A polymorph of tetra­ethyl­ammonium chloride

Yan, Y.; Mague, J.T.; Donahue, J.P.

doi:10.1107/S160053680902042X

organic compounds

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ISSN: 2056-9890

Volume 65| Part 7| July 2009| Page o1491

doi:10.1107/S160053680902042X

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A polymorph of tetraethylammonium chloride

Yong Yan,^a Joel T. Mague ^a and James P. Donahue ^a ^*

^aDepartment of Chemistry, Tulane University, 6400 Freret Street, New Orleans, LA 70118-5698, USA
^*Correspondence e-mail: donahue@tulane.edu

(Received 11 May 2009; accepted 28 May 2009; online 6 June 2009)

The structure of the title compound, C₈H₂₀N⁺·Cl⁻, is compared with a polymorph that was described earlier in the same space group. Differences in the conformations of the ethyl groups of the cation exist between the polymorphs. This study is given here in order to provide additional unit-cell data for use in qualitative identification of crystalline samples obtained in syntheses in which Et₄N⁺·Cl⁻ is either used or generated.

Related literature

A polymorph with three molecules in the asymmetric unit was earlier solved in the P2₁/n setting of this same space group (Staples, 1999 ). A discussion of crystal growth conditions that can affect the occurrence of polymorphs has been given by Hulliger (1994 ). For descriptions of chemistry involving tetraethylammonium chloride, see: McCleverty et al. (1967 ); Lorber et al. (1998 ); Donahue et al. (1998 ).

Experimental

Crystal data

C₈H₂₀N⁺·Cl⁻
M_r = 165.70
Monoclinic, P 2₁ /c
a = 8.429 (2) Å
b = 8.109 (2) Å
c = 14.499 (4) Å
β = 91.378 (3)°
V = 990.7 (4) Å³
Z = 4
Mo Kα radiation
μ = 0.32 mm⁻¹
T = 100 K
0.20 × 0.14 × 0.12 mm

Data collection

Bruker APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 2008b ) T_min = 0.876, T_max = 0.963
8314 measured reflections
2302 independent reflections
2038 reflections with I > 2σ(I)
R_int = 0.032

Refinement

R[F² > 2σ(F²)] = 0.030
wR(F²) = 0.083
S = 1.03
2302 reflections
95 parameters
H-atom parameters constrained
Δρ_max = 0.33 e Å⁻³
Δρ_min = −0.21 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ); cell refinement: SAINT (Bruker 2008 ); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008a ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008a); molecular graphics: SHELXTL (Sheldrick, 2008a); software used to prepare material for publication: SHELXTL.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S160053680902042X/pk2163sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S160053680902042X/pk2163Isup2.hkl

checkCIF report

Comment top

Tetraethylammonium chloride, Et₄N⁺Cl^- (Scheme 1), is frequently employed in inorganic synthesis as a convenient source of soluble countercations for anionic metal species. For instance, Et₄N⁺Cl^- is added to the reaction mixture in which Na₂[Fe₂(mnt)₄] is formed from Na₂(mnt) and FeCl₃ (mnt = (CN)₂C₂S₂(2-) = maleonitriledithiolate(2-)), thereby providing a metallodithiolene product that has useful solubility in common organic solvents (McCleverty et al., 1967). In other instances, Et₄N⁺Cl^- is generated as a byproduct of synthesis, as in the preparation of [Et₄N][M(OSiMe₃)(bdt)₂] (M = Mo or W; bdt = benzene-1,2-dithiolate(2-)) by silylation of the corresponding oxo bis(dithiolene) dianion (Lorber et al., 1998; Donahue et al., 1998). The frequency with which Et₄N⁺Cl^- is used or otherwise encountered in inorganic synthesis, and the ease with which crystalline samples may be occluded with colored impurities that obscure their identity, make desirable the availability of complete crystallographic data for this compound as a means for qualitatively identifying it and avoiding needless data collections.

White parallelpiped crystals of Et₄N⁺Cl^- grew without disorder (Fig. 1) in monoclinic space group P2₁/c with only one formula unit in the asymmetric unit and a Z value of 4 (Fig. 2). A view of the tetraethylammonium cation that is approximately orthogonal to a mean plane projection of the C and N atoms shows a propeller-like disposition of the ethyl groups around the central N atom (Fig. 1).

Related literature top

A polymorph with three molecules in the asymmetric unit was earlier solved in the P2₁/n setting of this same space group (Staples, 1999). For a discussion of crystal-growth conditions that can affect the occurrence of polymorphs, see: Hulliger (1994). For descriptions of chemistry involving tetraethylammonium chloride, see: McCleverty et al. (1967); Lorber et al. (1998); Donahue et al. (1998).

Experimental top

White parallelpiped crystals of Et₄N⁺Cl^- grew by diffusion of Et₂O vapor into an acetonitrile solution under a dry, N₂ atmosphere.

Computing details top

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker 2008); data reduction: SAINT (Bruker 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008b); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008b); molecular graphics: SHELXTL (Sheldrick, 2008b); software used to prepare material for publication: SHELXTL (Sheldrick, 2008b).

Figures top

	Fig. 1. Et₄N⁺Cl^- shown with 50% probability ellipsoids.
	Fig. 2. Unit cell of Et₄N⁺Cl^- in P2₁/c.

Tetraethylammonium chloride top

Crystal data top

C₈H₂₀N⁺·Cl⁻	F(000) = 368
M_r = 165.70	D_x = 1.111 Mg m⁻³
Monoclinic, P2₁/c	Melting point: not measured K
Hall symbol: -P 2ybc	Mo Kα radiation, λ = 0.71073 Å
a = 8.429 (2) Å	Cell parameters from 5930 reflections
b = 8.109 (2) Å	θ = 2.4–28.5°
c = 14.499 (4) Å	µ = 0.32 mm⁻¹
β = 91.378 (3)°	T = 100 K
V = 990.7 (4) Å³	Parallelepiped, colourless
Z = 4	0.20 × 0.14 × 0.12 mm

Data collection top

Bruker APEXII CCD diffractometer	2302 independent reflections
Radiation source: fine-focus sealed tube	2038 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.032
ϕ and ω scans	θ_max = 27.8°, θ_min = 2.4°
Absorption correction: multi-scan (SADABS; Sheldrick, 2008a)	h = −10→10
T_min = 0.876, T_max = 0.963	k = −10→10
8314 measured reflections	l = −18→18

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)] = 0.030	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.083	H-atom parameters constrained
S = 1.03	w = 1/[σ²(F_o²) + (0.0437P)² + 0.2706P] where P = (F_o² + 2F_c²)/3
2302 reflections	(Δ/σ)_max = 0.001
95 parameters	Δρ_max = 0.33 e Å⁻³
0 restraints	Δρ_min = −0.21 e Å⁻³

Crystal data top

C₈H₂₀N⁺·Cl⁻	V = 990.7 (4) Å³
M_r = 165.70	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 8.429 (2) Å	µ = 0.32 mm⁻¹
b = 8.109 (2) Å	T = 100 K
c = 14.499 (4) Å	0.20 × 0.14 × 0.12 mm
β = 91.378 (3)°

Data collection top

Bruker APEXII CCD diffractometer	2302 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 2008a)	2038 reflections with I > 2σ(I)
T_min = 0.876, T_max = 0.963	R_int = 0.032
8314 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.030	0 restraints
wR(F²) = 0.083	H-atom parameters constrained
S = 1.03	Δρ_max = 0.33 e Å⁻³
2302 reflections	Δρ_min = −0.21 e Å⁻³
95 parameters

Special details top

Experimental. The diffraction data were collected in three sets of 606 frames (0.3 °. width in ω) at ϕ = 0, 120 and 240 °. A scan time of 30 sec/frame was used.

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
Cl1	0.24449 (3)	0.49267 (3)	0.660880 (18)	0.02030 (10)
N1	0.25555 (10)	0.10663 (10)	0.86208 (6)	0.01401 (19)
C1	0.30638 (13)	0.09217 (13)	0.76286 (7)	0.0177 (2)
H1A	0.4027	0.0225	0.7610	0.021*
H1B	0.3350	0.2032	0.7402	0.021*
C2	0.18066 (15)	0.01931 (15)	0.69818 (8)	0.0252 (3)
H2A	0.1584	−0.0945	0.7166	0.038*
H2B	0.2191	0.0203	0.6349	0.038*
H2C	0.0833	0.0850	0.7012	0.038*
C3	0.19934 (13)	−0.05808 (13)	0.90007 (8)	0.0182 (2)
H3A	0.1879	−0.0473	0.9676	0.022*
H3B	0.0930	−0.0825	0.8730	0.022*
C4	0.30819 (14)	−0.20341 (14)	0.88139 (8)	0.0232 (2)
H4A	0.3011	−0.2321	0.8157	0.035*
H4B	0.2758	−0.2983	0.9183	0.035*
H4C	0.4178	−0.1735	0.8981	0.035*
C5	0.11843 (12)	0.22872 (13)	0.86575 (7)	0.0176 (2)
H5A	0.1432	0.3248	0.8265	0.021*
H5B	0.0218	0.1756	0.8393	0.021*
C6	0.08328 (14)	0.28976 (15)	0.96222 (8)	0.0251 (3)
H6A	0.0840	0.1963	1.0051	0.038*
H6B	−0.0213	0.3426	0.9619	0.038*
H6C	0.1644	0.3697	0.9819	0.038*
C7	0.39616 (12)	0.16349 (13)	0.92106 (7)	0.0167 (2)
H7A	0.4806	0.0789	0.9185	0.020*
H7B	0.3629	0.1720	0.9859	0.020*
C8	0.46431 (14)	0.32803 (14)	0.89185 (8)	0.0243 (3)
H8A	0.5208	0.3142	0.8340	0.036*
H8B	0.5382	0.3684	0.9400	0.036*
H8C	0.3780	0.4078	0.8827	0.036*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cl1	0.01788 (16)	0.02294 (16)	0.02008 (16)	−0.00039 (9)	0.00052 (11)	0.00271 (9)
N1	0.0142 (4)	0.0146 (4)	0.0132 (4)	0.0006 (3)	0.0001 (3)	0.0003 (3)
C1	0.0206 (5)	0.0200 (5)	0.0125 (5)	0.0022 (4)	0.0023 (4)	−0.0006 (4)
C2	0.0280 (6)	0.0301 (6)	0.0174 (6)	0.0023 (5)	−0.0054 (5)	−0.0035 (4)
C3	0.0202 (5)	0.0158 (5)	0.0185 (5)	−0.0023 (4)	0.0002 (4)	0.0027 (4)
C4	0.0281 (6)	0.0158 (5)	0.0256 (6)	0.0021 (4)	−0.0023 (5)	0.0008 (4)
C5	0.0158 (5)	0.0183 (5)	0.0187 (5)	0.0045 (4)	0.0008 (4)	0.0006 (4)
C6	0.0265 (6)	0.0276 (6)	0.0214 (6)	0.0090 (5)	0.0053 (4)	−0.0007 (4)
C7	0.0164 (5)	0.0182 (5)	0.0153 (5)	−0.0009 (4)	−0.0029 (4)	−0.0002 (4)
C8	0.0249 (6)	0.0224 (6)	0.0253 (6)	−0.0062 (5)	−0.0035 (5)	0.0013 (4)

Geometric parameters (Å, º) top

N1—C1	1.5153 (13)	C4—H4B	0.9800
N1—C7	1.5165 (13)	C4—H4C	0.9800
N1—C5	1.5238 (13)	C5—C6	1.5197 (16)
N1—C3	1.5246 (13)	C5—H5A	0.9900
C1—C2	1.5178 (16)	C5—H5B	0.9900
C1—H1A	0.9900	C6—H6A	0.9800
C1—H1B	0.9900	C6—H6B	0.9800
C2—H2A	0.9800	C6—H6C	0.9800
C2—H2B	0.9800	C7—C8	1.5170 (15)
C2—H2C	0.9800	C7—H7A	0.9900
C3—C4	1.5219 (15)	C7—H7B	0.9900
C3—H3A	0.9900	C8—H8A	0.9800
C3—H3B	0.9900	C8—H8B	0.9800
C4—H4A	0.9800	C8—H8C	0.9800

C1—N1—C7	108.90 (8)	C3—C4—H4C	109.5
C1—N1—C5	108.39 (8)	H4A—C4—H4C	109.5
C7—N1—C5	111.46 (8)	H4B—C4—H4C	109.5
C1—N1—C3	111.88 (8)	C6—C5—N1	114.12 (9)
C7—N1—C3	107.94 (8)	C6—C5—H5A	108.7
C5—N1—C3	108.30 (8)	N1—C5—H5A	108.7
N1—C1—C2	114.05 (9)	C6—C5—H5B	108.7
N1—C1—H1A	108.7	N1—C5—H5B	108.7
C2—C1—H1A	108.7	H5A—C5—H5B	107.6
N1—C1—H1B	108.7	C5—C6—H6A	109.5
C2—C1—H1B	108.7	C5—C6—H6B	109.5
H1A—C1—H1B	107.6	H6A—C6—H6B	109.5
C1—C2—H2A	109.5	C5—C6—H6C	109.5
C1—C2—H2B	109.5	H6A—C6—H6C	109.5
H2A—C2—H2B	109.5	H6B—C6—H6C	109.5
C1—C2—H2C	109.5	N1—C7—C8	113.96 (8)
H2A—C2—H2C	109.5	N1—C7—H7A	108.8
H2B—C2—H2C	109.5	C8—C7—H7A	108.8
C4—C3—N1	114.85 (9)	N1—C7—H7B	108.8
C4—C3—H3A	108.6	C8—C7—H7B	108.8
N1—C3—H3A	108.6	H7A—C7—H7B	107.7
C4—C3—H3B	108.6	C7—C8—H8A	109.5
N1—C3—H3B	108.6	C7—C8—H8B	109.5
H3A—C3—H3B	107.5	H8A—C8—H8B	109.5
C3—C4—H4A	109.5	C7—C8—H8C	109.5
C3—C4—H4B	109.5	H8A—C8—H8C	109.5
H4A—C4—H4B	109.5	H8B—C8—H8C	109.5

C7—N1—C1—C2	174.07 (9)	C1—N1—C5—C6	−164.83 (9)
C5—N1—C1—C2	−64.51 (11)	C7—N1—C5—C6	−45.00 (12)
C3—N1—C1—C2	54.83 (11)	C3—N1—C5—C6	73.60 (11)
C1—N1—C3—C4	47.32 (11)	C1—N1—C7—C8	58.94 (11)
C7—N1—C3—C4	−72.47 (11)	C5—N1—C7—C8	−60.59 (11)
C5—N1—C3—C4	166.71 (9)	C3—N1—C7—C8	−179.40 (9)

Experimental details

Crystal data
Chemical formula	C₈H₂₀N⁺·Cl⁻
M_r	165.70
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	100
a, b, c (Å)	8.429 (2), 8.109 (2), 14.499 (4)
β (°)	91.378 (3)
V (Å³)	990.7 (4)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.32
Crystal size (mm)	0.20 × 0.14 × 0.12

Data collection
Diffractometer	Bruker APEXII CCD diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 2008a)
T_min, T_max	0.876, 0.963
No. of measured, independent and observed [I > 2σ(I)] reflections	8314, 2302, 2038
R_int	0.032
(sin θ/λ)_max (Å⁻¹)	0.655

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.030, 0.083, 1.03
No. of reflections	2302
No. of parameters	95
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.33, −0.21

Computer programs: APEX2 (Bruker, 2009), SAINT (Bruker 2008), SHELXS97 (Sheldrick, 2008b), SHELXL97 (Sheldrick, 2008b), SHELXTL (Sheldrick, 2008b).

Acknowledgements

JTM gratefully acknowledges Tulane University for support of the Tulane Crystallography Laboratory.

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