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

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ISSN: 2056-9890

5-(3,4-Dimeth­­oxy­benzyl­­idene)-1,3-di­methyl-1,3-diazinane-2,4,6-trione

aDepartment of Chemistry, University of the Free State, PO Box 339, Bloemfontein 9300, South Africa
*Correspondence e-mail: muller.theunis@gmail.com

(Received 21 November 2011; accepted 8 December 2011; online 21 December 2011)

In the title compound, C15H16N2O5, the dihedral angle between 1,3-diazinane and benzene rings is only 4.27 (1)°. The essentially planar mol­ecular structure is characterized by a short intra­molecular C—H⋯O separation and by an exceptionally large bond angle of 138.25 (14)° at the bridging methine C atom. The meth­oxy groups deviate somewhat from the plane of the benzene ring, with C—C—O—C torsion angles of −15.6 (1) and 9.17 (6)°. In the crystal, mol­ecules form centrosymmetric dimers via donor–acceptor ππ inter­actions, with a centroid–centroid distance of 3.401 (1) Å.

Related literature

For the biological activity of 1,3-diazinane derivatives, see: Negwar (2001[Negwar, M. (2001). Organic-Chemical Drugs and their Synonyms, 7th Rev. and Engl. ed., Vol. 4, pp. 2873-2957. Berlin: Akademie.]); Tanaka et al. (1986[Tanaka, K., Chen, X., Kimura, T. & Yoneda, F. (1986). Chem. Pharm. Bull. 34, 3945-3948.], 1988[Tanaka, K., Chen, X., Kimura, T. & Yoneda, F. (1988). Chem. Pharm. Bull. 36, 66-69.]). For the use of pyridine-type ligands in catalysis models, see: Roodt et al. (2011[Roodt, A., Visser, H. G. & Brink, A. (2011). Crystallogr. Rev. 66, 241-280.]); van der Westhuizen et al. (2010[Westhuizen, H. J. van der, Meijboom, R., Schutte, M. & Roodt, A. (2010). Inorg. Chem. 49, 9599-9608.]). For related structures, see: Panchatcharam et al. (2009[Panchatcharam, R., Dhayalan, V., Mohanakrishnan, A. K., Chakkaravarthi, G. & Manivannan, V. (2009). Acta Cryst. E65, o2394.]); Rezende et al. (2005[Rezende, M. C., Dominguez, M., Wardell, J. L., Skakle, J. M. S., Low, J. N. & Glidewell, C. (2005). Acta Cryst. C61, o306-o311.]). For the synthesis, see: Prajapati et al. (2006[Prajapati, D. & Gohain, M. (2006). Beilstein J. Org. Chem. 2, No. 11, doi:10.1186/1860-5397-2-11.]). For standard bond lengths, see: Allen et al. (1987[Allen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1-19.]).

[Scheme 1]

Experimental

Crystal data
  • C15H16N2O5

  • Mr = 304.3

  • Triclinic, [P \overline 1]

  • a = 7.3086 (2) Å

  • b = 8.4033 (3) Å

  • c = 11.8705 (5) Å

  • α = 82.5685 (18)°

  • β = 77.6686 (17)°

  • γ = 71.1469 (15)°

  • V = 672.58 (4) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 0.11 mm−1

  • T = 100 K

  • 0.15 × 0.12 × 0.06 mm

Data collection
  • Bruker APEXII CCD diffractometer

  • Absorption correction: multi-scan (SADABS; Bruker, 2008[Bruker (2008). APEX2, SAINT-Plus and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]) Tmin = 0.984, Tmax = 0.994

  • 12172 measured reflections

  • 3233 independent reflections

  • 2478 reflections with I > 2σ(I)

  • Rint = 0.032

Refinement
  • R[F2 > 2σ(F2)] = 0.042

  • wR(F2) = 0.113

  • S = 1.05

  • 3233 reflections

  • 203 parameters

  • H-atom parameters constrained

  • Δρmax = 0.32 e Å−3

  • Δρmin = −0.30 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C7—H7⋯O3 0.93 2.08 2.871 (2) 142

Data collection: APEX2 (Bruker, 2008[Bruker (2008). APEX2, SAINT-Plus and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT-Plus (Bruker, 2008[Bruker (2008). APEX2, SAINT-Plus and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT-Plus; 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: DIAMOND (Brandenberg & Putz, 2005[Brandenberg, K. & Putz, H. (2005). DIAMOND. Crystal Impact, Bonn, Germany.]); software used to prepare material for publication: WinGX (Farrugia, 1999[Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837-838.]).

Supporting information


Comment top

Barbituric acid is the parent compound of barbiturate drugs, although by itself it is not pharmacologically active (Negwar et al., 2001). Benzyledenebarbituric acids are important building block in the synthesis of pyrazolo-[3,4]-1,3-diazinane derivatives which shows broad-spectrum biological activities (Tanaka et al., 1986 and 1988). We also synthesized some of the benzyledene barbituric acids which were successfully used to prepare pyrano[2,3-d]- and furopyrano[2,3-d] 1,3-diazinane derivatives (Prajapati et al., 2006). The title compound having molecular formula C15H16N2O5 can be prepared by the condensation of barbituric acid and 4,5-dimethoxybenzaldehyde. The bond C5—C6 of 1.453 (2) Å is longer than C3—C5 bond of 1.365 (2) Å that indicates C3—C5 as a formally double bond. This is in accordance with the literature (Panchatcharam et al. 2009 and Rezende et al. 2005).

Related literature top

For the biological activity of 1,3-diazinane derivatives, see: Negwar (2001); Tanaka et al. (1986, 1988). For the use of pyridine-type ligands in catalysis models, see: Roodt et al. (2011); van der Westhuizen et al. (2010). For related structures, see: Panchatcharam et al. (2009); Rezende et al. (2005). For the synthesis, see: Prajapati et al. (2006). For standard bond lengths, see: Allen et al. (1987).

Experimental top

Mixture of N,N-dimethylbarbituric acid (0.50 g, 3.2 mmol) and 4,5-dimethoxy benzaldehyde (0.53 g, 3.2 mmol) in ethanol (10 ml) was stirred at room temperature until completion of the reaction (monitored by TLC). The solids that precipitated during the course of the reaction were filtered and washed with diethyl ether (5 ml). The precipitate was subsequently dissolved in hot acetonitrile. Upon cooling to room temperature with a slow evaporation of the acetonitrile the crystals (mp 229–230 °C) suitable for single-crystal X-ray diffraction were obtained.

1H NMR (600 MHz): 3.42 (s, 3H, N—Me), 3.43 (s, 3H, N—Me), 3.99 (s, 3H, OMe), 3.40 (s, 3H, OMe), 6.97 (d, 1H), 7.81 (dd, 1H), 8.41 (d, 1H), 8.51(s, 1H).

13C {1H} NMR (150Mz): 28.5, 29.1, 56.1, 56.2, 110.4, 114.2, 116.6, 125.9, 132.6, 148.4, 151.4, 154.4, 159.2, 161.1, 163.3.

Refinement top

The aromatic H atoms were positioned geometrically and allowed to ride on their parent atoms, with Uiso(H) = 1.2Ueq(parent) of the parent atom with a C—H distance of 0.93. The methyl H atoms were placed in geometrically idealized positions and constrained to ride on its parent atoms with Uiso(H) = 1.5Ueq(C) and at a distance of 0.96 Å; their torsion angles were optimized from electron density

Computing details top

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT-Plus (Bruker, 2008); data reduction: SAINT-Plus (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenberg & Putz, 2005); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures top
[Figure 1] Fig. 1. Diamond representation of the title compound, showing the numbering scheme and displacement ellipsoids (50% probability).
[Figure 2] Fig. 2. Diamond representation of the title compound, showing the π-π interaction.
5-(3,4-Dimethoxybenzylidene)-1,3-dimethyl-1,3-diazinane-2,4,6-trione top
Crystal data top
C15H16N2O5Z = 2
Mr = 304.3F(000) = 320
Triclinic, P1Dx = 1.508 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 7.3086 (2) ÅCell parameters from 3146 reflections
b = 8.4033 (3) Åθ = 2.6–28.2°
c = 11.8705 (5) ŵ = 0.11 mm1
α = 82.5685 (18)°T = 100 K
β = 77.6686 (17)°Plate, yellow
γ = 71.1469 (15)°0.15 × 0.12 × 0.06 mm
V = 672.58 (4) Å3
Data collection top
Bruker APEXII CCD
diffractometer
2478 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.032
ϕ and ω scansθmax = 28°, θmin = 3.2°
Absorption correction: multi-scan
(SADABS; Bruker, 2008)
h = 99
Tmin = 0.984, Tmax = 0.994k = 1111
12172 measured reflectionsl = 1515
3233 independent reflections
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)] = 0.042Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.113H-atom parameters constrained
S = 1.05 w = 1/[σ2(Fo2) + (0.0512P)2 + 0.239P]
where P = (Fo2 + 2Fc2)/3
3233 reflections(Δ/σ)max = 0.003
203 parametersΔρmax = 0.32 e Å3
0 restraintsΔρmin = 0.30 e Å3
Crystal data top
C15H16N2O5γ = 71.1469 (15)°
Mr = 304.3V = 672.58 (4) Å3
Triclinic, P1Z = 2
a = 7.3086 (2) ÅMo Kα radiation
b = 8.4033 (3) ŵ = 0.11 mm1
c = 11.8705 (5) ÅT = 100 K
α = 82.5685 (18)°0.15 × 0.12 × 0.06 mm
β = 77.6686 (17)°
Data collection top
Bruker APEXII CCD
diffractometer
3233 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2008)
2478 reflections with I > 2σ(I)
Tmin = 0.984, Tmax = 0.994Rint = 0.032
12172 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0420 restraints
wR(F2) = 0.113H-atom parameters constrained
S = 1.05Δρmax = 0.32 e Å3
3233 reflectionsΔρmin = 0.30 e Å3
203 parameters
Special details top

Experimental. The intensity data was collected on a Bruker X8 ApexII 4 K Kappa CCD diffractometer using an exposure time of 15 s/frame. A total of 1821 frames were collected with a frame width of 0.5° covering up to θ = 28.18° with 99.7% completeness accomplished.

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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
C10.4027 (2)0.72599 (19)0.80997 (12)0.0160 (3)
C20.5148 (2)0.43533 (18)0.75097 (12)0.0150 (3)
C30.61438 (19)0.49161 (18)0.63713 (12)0.0135 (3)
C40.59797 (19)0.67081 (18)0.61360 (12)0.0144 (3)
C50.70824 (19)0.36478 (18)0.56448 (12)0.0139 (3)
H50.68950.26350.59790.017*
C60.82904 (19)0.34247 (18)0.44990 (12)0.0138 (3)
C70.89371 (19)0.46673 (18)0.37541 (12)0.0142 (3)
H70.85720.5760.39850.017*
C81.01025 (19)0.42763 (18)0.26903 (12)0.0138 (3)
C91.06655 (19)0.26239 (18)0.23180 (12)0.0142 (3)
C101.0028 (2)0.13956 (18)0.30414 (12)0.0160 (3)
H101.03820.03060.28070.019*
C110.8865 (2)0.17974 (18)0.41127 (12)0.0155 (3)
H110.84520.09630.4590.019*
C120.4873 (2)0.95348 (18)0.68221 (13)0.0186 (3)
H12A0.38641.00810.63750.028*
H12B0.61090.96440.64030.028*
H12C0.45511.00520.75440.028*
C130.3059 (2)0.5045 (2)0.93915 (13)0.0215 (3)
H13A0.28320.58520.99490.032*
H13B0.38260.3960.96640.032*
H13C0.18220.4980.92830.032*
C140.9864 (2)0.71432 (18)0.21141 (14)0.0203 (3)
H14A0.84680.74020.21770.03*
H14B1.03560.78150.14790.03*
H14C1.01440.73840.28170.03*
C151.2176 (2)0.08217 (19)0.07552 (14)0.0215 (3)
H15A1.290.00870.1220.032*
H15B1.29280.08480.00120.032*
H15C1.09490.06570.07240.032*
N10.41279 (17)0.55732 (16)0.82856 (10)0.0161 (3)
N20.50181 (17)0.77434 (15)0.70439 (10)0.0151 (3)
O51.18050 (15)0.23929 (13)0.12565 (9)0.0181 (2)
O10.31031 (16)0.82697 (14)0.88192 (9)0.0229 (3)
O20.51855 (15)0.28912 (13)0.77753 (9)0.0216 (3)
O30.66023 (15)0.73491 (13)0.52101 (9)0.0210 (3)
O41.07951 (14)0.53932 (13)0.19183 (9)0.0174 (2)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0140 (6)0.0205 (8)0.0140 (7)0.0057 (6)0.0022 (5)0.0026 (6)
C20.0151 (6)0.0175 (7)0.0130 (7)0.0061 (6)0.0020 (5)0.0008 (6)
C30.0134 (6)0.0152 (7)0.0116 (7)0.0049 (5)0.0022 (5)0.0006 (5)
C40.0129 (6)0.0161 (7)0.0135 (7)0.0035 (5)0.0013 (5)0.0022 (6)
C50.0138 (6)0.0149 (7)0.0135 (7)0.0058 (5)0.0027 (5)0.0013 (6)
C60.0128 (6)0.0156 (7)0.0128 (7)0.0041 (5)0.0024 (5)0.0010 (5)
C70.0148 (6)0.0137 (7)0.0141 (7)0.0048 (5)0.0006 (5)0.0028 (5)
C80.0136 (6)0.0147 (7)0.0134 (7)0.0061 (5)0.0014 (5)0.0009 (5)
C90.0134 (6)0.0164 (7)0.0124 (7)0.0042 (5)0.0015 (5)0.0023 (6)
C100.0172 (7)0.0137 (7)0.0167 (7)0.0040 (5)0.0024 (5)0.0032 (6)
C110.0161 (6)0.0151 (7)0.0160 (7)0.0070 (6)0.0023 (5)0.0012 (6)
C120.0216 (7)0.0140 (7)0.0201 (8)0.0058 (6)0.0013 (6)0.0034 (6)
C130.0228 (8)0.0279 (9)0.0138 (8)0.0110 (7)0.0020 (6)0.0015 (6)
C140.0237 (7)0.0153 (8)0.0203 (8)0.0067 (6)0.0005 (6)0.0010 (6)
C150.0267 (8)0.0176 (8)0.0184 (8)0.0053 (6)0.0009 (6)0.0067 (6)
N10.0171 (6)0.0192 (7)0.0118 (6)0.0075 (5)0.0008 (5)0.0008 (5)
N20.0164 (6)0.0144 (6)0.0143 (6)0.0055 (5)0.0007 (5)0.0013 (5)
O50.0226 (5)0.0156 (5)0.0142 (5)0.0063 (4)0.0041 (4)0.0049 (4)
O10.0253 (6)0.0234 (6)0.0184 (6)0.0077 (5)0.0040 (4)0.0085 (5)
O20.0284 (6)0.0173 (6)0.0177 (6)0.0099 (5)0.0016 (4)0.0015 (4)
O30.0271 (6)0.0154 (5)0.0160 (6)0.0056 (4)0.0031 (4)0.0008 (4)
O40.0214 (5)0.0133 (5)0.0154 (5)0.0067 (4)0.0033 (4)0.0008 (4)
Geometric parameters (Å, º) top
C1—O11.2150 (18)C10—C111.385 (2)
C1—N11.386 (2)C10—H100.93
C1—N21.3897 (19)C11—H110.93
C2—O21.2212 (19)C12—N21.467 (2)
C2—N11.3826 (19)C12—H12A0.96
C2—C31.489 (2)C12—H12B0.96
C3—C51.365 (2)C12—H12C0.96
C3—C41.466 (2)C13—N11.4716 (19)
C4—O31.2235 (17)C13—H13A0.96
C4—N21.3914 (19)C13—H13B0.96
C5—C61.453 (2)C13—H13C0.96
C5—H50.93C14—O41.4331 (19)
C6—C111.402 (2)C14—H14A0.96
C6—C71.413 (2)C14—H14B0.96
C7—C81.377 (2)C14—H14C0.96
C7—H70.93C15—O51.4400 (19)
C8—O41.3650 (18)C15—H15A0.96
C8—C91.416 (2)C15—H15B0.96
C9—O51.3525 (17)C15—H15C0.96
C9—C101.389 (2)
O1—C1—N1121.71 (14)N2—C12—H12A109.5
O1—C1—N2121.60 (14)N2—C12—H12B109.5
N1—C1—N2116.69 (12)H12A—C12—H12B109.5
O2—C2—N1119.59 (13)N2—C12—H12C109.5
O2—C2—C3123.24 (13)H12A—C12—H12C109.5
N1—C2—C3117.16 (13)H12B—C12—H12C109.5
C5—C3—C4127.56 (13)N1—C13—H13A109.5
C5—C3—C2113.69 (13)N1—C13—H13B109.5
C4—C3—C2118.73 (12)H13A—C13—H13B109.5
O3—C4—N2118.37 (14)N1—C13—H13C109.5
O3—C4—C3125.11 (13)H13A—C13—H13C109.5
N2—C4—C3116.51 (13)H13B—C13—H13C109.5
C3—C5—C6138.25 (14)O4—C14—H14A109.5
C3—C5—H5110.9O4—C14—H14B109.5
C6—C5—H5110.9H14A—C14—H14B109.5
C11—C6—C7117.75 (13)O4—C14—H14C109.5
C11—C6—C5115.55 (13)H14A—C14—H14C109.5
C7—C6—C5126.71 (13)H14B—C14—H14C109.5
C8—C7—C6120.66 (13)O5—C15—H15A109.5
C8—C7—H7119.7O5—C15—H15B109.5
C6—C7—H7119.7H15A—C15—H15B109.5
O4—C8—C7124.60 (13)O5—C15—H15C109.5
O4—C8—C9114.77 (12)H15A—C15—H15C109.5
C7—C8—C9120.64 (13)H15B—C15—H15C109.5
O5—C9—C10125.58 (13)C2—N1—C1124.99 (13)
O5—C9—C8115.28 (12)C2—N1—C13117.62 (13)
C10—C9—C8119.14 (13)C1—N1—C13117.39 (12)
C11—C10—C9119.85 (14)C1—N2—C4125.56 (13)
C11—C10—H10120.1C1—N2—C12117.23 (12)
C9—C10—H10120.1C4—N2—C12116.91 (12)
C10—C11—C6121.96 (13)C9—O5—C15117.89 (11)
C10—C11—H11119C8—O4—C14116.37 (11)
C6—C11—H11119
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C7—H7···O30.932.082.871 (2)142

Experimental details

Crystal data
Chemical formulaC15H16N2O5
Mr304.3
Crystal system, space groupTriclinic, P1
Temperature (K)100
a, b, c (Å)7.3086 (2), 8.4033 (3), 11.8705 (5)
α, β, γ (°)82.5685 (18), 77.6686 (17), 71.1469 (15)
V3)672.58 (4)
Z2
Radiation typeMo Kα
µ (mm1)0.11
Crystal size (mm)0.15 × 0.12 × 0.06
Data collection
DiffractometerBruker APEXII CCD
diffractometer
Absorption correctionMulti-scan
(SADABS; Bruker, 2008)
Tmin, Tmax0.984, 0.994
No. of measured, independent and
observed [I > 2σ(I)] reflections
12172, 3233, 2478
Rint0.032
(sin θ/λ)max1)0.661
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.042, 0.113, 1.05
No. of reflections3233
No. of parameters203
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.32, 0.30

Computer programs: APEX2 (Bruker, 2008), SAINT-Plus (Bruker, 2008), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenberg & Putz, 2005), WinGX (Farrugia, 1999).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C7—H7···O30.932.082.871 (2)141.7
 

Acknowledgements

The University of the Free State and Sasol Ltd are gratefully acknowledged, for financial support, and Johannes van Tonder for the NMR data and help with the synthesis of the title compound. Special thanks are due to Professor Andreas Roodt.

References

First citationAllen, F. H., Kennard, O., Watson, D. G., Brammer, L., Orpen, A. G. & Taylor, R. (1987). J. Chem. Soc. Perkin Trans. 2, pp. S1–19.  CrossRef Web of Science
First citationBrandenberg, K. & Putz, H. (2005). DIAMOND. Crystal Impact, Bonn, Germany.
First citationBruker (2008). APEX2, SAINT-Plus and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA.
First citationFarrugia, L. J. (1999). J. Appl. Cryst. 32, 837–838.  CrossRef CAS IUCr Journals
First citationNegwar, M. (2001). Organic–Chemical Drugs and their Synonyms, 7th Rev. and Engl. ed., Vol. 4, pp. 2873–2957. Berlin: Akademie.
First citationPanchatcharam, R., Dhayalan, V., Mohanakrishnan, A. K., Chakkaravarthi, G. & Manivannan, V. (2009). Acta Cryst. E65, o2394.  Web of Science CSD CrossRef IUCr Journals
First citationPrajapati, D. & Gohain, M. (2006). Beilstein J. Org. Chem. 2, No. 11, doi:10.1186/1860-5397-2-11.
First citationRezende, M. C., Dominguez, M., Wardell, J. L., Skakle, J. M. S., Low, J. N. & Glidewell, C. (2005). Acta Cryst. C61, o306–o311.  Web of Science CSD CrossRef CAS IUCr Journals
First citationRoodt, A., Visser, H. G. & Brink, A. (2011). Crystallogr. Rev. 66, 241–280.  Web of Science CrossRef
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals
First citationTanaka, K., Chen, X., Kimura, T. & Yoneda, F. (1986). Chem. Pharm. Bull. 34, 3945–3948.  CrossRef CAS
First citationTanaka, K., Chen, X., Kimura, T. & Yoneda, F. (1988). Chem. Pharm. Bull. 36, 66–69.
First citationWesthuizen, H. J. van der, Meijboom, R., Schutte, M. & Roodt, A. (2010). Inorg. Chem. 49, 9599–9608.  Web of Science PubMed

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