⋯H/H⋯Co have negligible contributions (respectively 2.7% and 1.5%). It can be concluded that the Cl⋯H/H⋯Cl interactions dominate in the title compound.

Figure 4
Hirshfeld surface of (I)

mapped over d_norm and the two-dimensional fingerprint plot for all interactions.

4.1. Synthesis and crystallization

A 1:1 mixture of trans-2,5-dimethylpiperazine and cobalt(II) chloride hexahydrate was dissolved in a solution of concentrated hydrochloric acid and the resulting solution was magnetically stirred for 1 h. After two weeks of evaporation, dark-blue prismatic crystals of (I) had formed, which were recovered by filtration and dried in air.

5. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. The N-bound and C-bound hydrogen atoms were positioned geometrically and treated as riding atoms: N—H = 0.86 Å, C—H = 0.96 Å with U_iso(H) = 1.2U_eq(N,C).

Table 2
Experimental details

Crystal data
Chemical formula	C₆H₁₆N₂²⁺·Cl₄Co²⁻
M_r	316.94
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	293
a, b, c (Å)	7.6431 (3), 11.9347 (6), 14.0058 (7)
β (°)	95.519 (4)
V (Å³)	1271.66 (10)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	2.15
Crystal size (mm)	0.15 × 0.10 × 0.08

Data collection
Diffractometer	Agilent SuperNova, Single source at offset, Eos
Absorption correction	Multi-scan (CrysAlis PRO; Agilent 2014 )
T_min, T_max	0.816, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections	4627, 1546, 1370
R_int	0.029
(sin θ/λ)_max (Å⁻¹)	0.685

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.028, 0.074, 1.08
No. of reflections	1546
No. of parameters	60
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.27, −0.59
Computer programs: CrysAlis PRO (Agilent, 2014), SIR92 (Altomare et al., 1994 ), SHELXL2017/1 (Sheldrick, 2015 ), DIAMOND (Brandenburg, 2006 ) and ORTEP-III (Burnett & Johnson, 1996 ).

Supporting information

CCDC reference: 1831453

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2056989021002954/hb7971sup1.cif

Two-dimensional fingerprint plots. DOI: https://doi.org/10.1107/S2056989021002954/hb7971sup3.pdf

checkCIF report

Computing details top

Data collection: CrysAlis PRO (Agilent, 2014); cell refinement: CrysAlis PRO (Agilent, 2014); data reduction: CrysAlis PRO (Agilent, 2014); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: SHELXL2017/1 (Sheldrick, 2015); molecular graphics: DIAMOND (Brandenburg, 2006) and ORTEP-III (Burnett & Johnson, 1996).

trans-2,5-Dimethylpiperazine-1,4-diium tetrachloridocobaltate(II) top

Crystal data top

C₆H₁₆N₂²⁺·Cl₄Co²⁻	F(000) = 644
M_r = 316.94	D_x = 1.655 Mg m⁻³
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 7.6431 (3) Å	Cell parameters from 2258 reflections
b = 11.9347 (6) Å	θ = 4.1–29.0°
c = 14.0058 (7) Å	µ = 2.15 mm⁻¹
β = 95.519 (4)°	T = 293 K
V = 1271.66 (10) Å³	Prism, blue
Z = 4	0.15 × 0.10 × 0.08 mm

Data collection top

Agilent SuperNova, Single source at offset, Eos diffractometer	1370 reflections with I > 2σ(I)
Detector resolution: 16.0233 pixels mm^-1	R_int = 0.029
ω scans	θ_max = 29.1°, θ_min = 3.4°
Absorption correction: multi-scan (CrysAlisPro; Agilent 2014)	h = −10→9
T_min = 0.816, T_max = 1.000	k = −15→15
4627 measured reflections	l = −18→13
1546 independent reflections

Refinement top

Refinement on F²	0 restraints
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F² > 2σ(F²)] = 0.028	H-atom parameters constrained
wR(F²) = 0.074	w = 1/[σ²(F_o²) + (0.0365P)² + 0.515P] where P = (F_o² + 2F_c²)/3
S = 1.08	(Δ/σ)_max = 0.027
1546 reflections	Δρ_max = 0.27 e Å⁻³
60 parameters	Δρ_min = −0.59 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.

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

	x	y	z	U_iso*/U_eq
Co1	0.500000	0.52995 (3)	0.750000	0.02694 (13)
Cl1	0.74705 (6)	0.42227 (4)	0.77647 (3)	0.03237 (14)
Cl2	0.54849 (7)	0.62944 (5)	0.61790 (4)	0.04332 (16)
N1	0.9250 (2)	0.51194 (13)	0.58839 (11)	0.0276 (3)
H1A	1.015221	0.493869	0.630538	0.033*
H1B	0.833857	0.527625	0.621121	0.033*
C1	0.8798 (2)	0.41357 (16)	0.52524 (14)	0.0290 (4)
H1C	0.774246	0.429831	0.483440	0.035*
H1D	0.856092	0.349324	0.564406	0.035*
C2	1.0282 (2)	0.38575 (15)	0.46508 (13)	0.0272 (4)
H2	1.130901	0.361989	0.507561	0.033*
C3	0.9775 (3)	0.29268 (17)	0.39440 (16)	0.0404 (5)
H3A	0.947344	0.226813	0.428597	0.061*
H3B	0.878228	0.315843	0.351734	0.061*
H3C	1.074621	0.276353	0.358031	0.061*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Co1	0.02007 (18)	0.0374 (2)	0.0236 (2)	0.000	0.00304 (14)	0.000
Cl1	0.0239 (2)	0.0401 (3)	0.0327 (3)	0.00345 (18)	0.00040 (18)	0.00462 (18)
Cl2	0.0334 (3)	0.0564 (3)	0.0408 (3)	0.0047 (2)	0.0073 (2)	0.0198 (2)
N1	0.0252 (7)	0.0368 (8)	0.0217 (8)	−0.0012 (6)	0.0072 (6)	0.0004 (6)
C1	0.0262 (9)	0.0337 (10)	0.0279 (10)	−0.0075 (7)	0.0065 (7)	−0.0013 (7)
C2	0.0253 (8)	0.0307 (9)	0.0255 (9)	0.0012 (7)	0.0023 (7)	0.0026 (7)
C3	0.0450 (11)	0.0375 (11)	0.0394 (12)	−0.0026 (9)	0.0074 (10)	−0.0076 (9)

Geometric parameters (Å, º) top

Co1—Cl2ⁱ	2.2588 (5)	C1—C2	1.513 (2)
Co1—Cl2	2.2588 (5)	C1—H1C	0.9700
Co1—Cl1	2.2846 (5)	C1—H1D	0.9700
Co1—Cl1ⁱ	2.2847 (5)	C2—C3	1.513 (3)
N1—C1	1.490 (2)	C2—H2	0.9800
N1—C2ⁱⁱ	1.494 (2)	C3—H3A	0.9600
N1—H1A	0.8900	C3—H3B	0.9600
N1—H1B	0.8900	C3—H3C	0.9600

Cl2ⁱ—Co1—Cl2	116.57 (3)	N1—C1—H1D	109.4
Cl2ⁱ—Co1—Cl1	111.157 (19)	C2—C1—H1D	109.4
Cl2—Co1—Cl1	103.324 (18)	H1C—C1—H1D	108.0
Cl2ⁱ—Co1—Cl1ⁱ	103.325 (18)	N1ⁱⁱ—C2—C1	109.15 (14)
Cl2—Co1—Cl1ⁱ	111.155 (19)	N1ⁱⁱ—C2—C3	109.31 (16)
Cl1—Co1—Cl1ⁱ	111.54 (3)	C1—C2—C3	111.50 (16)
C1—N1—C2ⁱⁱ	113.54 (15)	N1ⁱⁱ—C2—H2	108.9
C1—N1—H1A	108.9	C1—C2—H2	108.9
C2ⁱⁱ—N1—H1A	108.9	C3—C2—H2	108.9
C1—N1—H1B	108.9	C2—C3—H3A	109.5
C2ⁱⁱ—N1—H1B	108.9	C2—C3—H3B	109.5
H1A—N1—H1B	107.7	H3A—C3—H3B	109.5
N1—C1—C2	111.10 (14)	C2—C3—H3C	109.5
N1—C1—H1C	109.4	H3A—C3—H3C	109.5
C2—C1—H1C	109.4	H3B—C3—H3C	109.5

C2ⁱⁱ—N1—C1—C2	56.5 (2)	N1—C1—C2—C3	−174.91 (16)
N1—C1—C2—N1ⁱⁱ	−54.0 (2)

Symmetry codes: (i) −x+1, y, −z+3/2; (ii) −x+2, −y+1, −z+1.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···Cl1ⁱⁱⁱ	0.89	2.30	3.1777 (2)	171
N1—H1B···Cl1	0.89	2.65	3.2594 (2)	126
N1—H1B···Cl2	0.89	2.49	3.2631 (2)	145
C1—H1C···Cl2^iv	0.97	2.82	3.7065 (2)	153

Symmetry codes: (iii) −x+2, y, −z+3/2; (iv) −x+1, −y+1, −z+1.

Acknowledgements

We would like thank Professor Shu Hua Zhang from Guilin University of Technology for collecting the XRD data.

References

Agilent (2014). CrysAlis PRO. Agilent Technologies Ltd, Yarnton, England. Google Scholar
Altomare, A., Cascarano, G., Giacovazzo, C., Guagliardi, A., Burla, M. C., Polidori, G. & Camalli, M. (1994). J. Appl. Cryst. 27, 435. CrossRef Web of Science IUCr Journals Google Scholar
Ben Mleh, C., Roisnel, T. & Marouani, H. (2016). Acta Cryst. E72, 593–596. CSD CrossRef IUCr Journals Google Scholar
Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N. L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555–1573. CrossRef CAS Web of Science Google Scholar
Brandenburg, K. (2006). DIAMOND. Crystal Impact GbR, Bonn, Germany. Google Scholar
Burnett, M. N. & Johnson, C. K. (1996). ORTEPIII. Report ORNL-6895. Oak Ridge National Laboratory, Tennessee, USA. Google Scholar
Daszkiewicz, M. (2012). Struct. Chem. 23, 307–313. Web of Science CSD CrossRef CAS Google Scholar
Etter, M. C., MacDonald, J. C. & Bernstein, J. (1990). Acta Cryst. B46, 256–262. CrossRef ICSD CAS Web of Science IUCr Journals Google Scholar
Gatfaoui, S., Roisnel, T., Dhaouadi, H. & Marouani, H. (2014). Acta Cryst. E70, o725. CSD CrossRef IUCr Journals Google Scholar
McKinnon, J. J., Spackman, M. A. & Mitchell, A. S. (2004). Acta Cryst. B60, 627–668. Web of Science CrossRef CAS IUCr Journals Google Scholar
Pietraszko, A., Kirpichnikova, L. F., Sheleg, A. U. & Yachkovsky, A. Ya. (2006). Crystallogr. Rep. 51, 34–36. CrossRef CAS Google Scholar
Sheldrick, G. M. (2015). Acta Cryst. C71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Spackman, M. A. & Jayatilaka, D. (2009). CrystEngComm, 11, 19–32. Web of Science CrossRef CAS Google Scholar
Tahenti, M., Gatfaoui, S., Issaoui, N., Roisnel, T. & Marouani, H. (2020). J. Mol. Struct. 1207, 1–5. CSD CrossRef Google Scholar
Titi, A., Warad, I., Tillard, M., Touzani, R., Messali, M., El Kodadi, M., Eddike, D. & Zarrouk, A. (2020). J. Mol. Struct. 1217, 128422. CSD CrossRef Google Scholar
Vishwakarma, A. K., Kumari, R., Ghalsasi, P. S. & Arulsamy, N. (2017). J. Mol. Struct. 1141, 93–98. CSD CrossRef CAS Google Scholar
Wolff, S. K., Grimwood, D. J., McKinnon, J. J., Turner, M. J., Jayatilaka, D. & Spackman, M. A. (2013). Crystal Explorer. University of Western Australia. Google Scholar
Zeller, A., Herdtweck, E. & Strassner, T. (2005). Acta Cryst. C61, m46–m47. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Zhang, H., Fang, L. & Yuan, R. (2005). Acta Cryst. E61, m677–m678. Web of Science CSD CrossRef IUCr Journals Google Scholar

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