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 November 1; 64(Pt 11): o2189.
Published online 2008 October 25. doi:  10.1107/S1600536808034260
PMCID: PMC2959756

(E)-Methyl N′-(3,4-dimethoxy­benzyl­idene)hydrazinecarboxyl­ate

Abstract

The title compound, C11H14N2O4, crystallizes with two independent but essentially identical mol­ecules in the asymmetric unit. Each mol­ecule adopts a trans configuration with respect to the C=N bond. Mol­ecules are linked into a one-dimensional network by inter- and intra­molecular N—H(...)O and C—H(...)O hydrogen bonds.

Related literature

For general background, see: Parashar et al. (1988 [triangle]); Hadjoudis et al. (1987 [triangle]); Borg et al. (1999 [triangle]). For a related structure, see: Shang et al. (2007 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-64-o2189-scheme1.jpg

Experimental

Crystal data

  • C11H14N2O4
  • M r = 238.24
  • Triclinic, An external file that holds a picture, illustration, etc.
Object name is e-64-o2189-efi1.jpg
  • a = 8.5276 (11) Å
  • b = 8.5517 (11) Å
  • c = 8.6259 (11) Å
  • α = 92.919 (5)°
  • β = 94.209 (4)°
  • γ = 94.146 (5)°
  • V = 624.71 (14) Å3
  • Z = 2
  • Mo Kα radiation
  • μ = 0.10 mm−1
  • T = 273 (2) K
  • 0.23 × 0.21 × 0.20 mm

Data collection

  • Bruker SMART CCD area-detector diffractometer
  • Absorption correction: multi-scan (SADABS; Bruker, 2002 [triangle]) T min = 0.971, T max = 0.979
  • 3471 measured reflections
  • 2172 independent reflections
  • 1985 reflections with I > 2σ(I)
  • R int = 0.013

Refinement

  • R[F 2 > 2σ(F 2)] = 0.028
  • wR(F 2) = 0.080
  • S = 1.04
  • 2172 reflections
  • 314 parameters
  • 3 restraints
  • H-atom parameters constrained
  • Δρmax = 0.11 e Å−3
  • Δρmin = −0.10 e Å−3

Data collection: SMART (Bruker, 2002 [triangle]); cell refinement: SAINT (Bruker, 2002 [triangle]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: SHELXTL (Sheldrick, 2008 [triangle]); software used to prepare material for publication: SHELXTL.

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808034260/bg2215sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808034260/bg2215Isup2.hkl

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

Acknowledgments

The authors thank Hangzhou Vocational and Technical College, China, for financial support.

supplementary crystallographic information

Comment

Benzaldehydehydrazone derivatives have received considerable attentions for a long time due to their pharmacological activity (Parashar et al., 1988) and their photochromic properties(Hadjoudis et al., 1987). Meanwhile, it's an important intermidiate of 1,3,4-oxadiazoles, which have been reported to be versatile compounds with many properties(Borg et al., 1999). As a further investigation of this type of derivatives, we report herein the crystal structure of the title compound (I).

The title compound, C11H14N2O4 ,crystallizes with two independent, but essentially identical molecules in the asymmetric unit. Each essentially planar molecule of the unit adopts a trans configuration with respect to the C═N bond. in a molecule of the unit,the hydrazine carboxylic acid methyl ester group is slightly twisted away from the attached ring. The dihedral angle between the two essentially planar molecule of the unit is 81.67 (4)°. The bond lengths and angles agree with those observed for (E)-Methyl N'-(4-hydroxybenzylidene)hydrazinecarboxylate (Shang et al., 2007).

The molecules are linked into a one-dimensional network by intermolecular intramolecular N–H···O, C–H···O hydrogen bonds (Fig.2). Meanwhile, A C—H···π contact between benzene ring (centroid Cg1) and H atom of methoxy C13 further stabilizes the structure (Table 1).

Experimental

3,4-Dimethoxybenzaldehyde (1.66 g, 0.01 mol) and methyl hydrazinecarboxylate (0.9g, 0.01mol) were dissolved in stirred methanol (25ml) and left for 3.2h at room temperature. The resulting solid was filtered off and recrystallized from ethanol to give the title compound in 86% yield. Crystals suitable for X-ray analysis were obtained by slow evaporation of a ethanol solution at room temperature (m.p. 468-470 K).

Refinement

H atoms were included in the riding model approximation with N-H = 0.86Å. C-bound H atoms were positioned geometrically (C-H = 0.93Å and 0.96Å) and refined using a riding model, with Uiso(H) = 1.2-1.5Ueq(C). In the absence of significant anomalous dispersion effects, Friedel pairs were averaged.

Figures

Fig. 1.
Molecular structure of (I), showing 20% probability displacement ellipsoids and the atomic numbering.
Fig. 2.
Crystal packing of the title compound, viewed approximately down the a axis. Dashed lines indicate hydrogen bonds. H atoms not intervening in H-bonding were eliminated for clarity.

Crystal data

C11H14N2O4Z = 2
Mr = 238.24F(000) = 252
Triclinic, P1Dx = 1.267 Mg m3
Hall symbol: P 1Mo Kα radiation, λ = 0.71073 Å
a = 8.5276 (11) ÅCell parameters from 2172 reflections
b = 8.5517 (11) Åθ = 2.4–25.0°
c = 8.6259 (11) ŵ = 0.10 mm1
α = 92.919 (5)°T = 273 K
β = 94.209 (4)°Block, colourless
γ = 94.146 (5)°0.23 × 0.21 × 0.20 mm
V = 624.71 (14) Å3

Data collection

Bruker SMART CCD area-detector diffractometer2172 independent reflections
Radiation source: fine-focus sealed tube1985 reflections with I > 2σ(I)
graphiteRint = 0.013
[var phi] and ω scansθmax = 25.0°, θmin = 2.4°
Absorption correction: multi-scan (SADABS; Bruker, 2002)h = −9→10
Tmin = 0.971, Tmax = 0.979k = −10→9
3471 measured reflectionsl = −10→10

Refinement

Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.028H-atom parameters constrained
wR(F2) = 0.080w = 1/[σ2(Fo2) + (0.049P)2 + 0.0326P] where P = (Fo2 + 2Fc2)/3
S = 1.04(Δ/σ)max = 0.010
2172 reflectionsΔρmax = 0.11 e Å3
314 parametersΔρmin = −0.10 e Å3
3 restraintsExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.034 (6)

Special details

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 > 2sigma(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)

xyzUiso*/Ueq
C1−0.1778 (4)0.3653 (5)0.7975 (4)0.0950 (11)
H1A−0.22610.26820.82890.143*
H1B−0.25770.42720.75390.143*
H1C−0.12250.42200.88640.143*
C20.1762 (4)0.2088 (4)0.3329 (3)0.0765 (8)
H2A0.28700.24000.34090.115*
H2B0.12720.24840.24070.115*
H2C0.16090.09620.32740.115*
C30.0551 (3)0.2502 (3)0.7257 (3)0.0563 (6)
C40.0913 (3)0.1979 (3)0.8721 (3)0.0629 (6)
H40.02670.21870.95180.075*
C50.2224 (3)0.1151 (3)0.9009 (3)0.0614 (6)
H50.24460.07980.99980.074*
C60.3208 (3)0.0839 (3)0.7857 (2)0.0536 (5)
C70.2846 (3)0.1357 (3)0.6355 (2)0.0532 (5)
H70.34970.11500.55620.064*
C80.1542 (3)0.2161 (3)0.6063 (2)0.0518 (5)
C90.4603 (3)−0.0029 (3)0.8201 (3)0.0592 (6)
H90.4750−0.04520.91680.071*
C100.8018 (3)−0.1300 (3)0.6745 (3)0.0592 (6)
C111.0411 (4)−0.2537 (4)0.6641 (4)0.0831 (8)
H11A1.0612−0.17520.59090.125*
H11B1.0213−0.35470.60960.125*
H11C1.1313−0.25520.73740.125*
C120.8912 (4)0.8997 (4)0.1431 (4)0.0832 (9)
H12A0.88740.91510.25380.125*
H12B0.88690.99890.09630.125*
H12C0.98760.85460.12090.125*
C130.4029 (4)0.5264 (5)−0.1260 (4)0.1025 (12)
H13A0.43100.4251−0.16260.154*
H13B0.36170.5814−0.21240.154*
H13C0.32430.5137−0.05250.154*
C140.6174 (3)0.5505 (3)0.0681 (2)0.0507 (5)
C150.7418 (3)0.6523 (3)0.1397 (2)0.0537 (5)
C160.5874 (3)0.4031 (3)0.1205 (3)0.0526 (5)
H160.50470.33650.07280.063*
C170.8352 (3)0.6017 (3)0.2610 (3)0.0702 (7)
H170.91940.66720.30730.084*
C180.6816 (3)0.3529 (3)0.2460 (3)0.0567 (6)
C190.8042 (3)0.4530 (3)0.3147 (3)0.0718 (7)
H190.86690.42050.39800.086*
C200.6530 (3)0.1995 (3)0.3102 (3)0.0615 (6)
H200.71890.17380.39440.074*
C210.4159 (3)−0.1482 (3)0.2941 (3)0.0641 (6)
C220.3184 (5)−0.3964 (4)0.3679 (5)0.1022 (11)
H22A0.3118−0.43320.26040.153*
H22B0.2171−0.36590.39450.153*
H22C0.3501−0.47870.43210.153*
O1−0.0693 (2)0.3330 (2)0.6835 (2)0.0744 (5)
O20.1079 (2)0.2698 (2)0.46445 (18)0.0699 (5)
O30.8131 (2)−0.0794 (2)0.5477 (2)0.0717 (5)
O40.9058 (2)−0.2180 (3)0.7456 (2)0.0807 (6)
O50.7603 (2)0.7965 (2)0.08141 (19)0.0666 (5)
O60.5370 (2)0.6126 (2)−0.0536 (2)0.0718 (5)
O70.3145 (3)−0.1471 (3)0.1902 (3)0.0887 (6)
O80.4310 (3)−0.2649 (2)0.3923 (3)0.0874 (6)
N10.5617 (2)−0.0216 (2)0.7210 (2)0.0583 (5)
N20.6856 (3)−0.1066 (3)0.7687 (2)0.0703 (6)
H20.6889−0.14490.85910.084*
N30.5424 (3)0.0995 (2)0.2565 (2)0.0588 (5)
N40.5318 (3)−0.0368 (3)0.3347 (2)0.0673 (6)
H4A0.6002−0.05040.41020.081*

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
C10.081 (2)0.116 (3)0.097 (2)0.042 (2)0.0291 (18)0.017 (2)
C20.099 (2)0.0901 (19)0.0422 (12)0.0300 (16)−0.0048 (12)0.0068 (12)
C30.0583 (14)0.0597 (13)0.0518 (12)0.0102 (11)0.0027 (10)0.0076 (10)
C40.0675 (15)0.0741 (15)0.0496 (12)0.0091 (13)0.0129 (11)0.0103 (11)
C50.0705 (15)0.0721 (15)0.0427 (11)0.0089 (13)0.0001 (11)0.0165 (11)
C60.0577 (13)0.0558 (12)0.0471 (11)0.0071 (11)−0.0046 (10)0.0112 (9)
C70.0587 (13)0.0585 (13)0.0436 (11)0.0117 (11)0.0016 (9)0.0081 (9)
C80.0587 (13)0.0552 (13)0.0422 (10)0.0105 (11)−0.0015 (10)0.0090 (9)
C90.0674 (15)0.0662 (14)0.0452 (11)0.0133 (12)−0.0054 (11)0.0177 (10)
C100.0615 (14)0.0592 (13)0.0566 (13)0.0099 (11)−0.0093 (11)0.0135 (10)
C110.0677 (17)0.092 (2)0.090 (2)0.0219 (15)−0.0067 (15)0.0067 (16)
C120.091 (2)0.0815 (19)0.0730 (17)−0.0176 (17)−0.0081 (15)0.0207 (14)
C130.089 (2)0.105 (2)0.106 (2)−0.0075 (19)−0.053 (2)0.038 (2)
C140.0481 (12)0.0640 (14)0.0422 (11)0.0168 (11)−0.0008 (9)0.0126 (10)
C150.0551 (13)0.0624 (14)0.0448 (11)0.0102 (11)0.0017 (10)0.0110 (10)
C160.0486 (12)0.0607 (13)0.0496 (11)0.0114 (10)−0.0014 (9)0.0102 (10)
C170.0685 (16)0.0735 (17)0.0653 (15)0.0014 (13)−0.0223 (13)0.0166 (13)
C180.0585 (13)0.0636 (14)0.0504 (12)0.0180 (11)−0.0002 (10)0.0132 (10)
C190.0718 (17)0.0781 (18)0.0643 (15)0.0126 (14)−0.0234 (13)0.0233 (13)
C200.0662 (15)0.0662 (15)0.0537 (12)0.0176 (13)−0.0069 (11)0.0184 (11)
C210.0727 (16)0.0660 (16)0.0561 (13)0.0164 (14)0.0075 (12)0.0091 (11)
C220.111 (3)0.071 (2)0.128 (3)−0.0024 (19)0.041 (2)0.0078 (19)
N10.0612 (12)0.0607 (11)0.0540 (11)0.0133 (9)−0.0076 (10)0.0181 (8)
N20.0719 (13)0.0897 (16)0.0546 (11)0.0293 (12)−0.0013 (10)0.0319 (10)
N30.0676 (13)0.0635 (12)0.0486 (10)0.0196 (11)0.0029 (9)0.0168 (9)
N40.0769 (14)0.0669 (13)0.0583 (11)0.0081 (11)−0.0087 (10)0.0205 (10)
O10.0711 (11)0.0905 (13)0.0677 (11)0.0342 (10)0.0122 (9)0.0139 (10)
O20.0782 (11)0.0920 (12)0.0454 (8)0.0393 (10)0.0027 (8)0.0183 (8)
O30.0715 (12)0.0859 (12)0.0610 (10)0.0180 (10)0.0011 (8)0.0244 (9)
O40.0763 (13)0.0995 (14)0.0718 (12)0.0382 (11)0.0003 (10)0.0232 (10)
O50.0733 (11)0.0656 (11)0.0592 (9)−0.0022 (9)−0.0081 (8)0.0193 (8)
O60.0687 (11)0.0774 (12)0.0671 (10)0.0021 (9)−0.0223 (9)0.0287 (9)
O70.0872 (14)0.0865 (14)0.0891 (14)0.0035 (11)−0.0180 (12)0.0127 (11)
O80.1069 (16)0.0683 (12)0.0869 (13)0.0002 (11)0.0003 (12)0.0223 (10)

Geometric parameters (Å, °)

C1—O11.429 (3)C12—H12B0.9600
C1—H1A0.9600C12—H12C0.9600
C1—H1B0.9600C13—O61.402 (4)
C1—H1C0.9600C13—H13A0.9600
C2—O21.407 (3)C13—H13B0.9600
C2—H2A0.9600C13—H13C0.9600
C2—H2B0.9600C14—O61.363 (3)
C2—H2C0.9600C15—O51.359 (3)
C3—O11.355 (3)C15—C171.375 (3)
C3—C41.382 (3)C15—C141.407 (3)
C4—H40.9300C16—C141.374 (3)
C5—C41.381 (4)C16—H160.9300
C5—H50.9300C17—H170.9300
C6—C51.375 (3)C18—C191.380 (4)
C6—C71.411 (3)C18—C161.404 (3)
C6—C91.467 (3)C18—C201.461 (3)
C7—H70.9300C19—C171.389 (4)
C8—C71.363 (3)C19—H190.9300
C8—O21.369 (3)C20—N31.271 (3)
C8—C31.412 (3)C20—H200.9300
C9—N11.272 (3)C21—O71.200 (3)
C9—H90.9300C21—N41.336 (4)
C10—O31.204 (3)C21—O81.349 (3)
C10—O41.339 (3)C22—O81.422 (4)
C10—N21.347 (3)C22—H22A0.9600
C11—O41.438 (4)C22—H22B0.9600
C11—H11A0.9600C22—H22C0.9600
C11—H11B0.9600N1—N21.375 (3)
C11—H11C0.9600N2—H20.8600
C12—O51.425 (3)N3—N41.377 (3)
C12—H12A0.9600N4—H4A0.8600
O1—C1—H1A109.5O6—C13—H13B109.5
O1—C1—H1B109.5H13A—C13—H13B109.5
H1A—C1—H1B109.5O6—C13—H13C109.5
O1—C1—H1C109.5H13A—C13—H13C109.5
H1A—C1—H1C109.5H13B—C13—H13C109.5
H1B—C1—H1C109.5O6—C14—C16125.9 (2)
O2—C2—H2A109.5O6—C14—C15113.64 (19)
O2—C2—H2B109.5C16—C14—C15120.47 (19)
H2A—C2—H2B109.5O5—C15—C17124.6 (2)
O2—C2—H2C109.5O5—C15—C14116.08 (18)
H2A—C2—H2C109.5C17—C15—C14119.4 (2)
H2B—C2—H2C109.5C14—C16—C18119.9 (2)
O1—C3—C4126.0 (2)C14—C16—H16120.0
O1—C3—C8115.39 (19)C18—C16—H16120.0
C4—C3—C8118.6 (2)C15—C17—C19120.2 (2)
C5—C4—C3120.5 (2)C15—C17—H17119.9
C5—C4—H4119.7C19—C17—H17119.9
C3—C4—H4119.7C19—C18—C16119.2 (2)
C6—C5—C4121.0 (2)C19—C18—C20118.1 (2)
C6—C5—H5119.5C16—C18—C20122.6 (2)
C4—C5—H5119.5C18—C19—C17120.9 (2)
C5—C6—C7119.0 (2)C18—C19—H19119.6
C5—C6—C9119.85 (19)C17—C19—H19119.6
C7—C6—C9121.2 (2)N3—C20—C18123.1 (2)
C8—C7—C6120.1 (2)N3—C20—H20118.5
C8—C7—H7119.9C18—C20—H20118.5
C6—C7—H7119.9O7—C21—N4127.2 (3)
C7—C8—O2124.6 (2)O7—C21—O8124.9 (3)
C7—C8—C3120.68 (19)N4—C21—O8107.8 (2)
O2—C8—C3114.69 (19)O8—C22—H22A109.5
N1—C9—C6121.68 (18)O8—C22—H22B109.5
N1—C9—H9119.2H22A—C22—H22B109.5
C6—C9—H9119.2O8—C22—H22C109.5
O3—C10—O4124.9 (2)H22A—C22—H22C109.5
O3—C10—N2126.3 (2)H22B—C22—H22C109.5
O4—C10—N2108.8 (2)C9—N1—N2115.30 (18)
O4—C11—H11A109.5C10—N2—N1120.23 (19)
O4—C11—H11B109.5C10—N2—H2119.9
H11A—C11—H11B109.5N1—N2—H2119.9
O4—C11—H11C109.5C20—N3—N4114.63 (19)
H11A—C11—H11C109.5C21—N4—N3120.4 (2)
H11B—C11—H11C109.5C21—N4—H4A119.8
O5—C12—H12A109.5N3—N4—H4A119.8
O5—C12—H12B109.5C3—O1—C1118.0 (2)
H12A—C12—H12B109.5C8—O2—C2117.77 (18)
O5—C12—H12C109.5C10—O4—C11117.2 (2)
H12A—C12—H12C109.5C15—O5—C12118.1 (2)
H12B—C12—H12C109.5C14—O6—C13118.5 (2)
O6—C13—H13A109.5C21—O8—C22116.6 (3)
O2—C8—C3—O1−1.1 (3)C17—C15—C14—C161.2 (3)
C7—C8—C3—C4−1.2 (3)C18—C16—C14—O6178.9 (2)
O2—C8—C3—C4178.8 (2)C18—C16—C14—C15−0.2 (3)
C7—C8—C3—O1178.9 (2)O5—C15—C14—O61.9 (3)
C8—C3—C4—C50.5 (4)C17—C15—C14—O6−178.0 (2)
C6—C5—C4—C30.6 (4)O5—C15—C14—C16−178.9 (2)
O1—C3—C4—C5−179.6 (2)C19—C18—C16—C14−0.3 (3)
C7—C6—C5—C4−1.0 (4)C20—C18—C16—C14178.1 (2)
C9—C6—C5—C4179.3 (2)O5—C15—C17—C19178.4 (3)
O2—C8—C7—C6−179.2 (2)C14—C15—C17—C19−1.6 (4)
C3—C8—C7—C60.8 (3)C18—C19—C17—C151.1 (4)
C5—C6—C7—C80.3 (3)C16—C18—C19—C17−0.1 (4)
C9—C6—C7—C8180.0 (2)C20—C18—C19—C17−178.6 (3)
C5—C6—C9—N1−173.5 (2)C19—C18—C20—N3179.3 (2)
C7—C6—C9—N16.8 (4)C16—C18—C20—N30.8 (4)
C6—C9—N1—N2−179.4 (2)C18—C20—N3—N4−178.5 (2)
O3—C10—N2—N12.1 (4)O7—C21—N4—N31.5 (4)
O4—C10—N2—N1−178.7 (2)O8—C21—N4—N3−178.0 (2)
C9—N1—N2—C10−178.3 (2)C20—N3—N4—C21176.9 (2)
C4—C3—O1—C1−2.6 (4)C17—C15—O5—C124.1 (4)
C8—C3—O1—C1177.3 (3)C14—C15—O5—C12−175.8 (2)
C7—C8—O2—C215.2 (4)C16—C14—O6—C135.7 (4)
C3—C8—O2—C2−164.8 (2)C15—C14—O6—C13−175.1 (3)
O3—C10—O4—C110.3 (4)O7—C21—O8—C220.8 (4)
N2—C10—O4—C11−178.9 (2)N4—C21—O8—C22−179.6 (3)

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
N2—H2···O5i0.862.072.902 (3)164
N2—H2···O6i0.862.543.153 (3)129
N4—H4A···O30.862.132.968 (3)164
C11—H11A···O30.962.332.701 (4)102
C19—H19···O2ii0.932.553.337 (3)143
C13—H13A···Cg1iii0.962.943.531 (4)121

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

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: BG2215).

References

  • Borg, S., Vollinga, R. C., Labarre, M., Payza, K., Terenius, L. & Luthman, K. (1999). J. Med. Chem 42, 4331–4342. [PubMed]
  • Bruker (2002). SADABS, SMART and SAINT Bruker AXS Inc., Madison, Wisconsin, USA.
  • Hadjoudis, E., Vittorakis, M. & Moustakali-Mavridis, J. (1987). Tetrahedron, 43, 1345–1360.
  • Parashar, R. K., Sharma, R. C., Kumar, A. & Mohanm, G. (1988). Inorg. Chim Acta, 151, 201–208.
  • Shang, Z.-H., Zhang, H.-L. & Ding, Y. (2007). Acta Cryst. E63, o3394.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]

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