3,5-Bis(3-methyl-imidazolium-1-ylmeth-yl)toluene bis-(hexa-fluoro-phosphate).

The asymmetric unit of the title N-heterocyclic carbene compound, C(17)H(22)N(4) (2+)·2PF(6) (-), consists of one N-heterocyclic carbene dication and two hexa-fluoro-phosphate anions. The two imidazole rings are twisted away from but to the same side of the central toluene ring, making dihedral angles of 76.69 (7) and 78.03 (7)° with the central ring. In the crystal, the components are linked by C-H⋯F interactions, generating a three-dimensional network.

Related literature

For background to N-heterocyclic carbenes, see: Wanzlick & Schönherr (1968 ▶); Öfele (1968 ▶); Arduengo et al. (1991 ▶). For applications of N-heterocyclic carbene derivatives, see: Meyer et al. (2009 ▶); Ray et al. (2007 ▶); Medvetz et al. (2008 ▶). For a related structure, see: Jiang (2009 ▶). For the synthesis, see; Dias & Jin (1994 ▶). For the stability of the temperature controller used for the data collection, see: Cosier & Glazer (1986 ▶).

Experimental

Crystal data

C17H22N4 2+·2PF6 −

M = 572.33

Monoclinic,

a = 6.1289 (1) Å

b = 19.0139 (4) Å

c = 20.1770 (4) Å

β = 97.390 (1)°

V = 2331.78 (8) Å3

Z = 4

Mo Kα radiation

μ = 0.30 mm−1

T = 100 K

0.53 × 0.28 × 0.20 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer

Absorption correction: multi-scan (SADABS; Bruker, 2009 ▶) T min = 0.858, T max = 0.942

42881 measured reflections

11275 independent reflections

7988 reflections with I > 2σ(I)

R int = 0.034

Refinement

R[F 2 > 2σ(F 2)] = 0.052

wR(F 2) = 0.149

S = 1.03

11275 reflections

319 parameters

H-atom parameters constrained

Δρmax = 0.62 e Å−3

Δρmin = −0.44 e Å−3

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

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810003739/tk2620sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810003739/tk2620Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

C17H22N42+·2PF6−	F(000) = 1160
Mr = 572.33	Dx = 1.630 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 9980 reflections
a = 6.1289 (1) Å	θ = 2.3–33.1°
b = 19.0139 (4) Å	µ = 0.30 mm−1
c = 20.1770 (4) Å	T = 100 K
β = 97.390 (1)°	Block, colourless
V = 2331.78 (8) Å3	0.53 × 0.28 × 0.20 mm
Z = 4

Bruker SMART APEXII CCD area-detector diffractometer	11275 independent reflections
Radiation source: fine-focus sealed tube	7988 reflections with I > 2σ(I)
graphite	Rint = 0.034
φ and ω scans	θmax = 36.4°, θmin = 2.0°
Absorption correction: multi-scan (SADABS; Bruker, 2009)	h = −9→10
Tmin = 0.858, Tmax = 0.942	k = −31→31
42881 measured reflections	l = −33→33

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)] = 0.052	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.149	H-atom parameters constrained
S = 1.03	w = 1/[σ2(Fo2) + (0.0703P)2 + 0.7107P] where P = (Fo2 + 2Fc2)/3
11275 reflections	(Δ/σ)max = 0.001
319 parameters	Δρmax = 0.62 e Å−3
0 restraints	Δρmin = −0.44 e Å−3

Experimental. The crystal was placed in the cold stream of an Oxford Cryosystems Cobra open-flow nitrogen cryostat (Cosier & Glazer, 1986) operating at 100.0 (1) K.

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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.

	x	y	z	Uiso*/Ueq
N1	1.09705 (19)	0.13322 (5)	0.47609 (5)	0.02147 (19)
N2	1.01744 (18)	0.14740 (6)	0.57634 (5)	0.02158 (19)
N3	1.07523 (19)	0.45850 (6)	0.36551 (5)	0.0224 (2)
N4	0.89594 (19)	0.55547 (6)	0.34480 (6)	0.0241 (2)
C1	0.8951 (2)	0.20094 (7)	0.33537 (6)	0.0244 (2)
H1A	0.8258	0.1574	0.3299	0.029*
C2	0.7957 (2)	0.25985 (7)	0.30300 (6)	0.0229 (2)
C3	0.9031 (2)	0.32451 (7)	0.31150 (6)	0.0220 (2)
H3A	0.8388	0.3642	0.2904	0.026*
C4	1.1060 (2)	0.33027 (7)	0.35138 (6)	0.0224 (2)
C5	1.2019 (2)	0.27104 (7)	0.38343 (6)	0.0230 (2)
H5A	1.3370	0.2747	0.4101	0.028*
C6	1.0960 (2)	0.20638 (7)	0.37567 (6)	0.0229 (2)
C7	1.1966 (3)	0.14348 (7)	0.41401 (7)	0.0284 (3)
H7A	1.1736	0.1017	0.3864	0.034*
H7B	1.3539	0.1506	0.4249	0.034*
C8	1.1522 (2)	0.16744 (6)	0.53334 (6)	0.0216 (2)
H8A	1.2659	0.1999	0.5418	0.026*
C9	0.9202 (3)	0.09042 (7)	0.48282 (7)	0.0287 (3)
H9A	0.8481	0.0610	0.4503	0.034*
C10	0.8715 (2)	0.09935 (8)	0.54570 (7)	0.0293 (3)
H10A	0.7596	0.0770	0.5647	0.035*
C11	1.0210 (3)	0.17284 (9)	0.64499 (7)	0.0326 (3)
H11A	1.1495	0.2013	0.6568	0.049*
H11B	1.0243	0.1335	0.6749	0.049*
H11C	0.8917	0.2004	0.6483	0.049*
C12	1.2268 (2)	0.39980 (7)	0.36005 (8)	0.0286 (3)
H12A	1.3332	0.3979	0.4000	0.034*
H12B	1.3064	0.4076	0.3221	0.034*
C13	1.0490 (2)	0.51400 (7)	0.32521 (6)	0.0215 (2)
H13A	1.1257	0.5224	0.2891	0.026*
C14	0.9316 (3)	0.46493 (8)	0.41259 (7)	0.0310 (3)
H14A	0.9148	0.4333	0.4467	0.037*
C15	0.8204 (3)	0.52554 (8)	0.39983 (8)	0.0316 (3)
H15A	0.7131	0.5438	0.4236	0.038*
C16	0.8185 (3)	0.62160 (8)	0.31312 (8)	0.0360 (3)
H16A	0.9219	0.6376	0.2845	0.054*
H16B	0.8050	0.6563	0.3469	0.054*
H16C	0.6778	0.6143	0.2871	0.054*
C17	0.5767 (2)	0.25388 (8)	0.26001 (7)	0.0307 (3)
H17A	0.5086	0.2994	0.2553	0.046*
H17B	0.4836	0.2222	0.2806	0.046*
H17C	0.5982	0.2362	0.2168	0.046*
P1	0.48424 (5)	0.488905 (18)	0.175041 (16)	0.02100 (7)
F1	0.74701 (13)	0.49029 (5)	0.18064 (5)	0.03038 (18)
F2	0.48256 (17)	0.57311 (5)	0.17898 (5)	0.0381 (2)
F3	0.22094 (15)	0.48912 (6)	0.16927 (6)	0.0434 (2)
F4	0.46926 (17)	0.49406 (6)	0.09530 (4)	0.0407 (2)
F5	0.50201 (18)	0.48512 (7)	0.25471 (5)	0.0442 (3)
F6	0.48927 (19)	0.40533 (5)	0.16983 (6)	0.0488 (3)
P2	0.66006 (5)	0.168232 (18)	0.043019 (17)	0.02251 (8)
F7	0.39775 (14)	0.15921 (5)	0.03209 (5)	0.0366 (2)
F8	0.66196 (17)	0.16954 (6)	−0.03614 (5)	0.0412 (2)
F9	0.92024 (15)	0.17795 (6)	0.05369 (6)	0.0421 (2)
F10	0.69001 (18)	0.08453 (5)	0.04230 (6)	0.0420 (2)
F11	0.6604 (2)	0.16457 (8)	0.12203 (5)	0.0575 (4)
F12	0.62782 (18)	0.25150 (5)	0.04312 (7)	0.0552 (3)

	U11	U22	U33	U12	U13	U23
N1	0.0274 (5)	0.0155 (4)	0.0224 (4)	0.0010 (4)	0.0065 (4)	0.0017 (4)
N2	0.0240 (5)	0.0208 (5)	0.0200 (4)	0.0028 (4)	0.0029 (4)	0.0019 (4)
N3	0.0262 (5)	0.0190 (5)	0.0223 (4)	−0.0057 (4)	0.0044 (4)	0.0003 (4)
N4	0.0248 (5)	0.0214 (5)	0.0254 (5)	−0.0017 (4)	0.0010 (4)	−0.0041 (4)
C1	0.0336 (7)	0.0184 (5)	0.0230 (5)	−0.0047 (5)	0.0101 (5)	−0.0033 (4)
C2	0.0285 (6)	0.0220 (5)	0.0192 (5)	−0.0055 (4)	0.0072 (4)	−0.0028 (4)
C3	0.0268 (6)	0.0202 (5)	0.0195 (5)	−0.0020 (4)	0.0050 (4)	0.0006 (4)
C4	0.0265 (6)	0.0191 (5)	0.0223 (5)	−0.0025 (4)	0.0060 (4)	0.0007 (4)
C5	0.0251 (6)	0.0225 (5)	0.0220 (5)	0.0006 (4)	0.0060 (4)	0.0007 (4)
C6	0.0317 (6)	0.0186 (5)	0.0205 (5)	0.0023 (4)	0.0115 (4)	0.0002 (4)
C7	0.0401 (7)	0.0207 (6)	0.0275 (6)	0.0084 (5)	0.0158 (5)	0.0025 (5)
C8	0.0209 (5)	0.0187 (5)	0.0253 (5)	−0.0008 (4)	0.0034 (4)	−0.0007 (4)
C9	0.0364 (7)	0.0223 (6)	0.0268 (6)	−0.0105 (5)	0.0013 (5)	0.0016 (5)
C10	0.0290 (6)	0.0300 (7)	0.0292 (6)	−0.0090 (5)	0.0053 (5)	0.0062 (5)
C11	0.0418 (8)	0.0350 (7)	0.0211 (5)	0.0130 (6)	0.0048 (5)	−0.0007 (5)
C12	0.0238 (6)	0.0216 (6)	0.0402 (7)	−0.0035 (4)	0.0031 (5)	0.0041 (5)
C13	0.0232 (5)	0.0215 (5)	0.0201 (5)	−0.0031 (4)	0.0037 (4)	0.0003 (4)
C14	0.0437 (8)	0.0272 (6)	0.0247 (6)	−0.0118 (6)	0.0145 (5)	−0.0026 (5)
C15	0.0350 (7)	0.0304 (7)	0.0320 (6)	−0.0078 (5)	0.0146 (6)	−0.0107 (5)
C16	0.0386 (8)	0.0261 (7)	0.0395 (8)	0.0054 (6)	−0.0089 (6)	−0.0022 (6)
C17	0.0309 (7)	0.0333 (7)	0.0275 (6)	−0.0074 (5)	0.0022 (5)	−0.0039 (5)
P1	0.01773 (14)	0.02285 (15)	0.02274 (14)	0.00107 (10)	0.00376 (11)	0.00061 (11)
F1	0.0179 (3)	0.0379 (5)	0.0356 (4)	0.0027 (3)	0.0042 (3)	0.0001 (4)
F2	0.0392 (5)	0.0242 (4)	0.0517 (6)	0.0057 (4)	0.0091 (4)	−0.0031 (4)
F3	0.0176 (4)	0.0592 (7)	0.0538 (6)	−0.0036 (4)	0.0061 (4)	−0.0061 (5)
F4	0.0399 (5)	0.0593 (6)	0.0223 (4)	0.0208 (5)	0.0018 (4)	−0.0017 (4)
F5	0.0407 (5)	0.0687 (8)	0.0247 (4)	−0.0091 (5)	0.0100 (4)	0.0080 (4)
F6	0.0449 (6)	0.0229 (4)	0.0752 (8)	−0.0043 (4)	−0.0051 (5)	0.0019 (5)
P2	0.01778 (14)	0.02462 (16)	0.02537 (15)	0.00125 (11)	0.00367 (11)	−0.00180 (12)
F7	0.0190 (4)	0.0468 (5)	0.0443 (5)	−0.0040 (4)	0.0055 (3)	0.0089 (4)
F8	0.0350 (5)	0.0598 (7)	0.0299 (4)	0.0093 (4)	0.0084 (4)	0.0100 (4)
F9	0.0178 (4)	0.0478 (6)	0.0593 (6)	0.0006 (4)	−0.0010 (4)	0.0095 (5)
F10	0.0447 (6)	0.0269 (4)	0.0538 (6)	0.0047 (4)	0.0039 (5)	0.0042 (4)
F11	0.0468 (6)	0.1009 (11)	0.0251 (4)	0.0206 (6)	0.0064 (4)	−0.0085 (5)
F12	0.0356 (5)	0.0249 (5)	0.1015 (10)	0.0045 (4)	−0.0052 (6)	−0.0120 (5)

N1—C8	1.3310 (16)	C10—H10A	0.9300
N1—C9	1.3759 (18)	C11—H11A	0.9600
N1—C7	1.4752 (17)	C11—H11B	0.9600
N2—C8	1.3284 (17)	C11—H11C	0.9600
N2—C10	1.3691 (18)	C12—H12A	0.9700
N2—C11	1.4647 (17)	C12—H12B	0.9700
N3—C13	1.3294 (16)	C13—H13A	0.9300
N3—C14	1.3810 (18)	C14—C15	1.347 (2)
N3—C12	1.4652 (18)	C14—H14A	0.9300
N4—C13	1.3242 (17)	C15—H15A	0.9300
N4—C15	1.3795 (19)	C16—H16A	0.9600
N4—C16	1.4618 (19)	C16—H16B	0.9600
C1—C6	1.389 (2)	C16—H16C	0.9600
C1—C2	1.3965 (19)	C17—H17A	0.9600
C1—H1A	0.9300	C17—H17B	0.9600
C2—C3	1.3945 (17)	C17—H17C	0.9600
C2—C17	1.5059 (19)	P1—F6	1.5932 (10)
C3—C4	1.3959 (18)	P1—F5	1.5988 (10)
C3—H3A	0.9300	P1—F1	1.6001 (9)
C4—C5	1.3907 (18)	P1—F4	1.6027 (9)
C4—C12	1.5143 (18)	P1—F3	1.6029 (10)
C5—C6	1.3897 (18)	P1—F2	1.6031 (10)
C5—H5A	0.9300	P2—F9	1.5921 (10)
C6—C7	1.5123 (18)	P2—F11	1.5955 (11)
C7—H7A	0.9700	P2—F12	1.5957 (11)
C7—H7B	0.9700	P2—F8	1.5989 (10)
C8—H8A	0.9300	P2—F10	1.6024 (10)
C9—C10	1.351 (2)	P2—F7	1.6036 (9)
C9—H9A	0.9300
C8—N1—C9	108.59 (11)	N3—C12—H12B	109.3
C8—N1—C7	125.85 (12)	C4—C12—H12B	109.3
C9—N1—C7	125.40 (12)	H12A—C12—H12B	108.0
C8—N2—C10	108.76 (11)	N4—C13—N3	108.95 (11)
C8—N2—C11	126.01 (12)	N4—C13—H13A	125.5
C10—N2—C11	125.23 (12)	N3—C13—H13A	125.5
C13—N3—C14	108.23 (12)	C15—C14—N3	107.21 (12)
C13—N3—C12	125.92 (12)	C15—C14—H14A	126.4
C14—N3—C12	125.84 (12)	N3—C14—H14A	126.4
C13—N4—C15	108.57 (12)	C14—C15—N4	107.04 (13)
C13—N4—C16	125.75 (13)	C14—C15—H15A	126.5
C15—N4—C16	125.68 (13)	N4—C15—H15A	126.5
C6—C1—C2	120.95 (12)	N4—C16—H16A	109.5
C6—C1—H1A	119.5	N4—C16—H16B	109.5
C2—C1—H1A	119.5	H16A—C16—H16B	109.5
C3—C2—C1	118.63 (12)	N4—C16—H16C	109.5
C3—C2—C17	120.59 (12)	H16A—C16—H16C	109.5
C1—C2—C17	120.78 (12)	H16B—C16—H16C	109.5
C2—C3—C4	120.75 (12)	C2—C17—H17A	109.5
C2—C3—H3A	119.6	C2—C17—H17B	109.5
C4—C3—H3A	119.6	H17A—C17—H17B	109.5
C5—C4—C3	119.76 (12)	C2—C17—H17C	109.5
C5—C4—C12	118.82 (12)	H17A—C17—H17C	109.5
C3—C4—C12	121.41 (12)	H17B—C17—H17C	109.5
C6—C5—C4	120.04 (12)	F6—P1—F5	91.26 (7)
C6—C5—H5A	120.0	F6—P1—F1	89.61 (6)
C4—C5—H5A	120.0	F5—P1—F1	89.54 (5)
C1—C6—C5	119.86 (12)	F6—P1—F4	89.65 (6)
C1—C6—C7	120.87 (12)	F5—P1—F4	178.89 (7)
C5—C6—C7	119.21 (13)	F1—P1—F4	89.83 (5)
N1—C7—C6	110.66 (10)	F6—P1—F3	91.47 (6)
N1—C7—H7A	109.5	F5—P1—F3	90.62 (6)
C6—C7—H7A	109.5	F1—P1—F3	178.90 (6)
N1—C7—H7B	109.5	F4—P1—F3	89.99 (6)
C6—C7—H7B	109.5	F6—P1—F2	178.73 (7)
H7A—C7—H7B	108.1	F5—P1—F2	89.72 (6)
N2—C8—N1	108.46 (11)	F1—P1—F2	89.59 (5)
N2—C8—H8A	125.8	F4—P1—F2	89.36 (6)
N1—C8—H8A	125.8	F3—P1—F2	89.32 (6)
C10—C9—N1	106.89 (12)	F9—P2—F11	89.85 (6)
C10—C9—H9A	126.6	F9—P2—F12	90.39 (6)
N1—C9—H9A	126.6	F11—P2—F12	91.50 (8)
C9—C10—N2	107.30 (12)	F9—P2—F8	89.86 (6)
C9—C10—H10A	126.4	F11—P2—F8	178.32 (7)
N2—C10—H10A	126.4	F12—P2—F8	90.15 (7)
N2—C11—H11A	109.5	F9—P2—F10	90.15 (6)
N2—C11—H11B	109.5	F11—P2—F10	88.87 (7)
H11A—C11—H11B	109.5	F12—P2—F10	179.35 (7)
N2—C11—H11C	109.5	F8—P2—F10	89.47 (6)
H11A—C11—H11C	109.5	F9—P2—F7	179.46 (6)
H11B—C11—H11C	109.5	F11—P2—F7	90.30 (6)
N3—C12—C4	111.62 (11)	F12—P2—F7	89.09 (6)
N3—C12—H12A	109.3	F8—P2—F7	90.02 (6)
C4—C12—H12A	109.3	F10—P2—F7	90.37 (6)
C6—C1—C2—C3	0.45 (19)	C7—N1—C8—N2	175.98 (11)
C6—C1—C2—C17	−179.27 (12)	C8—N1—C9—C10	−0.46 (16)
C1—C2—C3—C4	0.19 (19)	C7—N1—C9—C10	−175.99 (12)
C17—C2—C3—C4	179.91 (12)	N1—C9—C10—N2	0.27 (17)
C2—C3—C4—C5	−0.45 (19)	C8—N2—C10—C9	0.01 (16)
C2—C3—C4—C12	178.79 (12)	C11—N2—C10—C9	179.28 (13)
C3—C4—C5—C6	0.08 (19)	C13—N3—C12—C4	−120.97 (14)
C12—C4—C5—C6	−179.19 (12)	C14—N3—C12—C4	57.56 (18)
C2—C1—C6—C5	−0.83 (19)	C5—C4—C12—N3	−141.60 (12)
C2—C1—C6—C7	176.25 (11)	C3—C4—C12—N3	39.15 (18)
C4—C5—C6—C1	0.56 (19)	C15—N4—C13—N3	−0.04 (15)
C4—C5—C6—C7	−176.57 (11)	C16—N4—C13—N3	−179.56 (12)
C8—N1—C7—C6	−81.82 (17)	C14—N3—C13—N4	0.27 (14)
C9—N1—C7—C6	92.95 (16)	C12—N3—C13—N4	179.02 (11)
C1—C6—C7—N1	−80.96 (15)	C13—N3—C14—C15	−0.40 (16)
C5—C6—C7—N1	96.14 (15)	C12—N3—C14—C15	−179.15 (12)
C10—N2—C8—N1	−0.30 (15)	N3—C14—C15—N4	0.37 (16)
C11—N2—C8—N1	−179.56 (12)	C13—N4—C15—C14	−0.21 (16)
C9—N1—C8—N2	0.47 (15)	C16—N4—C15—C14	179.31 (13)

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1A···F2i	0.93	2.47	3.3431 (16)	157
C5—H5A···F8ii	0.93	2.39	3.2686 (16)	157
C8—H8A···F12ii	0.93	2.40	3.2808 (16)	158
C9—H9A···F4i	0.93	2.41	3.2513 (19)	151
C10—H10A···F4iii	0.93	2.38	3.2967 (17)	169
C12—H12B···F5iv	0.97	2.42	3.3040 (18)	150
C14—H14A···F8iii	0.93	2.55	3.283 (2)	136
C14—H14A···F10iii	0.93	2.53	3.3050 (19)	141
C15—H15A···F7v	0.93	2.50	3.2568 (19)	139
C16—H16B···F9vi	0.96	2.48	3.135 (2)	125
C16—H16C···F2	0.96	2.48	3.314 (2)	146
C17—H17C···F11	0.96	2.42	3.3563 (18)	166

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C1—H1A⋯F2i	0.93	2.47	3.3431 (16)	157
C5—H5A⋯F8ii	0.93	2.39	3.2686 (16)	157
C8—H8A⋯F12ii	0.93	2.40	3.2808 (16)	158
C9—H9A⋯F4i	0.93	2.41	3.2513 (19)	151
C10—H10A⋯F4iii	0.93	2.38	3.2967 (17)	169
C12—H12B⋯F5iv	0.97	2.42	3.3040 (18)	150
C14—H14A⋯F8iii	0.93	2.55	3.283 (2)	136
C14—H14A⋯F10iii	0.93	2.53	3.3050 (19)	141
C15—H15A⋯F7v	0.93	2.50	3.2568 (19)	139
C16—H16B⋯F9vi	0.96	2.48	3.135 (2)	125
C16—H16C⋯F2	0.96	2.48	3.314 (2)	146
C17—H17C⋯F11	0.96	2.42	3.3563 (18)	166

Symmetry codes: (i) ; (ii) ; (iii) ; (iv) ; (v) ; (vi) .