PMCCPMCCPMCC

Search tips
Search criteria 

Advanced

 
Logo of actaeInternational Union of Crystallographysearchopen accessarticle submissionjournal home pagethis article
 
Acta Crystallogr Sect E Struct Rep Online. 2008 July 1; 64(Pt 7): m939.
Published online 2008 June 19. doi:  10.1107/S1600536808015924
PMCID: PMC2961780

Tetra­kis(μ-4-ethyl­benzoato-κ2 O:O′)­bis­[(4-ethyl­benzoic acid-κO)copper(II)]

Abstract

The molecule of the title compound, [Cu2(C9H9O2)4(C9H10O2)2], lies on a center of inversion. It consists of four bridging ethyl­benzoate ligands, forming a cage around two Cu atoms in a synsyn configuration, and two monodentate ethyl­benzoic acid ligands bonded apically to the square-planar Cu atoms. The Cu(...)Cu distance is 2.6047 (5) Å.

Related literature

For the synthesis of aromatic carboxylic acids, see: Kaeding (1967 [triangle]). For tetra­kis(μ2-2-methyl­benzoato)bis­(2-methyl­benzoic acid)dicopper(II), see: Sunil et al. (2008 [triangle]). For tetra­kis(μ2-2-fluoro­benzoato)bis­(2-fluoro­benzoic acid)dicopper(II), see: Valach et al. (2000 [triangle]). For tetra­kis(μ2benzoato) bis­(2-fluoro­benzoic acid)dicopper(II), see: Kawata et al. (1992 [triangle]). For tetra­kis-[μ-(2-phenoxy­benzoato-O,O′)]bis­[(2-phenoxy­benzoic acid)copper(II)], see: Mak & Yip (1990 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-64-0m939-scheme1.jpg

Experimental

Crystal data

  • [Cu2(C9H9O2)4(C9H10O2)2]
  • M r = 1024.07
  • Triclinic, An external file that holds a picture, illustration, etc.
Object name is e-64-0m939-efi1.jpg
  • a = 10.6167 (5) Å
  • b = 10.7394 (7) Å
  • c = 10.8096 (7) Å
  • α = 81.848 (3)°
  • β = 88.594 (3)°
  • γ = 79.468 (2)°
  • V = 1199.47 (12) Å3
  • Z = 1
  • Mo Kα radiation
  • μ = 0.95 mm−1
  • T = 100 (2) K
  • 0.54 × 0.4 × 0.39 mm

Data collection

  • Bruker Kappa APEXII diffractometer
  • Absorption correction: multi-scan (SADABS; Bruker, 2004 [triangle]) T min = 0.628, T max = 0.708
  • 15971 measured reflections
  • 5683 independent reflections
  • 4721 reflections with I > 2σ(I)
  • R int = 0.040

Refinement

  • R[F 2 > 2σ(F 2)] = 0.040
  • wR(F 2) = 0.103
  • S = 1.03
  • 5683 reflections
  • 311 parameters
  • H-atom parameters constrained
  • Δρmax = 0.50 e Å−3
  • Δρmin = −0.37 e Å−3

Data collection: APEX2 (Bruker, 2005 [triangle]); cell refinement: SAINT-Plus (Bruker, 2004 [triangle]); data reduction: SAINT-Plus and XPREP (Bruker, 2004 [triangle]); program(s) used to solve structure: SIR97 (Altomare et al., 1999 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: DIAMOND (Brandenburg & Putz, 2005 [triangle]); software used to prepare material for publication: WinGX (Farrugia, 1999 [triangle]).

Table 1
Selected bond lengths (Å)

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808015924/fi2063sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808015924/fi2063Isup2.hkl

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

Acknowledgments

Financial assistance from the University of the Free State and SASOL to ACS is gratefully acknowledged. Opinions, findings, conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of SASOL.

supplementary crystallographic information

Comment

The title compound forms part of the copper(II) complexes of the type [Cu2(RCO2)4L2] (R=aryl, L=monodentate ligand). This type of complex forms tetra-(carboxylato-O,O') bridges and four of the carboxylate groups hold together two Cu atoms (Fig. 1). The Cu···Cu distance in the title compound is 2.6047 (5) Å, probably displaying weak orbital interaction considering that the van der Waals radius of copper is 2.32 Å. The axial sites of each copper atom are bonded to a monodentate p-ethylbenzoic acid ligand. In turn the acid protons are hydrogen bonded to the cage carboxylate O atoms, O—H···O = 166.79° and O···O = 2.645 Å.

Neighbouring molecules stack with overlap between the axially bonded phenyl rings displaying a centroid to centroid distance of 4.2918 (3) Å and an interplanar distance of 3.6277 Å (Fig. 2 A). This inter-molecular interaction influence the dihedral angle displayed between the phenyl rings from the axially bonded monodentate ligands and the carboxylic oxygen plane, O1, O2, O1i and O2i (i = 1 - x, 1 - y, 2 - z). Molecular packing in the (0 0 h) plane is in a puckered pseudo-hexagonal close packing fashion. This close packing is stabilized by soft inter-molecular C···H contacts ranging from 2.720–2.813 Å (Fig. 2B).

Experimental

The complex [Cu2(C9H10O2)4(C9H11O2)2] was prepared by heating 4-ethylbenzoic acid (1.77 g, 11.81 mmol), copper carbonate (0.74 g, 3.34 mmol) and magnesium oxide (0.20 g, 4.98 mmol) under reflux, in toluene (15 ml) for 60 h. The product was extacted and crystallized from diethyl ether to yield a blue crystalline solid. (Yield: 80%)

Refinement

The H atoms were positioned geometrically and refined using a riding model with fixed C—H distances of 0.93 Å (CH) [Uiso(H) = 1.2Ueq] and 0.96 Å (CH3) [Uiso(H) = 1.5Ueq] respectively. Initial positions of methyl H-atoms were obtained from Fourier difference maps and refined as a fixed rotor.

The highest density peak is 0.50 located 0.65 Å from C14 and the deepest hole is -0.37 located at 0.68 Å from Cu1.

Figures

Fig. 1.
A view of (I) showing the atom-numbering scheme with displacement ellipsoids at the 30% probability level, non labelled atoms are symmetric equivalents. For the phenyl C-atoms, the first digit indicates ring number and the second digit the position of ...
Fig. 2.
(A) Hacked lines indicate overlap between ethylbenzoic groups of neighbouring molecules. (B) Indication of pseudo-hexagonal close packing along the c axis.

Crystal data

[Cu2(C9H9O2)4(C9H10O2)2]Z = 1
Mr = 1024.07F000 = 534
Triclinic, P1Dx = 1.418 Mg m3
Hall symbol: -P 1Mo Kα radiation λ = 0.71069 Å
a = 10.6167 (5) ÅCell parameters from 4441 reflections
b = 10.7394 (7) Åθ = 2.5–28.2º
c = 10.8096 (7) ŵ = 0.95 mm1
α = 81.848 (3)ºT = 100 (2) K
β = 88.594 (3)ºCuboid, blue
γ = 79.468 (2)º0.54 × 0.4 × 0.39 mm
V = 1199.47 (12) Å3

Data collection

Bruker Kappa APEXII diffractometer4721 reflections with I > 2σ(I)
Monochromator: graphiteRint = 0.040
T = 100(2) Kθmax = 28º
ω and [var phi] scansθmin = 2.5º
Absorption correction: multi-scan(SADABS; Bruker, 2004)h = −7→14
Tmin = 0.628, Tmax = 0.708k = −14→14
15971 measured reflectionsl = −14→14
5683 independent reflections

Refinement

Refinement on F2H-atom parameters constrained
Least-squares matrix: full  w = 1/[σ2(Fo2) + (0.0447P)2 + 0.9309P] where P = (Fo2 + 2Fc2)/3
R[F2 > 2σ(F2)] = 0.040(Δ/σ)max = 0.001
wR(F2) = 0.103Δρmax = 0.50 e Å3
S = 1.04Δρmin = −0.37 e Å3
5683 reflectionsExtinction correction: none
311 parameters

Special details

Experimental. The intensity data was collected on a Bruker X8 Apex II 4 K Kappa CCD diffractometer using an exposure time of 2 s/frame. A total of 1507 frames were collected with a frame width of 0.5° covering up to θ = 28.0° with 98.3% completeness accomplished.
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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2)

xyzUiso*/Ueq
Cu10.45033 (3)0.46672 (2)0.90347 (2)0.01213 (9)
O60.58444 (17)0.40202 (18)0.62540 (16)0.0239 (4)
H60.5990.44450.6790.036*
O10.60816 (15)0.51776 (15)0.82165 (14)0.0152 (3)
O30.36215 (15)0.64398 (14)0.86973 (14)0.0166 (3)
O40.54987 (16)0.29874 (15)0.96412 (14)0.0181 (3)
O20.30749 (15)0.42705 (15)1.01089 (14)0.0167 (3)
O50.40263 (15)0.39621 (15)0.73471 (14)0.0168 (3)
C510.4404 (2)0.2808 (2)0.5616 (2)0.0144 (4)
C110.8123 (2)0.58002 (19)0.80261 (19)0.0124 (4)
C300.3784 (2)0.7244 (2)0.94028 (19)0.0140 (4)
C530.3163 (2)0.1251 (2)0.5207 (2)0.0192 (5)
H530.25420.07590.5460.023*
C550.4715 (2)0.1870 (2)0.3717 (2)0.0172 (5)
H550.51340.18060.29570.021*
C520.3464 (2)0.2079 (2)0.5971 (2)0.0172 (5)
H520.30380.2150.67270.021*
C540.3778 (2)0.1138 (2)0.4054 (2)0.0169 (5)
C360.2111 (2)0.8866 (2)0.8178 (2)0.0171 (5)
H360.19560.8230.7730.02*
C160.9223 (2)0.5936 (2)0.8637 (2)0.0145 (4)
H160.92120.59180.950.017*
C100.6968 (2)0.55566 (19)0.87604 (19)0.0133 (4)
C310.3059 (2)0.8585 (2)0.9087 (2)0.0143 (4)
C340.1628 (2)1.1064 (2)0.8569 (2)0.0184 (5)
C320.3321 (2)0.9558 (2)0.9709 (2)0.0191 (5)
H320.39680.93841.03060.023*
C560.5043 (2)0.2694 (2)0.4481 (2)0.0162 (5)
H560.56820.31660.4240.019*
C120.8152 (2)0.5865 (2)0.6725 (2)0.0146 (4)
H120.7430.57770.630.018*
C5410.3421 (3)0.0255 (2)0.3213 (2)0.0235 (5)
H54A0.3627−0.06180.36330.028*
H54B0.39360.03130.24610.028*
C1411.1539 (2)0.6401 (2)0.5944 (2)0.0208 (5)
H14A1.18030.5710.54520.025*
H14B1.22280.63910.65210.025*
C500.4725 (2)0.3652 (2)0.6484 (2)0.0155 (5)
C130.9247 (2)0.6059 (2)0.6070 (2)0.0158 (5)
H130.92460.61140.52030.019*
C151.0327 (2)0.6096 (2)0.7979 (2)0.0164 (5)
H151.10590.61530.84080.02*
C141.0360 (2)0.6173 (2)0.6679 (2)0.0152 (4)
C642−0.0475 (3)1.2359 (3)0.9030 (3)0.0385 (7)
H64A−0.09231.17680.87170.058*
H64B−0.09891.320.89010.058*
H64C−0.03111.210.99070.058*
C6410.0790 (3)1.2371 (2)0.8338 (2)0.0254 (6)
H64D0.06281.26120.74490.03*
H64E0.12261.29970.86230.03*
C330.2619 (3)1.0788 (2)0.9443 (2)0.0229 (5)
H330.28121.14350.98520.028*
C350.1394 (2)1.0083 (2)0.7935 (2)0.0186 (5)
H350.07461.02530.73390.022*
C1421.1323 (3)0.7677 (3)0.5072 (3)0.0323 (6)
H14C1.06510.76880.4490.048*
H14D1.20990.77750.46230.048*
H14E1.10850.83670.55560.048*
C5420.2016 (3)0.0542 (2)0.2846 (2)0.0277 (6)
H54C0.14980.04630.35830.042*
H54D0.1855−0.00530.2310.042*
H54E0.18070.13970.24120.042*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
Cu10.01076 (16)0.01499 (14)0.01135 (13)−0.00383 (10)0.00010 (10)−0.00231 (9)
O60.0189 (10)0.0369 (10)0.0225 (9)−0.0156 (8)0.0057 (7)−0.0139 (7)
O10.0110 (8)0.0221 (8)0.0148 (7)−0.0076 (7)0.0005 (6)−0.0041 (6)
O30.0161 (9)0.0154 (7)0.0184 (8)−0.0022 (6)−0.0021 (7)−0.0032 (6)
O40.0212 (9)0.0164 (8)0.0168 (8)−0.0025 (7)−0.0044 (7)−0.0032 (6)
O20.0130 (8)0.0256 (8)0.0138 (7)−0.0087 (7)0.0014 (6)−0.0036 (6)
O50.0144 (9)0.0232 (8)0.0142 (7)−0.0042 (7)0.0001 (6)−0.0059 (6)
C510.0119 (12)0.0176 (10)0.0129 (10)−0.0019 (9)−0.0023 (8)0.0001 (8)
C110.0097 (11)0.0118 (9)0.0152 (10)−0.0021 (8)−0.0009 (8)−0.0005 (8)
C300.0114 (11)0.0179 (10)0.0130 (10)−0.0047 (9)0.0049 (8)−0.0008 (8)
C530.0187 (13)0.0212 (11)0.0195 (11)−0.0096 (10)0.0022 (10)−0.0010 (9)
C550.0149 (12)0.0217 (11)0.0139 (10)0.0000 (9)0.0025 (9)−0.0030 (9)
C520.0159 (12)0.0235 (11)0.0126 (10)−0.0057 (10)0.0022 (9)−0.0015 (9)
C540.0152 (12)0.0178 (11)0.0169 (11)0.0007 (9)−0.0032 (9)−0.0041 (9)
C360.0165 (12)0.0166 (10)0.0184 (11)−0.0035 (9)0.0004 (9)−0.0026 (8)
C160.0140 (12)0.0171 (10)0.0128 (10)−0.0039 (9)−0.0025 (9)−0.0019 (8)
C100.0147 (12)0.0124 (10)0.0122 (9)−0.0027 (9)−0.0021 (8)0.0009 (8)
C310.0111 (11)0.0164 (10)0.0155 (10)−0.0038 (9)0.0037 (9)−0.0014 (8)
C340.0192 (13)0.0159 (11)0.0191 (11)−0.0037 (9)0.0064 (9)0.0001 (9)
C320.0186 (13)0.0215 (11)0.0174 (11)−0.0029 (10)−0.0034 (9)−0.0040 (9)
C560.0107 (12)0.0200 (11)0.0180 (11)−0.0046 (9)0.0013 (9)−0.0015 (9)
C120.0112 (12)0.0175 (10)0.0161 (10)−0.0041 (9)−0.0022 (9)−0.0029 (8)
C5410.0256 (14)0.0240 (12)0.0239 (12)−0.0073 (11)0.0018 (11)−0.0101 (10)
C1410.0140 (12)0.0277 (12)0.0229 (12)−0.0086 (10)0.0037 (10)−0.0059 (10)
C500.0142 (12)0.0175 (10)0.0145 (10)−0.0032 (9)−0.0027 (9)−0.0008 (8)
C130.0145 (12)0.0196 (11)0.0133 (10)−0.0033 (9)0.0008 (9)−0.0025 (8)
C150.0118 (12)0.0185 (11)0.0199 (11)−0.0054 (9)−0.0041 (9)−0.0016 (9)
C140.0114 (12)0.0131 (10)0.0210 (11)−0.0030 (9)0.0021 (9)−0.0019 (8)
C6420.0278 (17)0.0213 (13)0.065 (2)−0.0006 (12)0.0111 (15)−0.0078 (13)
C6410.0290 (15)0.0182 (11)0.0273 (13)−0.0024 (11)0.0028 (11)−0.0008 (10)
C330.0306 (15)0.0184 (11)0.0211 (12)−0.0052 (11)0.0008 (11)−0.0067 (9)
C350.0147 (13)0.0198 (11)0.0202 (11)−0.0022 (9)−0.0024 (9)−0.0003 (9)
C1420.0232 (15)0.0422 (16)0.0296 (14)−0.0106 (13)−0.0002 (12)0.0071 (12)
C5420.0304 (16)0.0261 (13)0.0292 (13)−0.0071 (11)−0.0066 (11)−0.0086 (10)

Geometric parameters (Å, °)

Cu1—O31.9498 (15)C31—C321.392 (3)
Cu1—O41.9501 (16)C34—C331.394 (3)
Cu1—O21.9593 (16)C34—C351.397 (3)
Cu1—O12.0040 (16)C34—C6411.509 (3)
Cu1—O52.1761 (15)C32—C331.387 (3)
Cu1—Cu1i2.6047 (5)C32—H320.93
O6—C501.326 (3)C56—H560.93
O6—H60.82C12—C131.380 (3)
O1—C101.277 (3)C12—H120.93
O3—C301.267 (3)C541—C5421.517 (4)
O4—C30i1.267 (3)C541—H54A0.97
O2—C10i1.261 (2)C541—H54B0.97
O5—C501.223 (3)C141—C141.505 (3)
C51—C521.392 (3)C141—C1421.532 (3)
C51—C561.397 (3)C141—H14A0.97
C51—C501.479 (3)C141—H14B0.97
C11—C161.396 (3)C13—C141.400 (3)
C11—C121.398 (3)C13—H130.93
C11—C101.488 (3)C15—C141.396 (3)
C30—O4i1.267 (3)C15—H150.93
C30—C311.501 (3)C642—C6411.523 (4)
C53—C521.378 (3)C642—H64A0.96
C53—C541.403 (3)C642—H64B0.96
C53—H530.93C642—H64C0.96
C55—C561.386 (3)C641—H64D0.97
C55—C541.388 (3)C641—H64E0.97
C55—H550.93C33—H330.93
C52—H520.93C35—H350.93
C54—C5411.505 (3)C142—H14C0.96
C36—C351.381 (3)C142—H14D0.96
C36—C311.387 (3)C142—H14E0.96
C36—H360.93C542—H54C0.96
C16—C151.382 (3)C542—H54D0.96
C16—H160.93C542—H54E0.96
C10—O2i1.261 (2)
O3—Cu1—O4169.67 (6)C55—C56—C51119.3 (2)
O3—Cu1—O289.21 (7)C55—C56—H56120.3
O4—Cu1—O289.79 (7)C51—C56—H56120.3
O3—Cu1—O189.64 (7)C13—C12—C11120.3 (2)
O4—Cu1—O189.46 (7)C13—C12—H12119.8
O2—Cu1—O1169.42 (6)C11—C12—H12119.8
O3—Cu1—O5100.25 (6)C54—C541—C542113.8 (2)
O4—Cu1—O590.05 (6)C54—C541—H54A108.8
O2—Cu1—O599.99 (6)C542—C541—H54A108.8
O1—Cu1—O590.57 (6)C54—C541—H54B108.8
O3—Cu1—Cu1i86.32 (5)C542—C541—H54B108.8
O4—Cu1—Cu1i83.36 (5)H54A—C541—H54B107.7
O2—Cu1—Cu1i87.95 (5)C14—C141—C142112.7 (2)
O1—Cu1—Cu1i81.48 (4)C14—C141—H14A109.1
O5—Cu1—Cu1i169.69 (5)C142—C141—H14A109.1
C50—O6—H6109.5C14—C141—H14B109.1
C10—O1—Cu1125.79 (14)C142—C141—H14B109.1
C30—O3—Cu1120.62 (14)H14A—C141—H14B107.8
C30i—O4—Cu1124.01 (14)O5—C50—O6123.3 (2)
C10i—O2—Cu1120.97 (15)O5—C50—C51122.7 (2)
C50—O5—Cu1128.90 (15)O6—C50—C51113.97 (19)
C52—C51—C56119.6 (2)C12—C13—C14121.5 (2)
C52—C51—C50118.4 (2)C12—C13—H13119.2
C56—C51—C50122.0 (2)C14—C13—H13119.2
C16—C11—C12118.5 (2)C16—C15—C14120.9 (2)
C16—C11—C10120.04 (19)C16—C15—H15119.5
C12—C11—C10121.5 (2)C14—C15—H15119.5
O3—C30—O4i125.7 (2)C15—C14—C13117.8 (2)
O3—C30—C31117.29 (19)C15—C14—C141121.5 (2)
O4i—C30—C31117.03 (19)C13—C14—C141120.7 (2)
C52—C53—C54121.0 (2)C641—C642—H64A109.5
C52—C53—H53119.5C641—C642—H64B109.5
C54—C53—H53119.5H64A—C642—H64B109.5
C56—C55—C54121.9 (2)C641—C642—H64C109.5
C56—C55—H55119.1H64A—C642—H64C109.5
C54—C55—H55119.1H64B—C642—H64C109.5
C53—C52—C51120.3 (2)C34—C641—C642110.1 (2)
C53—C52—H52119.9C34—C641—H64D109.6
C51—C52—H52119.9C642—C641—H64D109.6
C55—C54—C53117.9 (2)C34—C641—H64E109.6
C55—C54—C541121.5 (2)C642—C641—H64E109.6
C53—C54—C541120.6 (2)H64D—C641—H64E108.2
C35—C36—C31120.3 (2)C32—C33—C34120.8 (2)
C35—C36—H36119.8C32—C33—H33119.6
C31—C36—H36119.8C34—C33—H33119.6
C15—C16—C11120.9 (2)C36—C35—C34121.1 (2)
C15—C16—H16119.5C36—C35—H35119.5
C11—C16—H16119.5C34—C35—H35119.5
O2i—C10—O1123.7 (2)C141—C142—H14C109.5
O2i—C10—C11117.84 (19)C141—C142—H14D109.5
O1—C10—C11118.46 (18)H14C—C142—H14D109.5
C36—C31—C32119.2 (2)C141—C142—H14E109.5
C36—C31—C30120.3 (2)H14C—C142—H14E109.5
C32—C31—C30120.5 (2)H14D—C142—H14E109.5
C33—C34—C35118.2 (2)C541—C542—H54C109.5
C33—C34—C641121.5 (2)C541—C542—H54D109.5
C35—C34—C641120.2 (2)H54C—C542—H54D109.5
C33—C32—C31120.3 (2)C541—C542—H54E109.5
C33—C32—H32119.9H54C—C542—H54E109.5
C31—C32—H32119.9H54D—C542—H54E109.5

Symmetry codes: (i) −x+1, −y+1, −z+2.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: FI2063).

References

  • Altomare, A., Burla, M. C., Camalli, M., Cascarano, G. L., Giacovazzo, C., Guagliardi, A., Moliterni, A. G. G., Polidori, G. & Spagna, R. (1999). J. Appl. Cryst.32, 115–119.
  • Brandenburg, K. & Putz, H. (2005). DIAMOND Crystal Impact GbR, Bonn, Germany.
  • Bruker (2004). SAINT-Plus (including XPREP) and SADABS Bruker AXS Inc., Madison, Wisconsin, USA.
  • Bruker (2005). APEX2 Bruker AXS Inc., Madison, Wisconsin, USA.
  • Farrugia, L. J. (1999). J. Appl. Cryst.32, 837–838.
  • Kaeding, W. W. (1967). J. Org. Chem.26, 3144–3148.
  • Kawata, T., Uekusa, H., Ohba, S., Furukawa, T., Tokii, T., Muto, Y. & Kato, M. (1992). Acta Cryst. B48, 253–261.
  • Mak, T. C. W. & Yip, W. H. (1990). Polyhedron, 9, 1667–1670.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]
  • Sunil, A. C., Bezuidenhoudt, B. C. B. & Janse van Rensburg, J. M. (2008). Acta Cryst. E64, m553–m554. [PMC free article] [PubMed]
  • Valach, F., Tokarcik, M., Maris, T., Watkin, D. J. & Prout, C. K. (2000). Z. Kristallogr.215, 56–60.

Articles from Acta Crystallographica Section E: Structure Reports Online are provided here courtesy of International Union of Crystallography