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

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890

3,5-Bis(2,4-di­nitro­phen­yl)-4-nitro-1H-pyrazole acetone monosolvate

aDeparment of Chemistry, University of Puerto Rico – Rio Piedras, San Juan, PR 00936, USA
*Correspondence e-mail: mathivathanan.logesh@gmail.com

(Received 17 October 2011; accepted 10 January 2012; online 14 January 2012)

The title structure, C15H7N7O10·C3H6O, was prepared by penta­nitration of 3,5-diphenyl-1H-pyrazole. The proton attached to a pyrazole N atom forms a hydrogen bond with the O atom of the acetone solvent mol­ecule, owing to the NO2 enhanced acidity of the proton. The NO2 group on the phenyl C atom is twisted by 33.9 (2)° from coplanarity with the ring in order to avoid a short intra­molecular O⋯O contact with an O atom of an adjacent pyrazole-bonded NO2 group.

Related literature

For the nitration of 1H-pyrazole, see: Maresca et al. (1997[Maresca, K. P., Rose, D. J. & Zubieta, J. (1997). Inorg. Chim. Acta, 260, 83-88.]). For the crystal structure of 3,5-diphenyl-1H-pyrazole, which shows a hydrogen-bonded tetra­meric structure, see: Raptis et al. (1993[Raptis, R. G., Staples, R. J., King, C. & Fackler, J. P. (1993). Acta Cryst. C49, 1716-1719.]). For a crystallographic and ab initio study of 1H-pyrazoles, see: Foces-Foces et al. (2000[Foces-Foces, C., Alkorta, I. & Elguero, J. (2000). Acta Cryst. B56, 1018-1028.]).

[Scheme 1]

Experimental

Crystal data
  • C15H7N7O10·C3H6O

  • Mr = 503.35

  • Monoclinic, P 21 /c

  • a = 14.886 (10) Å

  • b = 7.678 (5) Å

  • c = 19.801 (13) Å

  • β = 104.944 (9)°

  • V = 2187 (2) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.13 mm−1

  • T = 298 K

  • 0.31 × 0.19 × 0.18 mm

Data collection
  • Bruker SMART 1K CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2005[Bruker (2005). SMART, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.836, Tmax = 0.977

  • 15182 measured reflections

  • 5041 independent reflections

  • 2703 reflections with I > 2σ(I)

  • Rint = 0.068

Refinement
  • R[F2 > 2σ(F2)] = 0.064

  • wR(F2) = 0.202

  • S = 1.03

  • 5041 reflections

  • 332 parameters

  • H atoms treated by a mixture of independent and constrained refinement

  • Δρmax = 0.27 e Å−3

  • Δρmin = −0.27 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
N2—H2A⋯O11i 0.92 (3) 1.87 (4) 2.786 (4) 177 (3)
Symmetry code: (i) [x, -y+{\script{1\over 2}}, z-{\script{1\over 2}}].

Data collection: SMART (Bruker, 2005[Bruker (2005). SMART, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2005[Bruker (2005). SMART, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; 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

Aromatic electrophilic nitration (Maresca et al., 1997) of 3,5-diphenyl-1H-pyrazole using nitration mixture (H2SO4/HNO3) produces the title compound, 3,5-bis-(2,4-dinitrophenyl)-4-nitro-1H-pyrazole. The crystal structure of the parent 3,5-diphenyl-1H-pyrazole is a H-bonded tetrameric structure (Raptis et al., 1993), while the title compound (I) is not. Poly-nitration, in addition to a H-bonding to the solvent acetone molecule prevents tetramer formation in (I) (Fig. 1). H-bonding induced supramolecular network formation in 1H-pyrazoles has been summarized by Foces-Foces et al. (2000).

An intermolecular dipole-dipole interaction makes N4 and O2(1-x, y-1/2, 1/2-z) lie at 2.89 Å. In (I), all the NO2-groups are coplanar or nearly coplanar to their carrier rings, except the one attached to C5, which is twisted by 33.9 (2) relative to the phenyl ring in order to avoid a short intramolecular contact with O2.

Related literature top

For the nitration of 1H-pyrazole, see: Maresca et al. (1997). For the crystal structure of 3,5-diphenyl-1H-pyrazole, which shows a hydrogen-bonded tetrameric structure, see: Raptis et al. (1993). For a crystallographic and ab initio study of 1H-pyrazoles, see: Foces-Foces et al. (2000).

Experimental top

For a general procedure for nitration of pyrazole, see Maresca et al. (1997). A flask containing 5 ml of conc. H2SO4 and 5 ml HNO3 kept in an ice bath was charged with 3,5-diphenyl-1H-pyrazole (97%, Aldrich; 2.0 g, 9.07 mmol) followed by the addition of 10 ml of H2SO4. The mixture was heated at 110° C for 2 days. After conventional neutralization and extractions, several colourless crystals of the title compound (I) were obtained from acetone.

Refinement top

All non-hydrogen atoms were refined anisotropically. Most H-atoms were positioned geometrically (C—H = 0.93 and 0.96 Å) and treated as riding (Uiso(H) = 1.2Ueq(C)). The pyrazole nitrogen H2A was located in a difference Fourier map and was then fully refined.

Computing details top

Data collection: SMART (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005); 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. Molecular structure of the title compound (I) showing 30% thermal ellipsoids and atom labeling scheme. The symmetry transformation for the shown acetone molecule is x, 1/2-y, z-1/2.
3,5-Bis(2,4-dinitrophenyl)-4-nitro-1H-pyrazole acetone monosolvate top
Crystal data top
C15H7N7O10·C3H6OF(000) = 1032
Mr = 503.35Dx = 1.529 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 5811 reflections
a = 14.886 (10) Åθ = 2.1–27.1°
b = 7.678 (5) ŵ = 0.13 mm1
c = 19.801 (13) ÅT = 298 K
β = 104.944 (9)°Polygon, colourless
V = 2187 (2) Å30.31 × 0.19 × 0.18 mm
Z = 4
Data collection top
Bruker SMART 1K CCD
diffractometer
5041 independent reflections
Radiation source: fine-focus sealed tube2703 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.068
ϕ and ω scansθmax = 28.0°, θmin = 2.1°
Absorption correction: multi-scan
(SADABS; Bruker, 2005)
h = 1918
Tmin = 0.836, Tmax = 0.977k = 108
15182 measured reflectionsl = 2525
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.064H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.202 w = 1/[σ2(Fo2) + (0.0696P)2 + 1.6838P]
where P = (Fo2 + 2Fc2)/3
S = 1.03(Δ/σ)max = 0.005
5041 reflectionsΔρmax = 0.27 e Å3
332 parametersΔρmin = 0.27 e Å3
0 restraintsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0141 (17)
Crystal data top
C15H7N7O10·C3H6OV = 2187 (2) Å3
Mr = 503.35Z = 4
Monoclinic, P21/cMo Kα radiation
a = 14.886 (10) ŵ = 0.13 mm1
b = 7.678 (5) ÅT = 298 K
c = 19.801 (13) Å0.31 × 0.19 × 0.18 mm
β = 104.944 (9)°
Data collection top
Bruker SMART 1K CCD
diffractometer
5041 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2005)
2703 reflections with I > 2σ(I)
Tmin = 0.836, Tmax = 0.977Rint = 0.068
15182 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0640 restraints
wR(F2) = 0.202H atoms treated by a mixture of independent and constrained refinement
S = 1.03Δρmax = 0.27 e Å3
5041 reflectionsΔρmin = 0.27 e Å3
332 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
O10.47956 (18)0.0956 (4)0.26917 (13)0.0968 (10)
O20.59247 (15)0.0052 (4)0.22802 (11)0.0746 (7)
O30.55406 (17)0.1803 (3)0.08688 (13)0.0730 (7)
O40.70324 (18)0.1641 (3)0.12926 (15)0.0868 (8)
O50.82468 (17)0.3068 (4)0.00361 (16)0.0910 (9)
O60.7904 (2)0.5619 (4)0.03522 (18)0.1034 (10)
O70.3592 (2)0.3312 (4)0.12047 (15)0.0919 (8)
O80.2556 (2)0.5123 (4)0.13596 (16)0.1052 (10)
O90.0670 (4)0.3824 (9)0.2888 (3)0.205 (3)
O100.0655 (3)0.1292 (9)0.3325 (2)0.187 (3)
O110.13846 (15)0.4236 (3)0.49406 (14)0.0766 (7)
N10.38256 (16)0.1537 (3)0.05753 (13)0.0565 (6)
N20.31564 (17)0.0836 (4)0.08520 (13)0.0575 (7)
N30.0923 (3)0.2335 (10)0.2962 (2)0.1284 (19)
N40.2938 (2)0.3698 (4)0.14388 (16)0.0764 (8)
N50.6270 (2)0.1003 (3)0.10191 (14)0.0612 (7)
N60.77797 (18)0.4055 (4)0.02940 (16)0.0678 (7)
N70.50947 (19)0.0255 (4)0.22360 (13)0.0632 (7)
C10.46197 (19)0.1219 (4)0.10473 (14)0.0471 (6)
C20.44426 (18)0.0326 (4)0.16222 (14)0.0490 (7)
C30.34937 (19)0.0095 (4)0.14748 (14)0.0509 (7)
C40.54864 (18)0.1890 (4)0.09021 (13)0.0471 (6)
C50.62536 (19)0.0882 (4)0.08719 (14)0.0480 (6)
C60.70118 (19)0.1549 (4)0.06789 (15)0.0531 (7)
H60.75120.08470.06560.064*
C70.69967 (19)0.3305 (4)0.05218 (15)0.0521 (7)
C80.6277 (2)0.4380 (4)0.05695 (16)0.0563 (7)
H80.62950.55640.04740.068*
C90.5529 (2)0.3668 (4)0.07611 (15)0.0535 (7)
H90.50410.43880.07980.064*
C100.2870 (2)0.0633 (5)0.18751 (15)0.0578 (8)
C110.2586 (2)0.2379 (5)0.18530 (16)0.0624 (8)
C120.1955 (2)0.2936 (6)0.22124 (18)0.0798 (11)
H120.17640.40930.21930.096*
C130.1618 (2)0.1736 (7)0.25983 (19)0.0853 (13)
C140.1888 (3)0.0032 (7)0.2649 (2)0.0913 (13)
H140.16580.07440.29240.110*
C150.2510 (3)0.0513 (6)0.2283 (2)0.0812 (11)
H150.26940.16740.23100.097*
C160.0075 (3)0.2910 (6)0.4196 (2)0.0893 (12)
H16A0.01730.37610.38670.134*
H16B0.05490.30080.42440.134*
H16C0.01680.17640.40320.134*
C170.0743 (2)0.3214 (4)0.48844 (18)0.0609 (8)
C180.0603 (3)0.2265 (6)0.5498 (2)0.0834 (11)
H18A0.07000.10420.54440.125*
H18B0.00190.24540.55360.125*
H18C0.10380.26810.59130.125*
H2A0.256 (2)0.082 (5)0.0567 (18)0.075 (11)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0783 (17)0.142 (3)0.0701 (16)0.0068 (17)0.0195 (13)0.0425 (16)
O20.0506 (13)0.108 (2)0.0623 (13)0.0001 (12)0.0096 (10)0.0091 (12)
O30.0783 (16)0.0507 (13)0.1029 (18)0.0055 (12)0.0467 (14)0.0059 (12)
O40.0821 (17)0.0677 (16)0.114 (2)0.0257 (14)0.0310 (15)0.0248 (14)
O50.0710 (16)0.0891 (19)0.131 (2)0.0153 (14)0.0578 (16)0.0194 (17)
O60.100 (2)0.0686 (18)0.162 (3)0.0261 (16)0.069 (2)0.0075 (18)
O70.108 (2)0.0742 (18)0.106 (2)0.0130 (16)0.0497 (18)0.0134 (15)
O80.124 (2)0.0762 (19)0.103 (2)0.0379 (18)0.0081 (18)0.0121 (15)
O90.189 (5)0.263 (7)0.197 (5)0.123 (5)0.111 (4)0.003 (4)
O100.159 (4)0.299 (7)0.145 (4)0.057 (4)0.116 (3)0.024 (4)
O110.0555 (13)0.0701 (15)0.0989 (18)0.0122 (12)0.0104 (12)0.0034 (13)
N10.0487 (13)0.0669 (16)0.0573 (14)0.0051 (12)0.0197 (11)0.0084 (12)
N20.0440 (13)0.0720 (18)0.0573 (14)0.0031 (12)0.0145 (12)0.0073 (12)
N30.082 (3)0.223 (6)0.088 (3)0.044 (3)0.036 (2)0.024 (3)
N40.085 (2)0.069 (2)0.0689 (18)0.0151 (17)0.0088 (16)0.0013 (15)
N50.0655 (17)0.0499 (15)0.0749 (17)0.0105 (14)0.0305 (14)0.0040 (12)
N60.0544 (15)0.069 (2)0.0849 (19)0.0030 (14)0.0275 (14)0.0056 (15)
N70.0565 (15)0.0789 (19)0.0539 (14)0.0019 (13)0.0134 (12)0.0097 (13)
C10.0482 (15)0.0452 (15)0.0502 (14)0.0015 (12)0.0168 (12)0.0008 (11)
C20.0481 (15)0.0528 (17)0.0472 (14)0.0007 (12)0.0143 (12)0.0030 (12)
C30.0504 (16)0.0543 (17)0.0508 (15)0.0001 (13)0.0182 (12)0.0013 (12)
C40.0461 (14)0.0479 (15)0.0485 (14)0.0028 (12)0.0140 (12)0.0001 (11)
C50.0493 (15)0.0420 (15)0.0543 (15)0.0060 (12)0.0163 (12)0.0016 (12)
C60.0470 (15)0.0532 (17)0.0608 (17)0.0090 (13)0.0167 (13)0.0000 (13)
C70.0443 (15)0.0521 (17)0.0617 (17)0.0024 (13)0.0171 (13)0.0002 (13)
C80.0584 (17)0.0437 (15)0.0699 (18)0.0006 (14)0.0224 (15)0.0004 (13)
C90.0545 (16)0.0461 (16)0.0637 (17)0.0062 (13)0.0221 (14)0.0014 (13)
C100.0495 (16)0.070 (2)0.0552 (16)0.0024 (15)0.0162 (13)0.0050 (14)
C110.0522 (17)0.075 (2)0.0559 (17)0.0110 (16)0.0071 (14)0.0053 (15)
C120.064 (2)0.103 (3)0.067 (2)0.030 (2)0.0062 (17)0.015 (2)
C130.058 (2)0.140 (4)0.062 (2)0.020 (2)0.0228 (17)0.011 (2)
C140.078 (3)0.129 (4)0.080 (3)0.006 (3)0.044 (2)0.004 (2)
C150.079 (2)0.093 (3)0.085 (2)0.003 (2)0.047 (2)0.007 (2)
C160.071 (2)0.094 (3)0.094 (3)0.009 (2)0.006 (2)0.009 (2)
C170.0443 (16)0.0538 (18)0.084 (2)0.0033 (14)0.0152 (15)0.0014 (15)
C180.070 (2)0.090 (3)0.094 (3)0.002 (2)0.028 (2)0.006 (2)
Geometric parameters (Å, º) top
O1—N71.228 (3)C4—C91.398 (4)
O2—N71.226 (3)C5—C61.380 (4)
O3—N51.216 (3)C6—C71.382 (4)
O4—N51.226 (3)C6—H60.9300
O5—N61.225 (4)C7—C81.375 (4)
O6—N61.216 (4)C8—C91.378 (4)
O7—N41.218 (4)C8—H80.9300
O8—N41.224 (4)C9—H90.9300
O9—N31.200 (8)C10—C151.391 (5)
O10—N31.209 (7)C10—C111.402 (5)
O11—C171.219 (4)C11—C121.385 (5)
N1—C11.327 (4)C12—C131.372 (6)
N1—N21.365 (3)C12—H120.9300
N2—C31.333 (4)C13—C141.365 (6)
N2—H2A0.92 (3)C14—C151.380 (5)
N3—C131.480 (5)C14—H140.9300
N4—C111.481 (5)C15—H150.9300
N5—C51.476 (4)C16—C171.484 (5)
N6—C71.471 (4)C16—H16A0.9600
N7—C21.418 (4)C16—H16B0.9600
C1—C21.411 (4)C16—H16C0.9600
C1—C41.485 (4)C17—C181.477 (5)
C2—C31.378 (4)C18—H18A0.9600
C3—C101.478 (4)C18—H18B0.9600
C4—C51.394 (4)C18—H18C0.9600
C1—N1—N2104.7 (2)C7—C8—C9118.7 (3)
C3—N2—N1113.6 (2)C7—C8—H8120.7
C3—N2—H2A130 (2)C9—C8—H8120.7
N1—N2—H2A116 (2)C8—C9—C4121.6 (3)
O9—N3—O10124.3 (5)C8—C9—H9119.2
O9—N3—C13118.2 (6)C4—C9—H9119.2
O10—N3—C13117.5 (6)C15—C10—C11117.7 (3)
O7—N4—O8124.0 (4)C15—C10—C3117.4 (3)
O7—N4—C11118.4 (3)C11—C10—C3124.8 (3)
O8—N4—C11117.6 (3)C12—C11—C10121.2 (4)
O3—N5—O4125.0 (3)C12—C11—N4117.2 (3)
O3—N5—C5118.6 (3)C10—C11—N4121.6 (3)
O4—N5—C5116.4 (3)C13—C12—C11118.2 (4)
O6—N6—O5124.1 (3)C13—C12—H12120.9
O6—N6—C7118.1 (3)C11—C12—H12120.9
O5—N6—C7117.7 (3)C14—C13—C12122.9 (3)
O2—N7—O1123.6 (3)C14—C13—N3119.5 (5)
O2—N7—C2118.4 (2)C12—C13—N3117.7 (5)
O1—N7—C2118.0 (3)C13—C14—C15118.4 (4)
N1—C1—C2109.9 (2)C13—C14—H14120.8
N1—C1—C4117.4 (2)C15—C14—H14120.8
C2—C1—C4132.7 (2)C14—C15—C10121.6 (4)
C3—C2—C1106.6 (2)C14—C15—H15119.2
C3—C2—N7125.4 (3)C10—C15—H15119.2
C1—C2—N7128.0 (3)C17—C16—H16A109.5
N2—C3—C2105.2 (2)C17—C16—H16B109.5
N2—C3—C10121.2 (3)H16A—C16—H16B109.5
C2—C3—C10133.4 (3)C17—C16—H16C109.5
C5—C4—C9117.0 (3)H16A—C16—H16C109.5
C5—C4—C1125.3 (3)H16B—C16—H16C109.5
C9—C4—C1117.7 (2)O11—C17—C18121.1 (3)
C6—C5—C4122.9 (3)O11—C17—C16120.6 (3)
C6—C5—N5116.5 (2)C18—C17—C16118.4 (3)
C4—C5—N5120.6 (2)C17—C18—H18A109.5
C5—C6—C7117.2 (3)C17—C18—H18B109.5
C5—C6—H6121.4H18A—C18—H18B109.5
C7—C6—H6121.4C17—C18—H18C109.5
C8—C7—C6122.5 (3)H18A—C18—H18C109.5
C8—C7—N6118.6 (3)H18B—C18—H18C109.5
C6—C7—N6118.9 (3)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N2—H2A···O11i0.92 (3)1.87 (4)2.786 (4)177 (3)
Symmetry code: (i) x, y+1/2, z1/2.

Experimental details

Crystal data
Chemical formulaC15H7N7O10·C3H6O
Mr503.35
Crystal system, space groupMonoclinic, P21/c
Temperature (K)298
a, b, c (Å)14.886 (10), 7.678 (5), 19.801 (13)
β (°) 104.944 (9)
V3)2187 (2)
Z4
Radiation typeMo Kα
µ (mm1)0.13
Crystal size (mm)0.31 × 0.19 × 0.18
Data collection
DiffractometerBruker SMART 1K CCD
diffractometer
Absorption correctionMulti-scan
(SADABS; Bruker, 2005)
Tmin, Tmax0.836, 0.977
No. of measured, independent and
observed [I > 2σ(I)] reflections
15182, 5041, 2703
Rint0.068
(sin θ/λ)max1)0.661
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.064, 0.202, 1.03
No. of reflections5041
No. of parameters332
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.27, 0.27

Computer programs: SMART (Bruker, 2005), SAINT (Bruker, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N2—H2A···O11i0.92 (3)1.87 (4)2.786 (4)177 (3)
Symmetry code: (i) x, y+1/2, z1/2.
 

Acknowledgements

The author thanks IFN-EPSCoR at the University of Puerto Rico for a graduate fellowship and Dr Raphael G. Raptis for his comments and for the use of X-ray facilities.

References

First citationBruker (2005). SMART, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
First citationFoces-Foces, C., Alkorta, I. & Elguero, J. (2000). Acta Cryst. B56, 1018–1028.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationMaresca, K. P., Rose, D. J. & Zubieta, J. (1997). Inorg. Chim. Acta, 260, 83–88.  CSD CrossRef CAS Web of Science Google Scholar
First citationRaptis, R. G., Staples, R. J., King, C. & Fackler, J. P. (1993). Acta Cryst. C49, 1716–1719.  CSD CrossRef CAS Web of Science IUCr Journals Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals 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