Butane-1,4-di­ammonium hexa­fluoro­silicate

The title compound, [NH₃(CH₂)₄NH₃]²⁺·SiF₆²⁻, is a hybrid built from an organic butane-1,4-di­ammonium dication linked to a hexa­fluoro­silicate mineral anion. Both ions posses inversion symmetry. In the anion the Si atom is located on an inversion center, while in the cation the center of inversion is situated at the mid-point of the central —CH₂—CH₂— bond. The Si atom is surrounded by six F atoms, forming a slightly distorted SiF₆²⁻ octa­hedron. These octa­hedra are linked to the organic cations through N—H⋯F hydrogen bonds, forming a three-dimensional network.

Related literature

For background to potential physical properties, see: Ouasri et al. (2003); Elyoubi et al. (2004). For similar compounds, see: Jeghnou et al. (2005); Rhandour et al. (2011); Ouasri et al. (2012, 2013a,b, 2014).

Experimental

Crystal data

• C₄H₁₄N₂²⁺·SiF₆²⁻

• M_r = 232.26

• Triclinic,

• a = 5.796 (1) Å

• b = 5.889 (1) Å

• c = 7.774 (2) Å

• α = 87.02 (1)°

• β = 82.15 (1)°

• γ = 61.87 (1)°

• V = 231.79 (8) ų

• Z = 1

• Mo Kα radiation

• μ = 0.31 mm⁻¹

• T = 296 K

• 0.36 × 0.32 × 0.27 mm

Data collection

• Bruker X8 APEX diffractometer

• Absorption correction: multi-scan (SADABS; Bruker, 2009) T_min = 0.512, T_max = 0.640

• 5351 measured reflections

• 1285 independent reflections

• 1185 reflections with I > 2σ(I)

• R_int = 0.025

Refinement

• R[F² > 2σ(F²)] = 0.038

• wR(F²) = 0.108

• S = 1.05

• 1285 reflections

• 61 parameters

• H-atom parameters constrained

• Δρ_max = 0.74 e Å⁻³

• Δρ_min = −0.33 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1NA⋯F2	0.89	2.31	3.017 (2)	137
N1—H1NA⋯F3	0.89	2.39	3.134 (2)	142
N1—H1NB⋯F3^i	0.89	2.02	2.890 (2)	167
N1—H1NC⋯F1^ii	0.89	2.04	2.864 (2)	154
Symmetry codes: (i) -x, -y+1, -z; (ii) x-1, y, z.

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT-Plus (Bruker, 2009); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: PLATON (Spek, 2009) and publCIF (Westrip, 2010).

Supporting information

S1. Comment

The alkanediammonium halogenometallate salts family with the general formula (NH₃(CH₂)_nNH₃)MX₆ where M: Sn, Si, Te and X: Cl, Br, I and F, have recently attracted the interest of many investigators due to their potential physical properties (Ouasri et al., 2003; Elyoubi et al., 2004). X-ray, thermal and vibrational studies of phase transitions have also been performed for highly related compounds belonging to the alkanediammonium halogenobismuthate salts family as the pentachlorobismuthate one (NH₃(CH₂)_nNH₃)BiCl₅ (Jeghnou et al., 2005; Ouasri et al., 2012; Rhandour et al., 2011; Ouasri et al., 2013a; Ouasri et al., 2013b; Ouasri et al., 2014). The aim of the present paper was to study the recently synthesized butanediammonium hexafluorosilicate (NH₃(CH₂)₄NH₃)SiF₆ crystal, by X-ray diffraction at room temperature.

The structure of the title compound is built up from inorganic anions linked to the organic cations trough hydrogen bonds. In this structure, all atoms are in general positions, except the silicon atom (Si1 (1/2, 0, 0) which is located at a crystallographic centre of inversion of the P1 space group. In addition, the centre of the bond C2—C2i is also situated on another crystallographic centre of inversion. The asymmetric unit therefore contains only one half of the organic cation and one SiF₃ moiety. The remaining atoms of the unit cell are generated by symmetry operations.

The silicon atom is surrounded by six fluorine atoms building a slightly distorted SiF₆^2- octahedron. SiF₆^2- octahedra are linked to the organic cations through N–H···F hydrogen bonds producing an infinite two-dimensional layer parallel to (0 1 1) (Fig.2 and Table 1).

Related literature

For background to potential physical properties, see: Ouasri et al. (2003); Elyoubi et al. (2004). For similar compounds, see: Jeghnou et al. (2005); Ouasri et al. (2012); Rhandour et al. (2011); Ouasri et al. (2013a,b, 2014).

S2. Experimental

(NH₃(CH₂)₄NH₃)SiF₆ single crystals were obtained by slow evaporation, at room temperature, of an aqueous solution containing stoichiometric amounts of butane-1,4-diamine, NH₂(CH₂)₄NH₂, and H₂SiF₆ acid.

S3. Refinement

H atoms were located in a difference map and treated as riding with C—H = 0.97 Å, and 0.893 Å for CH₂ and N–H, respectively. Thermal parameters of all hydrogen atoms were refeined with U_iso(H) = 1.2 U_eq(methylene) and U_iso(H) = 1.5 U_eq(N) for the ammonium groups.

Computing details

Data collection: APEX2 (Bruker, 2009); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: PLATON (Spek, 2009) and publCIF (Westrip, 2010).

Figures

	Fig. 1. Molecular structure of the title compound with the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are represented as small circles.
	Fig. 2. Three dimensional plot of the title compound, showing inorganic sheets linked through N–H···F hydrogen bonds to the organic layers (dashed lines).

Butane-1,4-diammonium hexafluorosilicate

Crystal data

C4H14N2^2+·SiF6^2^−	Z = 1
Mr = 232.26	F(000) = 120
Triclinic, p1	Dx = 1.664 Mg m^−3
Hall symbol: -p 1	Mo Kα radiation, λ = 0.71073 Å
a = 5.796 (1) Å	Cell parameters from 1285 reflections
b = 5.889 (1) Å	θ = 3.9–29.6°
c = 7.774 (2) Å	µ = 0.31 mm^−1
α = 87.02 (1)°	T = 296 K
β = 82.15 (1)°	Block, colourless
γ = 61.87 (1)°	0.36 × 0.32 × 0.27 mm
V = 231.79 (8) Å^3

Data collection

Bruker X8 APEX diffractometer	1285 independent reflections
Radiation source: fine-focus sealed tube	1185 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.025
φ and ω scans	θmax = 29.6°, θmin = 3.9°
Absorption correction: multi-scan (SADABS; Bruker, 2009)	h = −7→8
Tmin = 0.512, Tmax = 0.640	k = −8→8
5351 measured reflections	l = −10→10

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.038	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.108	H-atom parameters constrained
S = 1.05	w = 1/[σ^2(Fo^2) + (0.0549P)^2 + 0.127P] where P = (Fo^2 + 2Fc^2)/3
1285 reflections	(Δ/σ)max < 0.001
61 parameters	Δρmax = 0.74 e Å^−3
0 restraints	Δρmin = −0.33 e Å^−3

Special details

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 > 2σ(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 (Ų)

	x	y	z	Uiso*/Ueq
C1	−0.1629 (3)	0.2744 (4)	0.3650 (2)	0.0394 (4)
H1A	0.0138	0.2407	0.3801	0.047*
H1B	−0.1739	0.1160	0.3876	0.047*
C2	−0.3593 (4)	0.4783 (4)	0.4953 (2)	0.0435 (4)
H2A	−0.3573	0.6396	0.4663	0.052*
H2B	−0.3024	0.4297	0.6094	0.052*
N1	−0.2086 (2)	0.3508 (2)	0.18267 (15)	0.0269 (3)
H1NA	−0.0891	0.2252	0.1110	0.040*
H1NB	−0.1946	0.4939	0.1603	0.040*
H1NC	−0.3695	0.3792	0.1675	0.040*
Si1	0.5000	0.0000	0.0000	0.02400 (16)
F1	0.35813 (19)	0.26912 (18)	0.12542 (14)	0.0381 (3)
F2	0.3234 (2)	−0.1206 (2)	0.12259 (14)	0.0426 (3)
F3	0.2526 (2)	0.1424 (2)	−0.12459 (15)	0.0445 (3)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0304 (7)	0.0470 (9)	0.0266 (7)	−0.0069 (7)	−0.0029 (5)	0.0022 (6)
C2	0.0368 (9)	0.0649 (12)	0.0278 (7)	−0.0233 (8)	0.0014 (6)	−0.0109 (7)
N1	0.0262 (6)	0.0287 (6)	0.0236 (5)	−0.0117 (5)	0.0007 (4)	−0.0032 (4)
Si1	0.0193 (3)	0.0203 (3)	0.0312 (3)	−0.00873 (19)	0.00039 (18)	−0.00429 (18)
F1	0.0318 (5)	0.0310 (5)	0.0487 (6)	−0.0135 (4)	0.0061 (4)	−0.0182 (4)
F2	0.0412 (6)	0.0386 (5)	0.0505 (6)	−0.0251 (5)	0.0122 (4)	−0.0037 (4)
F3	0.0405 (6)	0.0350 (5)	0.0593 (7)	−0.0143 (4)	−0.0245 (5)	0.0034 (5)

Geometric parameters (Å, º)

C1—N1	1.4853 (19)	N1—H1NB	0.8900
C1—C2	1.512 (2)	N1—H1NC	0.8900
C1—H1A	0.9700	Si1—F2^ii	1.6757 (10)
C1—H1B	0.9700	Si1—F2	1.6757 (10)
C2—C2^i	1.519 (4)	Si1—F1	1.6886 (9)
C2—H2A	0.9700	Si1—F1^ii	1.6886 (9)
C2—H2B	0.9700	Si1—F3	1.6908 (10)
N1—H1NA	0.8900	Si1—F3^ii	1.6908 (10)
N1—C1—C2	112.70 (13)	H1NB—N1—H1NC	109.5
N1—C1—H1A	109.1	F2^ii—Si1—F2	180.0
C2—C1—H1A	109.1	F2^ii—Si1—F1	89.09 (5)
N1—C1—H1B	109.1	F2—Si1—F1	90.91 (5)
C2—C1—H1B	109.1	F2^ii—Si1—F1^ii	90.91 (5)
H1A—C1—H1B	107.8	F2—Si1—F1^ii	89.09 (5)
C1—C2—C2^i	114.65 (19)	F1—Si1—F1^ii	180.0
C1—C2—H2A	108.6	F2^ii—Si1—F3	91.03 (6)
C2^i—C2—H2A	108.6	F2—Si1—F3	88.98 (6)
C1—C2—H2B	108.6	F1—Si1—F3	89.04 (6)
C2^i—C2—H2B	108.6	F1^ii—Si1—F3	90.96 (6)
H2A—C2—H2B	107.6	F2^ii—Si1—F3^ii	88.97 (6)
C1—N1—H1NA	109.5	F2—Si1—F3^ii	91.02 (6)
C1—N1—H1NB	109.5	F1—Si1—F3^ii	90.96 (6)
H1NA—N1—H1NB	109.5	F1^ii—Si1—F3^ii	89.04 (6)
C1—N1—H1NC	109.5	F3—Si1—F3^ii	180.0
H1NA—N1—H1NC	109.5

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1NA···F2	0.89	2.31	3.017 (2)	137
N1—H1NA···F3	0.89	2.39	3.134 (2)	142
N1—H1NB···F3^iii	0.89	2.02	2.890 (2)	167
N1—H1NC···F1^iv	0.89	2.04	2.864 (2)	154

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