Bis(tri­ethyl­ammonium) tetra­bromido­zincate

Seck, G.A.; Sene, A.; Diop, L.; Schmidt, H.

doi:10.1107/S2414314616013171

metal-organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 1| Part 8| August 2016| x161317

doi:10.1107/S2414314616013171

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Bis(triethylammonium) tetrabromidozincate

Gorgui Awa Seck,^a Aboubacary Sene,^a Libasse Diop ^a ^* and Horst Schmidt ^b

^aLaboratoire de Chimie Minérale et Analytique, Département de Chimie, Faculté des Sciences et Techniques, Université Cheikh Anta Diop, Dakar, Senegal, and ^bInstitute of Inorganic Chemistry, TU Bergakademie Freiberg, Leipziger Strasse 29, D-09596 Freiberg, Germany
^*Correspondence e-mail: dlibasse@gmail.com

Edited by H. Stoeckli-Evans, University of Neuchâtel, Switzerland (Received 8 August 2016; accepted 16 August 2016; online 19 August 2016)

The title molecular salt, (C₆H₁₆N)[ZnBr₄], consists of a tetrahedral tetrabromidozincate dianion and two triethylammonium cations linked by N—H⋯Br hydrogen bonds. In the crystal, these three-membered units are linked via C—H⋯Br hydrogen bonds, forming layers parallel to the ab plane.

Keywords: crystal structure; tetrahedral; tetrabromozincate; triethylammonium ions; N—H⋯Br hydrogen bonds.

CCDC reference: 1499335

Structure description

Many authors worldwide have synthesized ammonium salts of numerous acids for different purposes (Mouchaham et al., 2015 ; Hamdouni et al., 2015 ). A heterodinuclear complex containing [ZnBr₄]²⁻ and triethylammonium ions with an Ru component has been reported (Mauthner et al., 1999 ). The Senegalese group has used amines such as dipropylamine, diisopropylamine, monocyclohexylamine, dicyclohexylamine, dibutylamine, methyl-2-imidazole, ethylendiamine for obtaining the corresponding salts with sulfuric, oxalic and sulfonic acids and have reacted theirs salts with stannic organo- or halidostannate compounds or transition metal halides (Sarr et al., 2014 ; Diop et al., 2016 ). In this context, (Et₃NH)₂·C₂O₄ has been allowed to react in ethanol with ZnBr₂ and crystals of the title molecular salt were obtained.

The molecular structure of the title molecular salt is shown in Fig. 1. It consists of a tetrahedral [ZnBr₄]²⁻ dianion and two triethylammonium ions linked by N—H⋯Br hydrogen bonds (Table 1). The four Br atoms are non-equivalent; their distances range from 2.3945 (13) to 2.4408 (14) Å. Two of the Br atoms, Br3 and Br4, are involved in hydrogen bonds (Fig. 1 and Table 1) and their distances to the Zn atom are 2.4408 (14) and 2.4228 (13) Å, respectively. Atoms Br1 and Br2, which are not involved in N—H⋯Br hydrogen bonding, have shorter Zn—Br bond lengths [2.3945 (13) and 2.3947 (13) Å, respectively]. The Br—Zn—Br angles vary from 107.20 (2) to 112.91 (2)°, indicating a slightly distorted tetrahedron around the Zn atom with a τ₄ geometry index of 0.95 (for a perfect tetrahedron τ₄ is equal to 1; Yang et al., 2007 ).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯Br4	0.94 (3)	2.44 (3)	3.367 (3)	166 (3)
N2—H2⋯Br3ⁱ	0.81 (4)	2.58 (4)	3.380 (3)	171 (3)
C7—H7B⋯Br3ⁱⁱ	0.97	2.92	3.791 (5)	150
C9—H9B⋯Br1ⁱⁱⁱ	0.97	2.84	3.715 (5)	150
Symmetry codes: (i) $[x-{\script{1\over 2}}, y, -z+{\script{1\over 2}}]$ ; (ii) x-1, y, z; (iii) $[-x+{\script{3\over 2}}, y+{\script{1\over 2}}, z]$ .

Figure 1
A view of the molecular structure of the title molecular salt, showing the atom labelling. Displacement ellipsoids are drawn at the 50% probability level. The N—H⋯Br hydrogen bonds are shown as dashed lines (see Table 1

). [Symmetry code: (i) x + $[{1\over 2}]$ , y, −z + $[{1\over 2}]$ .]

In the crystal, the (Et₃NH)₂·ZnBr₄ hydrogen-bonded species are connected to their neighbours through C—H⋯Br hydrogen bonds, forming layers parallel to the ab plane (Table 1 and Fig. 2).

Figure 2
A view along the c axis of the crystal packing of the title molecular salt. Hydrogen bonds are shown as dashed lines (see Table 1

) and H atoms not involved in these interactions have been omitted for clarity.

Synthesis and crystallization

Oxalic acid was totally neutralized with Et₃NH in water giving (Et₃NH)₂C₂O₄, which was then mixed with ZnBr₂ in ethanol in a 1:1 ratio. A white precipitate was obtained and filtered. The filtrate was allowed to evaporate slowly at room temperature giving colourless crystals of the title molecular salt, suitable for X-ray diffraction analysis.

Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2.

Table 2
Experimental details

Crystal data
Chemical formula	(C₆H₁₆N)₂[ZnBr₄]
M_r	589.40
Crystal system, space group	Orthorhombic, Pbca
Temperature (K)	150
a, b, c (Å)	12.383 (6), 13.145 (6), 26.510 (11)
V (Å³)	4315 (4)
Z	8
Radiation type	Mo Kα
μ (mm⁻¹)	8.54
Crystal size (mm)	0.5 × 0.2 × 0.1

Data collection
Diffractometer	Stoe IPDS 2T
Absorption correction	Integration (Coppens, 1970 )
T_min, T_max	0.074, 0.135
No. of measured, independent and observed [I > 2σ(I)] reflections	35899, 4604, 3820
R_int	0.066
(sin θ/λ)_max (Å⁻¹)	0.635

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.024, 0.045, 1.02
No. of reflections	4597
No. of parameters	186
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.69, −0.54
Computer programs: X-AREA (Stoe & Cie, 2009 ), X-RED (Stoe & Cie, 2009), SHELXS97 (Sheldrick, 2008 ), Mercury (Macrae et al., 2008 ), SHELXL2014 (Sheldrick, 2015 ), PLATON (Spek, 2009 ) and publCIF (Westrip, 2010 ).

Structural data

CCDC reference: 1499335

Crystal structure: contains datablocks I, Global. DOI: 10.1107/S2414314616013171/su5321sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S2414314616013171/su5321Isup2.hkl

checkCIF report

Computing details top

Data collection: X-AREA (Stoe & Cie, 2009); cell refinement: X-AREA (Stoe & Cie, 2009); data reduction: X-RED (Stoe & Cie, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL2014 (Sheldrick, 2015), PLATON (Spek, 2009) and publCIF (Westrip, 2010).

Bis(triethylammonium) tetrabromidozincate top

Crystal data top

(C₆H₁₆N)₂[ZnBr₄]	D_x = 1.814 Mg m⁻³
M_r = 589.40	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Pbca	Cell parameters from 707 reflections
a = 12.383 (6) Å	θ = 2.8–24.4°
b = 13.145 (6) Å	µ = 8.54 mm⁻¹
c = 26.510 (11) Å	T = 150 K
V = 4315 (4) Å³	Plate, colourless
Z = 8	0.5 × 0.2 × 0.1 mm
F(000) = 2304

Data collection top

Stoe IPDS 2T diffractometer	4604 independent reflections
Radiation source: sealed X-ray tube, 12 x 0.4 mm long-fine focus	3820 reflections with I > 2σ(I)
Detector resolution: 6.67 pixels mm^-1	R_int = 0.066
combination of /w– and /f–scans	θ_max = 26.8°, θ_min = 2.4°
Absorption correction: integration (Coppens, 1970)	h = −15→15
T_min = 0.074, T_max = 0.135	k = −16→16
35899 measured reflections	l = −33→31

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: mixed
wR(F²) = 0.045	H atoms treated by a mixture of independent and constrained refinement
S = 1.02	w = 1/[σ²(F_o²) + (0.0131P)² + 0.7809P] where P = (F_o² + 2F_c²)/3
4597 reflections	(Δ/σ)_max = 0.001
186 parameters	Δρ_max = 0.69 e Å⁻³
0 restraints	Δρ_min = −0.54 e Å⁻³

Special details top

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell esds are taken into account in the estimation of distances, angles and torsion angles

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

	x	y	z	U_iso*/U_eq
Br1	1.07931 (3)	0.07296 (3)	0.37735 (2)	0.0331 (1)
Br2	0.77855 (3)	0.15351 (3)	0.41392 (2)	0.0375 (1)
Br3	0.90854 (3)	0.23837 (3)	0.28535 (2)	0.0347 (1)
Br4	1.01299 (3)	0.35305 (3)	0.41642 (2)	0.0454 (1)
Zn1	0.94409 (3)	0.20302 (3)	0.37420 (2)	0.0270 (1)
N1	0.8953 (2)	0.2988 (2)	0.52772 (10)	0.0266 (8)
C1	0.8993 (3)	0.1880 (2)	0.54246 (13)	0.0300 (10)
C2	1.0072 (3)	0.1401 (3)	0.53058 (14)	0.0406 (11)
C3	0.7812 (2)	0.3369 (3)	0.52691 (14)	0.0323 (10)
C4	0.7718 (3)	0.4452 (3)	0.50953 (15)	0.0417 (12)
C5	0.9698 (3)	0.3640 (3)	0.55787 (15)	0.0379 (11)
C6	0.9399 (4)	0.3717 (3)	0.61273 (15)	0.0600 (14)
N2	0.2290 (2)	0.4253 (2)	0.23986 (11)	0.0305 (9)
C7	0.1726 (3)	0.3843 (4)	0.28569 (14)	0.0487 (13)
C8	0.2462 (3)	0.3374 (3)	0.32364 (13)	0.0419 (13)
C9	0.2943 (3)	0.5177 (3)	0.25324 (16)	0.0470 (12)
C10	0.3711 (3)	0.5483 (4)	0.21273 (17)	0.0563 (16)
C11	0.1516 (3)	0.4464 (3)	0.19735 (14)	0.0390 (11)
C12	0.1047 (3)	0.3521 (3)	0.17426 (14)	0.0407 (12)
H1	0.918 (3)	0.308 (2)	0.4941 (12)	0.023 (8)*
H1A	0.84290	0.15150	0.52470	0.0360*
H1B	0.88530	0.18190	0.57830	0.0360*
H2A	1.02130	0.14560	0.49510	0.0610*
H2B	1.00590	0.06960	0.54010	0.0610*
H2C	1.06300	0.17450	0.54900	0.0610*
H3A	0.75100	0.33130	0.56060	0.0390*
H3B	0.73880	0.29390	0.50470	0.0390*
H4A	0.80090	0.48960	0.53490	0.0620*
H4B	0.69720	0.46140	0.50390	0.0620*
H4C	0.81140	0.45380	0.47870	0.0620*
H5A	0.97060	0.43180	0.54340	0.0460*
H5B	1.04240	0.33670	0.55530	0.0460*
H6A	0.86730	0.39670	0.61570	0.0900*
H6B	0.98840	0.41770	0.62940	0.0900*
H6C	0.94480	0.30570	0.62810	0.0900*
H2	0.271 (3)	0.382 (3)	0.2304 (13)	0.027 (10)*
H7A	0.13310	0.43920	0.30170	0.0580*
H7B	0.12040	0.33360	0.27500	0.0580*
H8A	0.28780	0.28460	0.30790	0.0630*
H8B	0.20430	0.30900	0.35070	0.0630*
H8C	0.29400	0.38840	0.33680	0.0630*
H9A	0.24560	0.57390	0.26000	0.0560*
H9B	0.33460	0.50410	0.28390	0.0560*
H10A	0.41190	0.49010	0.20200	0.0840*
H10B	0.41940	0.59940	0.22540	0.0840*
H10C	0.33150	0.57520	0.18460	0.0840*
H11A	0.09320	0.48850	0.20990	0.0470*
H11B	0.18900	0.48470	0.17140	0.0470*
H12A	0.16200	0.31020	0.16140	0.0610*
H12B	0.05720	0.37060	0.14720	0.0610*
H12C	0.06510	0.31520	0.19940	0.0610*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Br1	0.0319 (2)	0.0318 (2)	0.0355 (2)	0.0054 (2)	−0.0045 (2)	−0.0037 (2)
Br2	0.0293 (2)	0.0476 (2)	0.0356 (2)	−0.0069 (2)	0.0061 (1)	0.0024 (2)
Br3	0.0343 (2)	0.0374 (2)	0.0324 (2)	0.0045 (2)	0.0021 (2)	0.0077 (2)
Br4	0.0590 (2)	0.0294 (2)	0.0479 (2)	−0.0174 (2)	0.0234 (2)	−0.0132 (2)
Zn1	0.0272 (2)	0.0244 (2)	0.0294 (2)	−0.0007 (2)	0.0036 (2)	−0.0002 (2)
N1	0.0255 (14)	0.0247 (14)	0.0297 (14)	−0.0031 (12)	0.0046 (11)	−0.0023 (12)
C1	0.0351 (18)	0.0218 (17)	0.0331 (17)	−0.0007 (15)	0.0026 (14)	−0.0016 (14)
C2	0.046 (2)	0.034 (2)	0.0419 (19)	0.0124 (18)	0.0048 (17)	0.0007 (18)
C3	0.0246 (16)	0.0295 (19)	0.0429 (19)	0.0007 (15)	0.0031 (15)	−0.0050 (16)
C4	0.034 (2)	0.036 (2)	0.055 (2)	0.0075 (17)	−0.0011 (17)	−0.0007 (19)
C5	0.0260 (17)	0.0247 (19)	0.063 (2)	−0.0015 (15)	−0.0083 (16)	−0.0043 (18)
C6	0.090 (3)	0.040 (2)	0.050 (2)	−0.006 (2)	−0.033 (2)	−0.006 (2)
N2	0.0283 (15)	0.0290 (16)	0.0341 (16)	−0.0002 (14)	−0.0049 (12)	−0.0020 (13)
C7	0.0312 (18)	0.074 (3)	0.041 (2)	−0.001 (2)	0.0059 (17)	0.002 (2)
C8	0.0378 (19)	0.053 (3)	0.0350 (17)	−0.0027 (19)	0.0076 (17)	0.0070 (19)
C9	0.049 (2)	0.041 (2)	0.051 (2)	−0.0059 (19)	−0.0137 (19)	−0.005 (2)
C10	0.046 (2)	0.056 (3)	0.067 (3)	−0.021 (2)	−0.015 (2)	0.020 (2)
C11	0.0360 (19)	0.036 (2)	0.045 (2)	0.0021 (17)	−0.0153 (17)	−0.0002 (17)
C12	0.042 (2)	0.038 (2)	0.042 (2)	−0.0006 (19)	−0.0147 (16)	−0.0030 (18)

Geometric parameters (Å, º) top

Br1—Zn1	2.3945 (13)	C5—H5B	0.9700
Br2—Zn1	2.3947 (13)	C5—H5A	0.9700
Br3—Zn1	2.4408 (14)	C6—H6B	0.9600
Br4—Zn1	2.4228 (13)	C6—H6C	0.9600
N1—C5	1.492 (5)	C6—H6A	0.9600
N1—C1	1.509 (4)	N2—H2	0.81 (4)
N1—C3	1.499 (4)	C7—C8	1.491 (5)
N1—H1	0.94 (3)	C9—C10	1.490 (6)
C1—C2	1.510 (5)	C11—C12	1.500 (6)
C3—C4	1.501 (6)	C7—H7A	0.9700
C5—C6	1.504 (6)	C7—H7B	0.9700
C1—H1A	0.9700	C8—H8C	0.9600
C1—H1B	0.9700	C8—H8A	0.9600
C2—H2B	0.9600	C8—H8B	0.9600
C2—H2C	0.9600	C9—H9B	0.9700
C2—H2A	0.9600	C9—H9A	0.9700
N2—C11	1.505 (5)	C10—H10A	0.9600
N2—C7	1.501 (5)	C10—H10B	0.9600
N2—C9	1.502 (5)	C10—H10C	0.9600
C3—H3A	0.9700	C11—H11A	0.9700
C3—H3B	0.9700	C11—H11B	0.9700
C4—H4C	0.9600	C12—H12B	0.9600
C4—H4A	0.9600	C12—H12C	0.9600
C4—H4B	0.9600	C12—H12A	0.9600

Br1—Zn1—Br3	107.20 (2)	H6A—C6—H6C	109.00
Br1—Zn1—Br4	108.59 (2)	C5—C6—H6C	110.00
Br2—Zn1—Br3	108.77 (2)	H6A—C6—H6B	109.00
Br2—Zn1—Br4	108.64 (2)	C5—C6—H6B	109.00
Br3—Zn1—Br4	110.75 (2)	H6B—C6—H6C	110.00
Br1—Zn1—Br2	112.91 (2)	C5—C6—H6A	109.00
C1—N1—C5	113.3 (3)	C11—N2—H2	108 (2)
C1—N1—C3	110.9 (3)	C7—N2—H2	107 (3)
C3—N1—C5	113.5 (3)	C9—N2—H2	107 (3)
C1—N1—H1	111.0 (16)	N2—C7—C8	114.2 (3)
N1—C1—C2	112.2 (3)	N2—C9—C10	113.1 (3)
C3—N1—H1	103 (2)	N2—C11—C12	113.6 (3)
C5—N1—H1	104 (2)	N2—C7—H7B	109.00
N1—C3—C4	113.2 (3)	N2—C7—H7A	109.00
N1—C5—C6	113.9 (3)	C8—C7—H7A	109.00
C2—C1—H1B	109.00	C8—C7—H7B	109.00
H1A—C1—H1B	108.00	H7A—C7—H7B	108.00
N1—C1—H1A	109.00	H8A—C8—H8B	109.00
N1—C1—H1B	109.00	H8A—C8—H8C	109.00
C2—C1—H1A	109.00	H8B—C8—H8C	109.00
C7—N2—C9	110.5 (3)	C7—C8—H8A	109.00
C1—C2—H2A	110.00	C7—C8—H8B	110.00
C1—C2—H2B	109.00	C7—C8—H8C	109.00
C1—C2—H2C	110.00	C10—C9—H9A	109.00
H2A—C2—H2B	109.00	N2—C9—H9A	109.00
H2A—C2—H2C	109.00	N2—C9—H9B	109.00
H2B—C2—H2C	109.00	C10—C9—H9B	109.00
C7—N2—C11	112.1 (3)	H9A—C9—H9B	108.00
C9—N2—C11	111.8 (3)	C9—C10—H10B	110.00
N1—C3—H3A	109.00	C9—C10—H10A	110.00
C4—C3—H3B	109.00	H10A—C10—H10B	109.00
N1—C3—H3B	109.00	H10A—C10—H10C	109.00
C4—C3—H3A	109.00	C9—C10—H10C	109.00
H3A—C3—H3B	108.00	H10B—C10—H10C	109.00
H4B—C4—H4C	109.00	C12—C11—H11A	109.00
C3—C4—H4C	109.00	C12—C11—H11B	109.00
H4A—C4—H4B	110.00	N2—C11—H11A	109.00
H4A—C4—H4C	109.00	N2—C11—H11B	109.00
C3—C4—H4B	109.00	H11A—C11—H11B	108.00
C3—C4—H4A	109.00	H12B—C12—H12C	110.00
N1—C5—H5B	109.00	C11—C12—H12A	109.00
N1—C5—H5A	109.00	C11—C12—H12B	109.00
H5A—C5—H5B	108.00	C11—C12—H12C	109.00
C6—C5—H5A	109.00	H12A—C12—H12B	109.00
C6—C5—H5B	109.00	H12A—C12—H12C	110.00

C3—N1—C1—C2	164.9 (3)	C9—N2—C7—C8	−69.6 (4)
C5—N1—C1—C2	−66.1 (4)	C11—N2—C7—C8	165.0 (3)
C1—N1—C3—C4	−176.6 (3)	C7—N2—C9—C10	167.1 (3)
C5—N1—C3—C4	54.5 (4)	C11—N2—C9—C10	−67.4 (4)
C1—N1—C5—C6	−66.3 (4)	C7—N2—C11—C12	−69.5 (4)
C3—N1—C5—C6	61.4 (4)	C9—N2—C11—C12	165.8 (3)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···Br4	0.94 (3)	2.44 (3)	3.367 (3)	166 (3)
N2—H2···Br3ⁱ	0.81 (4)	2.58 (4)	3.380 (3)	171 (3)
C7—H7B···Br3ⁱⁱ	0.97	2.92	3.791 (5)	150
C9—H9B···Br1ⁱⁱⁱ	0.97	2.84	3.715 (5)	150

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

Acknowledgements

The authors acknowledge the Cheikh Anta Diop University of Dakar (Sénégal) and the University of Freiberg (Germany) for financial support. The authors are grateful to Dr A. G. Oliver (University of Notre Dame-Notre Dame, USA) for helpful discussions.

References

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