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

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890

3-[Bis(di­methyl­amino)­methyl­ene]-1,1-di­phenyl­urea

aFakultät Chemie/Organische Chemie, Hochschule Aalen, Beethovenstrasse 1, D-73430 Aalen, Germany
*Correspondence e-mail: Ioannis.Tiritiris@htw-aalen.de

(Received 20 September 2012; accepted 1 October 2012; online 6 October 2012)

In the title compound, C18H22N4O, the C=N and C—N bond lengths in the CN3 unit are 1.3179 (11), 1.3551 (11) and 1.3737 (11) Å, indicating double- and single-bond character, respectively. The N—C—N angles are 115.91 (8), 118.20 (8) and 125.69 (8), showing a deviation of the CN3 plane from an ideal trigonal–planar geometry. The bonds between the N atoms and the terminal C-methyl groups all have values close to a typical single bond [1.4529 (12)–1.4624 (12) Å]. The dihedral angle between the phenyl rings is 79.63 (4)°. In the crystal, the mol­ecules are connected via weak C—H⋯O hydrogen bonds, generating chains along [100].

Related literature

For synthesis of N-dimethyl­carbamoyl-N′,N′,N′′,N′′-tetra­methyl­guanidine, see: Möllers et al. (2003[Möllers, C., Prigge, J., Wibbeling, B., Fröhlich, R., Brockmeyer, A., Schäfer, H. J., Schmälzlin, E., Bräuchle, C., Meerholz, K. & Würthwein, E.-U. (2003). Eur. J. Org. Chem. 1198-1208.]). For the crystal structures of 2- and 5-azido-N-(diphenyl­carbamo­yl) proline methyl ester, see: Lynch et al. (1995[Lynch, V. M., Hulme, C., Magnus, P. & Davis, B. E. (1995). Acta Cryst. C51, 2598-2601.]).

[Scheme 1]

Experimental

Crystal data
  • C18H22N4O

  • Mr = 310.40

  • Monoclinic, P 21 /c

  • a = 7.9321 (3) Å

  • b = 17.0477 (9) Å

  • c = 12.2151 (6) Å

  • β = 98.583 (2)°

  • V = 1633.28 (13) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 0.08 mm−1

  • T = 100 K

  • 0.25 × 0.20 × 0.15 mm

Data collection
  • Bruker Kappa APEXII Duo diffractometer

  • 51490 measured reflections

  • 4990 independent reflections

  • 4200 reflections with I > 2σ(I)

  • Rint = 0.029

Refinement
  • R[F2 > 2σ(F2)] = 0.039

  • wR(F2) = 0.105

  • S = 1.04

  • 4990 reflections

  • 212 parameters

  • H-atom parameters constrained

  • Δρmax = 0.37 e Å−3

  • Δρmin = −0.23 e Å−3

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C11—H11A⋯O1i 0.95 2.59 3.3893 (12) 141
Symmetry code: (i) x-1, y, z.

Data collection: APEX2 (Bruker, 2008[Bruker (2008). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2008[Bruker (2008). APEX2 and SAINT. 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: DIAMOND (Brandenburg & Putz, 2005[Brandenburg, K. & Putz, H. (2005). DIAMOND. Crystal Impact GbR, D-53002 Bonn, Germany.]); software used to prepare material for publication: SHELXL97.

Supporting information


Comment top

3-[bis(dimethylamino)methylene]-1,1-diphenylurea - also known as N-diphenylcarbamoyl-N',N',N'',N''- tetramethylguanidine - is a guanidine derivative bearing an additional urea moiety. Similar to 3-[bis(dimethylamino)methylene]-1,1-dimethylurea (N-dimethylcarbamoyl- N',N',N'',N''-tetramethylguanidine; Möllers et al., 2003), it can be used as a ligand in coordination chemistry to coordinate transition metals through one imino nitrogen and one carbonyl oxygen atom. Therefore, it proved to be important to determine the hitherto unknown crystal structure of the free ligand, to enable comparative investigations. According to the structure analysis, the C1–N3 bond in the title compound is 1.3179 (11) Å, indicating double bond character. The bond lengths C1–N2 = 1.3551 (11) Å and C1–N1 = 1.3737 (11) Å are elongated and characteristic for Cimine–Namine single bonds. The N–C1–N angles are: 115.91 (8)° (N1–C1–N2), 118.20 (8)° (N2–C1–N3) and 125.69 (8)° (N1–C1–N3), showing a deviation of the CN3 plane from an ideal trigonal-planar geometry. Bonds between N atoms and terminal C-methyl groups all have values close to typical single bonds (1.4529 (12)–1.4624 (12) Å). The C–O bond length in the diphenylcarbamoyl group is C6–O1 = 1.2305 (11) Å, and shows the expected double-bond character. The N–C bond lengths in the carbamoyl moiety are: N3–C6 = 1.3722 (11) Å, N4–C6 = 1.4028 (11) Å, N4–C13 = 1.4266 (11) Å and N4–C7 = 1.4367 (11) Å. They agree very well with X-ray structural data of the compounds 2- and 5-azido-N- (diphenylcarbamoyl)proline methyl ester (Lynch et al., 1995). The dihedral angle C1–N3–C6–N4 is -161.69 (8)° and the angle between the planes N1/C1/N2 and O1/C6/N4 is 51.68 (8)°, which shows a significant twisting of the diphenylcarbamoyl group relative to the CN3 plane (Fig. 1). Weak C–H···O hydrogen bonds between aromatic hydrogen atoms and carbonyl oxygen atoms of neighboring molecules have been determined [d(H···O) = 2.59 Å] (Tab. 1), generating a chain along the ab-plane (Fig. 2). On the other hand, intermolecular C–H···N hydrogen bonds play no prominent role in the stabilization of the crystal structure.

Related literature top

For synthesis of N-dimethylcarbamoyl-N',N',N'',N''-tetramethylguanidine, see: Möllers et al. (2003). For the crystal structures of 2- and 5-azido-N-(diphenylcarbamoyl) proline methyl ester, see: Lynch et al. (1995).

Experimental top

The title compound was obtained by heating two equivalents (60.4 mmol) of N',N',N'',N''-tetramethylguanidine with one equivalent (30.2 mmol) N,N-diphenylcarbamoyl chloride in acetonitrile for three hours under reflux. After cooling to room temperature the precipitated N',N',N'',N''-tetramethylguanidinium chloride was filtered off and the solvent was removed. The residue was redissolved in diethylether and the insoluble part was filtered off. After evaporation of the solvent a colorless solid was been obtained. The title compound crystallized from a saturated acetonitrile solution after several days at 273 K, forming colorless single crystals. Yield: 7.6 g (81%)

Refinement top

The hydrogen atoms of the methyl groups were allowed to rotate with a fixed angle around the C–N bond to best fit the experimental electron density, with Uiso(H) set to 1.5 Ueq(C) and d(C—H) = 0.98 Å. H atoms of the aromatic rings were placed in calculated positions with (C—H) = 0.95 Å. They were included in the refinement using the riding model approximation, with Uiso(H) set to 1.2 Ueq(C).

Computing details top

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

Figures top
[Figure 1] Fig. 1. Molecular structure of the title compound with displacement ellipsoids at the 50% probability level.
[Figure 2] Fig. 2. C–H···O hydrogen bonds between the molecules, ab-view. Hydrogen bonds are indicated by dashed lines.
3-[Bis(dimethylamino)methylene]-1,1-diphenylurea top
Crystal data top
C18H22N4OF(000) = 664
Mr = 310.40Dx = 1.262 Mg m3
Monoclinic, P21/cMelting point: 427 K
Hall symbol: -P 2ybcMo Kα radiation, λ = 0.71073 Å
a = 7.9321 (3) ÅCell parameters from 4990 reflections
b = 17.0477 (9) Åθ = 2.1–30.5°
c = 12.2151 (6) ŵ = 0.08 mm1
β = 98.583 (2)°T = 100 K
V = 1633.28 (13) Å3Block, colorless
Z = 40.25 × 0.20 × 0.15 mm
Data collection top
Bruker Kappa APEXII Duo
diffractometer
4200 reflections with I > 2σ(I)
Radiation source: sealed tubeRint = 0.029
Graphite monochromatorθmax = 30.5°, θmin = 2.1°
ϕ scans, and ω scansh = 1111
51490 measured reflectionsk = 2424
4990 independent reflectionsl = 1716
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)] = 0.039Hydrogen site location: difference Fourier map
wR(F2) = 0.105H-atom parameters constrained
S = 1.04 w = 1/[σ2(Fo2) + (0.0541P)2 + 0.4544P]
where P = (Fo2 + 2Fc2)/3
4990 reflections(Δ/σ)max < 0.001
212 parametersΔρmax = 0.37 e Å3
0 restraintsΔρmin = 0.23 e Å3
Crystal data top
C18H22N4OV = 1633.28 (13) Å3
Mr = 310.40Z = 4
Monoclinic, P21/cMo Kα radiation
a = 7.9321 (3) ŵ = 0.08 mm1
b = 17.0477 (9) ÅT = 100 K
c = 12.2151 (6) Å0.25 × 0.20 × 0.15 mm
β = 98.583 (2)°
Data collection top
Bruker Kappa APEXII Duo
diffractometer
4200 reflections with I > 2σ(I)
51490 measured reflectionsRint = 0.029
4990 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0390 restraints
wR(F2) = 0.105H-atom parameters constrained
S = 1.04Δρmax = 0.37 e Å3
4990 reflectionsΔρmin = 0.23 e Å3
212 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
C10.37589 (11)0.11725 (5)0.29192 (7)0.01420 (17)
N10.44747 (10)0.12889 (5)0.40021 (7)0.01682 (16)
C20.63269 (12)0.12487 (6)0.43072 (8)0.0215 (2)
H2A0.68200.09650.37330.032*
H2B0.66060.09730.50150.032*
H2C0.67960.17810.43790.032*
C30.36063 (13)0.17835 (6)0.47145 (8)0.02078 (19)
H3A0.39710.23290.46540.031*
H3B0.38930.16080.54840.031*
H3C0.23710.17460.44850.031*
N20.41847 (10)0.04945 (4)0.24502 (7)0.01680 (16)
C40.47540 (14)0.02051 (6)0.30890 (9)0.0239 (2)
H4A0.47020.01100.38740.036*
H4B0.59300.03270.29920.036*
H4C0.40130.06480.28290.036*
C50.36459 (14)0.03644 (6)0.12745 (8)0.0218 (2)
H5A0.25320.01040.11620.033*
H5B0.44830.00320.09820.033*
H5C0.35600.08690.08860.033*
N30.26184 (10)0.16304 (4)0.23400 (7)0.01607 (16)
C60.27494 (11)0.24288 (5)0.24670 (7)0.01419 (16)
O10.40355 (8)0.28089 (4)0.28186 (6)0.01803 (14)
N40.12115 (10)0.28111 (4)0.20749 (7)0.01481 (15)
C70.02172 (11)0.23987 (5)0.14776 (7)0.01345 (16)
C80.00729 (12)0.20271 (5)0.04806 (7)0.01524 (17)
H8A0.09830.20330.02020.018*
C90.14748 (12)0.16466 (5)0.01074 (8)0.01697 (18)
H9A0.13690.13870.07820.020*
C100.30287 (12)0.16456 (5)0.02879 (8)0.01796 (18)
H10A0.39890.13920.01200.022*
C110.31730 (12)0.20166 (5)0.12827 (8)0.01758 (18)
H11A0.42320.20140.15570.021*
C120.17678 (12)0.23931 (5)0.18795 (8)0.01584 (17)
H12A0.18690.26450.25600.019*
C130.10260 (11)0.36346 (5)0.22264 (7)0.01373 (16)
C140.01332 (12)0.40811 (5)0.13736 (8)0.01772 (18)
H14A0.02810.38420.06830.021*
C150.01532 (13)0.48785 (5)0.15331 (9)0.0216 (2)
H15A0.07740.51780.09520.026*
C160.04600 (13)0.52374 (5)0.25311 (9)0.0221 (2)
H16A0.02590.57790.26380.026*
C170.13735 (13)0.47939 (5)0.33744 (8)0.02066 (19)
H17A0.18110.50380.40570.025*
C180.16545 (12)0.39969 (5)0.32295 (8)0.01654 (18)
H180.22740.37000.38130.020*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0131 (4)0.0118 (4)0.0181 (4)0.0006 (3)0.0039 (3)0.0001 (3)
N10.0154 (4)0.0174 (3)0.0175 (4)0.0034 (3)0.0019 (3)0.0007 (3)
C20.0164 (4)0.0251 (5)0.0222 (5)0.0006 (4)0.0001 (3)0.0032 (4)
C30.0236 (5)0.0201 (4)0.0195 (4)0.0025 (4)0.0061 (4)0.0027 (3)
N20.0200 (4)0.0120 (3)0.0186 (4)0.0032 (3)0.0038 (3)0.0001 (3)
C40.0307 (5)0.0137 (4)0.0288 (5)0.0067 (4)0.0097 (4)0.0038 (4)
C50.0283 (5)0.0174 (4)0.0201 (4)0.0012 (4)0.0047 (4)0.0049 (3)
N30.0155 (4)0.0105 (3)0.0212 (4)0.0007 (3)0.0005 (3)0.0004 (3)
C60.0143 (4)0.0125 (4)0.0158 (4)0.0007 (3)0.0021 (3)0.0006 (3)
O10.0147 (3)0.0144 (3)0.0244 (3)0.0018 (2)0.0008 (3)0.0017 (2)
N40.0140 (3)0.0094 (3)0.0201 (4)0.0000 (3)0.0005 (3)0.0019 (3)
C70.0143 (4)0.0092 (3)0.0163 (4)0.0005 (3)0.0004 (3)0.0005 (3)
C80.0158 (4)0.0138 (4)0.0166 (4)0.0002 (3)0.0041 (3)0.0000 (3)
C90.0213 (4)0.0140 (4)0.0151 (4)0.0003 (3)0.0011 (3)0.0010 (3)
C100.0174 (4)0.0132 (4)0.0222 (4)0.0021 (3)0.0008 (3)0.0004 (3)
C110.0146 (4)0.0157 (4)0.0229 (4)0.0009 (3)0.0044 (3)0.0018 (3)
C120.0176 (4)0.0133 (4)0.0170 (4)0.0005 (3)0.0040 (3)0.0005 (3)
C130.0132 (4)0.0100 (4)0.0187 (4)0.0005 (3)0.0045 (3)0.0005 (3)
C140.0174 (4)0.0137 (4)0.0213 (4)0.0006 (3)0.0002 (3)0.0002 (3)
C150.0199 (4)0.0131 (4)0.0309 (5)0.0027 (3)0.0011 (4)0.0035 (4)
C160.0214 (5)0.0116 (4)0.0344 (5)0.0012 (3)0.0080 (4)0.0028 (4)
C170.0242 (5)0.0155 (4)0.0233 (5)0.0017 (3)0.0070 (4)0.0055 (3)
C180.0196 (4)0.0138 (4)0.0169 (4)0.0008 (3)0.0050 (3)0.0004 (3)
Geometric parameters (Å, º) top
C1—N31.3179 (11)N4—C71.4367 (11)
C1—N21.3551 (11)C7—C121.3907 (13)
C1—N11.3737 (11)C7—C81.3925 (12)
N1—C31.4566 (12)C8—C91.3909 (12)
N1—C21.4624 (12)C8—H8A0.9500
C2—H2A0.9800C9—C101.3893 (14)
C2—H2B0.9800C9—H9A0.9500
C2—H2C0.9800C10—C111.3897 (14)
C3—H3A0.9800C10—H10A0.9500
C3—H3B0.9800C11—C121.3940 (13)
C3—H3C0.9800C11—H11A0.9500
N2—C51.4529 (12)C12—H12A0.9500
N2—C41.4594 (12)C13—C141.3949 (12)
C4—H4A0.9800C13—C181.3961 (12)
C4—H4B0.9800C14—C151.3967 (13)
C4—H4C0.9800C14—H14A0.9500
C5—H5A0.9800C15—C161.3857 (15)
C5—H5B0.9800C15—H15A0.9500
C5—H5C0.9800C16—C171.3910 (14)
N3—C61.3722 (11)C16—H16A0.9500
C6—O11.2305 (11)C17—C181.3923 (12)
C6—N41.4028 (11)C17—H17A0.9500
N4—C131.4266 (11)C18—H180.9500
N3—C1—N2118.20 (8)C6—N4—C7121.73 (7)
N3—C1—N1125.69 (8)C13—N4—C7117.30 (7)
N2—C1—N1115.91 (8)C12—C7—C8119.87 (8)
C1—N1—C3119.63 (8)C12—C7—N4119.75 (8)
C1—N1—C2119.59 (8)C8—C7—N4120.34 (8)
C3—N1—C2114.93 (8)C9—C8—C7120.00 (9)
N1—C2—H2A109.5C9—C8—H8A120.0
N1—C2—H2B109.5C7—C8—H8A120.0
H2A—C2—H2B109.5C10—C9—C8120.24 (8)
N1—C2—H2C109.5C10—C9—H9A119.9
H2A—C2—H2C109.5C8—C9—H9A119.9
H2B—C2—H2C109.5C9—C10—C11119.76 (8)
N1—C3—H3A109.5C9—C10—H10A120.1
N1—C3—H3B109.5C11—C10—H10A120.1
H3A—C3—H3B109.5C10—C11—C12120.20 (9)
N1—C3—H3C109.5C10—C11—H11A119.9
H3A—C3—H3C109.5C12—C11—H11A119.9
H3B—C3—H3C109.5C7—C12—C11119.92 (8)
C1—N2—C5119.54 (8)C7—C12—H12A120.0
C1—N2—C4123.21 (8)C11—C12—H12A120.0
C5—N2—C4115.19 (8)C14—C13—C18119.28 (8)
N2—C4—H4A109.5C14—C13—N4119.39 (8)
N2—C4—H4B109.5C18—C13—N4121.27 (8)
H4A—C4—H4B109.5C13—C14—C15120.13 (9)
N2—C4—H4C109.5C13—C14—H14A119.9
H4A—C4—H4C109.5C15—C14—H14A119.9
H4B—C4—H4C109.5C16—C15—C14120.62 (9)
N2—C5—H5A109.5C16—C15—H15A119.7
N2—C5—H5B109.5C14—C15—H15A119.7
H5A—C5—H5B109.5C15—C16—C17119.15 (9)
N2—C5—H5C109.5C15—C16—H16A120.4
H5A—C5—H5C109.5C17—C16—H16A120.4
H5B—C5—H5C109.5C16—C17—C18120.79 (9)
C1—N3—C6119.50 (8)C16—C17—H17A119.6
O1—C6—N3127.35 (8)C18—C17—H17A119.6
O1—C6—N4120.53 (8)C17—C18—C13120.02 (9)
N3—C6—N4112.02 (7)C17—C18—H18120.0
C6—N4—C13120.94 (7)C13—C18—H18120.0
N3—C1—N1—C321.15 (14)C12—C7—C8—C90.43 (13)
N2—C1—N1—C3153.60 (9)N4—C7—C8—C9178.31 (8)
N3—C1—N1—C2130.58 (10)C7—C8—C9—C100.95 (13)
N2—C1—N1—C254.67 (12)C8—C9—C10—C110.94 (13)
N3—C1—N2—C511.89 (13)C9—C10—C11—C120.41 (14)
N1—C1—N2—C5172.95 (8)C8—C7—C12—C110.09 (13)
N3—C1—N2—C4151.00 (9)N4—C7—C12—C11177.79 (8)
N1—C1—N2—C424.16 (13)C10—C11—C12—C70.11 (13)
N2—C1—N3—C6146.79 (9)C6—N4—C13—C14140.27 (9)
N1—C1—N3—C638.57 (14)C7—N4—C13—C1437.84 (12)
C1—N3—C6—O122.08 (15)C6—N4—C13—C1842.63 (13)
C1—N3—C6—N4161.69 (8)C7—N4—C13—C18139.26 (9)
O1—C6—N4—C139.58 (13)C18—C13—C14—C151.21 (14)
N3—C6—N4—C13173.89 (8)N4—C13—C14—C15175.95 (9)
O1—C6—N4—C7168.45 (8)C13—C14—C15—C160.78 (15)
N3—C6—N4—C78.08 (12)C14—C15—C16—C170.25 (15)
C6—N4—C7—C12121.44 (9)C15—C16—C17—C180.84 (15)
C13—N4—C7—C1260.46 (11)C16—C17—C18—C130.40 (15)
C6—N4—C7—C860.69 (12)C14—C13—C18—C170.63 (14)
C13—N4—C7—C8117.41 (9)N4—C13—C18—C17176.47 (9)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C11—H11A···O1i0.952.593.3893 (12)141
Symmetry code: (i) x1, y, z.

Experimental details

Crystal data
Chemical formulaC18H22N4O
Mr310.40
Crystal system, space groupMonoclinic, P21/c
Temperature (K)100
a, b, c (Å)7.9321 (3), 17.0477 (9), 12.2151 (6)
β (°) 98.583 (2)
V3)1633.28 (13)
Z4
Radiation typeMo Kα
µ (mm1)0.08
Crystal size (mm)0.25 × 0.20 × 0.15
Data collection
DiffractometerBruker Kappa APEXII Duo
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
51490, 4990, 4200
Rint0.029
(sin θ/λ)max1)0.715
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.039, 0.105, 1.04
No. of reflections4990
No. of parameters212
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.37, 0.23

Computer programs: APEX2 (Bruker, 2008), SAINT (Bruker, 2008), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg & Putz, 2005).

Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C11—H11A···O1i0.952.593.3893 (12)141
Symmetry code: (i) x1, y, z.
 

Acknowledgements

The author thanks Dr W. Frey (Institut für Organische Chemie, Universität Stuttgart) for the data collection.

References

First citationBrandenburg, K. & Putz, H. (2005). DIAMOND. Crystal Impact GbR, D-53002 Bonn, Germany.
First citationBruker (2008). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.
First citationLynch, V. M., Hulme, C., Magnus, P. & Davis, B. E. (1995). Acta Cryst. C51, 2598–2601.  CSD CrossRef CAS Web of Science IUCr Journals
First citationMöllers, C., Prigge, J., Wibbeling, B., Fröhlich, R., Brockmeyer, A., Schäfer, H. J., Schmälzlin, E., Bräuchle, C., Meerholz, K. & Würthwein, E.-U. (2003). Eur. J. Org. Chem. 1198–1208.
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals

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