organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890

1-Benzyl-3-phenyl­imidazolium hexa­fluoro­phosphate

aSchool of Chemistry and Chemical Engineering, China West Normal University, Nanchong 637002, People's Republic of China
*Correspondence e-mail: jphdp868@126.com

(Received 29 July 2009; accepted 11 August 2009; online 19 August 2009)

in the title compound, C16H15N2+·PF6, a precursor of N-heterocyclic carbene, the phenyl and benzyl rings are twisted away from the central imidazolium ring system, making dihedral angles of 70.30 (8) and 32.03 (10)°, respectively. The crystal structure is stabilized by C—H⋯F hydrogen bonds. Furthermore, P—F⋯π inter­actions involving imidazolium rings are observed [F⋯π = 2.9857 (16), P⋯π = 4.1630 (16) Å, P—F⋯π = 127.92 (6)°].

Related literature

The first stable N-heterocyclic carbene was isolated by Arduengo et al. (1991[Arduengo, A. J., Harlow, R. L. & Kline, M. (1991). J. Am. Chem. Soc. 113, 361-363.]). For the synthesis, see: Liu et al. (2003[Liu, J. P., Chen, J. B., Zhao, J. F., Zhao, Y. H., li, L. & Zhang, H. B. (2003). Synthesis, pp. 2661-2666.]). For related structures, see: Wan et al. (2008[Wan, Y., Xin, H., Chen, X., Xu, H. & Wu, H. (2008). Acta Cryst. E64, o2159.]). For related structures, see: Newman et al. (2007[Newman, C. P., Clarkson, G. J. & Rourke, J. P. (2007). J. Organomet. Chem. 692, 4962-4968.]); Herrmann (2002[Herrmann, W. A. (2002). Angew. Chem. Int. Ed. 41, 1290-1309.]); Yang et al. (2009[Yang, X. D., Zeng, X. H., Zhang, Y. L., Qing, C., Song, W. J., Li, L. & Zhang, H. B. (2009). Bioorg. Med. Chem. Lett. 19, 1892-1895.]).

[Scheme 1]

Experimental

Crystal data
  • C16H15N2+·PF6

  • Mr = 380.27

  • Triclinic, [P \overline 1]

  • a = 9.221 (2) Å

  • b = 10.046 (3) Å

  • c = 10.108 (2) Å

  • α = 110.733 (2)°

  • β = 91.969 (2)°

  • γ = 110.315 (2)°

  • V = 807.9 (3) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 0.24 mm−1

  • T = 93 K

  • 0.43 × 0.40 × 0.37 mm

Data collection
  • Rigaku SPIDER diffractometer

  • Absorption correction: multi-scan (ABSCOR; Higashi, 1995[Higashi, T. (1995). ABSCOR. Rigaku Corporation, Tokyo, Japan.]) Tmin = 0.905, Tmax = 0.919

  • 4739 measured reflections

  • 2902 independent reflections

  • 2361 reflections with I > 2σ(I)

  • Rint = 0.017

Refinement
  • R[F2 > 2σ(F2)] = 0.035

  • wR(F2) = 0.084

  • S = 1.00

  • 2902 reflections

  • 226 parameters

  • H-atom parameters constrained

  • Δρmax = 0.22 e Å−3

  • Δρmin = −0.28 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C7—H7⋯F1i 0.95 2.50 3.099 (2) 121
C8—H8⋯F6i 0.95 2.50 3.392 (2) 156
C9—H9⋯F5ii 0.95 2.34 3.247 (2) 159
C10—H10A⋯F4ii 0.99 2.49 3.444 (2) 161
C10—H10B⋯F3iii 0.99 2.49 3.455 (3) 164
Symmetry codes: (i) x-1, y-1, z; (ii) x-1, y-1, z-1; (iii) -x+1, -y+1, -z+1.

Data collection: RAPID-AUTO (Rigaku/MSC, 2004[Rigaku/MSC (2004). RAPID-AUTO and CrystalStructure. Rigaku/MSC Inc., The Woodlands, Texas, USA.]); cell refinement: RAPID-AUTO; data reduction: RAPID-AUTO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); software used to prepare material for publication: SHELXTL.

Supporting information


Comment top

Initiated by the isolation of the first stable N-heterocyclic carbene (NHC) by Arduengo et al. (1991), numerous stable NHC ligands has been prepared. 1,3-Disubstitutedimidazolium salts are considerable good precursor for synthesis of transition metal NHCs. In addition, the study of biological activities of imidazolium salts have been reported during these years. We report herein the synthesis and crystal structure of the title compound (I).

In (I), bond lengths and angles in title molecule (Fig. 1) are normal. The phenyl ring make dihedral angles with the benzyl ring and the imidazolium ring of 70.30 (8)° and 32.03 (10)°, respectively.

The crystal structure is stabilized by C—H···F hydrogen bonds (Table 1). Furthermore, P—F···π interactions involving imidazolium rings [F1···Cg1iv = 2.9857 (16) Å, P1···Cg1iv = 4.1630 (16) Å, P1—F1··· Cg1iv = 127.92 (6)°, where Cg1 is a centroid of the N1/N2/C7–C9 ring; symmetry code: (iv) -x+2, -y+1, -z+1] are observed.

Related literature top

The first stable N-heterocyclic carbene was isolated by

Arduengo et al. (1991). For the synthesis, see: Liu et al. (2003). For related structures, see: Wan et al. (2008). For related literature [on what subject?], see: Newman et al. (2007); Herrmann (2002); Yang et al. (2009).

Experimental top

The title compound was prepared according to the reported procedure of Liu et al. (2003). Colourless single crystals suitable for X-ray diffraction were obtained by recrystallization from dichloromethane and pPetroleum ether.

Refinement top

H atoms were placed in calculated positions with C—H = 0.95–0.9900 Å, and refined in riding mode with Uiso(H) = 1.2Ueq(C).

Computing details top

Data collection: RAPID-AUTO (Rigaku/MSC, 2004); cell refinement: RAPID-AUTO (Rigaku/MSC, 2004); data reduction: RAPID-AUTO (Rigaku/MSC, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title compound, showing 30% probability displacement ellipsoids and the atomic numbering.
1-Benzyl-3-phenylimidazolium hexafluorophosphate top
Crystal data top
C16H15N2+·PF6Z = 2
Mr = 380.27F(000) = 388
Triclinic, P1Dx = 1.563 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 9.221 (2) ÅCell parameters from 2516 reflections
b = 10.046 (3) Åθ = 3.1–27.5°
c = 10.108 (2) ŵ = 0.24 mm1
α = 110.733 (2)°T = 93 K
β = 91.969 (2)°Block, colourless
γ = 110.315 (2)°0.43 × 0.40 × 0.37 mm
V = 807.9 (3) Å3
Data collection top
Rigaku SPIDER
diffractometer
2902 independent reflections
Radiation source: Rotating Anode2361 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.017
ω scansθmax = 25.5°, θmin = 3.1°
Absorption correction: multi-scan
(ABSCOR; Higashi, 1995)
h = 117
Tmin = 0.905, Tmax = 0.919k = 1112
4739 measured reflectionsl = 1211
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.035Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.084H-atom parameters constrained
S = 1.00 w = 1/[σ2(Fo2) + (0.043P)2 + 0.066P]
where P = (Fo2 + 2Fc2)/3
2902 reflections(Δ/σ)max < 0.001
226 parametersΔρmax = 0.22 e Å3
0 restraintsΔρmin = 0.28 e Å3
Crystal data top
C16H15N2+·PF6γ = 110.315 (2)°
Mr = 380.27V = 807.9 (3) Å3
Triclinic, P1Z = 2
a = 9.221 (2) ÅMo Kα radiation
b = 10.046 (3) ŵ = 0.24 mm1
c = 10.108 (2) ÅT = 93 K
α = 110.733 (2)°0.43 × 0.40 × 0.37 mm
β = 91.969 (2)°
Data collection top
Rigaku SPIDER
diffractometer
2902 independent reflections
Absorption correction: multi-scan
(ABSCOR; Higashi, 1995)
2361 reflections with I > 2σ(I)
Tmin = 0.905, Tmax = 0.919Rint = 0.017
4739 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0350 restraints
wR(F2) = 0.084H-atom parameters constrained
S = 1.00Δρmax = 0.22 e Å3
2902 reflectionsΔρmin = 0.28 e Å3
226 parameters
Special details top

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
xyzUiso*/Ueq
P11.23197 (5)1.00569 (5)0.79232 (5)0.02127 (14)
F11.38948 (11)1.06413 (12)0.73171 (11)0.0297 (3)
F21.07593 (13)0.94747 (15)0.85307 (13)0.0444 (3)
F31.16399 (13)1.10464 (14)0.73467 (12)0.0380 (3)
F41.30246 (13)0.90834 (14)0.85235 (12)0.0381 (3)
F51.30920 (14)1.15038 (13)0.94289 (11)0.0427 (3)
F61.15883 (14)0.86186 (13)0.64242 (12)0.0433 (3)
N10.47043 (15)0.20046 (16)0.35708 (14)0.0188 (3)
N20.28468 (15)0.02584 (16)0.25378 (14)0.0192 (3)
C10.5504 (2)0.4242 (2)0.29382 (18)0.0235 (4)
H10.45930.37400.22110.028*
C20.6550 (2)0.5713 (2)0.31694 (19)0.0255 (4)
H20.63670.62160.25810.031*
C30.7858 (2)0.6454 (2)0.42503 (18)0.0241 (4)
H30.85530.74750.44220.029*
C40.8153 (2)0.5709 (2)0.50786 (19)0.0270 (4)
H40.90610.62130.58100.032*
C50.7131 (2)0.4229 (2)0.48495 (19)0.0243 (4)
H50.73370.37140.54160.029*
C60.58132 (19)0.3514 (2)0.37897 (18)0.0191 (4)
C70.4319 (2)0.1417 (2)0.46130 (18)0.0218 (4)
H70.47870.19120.56020.026*
C80.3160 (2)0.0014 (2)0.39716 (18)0.0223 (4)
H80.26520.06620.44230.027*
C90.37939 (19)0.0950 (2)0.23205 (18)0.0194 (4)
H90.38220.10510.14210.023*
C100.1627 (2)0.1631 (2)0.14214 (19)0.0233 (4)
H10A0.17720.15950.04670.028*
H10B0.05800.16120.15810.028*
C110.16757 (19)0.3114 (2)0.14213 (17)0.0197 (4)
C120.28553 (19)0.3616 (2)0.08983 (18)0.0224 (4)
H120.36910.29830.05980.027*
C130.2811 (2)0.5030 (2)0.08160 (18)0.0254 (4)
H130.36140.53680.04530.030*
C140.1600 (2)0.5965 (2)0.12598 (18)0.0255 (4)
H140.15690.69410.11950.031*
C150.0439 (2)0.5460 (2)0.17967 (18)0.0248 (4)
H150.03850.60870.21130.030*
C160.04776 (19)0.4049 (2)0.18733 (17)0.0219 (4)
H160.03250.37130.22400.026*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
P10.0232 (3)0.0215 (3)0.0217 (3)0.0089 (2)0.0073 (2)0.0108 (2)
F10.0233 (5)0.0358 (7)0.0297 (6)0.0075 (5)0.0084 (5)0.0159 (5)
F20.0366 (7)0.0571 (9)0.0629 (8)0.0237 (6)0.0301 (6)0.0422 (7)
F30.0390 (7)0.0481 (8)0.0470 (7)0.0250 (6)0.0148 (6)0.0323 (7)
F40.0498 (7)0.0469 (8)0.0437 (7)0.0330 (6)0.0230 (6)0.0315 (6)
F50.0644 (8)0.0339 (7)0.0229 (6)0.0196 (6)0.0073 (6)0.0029 (6)
F60.0445 (7)0.0274 (7)0.0348 (7)0.0020 (6)0.0008 (5)0.0025 (6)
N10.0206 (7)0.0181 (8)0.0174 (8)0.0075 (6)0.0029 (6)0.0066 (7)
N20.0197 (7)0.0187 (8)0.0184 (8)0.0076 (6)0.0021 (6)0.0063 (7)
C10.0236 (9)0.0251 (10)0.0214 (10)0.0088 (8)0.0026 (8)0.0094 (8)
C20.0305 (10)0.0247 (10)0.0259 (10)0.0122 (8)0.0077 (8)0.0134 (9)
C30.0251 (9)0.0209 (10)0.0239 (10)0.0065 (8)0.0083 (8)0.0081 (8)
C40.0244 (9)0.0275 (11)0.0228 (10)0.0061 (8)0.0002 (8)0.0070 (9)
C50.0264 (9)0.0238 (10)0.0227 (10)0.0086 (8)0.0015 (8)0.0103 (9)
C60.0211 (9)0.0178 (9)0.0177 (9)0.0081 (7)0.0058 (7)0.0053 (8)
C70.0308 (10)0.0232 (10)0.0148 (9)0.0128 (8)0.0059 (7)0.0086 (8)
C80.0292 (10)0.0234 (10)0.0174 (9)0.0121 (8)0.0070 (8)0.0093 (8)
C90.0203 (8)0.0216 (10)0.0164 (9)0.0088 (7)0.0023 (7)0.0068 (8)
C100.0210 (9)0.0238 (10)0.0216 (10)0.0059 (8)0.0007 (7)0.0078 (8)
C110.0202 (8)0.0204 (10)0.0146 (9)0.0059 (7)0.0017 (7)0.0049 (8)
C120.0187 (9)0.0248 (10)0.0218 (10)0.0060 (8)0.0038 (7)0.0092 (8)
C130.0233 (9)0.0292 (11)0.0229 (10)0.0120 (8)0.0007 (8)0.0079 (9)
C140.0293 (10)0.0209 (10)0.0218 (10)0.0065 (8)0.0052 (8)0.0073 (8)
C150.0225 (9)0.0265 (11)0.0205 (10)0.0019 (8)0.0006 (8)0.0116 (9)
C160.0200 (9)0.0264 (10)0.0147 (9)0.0063 (8)0.0007 (7)0.0057 (8)
Geometric parameters (Å, º) top
P1—F21.5875 (11)C5—C61.378 (2)
P1—F31.5933 (11)C5—H50.9500
P1—F61.5942 (12)C7—C81.345 (2)
P1—F11.5978 (11)C7—H70.9500
P1—F51.6052 (12)C8—H80.9500
P1—F41.6066 (11)C9—H90.9500
N1—C91.336 (2)C10—C111.505 (2)
N1—C71.380 (2)C10—H10A0.9900
N1—C61.437 (2)C10—H10B0.9900
N2—C91.323 (2)C11—C161.389 (2)
N2—C81.376 (2)C11—C121.396 (2)
N2—C101.474 (2)C12—C131.379 (2)
C1—C21.385 (2)C12—H120.9500
C1—C61.389 (2)C13—C141.391 (2)
C1—H10.9500C13—H130.9500
C2—C31.383 (2)C14—C151.386 (2)
C2—H20.9500C14—H140.9500
C3—C41.380 (2)C15—C161.380 (2)
C3—H30.9500C15—H150.9500
C4—C51.386 (2)C16—H160.9500
C4—H40.9500
F2—P1—F390.46 (6)C5—C6—C1121.20 (17)
F2—P1—F690.77 (7)C5—C6—N1120.21 (15)
F3—P1—F690.53 (7)C1—C6—N1118.58 (15)
F2—P1—F1179.73 (6)C8—C7—N1107.46 (15)
F3—P1—F189.79 (6)C8—C7—H7126.3
F6—P1—F189.34 (6)N1—C7—H7126.3
F2—P1—F590.23 (7)C7—C8—N2107.13 (15)
F3—P1—F590.14 (7)C7—C8—H8126.4
F6—P1—F5178.80 (7)N2—C8—H8126.4
F1—P1—F589.66 (6)N2—C9—N1108.96 (14)
F2—P1—F489.83 (6)N2—C9—H9125.5
F3—P1—F4179.11 (7)N1—C9—H9125.5
F6—P1—F490.31 (7)N2—C10—C11112.54 (14)
F1—P1—F489.92 (6)N2—C10—H10A109.1
F5—P1—F489.02 (7)C11—C10—H10A109.1
C9—N1—C7107.81 (14)N2—C10—H10B109.1
C9—N1—C6125.48 (14)C11—C10—H10B109.1
C7—N1—C6126.60 (15)H10A—C10—H10B107.8
C9—N2—C8108.63 (14)C16—C11—C12118.95 (16)
C9—N2—C10124.79 (14)C16—C11—C10119.61 (15)
C8—N2—C10126.53 (14)C12—C11—C10121.34 (15)
C2—C1—C6118.79 (17)C13—C12—C11120.18 (16)
C2—C1—H1120.6C13—C12—H12119.9
C6—C1—H1120.6C11—C12—H12119.9
C3—C2—C1120.50 (17)C12—C13—C14120.50 (17)
C3—C2—H2119.8C12—C13—H13119.8
C1—C2—H2119.8C14—C13—H13119.8
C4—C3—C2119.89 (17)C15—C14—C13119.44 (17)
C4—C3—H3120.1C15—C14—H14120.3
C2—C3—H3120.1C13—C14—H14120.3
C3—C4—C5120.38 (17)C16—C15—C14120.11 (16)
C3—C4—H4119.8C16—C15—H15119.9
C5—C4—H4119.8C14—C15—H15119.9
C6—C5—C4119.21 (17)C15—C16—C11120.81 (16)
C6—C5—H5120.4C15—C16—H16119.6
C4—C5—H5120.4C11—C16—H16119.6
C6—C1—C2—C31.4 (3)C8—N2—C9—N10.49 (18)
C1—C2—C3—C41.9 (3)C10—N2—C9—N1177.44 (14)
C2—C3—C4—C51.0 (3)C7—N1—C9—N20.77 (18)
C3—C4—C5—C60.3 (3)C6—N1—C9—N2175.77 (14)
C4—C5—C6—C10.8 (3)C9—N2—C10—C11132.27 (16)
C4—C5—C6—N1177.50 (15)C8—N2—C10—C1150.2 (2)
C2—C1—C6—C50.0 (3)N2—C10—C11—C16109.96 (17)
C2—C1—C6—N1178.40 (15)N2—C10—C11—C1273.7 (2)
C9—N1—C6—C5151.02 (16)C16—C11—C12—C130.9 (2)
C7—N1—C6—C533.1 (2)C10—C11—C12—C13175.41 (16)
C9—N1—C6—C130.6 (2)C11—C12—C13—C140.4 (3)
C7—N1—C6—C1145.30 (16)C12—C13—C14—C150.4 (3)
C9—N1—C7—C80.76 (18)C13—C14—C15—C160.7 (2)
C6—N1—C7—C8175.73 (15)C14—C15—C16—C110.2 (2)
N1—C7—C8—N20.46 (18)C12—C11—C16—C150.6 (2)
C9—N2—C8—C70.01 (18)C10—C11—C16—C15175.78 (15)
C10—N2—C8—C7177.88 (15)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C7—H7···F1i0.952.503.099 (2)121
C8—H8···F6i0.952.503.392 (2)156
C9—H9···F5ii0.952.343.247 (2)159
C10—H10A···F4ii0.992.493.444 (2)161
C10—H10B···F3iii0.992.493.455 (3)164
Symmetry codes: (i) x1, y1, z; (ii) x1, y1, z1; (iii) x+1, y+1, z+1.

Experimental details

Crystal data
Chemical formulaC16H15N2+·PF6
Mr380.27
Crystal system, space groupTriclinic, P1
Temperature (K)93
a, b, c (Å)9.221 (2), 10.046 (3), 10.108 (2)
α, β, γ (°)110.733 (2), 91.969 (2), 110.315 (2)
V3)807.9 (3)
Z2
Radiation typeMo Kα
µ (mm1)0.24
Crystal size (mm)0.43 × 0.40 × 0.37
Data collection
DiffractometerRigaku SPIDER
diffractometer
Absorption correctionMulti-scan
(ABSCOR; Higashi, 1995)
Tmin, Tmax0.905, 0.919
No. of measured, independent and
observed [I > 2σ(I)] reflections
4739, 2902, 2361
Rint0.017
(sin θ/λ)max1)0.606
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.035, 0.084, 1.00
No. of reflections2902
No. of parameters226
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.22, 0.28

Computer programs: RAPID-AUTO (Rigaku/MSC, 2004), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C7—H7···F1i0.952.503.099 (2)121
C8—H8···F6i0.952.503.392 (2)156
C9—H9···F5ii0.952.343.247 (2)159
C10—H10A···F4ii0.992.493.444 (2)161
C10—H10B···F3iii0.992.493.455 (3)164
Symmetry codes: (i) x1, y1, z; (ii) x1, y1, z1; (iii) x+1, y+1, z+1.
 

Acknowledgements

The authors thank the Fund Projects of Sichuan Educational department (grant No. 2005 A104).

References

First citationArduengo, A. J., Harlow, R. L. & Kline, M. (1991). J. Am. Chem. Soc. 113, 361–363.  CSD CrossRef CAS Web of Science Google Scholar
First citationHerrmann, W. A. (2002). Angew. Chem. Int. Ed. 41, 1290–1309.  Web of Science CrossRef CAS Google Scholar
First citationHigashi, T. (1995). ABSCOR. Rigaku Corporation, Tokyo, Japan.  Google Scholar
First citationLiu, J. P., Chen, J. B., Zhao, J. F., Zhao, Y. H., li, L. & Zhang, H. B. (2003). Synthesis, pp. 2661–2666.  Google Scholar
First citationNewman, C. P., Clarkson, G. J. & Rourke, J. P. (2007). J. Organomet. Chem. 692, 4962–4968.  Web of Science CSD CrossRef CAS Google Scholar
First citationRigaku/MSC (2004). RAPID-AUTO and CrystalStructure. Rigaku/MSC Inc., The Woodlands, Texas, USA.  Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationWan, Y., Xin, H., Chen, X., Xu, H. & Wu, H. (2008). Acta Cryst. E64, o2159.  Web of Science CSD CrossRef IUCr Journals Google Scholar
First citationYang, X. D., Zeng, X. H., Zhang, Y. L., Qing, C., Song, W. J., Li, L. & Zhang, H. B. (2009). Bioorg. Med. Chem. Lett. 19, 1892–1895.  Web of Science CrossRef PubMed CAS Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Follow Acta Cryst. E
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds