Crystal structure of bis­(2-amino-5-chloro­pyridinium) tetra­chlorido­cobaltate(II)

Mghandef, M.; Boughzala, H.

doi:10.1107/S2056989015007707

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Volume 71| Part 5| May 2015| Pages 555-557

https://doi.org/10.1107/S2056989015007707

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Crystal structure of bis(2-amino-5-chloropyridinium) tetrachloridocobaltate(II)

Marwa Mghandef ^a and Habib Boughzala ^a ^*

^aLaboratoire de Matériaux et Cristallochimie, Faculté des Sciences de Tunis, Université de Tunis El Manar, 2092 Manar II Tunis, Tunisia
^*Correspondence e-mail: habib.boughzala@ipein.rnu.tn

Edited by M. Weil, Vienna University of Technology, Austria (Received 11 April 2015; accepted 19 April 2015; online 25 April 2015)

The title salt, (C₅H₆ClN₂)₂[CoCl₄], was synthesized by slow evaporation of an aqueous solution at room temperature. The asymmetric unit consists of two essentially planar (C₅H₆ClN₂)⁺ cations [maximum deviations = 0.010 (3) and 0.014 (3) Å] that are nearly perpendicular to each other [dihedral angle = 84.12 (7)°]. They are bonded through N—H⋯Cl hydrogen bonds to distorted [CoCl₄]²⁻ tetrahedra, leading to the formation of undulating layers parallel to (100). The structure is isotypic with the Zn analogue [Kefi et. al (2011). Acta Cryst. E67, m355–m356.]

Keywords: crystal structure; cobalt(II) complex; 2-amino-5-chloropyridine; hydrogen bonding.

CCDC reference: 990478

1. Chemical context

Organic–inorganic hybrid compounds frequently exhibit self-organized structures and can combine organic and inorganic characteristics (Parent et al., 2007 ; Zheng et al., 2010 ; Chang et al., 2011 ). In particular, anionic cobalt halides associated with organic counter-cations have some interesting physical properties, such as luminescence, in which we are interested. In this communication, we report the synthesis and crystal structure of the new organic–inorganic hybrid compound bis(2-amino-5-chloropyridinium) tetrachloridocobaltate(II), (C₅H₆ClN₂)₂[CoCl₄].

2. Structural commentary

The asymmetric unit of the title compound consists of two 2-amino-5-chloropyridinium cations (cat1 consists of ring C1–C5/N2 and cat2 consists of ring C9–C10/N3) and one isolated [CoCl₄]²⁻ anion (Fig. 1).

Figure 1
The molecular entities of (C₅H₆ClN₂)₂[CoCl₄], showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.

The organic cations are nearly planar exhibiting small maximum deviations of 0.010 (3) and 0.014 (3) Å for atoms N2 and C6, respectively. The two least-squares planes of the two cations are nearly perpendicular to each other [84.12 (7)°]. The bond angles C4—N2—C5 [123.6 (3)°] and C9—N3—C10 [123.3 (3)°] in the rings of cat1 and cat2, respectively, confirm the presence of pyridinium cations. Previous studies (Jin et al., 2001 ) showed that a pyridinium cation possesses an expanded C—N(H)—C angle in comparison with the parent pyridine (117°). This geometrical characteristic is in agreement with an imine–enamine resonance (Jin et al., 2005 ) and contributes to the structural stability.

In the [CoCl₄]²⁻ anion, the Co—Cl bond lengths range from 2.2645 (12) to 2.2934 (12) Å and the Cl—Co—Cl angles range from 104.84 (5) to 118.58 (5)°, revealing considerable distortions from the ideal tetrahedral geometry. These values are in agreement with those observed in similar compounds (Dhieb et al., 2014 ; Mghandef & Boughzala, 2014 ; Oh et al., 2011 ). The different Co—Cl bond lengths in the [CoCl₄]²⁻ anion are related to the number of hydrogen bonds accepted by the Cl atoms. The Co—Cl1 and Co—Cl4 bonds are longer than the Co—Cl2 and Co—Cl3 bonds because atoms Cl1 and Cl4 are each acceptors of two hydrogen bonds from cat2 and cat1, respectively.

3. Supramolecular features

Each CoCl₄ tetrahedron is linked to four cations (two cat1 and two cat2) by hydrogen bonds (Fig. 2 and Table 1). Atom Cl1 is doubly linked to one cat2 cation by N3—HN3⋯Cl1 and N4—H4A⋯Cl1, and atom Cl2 establishes one hydrogen bond with a symmetry-related cat2 cation via N4—H4B⋯Cl2. Atom Cl3 is linked to cation cat1 by N1—H1B⋯Cl3 and atom Cl4 again shares two hydrogen bonds (N1—H1A⋯Cl4 and N2—HN2⋯Cl4) with a second symmetry-related cat1 cation. The hydrogen-bonding environments of the two cations are similar. Both are linked to two CoCl₄ tetrahedra by three hydrogen bonds (Fig. 3)

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1A⋯Cl4ⁱ	0.86	2.64	3.400 (4)	148
N1—H1B⋯Cl3ⁱⁱ	0.86	2.47	3.317 (3)	169
N2—HN2⋯Cl4ⁱ	0.86	2.42	3.238 (3)	160
N3—HN3⋯Cl1ⁱⁱⁱ	0.86	2.42	3.251 (3)	164
N4—H4A⋯Cl1ⁱⁱⁱ	0.86	2.77	3.519 (4)	147
N4—H4B⋯Cl2^iv	0.86	2.80	3.541 (4)	145
Symmetry codes: (i) -x+2, -y+1, -z+1; (ii) $[x, -y+{\script{3\over 2}}, z+{\script{1\over 2}}]$ ; (iii) $[-x+1, y+{\script{1\over 2}}, -z+{\script{1\over 2}}]$ ; (iv) -x+1, -y+1, -z+1.

Figure 2
The environment of the CoCl₄ tetrahedron.

Figure 3
The environment around the cations (cat1 or cat2).

The crystal packing can be described by an alternate stacking of cations and anions with a –cat1–[CoCl₄]–cat2–[CoCl₄]– sequence along [100], as shown in Fig. 4. Between antiparallel aligned cat2 cations, π–π interactions are also present [centroid-to-centroid separation = 3.900 (2) Å]. The stacked cations and anions are linked through N—H⋯Cl hydrogen bonds into zigzag layers parallel to (100) (Fig. 5).

Figure 4
Projection of the crystal structure along [010] showing the –cat1–[CoCl₄]–cat2–[CoCl₄]– sequence stacked along [100].

Figure 5
Projection of the crystal structure along [001] showing the layered character of the hydrogen-bonded components.

4. Database survey

A systematic search procedure in the Cambridge Structural Database (Groom & Allen, 2014 ) indicates a total of 32 hits for the 2-amino-5-chloropyridinium cation with various counter-anions. For tetrahalogenidometalate anions, the following structures have been reported: (C₅H₆ClN₂)₂[ZnCl₄]·H₂O (Coomer et al., 2007 ); (C₅H₆ClN₂)₂[ZnCl₄] (Kefi et al., 2011a ); (C₅H₆ClN₂)₂[CdCl₄]·H₂O (Kefi et al., 2011b ); (C₅H₆ClN₂)₂[CuCl₄] (Parsons et al., 2006 ); (C₅H₆ClN₂)₂[CuBr₄] (Woodward et al., 2002 ). The title compound is isotypic with the Zn analogue (C₅H₆ClN₂)₂[ZnCl₄] (Kefi et al., 2011a).

5. Synthesis and crystallization

A mixture of cobalt(II) chloride and 2-amino-5-chloropyridine (molar ratio 1:1) was dissolved in an aqueous solution of hydrochloric acid with 5 ml of ethanol. The mixture was stirred and then kept at room temperature. Blue crystals of the title compound were obtained after two weeks.

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. H atoms were placed geometrically and included as riding contributions, with N—H = 0.86 Å and C—H = 0.93 Å and with U_iso(H) = 1.2U_eq(N,C).

Table 2
Experimental details

Crystal data
Chemical formula	(C₅H₆ClN₂)₂[CoCl₄]
M_r	459.87
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	298
a, b, c (Å)	13.519 (2), 14.945 (3), 8.725 (2)
β (°)	92.858 (3)
V (Å³)	1760.6 (6)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	1.88
Crystal size (mm)	0.5 × 0.3 × 0.2

Data collection
Diffractometer	Enraf–Nonius CAD-4
Absorption correction	ψ scan (North et al., 1968 )
T_min, T_max	0.423, 0.649
No. of measured, independent and observed [I > 2σ(I)] reflections	6241, 3707, 2121
R_int	0.039
(sin θ/λ)_max (Å⁻¹)	0.638

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.041, 0.109, 0.99
No. of reflections	3707
No. of parameters	190
H-atom treatment	H-atom parameters not refined
Δρ_max, Δρ_min (e Å⁻³)	0.52, −0.34
Computer programs: CAD-4 EXPRESS (Enraf–Nonius, 1994 ), XCAD4 (Harms & Wocadlo, 1995 ), SHELXS97 and SHELXL97 (Sheldrick, 2008 ), DIAMOND (Brandenburg, 2008 ) and publCIF (Westrip, 2010 ).

Supporting information

CCDC reference: 990478

Crystal structure: contains datablocks I, New_Global_Publ_Block. DOI: https://doi.org/10.1107/S2056989015007707/wm5146sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989015007707/wm5146Isup2.hkl

checkCIF report

Computing details top

Data collection: CAD-4 EXPRESS (Enraf–Nonius, 1994); cell refinement: CAD-4 EXPRESS (Enraf–Nonius, 1994); data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2008); software used to prepare material for publication: publCIF (Westrip, 2010).

Bis(2-amino-5-chloropyridinium) tetrachloridocobaltate(II) top

Crystal data top

(C₅H₆ClN₂)₂[CoCl₄]	F(000) = 916
M_r = 459.87	D_x = 1.735 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 25 reflections
a = 13.519 (2) Å	θ = 10–15°
b = 14.945 (3) Å	µ = 1.88 mm⁻¹
c = 8.725 (2) Å	T = 298 K
β = 92.858 (3)°	Prism, blue
V = 1760.6 (6) Å³	0.5 × 0.3 × 0.2 mm
Z = 4

Data collection top

Enraf–Nonius CAD-4 diffractometer	2121 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.039
Graphite monochromator	θ_max = 27.0°, θ_min = 2.0°
non–profiled ω/2τ scans	h = −17→17
Absorption correction: ψ scan (North et al., 1968)	k = −19→1
T_min = 0.423, T_max = 0.649	l = −11→5
6241 measured reflections	2 standard reflections every 120 min
3707 independent reflections	intensity decay: 6%

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)] = 0.041	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.109	H-atom parameters not refined
S = 0.99	w = 1/[σ²(F_o²) + (0.0443P)²] where P = (F_o² + 2F_c²)/3
3707 reflections	(Δ/σ)_max < 0.001
190 parameters	Δρ_max = 0.52 e Å⁻³
0 restraints	Δρ_min = −0.34 e Å⁻³

Special details top

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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 > σ(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
Co	0.75262 (3)	0.48488 (3)	0.01742 (6)	0.03927 (16)
Cl1	0.66040 (7)	0.47789 (7)	−0.20888 (12)	0.0475 (3)
Cl2	0.64020 (8)	0.48540 (8)	0.20135 (13)	0.0580 (3)
Cl3	0.85951 (8)	0.60044 (7)	0.05556 (14)	0.0580 (3)
Cl4	0.84305 (8)	0.35504 (7)	0.03059 (15)	0.0690 (4)
Cl5	0.83772 (8)	0.37281 (8)	0.53616 (14)	0.0646 (3)
Cl6	0.68358 (8)	0.75291 (9)	0.29194 (14)	0.0672 (4)
N1	0.9792 (2)	0.7278 (2)	0.7188 (4)	0.0616 (11)
H1A	1.0247	0.7306	0.7912	0.074*
H1B	0.9565	0.7762	0.6768	0.074*
N2	0.9798 (2)	0.5740 (2)	0.7372 (4)	0.0430 (8)
HN2	1.0261	0.5790	0.8078	0.052*
N3	0.4647 (2)	0.8197 (2)	0.5514 (4)	0.0444 (8)
HN3	0.4394	0.8686	0.5834	0.053*
N4	0.3491 (2)	0.7428 (2)	0.6902 (4)	0.0557 (9)
H4A	0.3264	0.7931	0.7210	0.067*
H4B	0.3233	0.6935	0.7195	0.067*
C1	0.8770 (3)	0.4802 (3)	0.5868 (5)	0.0427 (9)
C2	0.8694 (3)	0.6385 (3)	0.5537 (5)	0.0498 (11)
H2	0.8425	0.6887	0.5045	0.060*
C3	0.8370 (3)	0.5557 (3)	0.5125 (5)	0.0503 (11)
H3	0.7880	0.5492	0.4346	0.060*
C4	0.9472 (3)	0.4907 (2)	0.6989 (5)	0.0458 (10)
H4	0.9736	0.4411	0.7504	0.055*
C5	0.9440 (3)	0.6484 (2)	0.6714 (5)	0.0418 (9)
C6	0.5837 (3)	0.7483 (3)	0.4092 (4)	0.0451 (10)
C7	0.5437 (3)	0.6658 (3)	0.4521 (5)	0.0550 (11)
H7	0.5707	0.6129	0.4168	0.066*
C8	0.4669 (3)	0.6625 (3)	0.5436 (5)	0.0536 (11)
H8	0.4413	0.6075	0.5720	0.064*
C9	0.4253 (3)	0.7413 (3)	0.5959 (4)	0.0444 (10)
C10	0.5418 (3)	0.8250 (3)	0.4591 (4)	0.0433 (9)
H10	0.5659	0.8804	0.4301	0.052*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Co	0.0394 (3)	0.0288 (3)	0.0492 (4)	−0.0023 (2)	−0.0018 (2)	−0.0013 (3)
Cl1	0.0502 (5)	0.0460 (6)	0.0459 (6)	0.0005 (5)	−0.0002 (4)	0.0005 (5)
Cl2	0.0679 (6)	0.0542 (7)	0.0534 (7)	−0.0144 (5)	0.0158 (5)	−0.0045 (6)
Cl3	0.0587 (6)	0.0409 (6)	0.0740 (8)	−0.0159 (5)	−0.0008 (5)	−0.0049 (6)
Cl4	0.0673 (7)	0.0336 (6)	0.1025 (10)	0.0110 (5)	−0.0328 (7)	−0.0098 (6)
Cl5	0.0688 (7)	0.0414 (6)	0.0842 (9)	−0.0114 (5)	0.0087 (6)	−0.0175 (6)
Cl6	0.0545 (6)	0.0911 (10)	0.0556 (7)	0.0035 (6)	−0.0007 (5)	0.0019 (7)
N1	0.072 (2)	0.031 (2)	0.079 (3)	−0.0005 (17)	−0.020 (2)	0.0032 (19)
N2	0.0468 (17)	0.0315 (18)	0.050 (2)	0.0029 (14)	−0.0070 (15)	0.0019 (16)
N3	0.058 (2)	0.0224 (16)	0.052 (2)	0.0068 (15)	−0.0028 (17)	−0.0015 (16)
N4	0.060 (2)	0.048 (2)	0.058 (2)	−0.0021 (17)	−0.0021 (19)	0.0081 (19)
C1	0.046 (2)	0.035 (2)	0.048 (2)	−0.0022 (18)	0.0102 (18)	−0.008 (2)
C2	0.049 (2)	0.041 (2)	0.058 (3)	0.0069 (19)	−0.009 (2)	0.010 (2)
C3	0.044 (2)	0.050 (3)	0.055 (3)	0.0022 (19)	−0.0083 (19)	−0.002 (2)
C4	0.054 (2)	0.025 (2)	0.058 (3)	0.0077 (17)	0.005 (2)	0.003 (2)
C5	0.044 (2)	0.031 (2)	0.051 (3)	0.0023 (17)	0.0027 (18)	0.006 (2)
C6	0.049 (2)	0.048 (3)	0.038 (2)	0.0016 (19)	−0.0102 (18)	−0.001 (2)
C7	0.082 (3)	0.035 (2)	0.048 (3)	0.007 (2)	−0.002 (2)	−0.001 (2)
C8	0.080 (3)	0.032 (2)	0.049 (3)	−0.006 (2)	0.003 (2)	0.005 (2)
C9	0.050 (2)	0.037 (2)	0.045 (2)	−0.0010 (18)	−0.0099 (19)	0.006 (2)
C10	0.049 (2)	0.037 (2)	0.043 (2)	−0.0078 (18)	−0.0065 (19)	0.0046 (19)

Geometric parameters (Å, º) top

Co—Cl2	2.2645 (12)	N4—H4A	0.8600
Co—Cl3	2.2657 (11)	N4—H4B	0.8600
Co—Cl1	2.2843 (12)	C1—C4	1.337 (5)
Co—Cl4	2.2934 (12)	C1—C3	1.397 (6)
Cl5—C1	1.741 (4)	C2—C3	1.355 (6)
Cl6—C6	1.735 (4)	C2—C5	1.410 (5)
N1—C5	1.337 (5)	C2—H2	0.9300
N1—H1A	0.8600	C3—H3	0.9300
N1—H1B	0.8600	C4—H4	0.9300
N2—C5	1.331 (4)	C6—C10	1.360 (5)
N2—C4	1.357 (5)	C6—C7	1.405 (6)
N2—HN2	0.8600	C7—C8	1.342 (6)
N3—C10	1.351 (5)	C7—H7	0.9300
N3—C9	1.352 (5)	C8—C9	1.392 (6)
N3—HN3	0.8600	C8—H8	0.9300
N4—C9	1.351 (5)	C10—H10	0.9300

Cl2—Co—Cl3	109.81 (5)	C2—C3—C1	120.1 (4)
Cl2—Co—Cl1	104.84 (5)	C2—C3—H3	119.9
Cl3—Co—Cl1	118.58 (5)	C1—C3—H3	119.9
Cl2—Co—Cl4	110.02 (5)	C1—C4—N2	119.9 (4)
Cl3—Co—Cl4	107.65 (5)	C1—C4—H4	120.1
Cl1—Co—Cl4	105.73 (4)	N2—C4—H4	120.1
C5—N1—H1A	120.0	N2—C5—N1	119.5 (3)
C5—N1—H1B	120.0	N2—C5—C2	117.2 (3)
H1A—N1—H1B	120.0	N1—C5—C2	123.3 (3)
C5—N2—C4	123.6 (3)	C10—C6—C7	118.8 (4)
C5—N2—HN2	118.2	C10—C6—Cl6	120.2 (3)
C4—N2—HN2	118.2	C7—C6—Cl6	120.9 (3)
C10—N3—C9	123.3 (3)	C8—C7—C6	120.7 (4)
C10—N3—HN3	118.4	C8—C7—H7	119.7
C9—N3—HN3	118.4	C6—C7—H7	119.7
C9—N4—H4A	120.0	C7—C8—C9	120.1 (4)
C9—N4—H4B	120.0	C7—C8—H8	120.0
H4A—N4—H4B	120.0	C9—C8—H8	120.0
C4—C1—C3	119.2 (4)	N4—C9—N3	118.9 (4)
C4—C1—Cl5	119.4 (3)	N4—C9—C8	123.1 (4)
C3—C1—Cl5	121.4 (3)	N3—C9—C8	117.9 (4)
C3—C2—C5	119.9 (4)	N3—C10—C6	119.2 (4)
C3—C2—H2	120.0	N3—C10—H10	120.4
C5—C2—H2	120.0	C6—C10—H10	120.4

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···Cl4ⁱ	0.86	2.64	3.400 (4)	148
N1—H1B···Cl3ⁱⁱ	0.86	2.47	3.317 (3)	169
N2—HN2···Cl4ⁱ	0.86	2.42	3.238 (3)	160
N3—HN3···Cl1ⁱⁱⁱ	0.86	2.42	3.251 (3)	164
N4—H4A···Cl1ⁱⁱⁱ	0.86	2.77	3.519 (4)	147
N4—H4B···Cl2^iv	0.86	2.80	3.541 (4)	145

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

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