1,1′-(p-Phenyl­ene)bis­(1H-imidazol-3-ium) hexafluoridosilicate(IV)

In the title compound, C₁₂H₁₂N₄²⁺·SiF₆²⁻, both the dication and the dianion are centrosymmetric. The dihedral angle between the 1H-imidazol-3-ium ring and the benzene ring is 27.80 (11)°. An N—H...F hydrogen bond helps to establish the packing.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.031
• wR factor = 0.080
• Data-to-parameter ratio = 10.2

checkCIF/PLATON results

No syntax errors found



Alert level C
ABSTM02_ALERT_3_C  The ratio of expected to reported Tmax/Tmin(RR') is < 0.90
            Tmin and Tmax reported:      0.836     1.000
            Tmin(prime) and Tmax expected:      0.995     0.997
            RR(prime) =      0.838
            Please check that your absorption correction is appropriate.
PLAT061_ALERT_3_C Tmax/Tmin Range Test RR' too Large .............       0.84
PLAT154_ALERT_1_C The su's on the Cell Angles are Equal  (x 10000)       3000 Deg.
PLAT222_ALERT_3_C Large Non-Solvent    H     Ueq(max)/Ueq(min) ...       3.40 Ratio
PLAT431_ALERT_2_C Short Inter HL..A Contact  F2     ..  N2      ..       3.01 Ang.

Alert level G
ABSTM02_ALERT_3_G  When printed, the submitted absorption T values will be
            replaced by the scaled T values. Since the ratio of scaled T's
            is identical to the ratio of reported T values, the scaling
            does not imply a change to the absorption corrections used in
            the study.
            Ratio of Tmax expected/reported      0.997
            Tmax scaled      0.997 Tmin scaled      0.834
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature .        293 K

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   5 ALERT level C = Check and explain
   3 ALERT level G = General alerts; check

   3 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   4 ALERT type 3 Indicator that the structure quality may be low
   0 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

---

S1. Comment

The title compound, (I), (Fig. 1) was obtained unexpectedly as the product of an attempted synthesis of a network complex of Mn(IV) using methanol and chloroform as the solvent. The dihedral angle between the 1H-imidazol-3-ium ring and the benzene ring of the cation is 27.80 (11)°.

An N—H···F hydrogen bond (Table 1) helps to establish the packing (Fig. 2), as well as electrostatic interactions.

Related literature

For the amine synthesis, see: Cristau et al. (2004).

S2. Experimental

The ligand 1,4-di(1H-imidazol-1-yl)benzene was prepared according to the method of Cristau et al. (2004) from imidazole and 1,4-dibromobenzene. A buffer layer of a solution (8 ml) of methanol and chloroform (1:1) was carefully layered over the chloroform solution of the ligand (0.05 mmol, 6 ml). Then a methanol solution of Mn(SiF₆)₂ (0.05 mmol, 6 ml) was layered over the buffer layer. Colourless plates of (I) appeared at the boundary between methanol and chloroform after two weeks at room temperature.

S3. Refinement

The C-bound H atoms were positioned geometrically and refined in the riding-model approximation, with C—H = 0.93 Å and U_iso(H) = 1.2U_eq.

The N-bound H atom was located in a difference map and its position was freely refined with U_iso(H) = 1.2U_eq(N).

Computing details

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1997); software used to prepare material for publication: SHELXTL.

Figures

	Fig. 1. The molecular structure of (I). Displacement ellipsoids are drawn at the 30% probability level and H atoms are shown as small spheres of arbitrary radius. Atoms with suffix A in the cation and anion are generated by the symmety operations (1 - x, 1 - y, z) and (1 - x, -y, 1 - z).
	Fig. 2. The crystal packing for (I).

1,1'-(p-Phenylene)bis(1H-imidazol-3-ium) hexafluorosilicate(IV)

Crystal data

C12H12N4^2+·SiF6^2^−	Z = 1
Mr = 354.35	F(000) = 180
Triclinic, P1	Dx = 1.822 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 6.5608 (13) Å	Cell parameters from 869 reflections
b = 6.8060 (14) Å	θ = 2.5–27.9°
c = 8.7799 (18) Å	µ = 0.26 mm^−1
α = 85.88 (3)°	T = 293 K
β = 70.38 (3)°	Block, colourless
γ = 61.59 (3)°	0.02 × 0.02 × 0.01 mm
V = 322.97 (17) Å^3

Data collection

Bruker SMART 1000 CCD diffractometer	1119 independent reflections
Radiation source: fine-focus sealed tube	894 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.035
Detector resolution: 9 pixels mm^-1	θmax = 25.0°, θmin = 2.5°
ω scans	h = −7→7
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	k = −6→8
Tmin = 0.836, Tmax = 1.000	l = −10→10
3116 measured reflections

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)] = 0.031	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.080	H atoms treated by a mixture of independent and constrained refinement
S = 1.02	w = 1/[σ^2(Fo^2) + (0.0515P)^2] where P = (Fo^2 + 2Fc^2)/3
1119 reflections	(Δ/σ)max = 0.001
110 parameters	Δρmax = 0.27 e Å^−3
0 restraints	Δρmin = −0.30 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 > 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 (Ų)

	x	y	z	Uiso*/Ueq
Si1	0.5000	0.0000	0.5000	0.0108 (2)
F3	0.50781 (19)	0.24334 (18)	0.52554 (12)	0.0157 (3)
F2	0.4698 (2)	−0.03743 (19)	0.69557 (12)	0.0180 (3)
F1	0.19141 (19)	0.14648 (18)	0.55382 (13)	0.0170 (3)
N1	−0.0959 (3)	0.2524 (3)	0.30612 (19)	0.0134 (4)
N2	0.1761 (3)	0.3241 (3)	0.13441 (18)	0.0109 (4)
C5	0.4441 (3)	0.4009 (3)	−0.1021 (2)	0.0125 (4)
H5	0.4065	0.3334	−0.1694	0.015*
C6	0.6031 (3)	0.4874 (3)	−0.1677 (2)	0.0125 (4)
H6	0.6720	0.4806	−0.2799	0.015*
C4	0.3405 (3)	0.4160 (3)	0.0661 (2)	0.0111 (4)
C1	0.0019 (3)	0.3849 (3)	0.2819 (2)	0.0130 (4)
H1	−0.0423	0.5024	0.3552	0.016*
C3	0.1846 (3)	0.1430 (3)	0.0630 (2)	0.0126 (4)
H3	0.2877	0.0672	−0.0399	0.015*
C2	0.0149 (3)	0.0993 (3)	0.1719 (2)	0.0138 (4)
H2	−0.0210	−0.0138	0.1587	0.017*
H1A	−0.212 (5)	0.239 (5)	0.392 (3)	0.051 (8)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Si1	0.0114 (4)	0.0117 (4)	0.0090 (4)	−0.0065 (3)	−0.0016 (3)	−0.0002 (3)
F3	0.0152 (6)	0.0141 (6)	0.0162 (6)	−0.0092 (5)	0.0005 (5)	−0.0025 (4)
F2	0.0231 (7)	0.0216 (7)	0.0101 (6)	−0.0123 (5)	−0.0042 (5)	0.0010 (5)
F1	0.0128 (6)	0.0174 (6)	0.0191 (6)	−0.0069 (5)	−0.0033 (5)	−0.0015 (5)
N1	0.0121 (9)	0.0175 (9)	0.0127 (9)	−0.0096 (7)	−0.0030 (7)	0.0026 (7)
N2	0.0099 (8)	0.0121 (9)	0.0103 (8)	−0.0053 (7)	−0.0028 (6)	0.0004 (6)
C5	0.0150 (10)	0.0118 (10)	0.0129 (10)	−0.0069 (8)	−0.0065 (8)	0.0012 (7)
C6	0.0126 (10)	0.0136 (10)	0.0088 (9)	−0.0050 (8)	−0.0024 (8)	0.0001 (7)
C4	0.0080 (9)	0.0083 (10)	0.0142 (9)	−0.0029 (8)	−0.0021 (7)	0.0015 (7)
C1	0.0109 (10)	0.0157 (10)	0.0111 (9)	−0.0054 (8)	−0.0036 (8)	0.0002 (7)
C3	0.0113 (10)	0.0116 (10)	0.0139 (9)	−0.0051 (8)	−0.0030 (8)	−0.0027 (8)
C2	0.0144 (10)	0.0123 (10)	0.0167 (10)	−0.0073 (8)	−0.0058 (8)	0.0001 (8)

Geometric parameters (Å, º)

Si1—F2^i	1.6761 (11)	N2—C4	1.438 (2)
Si1—F2	1.6761 (11)	C5—C6	1.378 (2)
Si1—F1	1.6795 (12)	C5—C4	1.391 (2)
Si1—F1^i	1.6795 (13)	C5—H5	0.9300
Si1—F3	1.7140 (11)	C6—C4^ii	1.379 (3)
Si1—F3^i	1.7140 (11)	C6—H6	0.9300
N1—C1	1.305 (2)	C4—C6^ii	1.379 (3)
N1—C2	1.372 (2)	C1—H1	0.9300
N1—H1A	0.91 (2)	C3—C2	1.342 (3)
N2—C1	1.337 (2)	C3—H3	0.9300
N2—C3	1.392 (2)	C2—H2	0.9300
F2^i—Si1—F2	180.0	C3—N2—C4	125.57 (15)
F2^i—Si1—F1	90.51 (7)	C6—C5—C4	119.04 (17)
F2—Si1—F1	89.49 (7)	C6—C5—H5	120.5
F2^i—Si1—F1^i	89.49 (7)	C4—C5—H5	120.5
F2—Si1—F1^i	90.51 (7)	C5—C6—C4^ii	119.68 (17)
F1—Si1—F1^i	180.0	C5—C6—H6	120.2
F2^i—Si1—F3	90.12 (6)	C4^ii—C6—H6	120.2
F2—Si1—F3	89.88 (6)	C6^ii—C4—C5	121.27 (17)
F1—Si1—F3	89.79 (6)	C6^ii—C4—N2	119.73 (16)
F1^i—Si1—F3	90.21 (6)	C5—C4—N2	118.99 (16)
F2^i—Si1—F3^i	89.88 (6)	N1—C1—N2	108.74 (17)
F2—Si1—F3^i	90.12 (6)	N1—C1—H1	125.6
F1—Si1—F3^i	90.21 (6)	N2—C1—H1	125.6
F1^i—Si1—F3^i	89.79 (6)	C2—C3—N2	106.52 (16)
F3—Si1—F3^i	180.0	C2—C3—H3	126.7
C1—N1—C2	109.41 (16)	N2—C3—H3	126.7
C1—N1—H1A	133.6 (18)	C3—C2—N1	107.38 (17)
C2—N1—H1A	116.9 (18)	C3—C2—H2	126.3
C1—N2—C3	107.95 (15)	N1—C2—H2	126.3
C1—N2—C4	126.30 (16)
C4—C5—C6—C4^ii	0.9 (3)	C2—N1—C1—N2	−0.1 (2)
C6—C5—C4—C6^ii	−0.9 (3)	C3—N2—C1—N1	0.4 (2)
C6—C5—C4—N2	−179.50 (17)	C4—N2—C1—N1	−174.84 (16)
C1—N2—C4—C6^ii	25.2 (3)	C1—N2—C3—C2	−0.6 (2)
C3—N2—C4—C6^ii	−149.18 (18)	C4—N2—C3—C2	174.70 (16)
C1—N2—C4—C5	−156.19 (18)	N2—C3—C2—N1	0.5 (2)
C3—N2—C4—C5	29.4 (3)	C1—N1—C2—C3	−0.3 (2)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···F3^iii	0.91 (3)	1.81 (3)	2.692 (2)	164 (3)

Symmetry code: (iii) x−1, y, z.