supplementary materials


Acta Cryst. (2007). E63, o3883    [ doi:10.1107/S1600536807040895 ]

1-(4-Ethynylphenyl)-3,5-dimethylbiuret

W. T. A. Harrison

Abstract top

In the title compound, C12H13N3O2, an intramolecular N-H...O bond helps to establish the near-planar conformation; the two -NH-CO-N- fragments of the biuret backbone are twisted by 4.96 (10)°. An acute intermolecular N-H...O hydrogen bond helps to define the crystal packing.

Comment top

The title compound, (I), was prepared as an intermediate in the synthesis of new multidentate porphyrin-like ligands.

On progressing along the chain formed by atoms N1, C9, N2, C11, and N3 (Fig. 1), the C–N bond lengths in (I) show a short-long-long-short pattern, although all of them are intermediate between typical C–N single (1.47 Å) and C=N double (1.30 Å) bonds. Bond-angle sums about the three N atoms in (I) yielded values of 360.0° in each case suggesting that all these species can be regarded as being sp2 hybridized, indicating a significant degree of electronic delocalization over the entire biuret fragment (Carugo et al., 1992).

Similar variations in C–N bond-lengths to those of (I) were seen in biuret monohydrate (Craven, 1973), although other biurets show a distinctly different pattern, such as the monoclinic polymorph of 1-(2,6-difluorobenzoyl)-5-(4-chlorophenyl)biuret (Deschamps et al., 1998) in which a short-long-short-long sequence [C–N = 1.344 (4), 1.412 (4), 1.352 (4) and 1.407 (4) Å] occurs.

The two –NH—CO—N– fragments making up the biuret unit in (I) are planar within experimental error. The dihedral angle between these two groupings is 4.96 (10)°, which is at the lower end of the range of this parameter observed in related compounds (Carugo et al., 1992).

The ethynylphenyl moiety (atoms C1—C8) in (I) is twisted by 11.23 (7)° with respect to the N1/C9/O1/N2, grouping, although the C6—N1 bond [1.4026 (19) Å] appears to have significant double bond character. A PLATON analysis (Spek, 2003) of (I) suggested that the C2—C3 bond is unusually long [1.443 (2) Å] for a C(sp)—C(sp2) contact. However, a similar bond length (1.445 Å; s.u. not stated) has been seen for the equivalent bond in 1,4-diethynylbenzene (Ahmed et al., 1972).

A bent, intramolecular, N1—H1···O2 bond is present in (I) (Table 1), with the component atoms making up a six-ring loop, this being a common motif in biurets (Carugo et al., 1992).

In the crystal of (I), the molecules are linked into infinite chains which propagate in [010] by way of the N3—H3···O1i bond (see Table 1). There are no significant π-π, C—H···O or C—H···π interactions in (I).

Related literature top

For related structures, see: Ahmed et al. (1972); Craven (1973); Carugo et al. (1992); Deschamps et al. (1998). For geometric analysis, see Spek (2003).

Experimental top

The title compound was prepared by reacting 1-(4-ethynylphenyl)biuret with MeI in THF (Aiken & Plater, 2007, unpublished work).

Refinement top

The H atoms were placed geometrically (N—H = 0.86 Å; C—H = 0.93–0.96 Å) and refined as riding with Uiso(H) = 1.2Ueq(carrier) or 1.5Ueq(methyl C). The methyl group was allowed to rotate, but not to tip, to best fit the electron density.

Computing details top

Data collection: SMART (Bruker, 1999); cell refinement: SAINT (Bruker, 1999); data reduction: SAINT (Bruker, 1999); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

Figures top
[Figure 1] Fig. 1. The molecular structure of (I) (50% displacement ellipsoids, arbitrary spheres for the H atoms, hydrogen bond indicated by a double dashed line).
1-(4-Ethynylphenyl)-3,5-dimethylbiuret top
Crystal data top
C12H13N3O2F000 = 488
Mr = 231.25Dx = 1.285 Mg m3
Monoclinic, P21/nMo Kα radiation
λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 2287 reflections
a = 6.7870 (5) Åθ = 2.2–25.0º
b = 11.1876 (8) ŵ = 0.09 mm1
c = 15.8669 (11) ÅT = 293 (2) K
β = 97.180 (2)ºBlock, colourless
V = 1195.33 (15) Å30.36 × 0.30 × 0.20 mm
Z = 4
Data collection top
Bruker SMART1000 CCD
diffractometer
1465 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.024
Monochromator: graphiteθmax = 25.0º
T = 293(2) Kθmin = 2.2º
ω scansh = 6→8
Absorption correction: nonek = 12→13
6817 measured reflectionsl = 18→18
2101 independent reflections
Refinement top
Refinement on F2Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: fullH-atom parameters constrained
R[F2 > 2σ(F2)] = 0.037  w = 1/[σ2(Fo2) + (0.0645P)2]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.105(Δ/σ)max = 0.001
S = 0.98Δρmax = 0.15 e Å3
2101 reflectionsΔρmin = 0.11 e Å3
157 parametersExtinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.016 (3)
Crystal data top
C12H13N3O2V = 1195.33 (15) Å3
Mr = 231.25Z = 4
Monoclinic, P21/nMo Kα
a = 6.7870 (5) ŵ = 0.09 mm1
b = 11.1876 (8) ÅT = 293 (2) K
c = 15.8669 (11) Å0.36 × 0.30 × 0.20 mm
β = 97.180 (2)º
Data collection top
Bruker SMART1000 CCD
diffractometer
2101 independent reflections
Absorption correction: none1465 reflections with I > 2σ(I)
6817 measured reflectionsRint = 0.024
Refinement top
R[F2 > 2σ(F2)] = 0.037157 parameters
wR(F2) = 0.105H-atom parameters constrained
S = 0.98Δρmax = 0.15 e Å3
2101 reflectionsΔρmin = 0.11 e Å3
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 > 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) top
xyzUiso*/Ueq
O10.24431 (16)0.54995 (11)0.34396 (7)0.0731 (4)
O20.71481 (14)0.32197 (11)0.35264 (7)0.0689 (4)
N10.56872 (18)0.51965 (11)0.39439 (8)0.0569 (4)
H10.66180.46720.39610.068*
N20.38323 (17)0.37021 (12)0.31831 (7)0.0527 (3)
N30.51702 (19)0.19015 (13)0.27910 (9)0.0709 (4)
H30.40210.17360.25240.085*
C10.8880 (3)1.02491 (19)0.60840 (13)0.0836 (6)
H1A0.93751.09150.63910.100*
C20.8256 (3)0.94085 (17)0.56966 (10)0.0660 (5)
C30.7550 (2)0.83572 (14)0.52261 (10)0.0577 (4)
C40.8886 (2)0.74785 (15)0.50449 (10)0.0643 (5)
H41.02360.75790.52180.077*
C50.8221 (2)0.64615 (15)0.46107 (10)0.0619 (4)
H50.91310.58850.44890.074*
C60.6211 (2)0.62841 (14)0.43513 (9)0.0523 (4)
C70.4871 (2)0.71615 (15)0.45250 (10)0.0588 (4)
H70.35210.70630.43510.071*
C80.5556 (2)0.81836 (15)0.49591 (10)0.0617 (4)
H80.46500.87670.50740.074*
C90.3921 (2)0.48661 (15)0.35301 (9)0.0528 (4)
C100.1859 (2)0.32878 (16)0.28153 (10)0.0676 (5)
H10A0.08620.38050.29950.101*
H10B0.16510.24870.30030.101*
H10C0.17720.33000.22070.101*
C110.5479 (2)0.29428 (15)0.31843 (9)0.0535 (4)
C120.6776 (3)0.1042 (2)0.28120 (15)0.0998 (7)
H12A0.64110.04220.24040.150*
H12B0.70280.06980.33690.150*
H12C0.79530.14360.26770.150*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0518 (7)0.0721 (8)0.0894 (9)0.0121 (6)0.0144 (6)0.0026 (6)
O20.0386 (6)0.0772 (8)0.0882 (8)0.0008 (5)0.0033 (5)0.0225 (6)
N10.0416 (7)0.0594 (8)0.0672 (8)0.0029 (6)0.0024 (6)0.0024 (6)
N20.0377 (7)0.0630 (8)0.0552 (7)0.0028 (5)0.0020 (5)0.0025 (6)
N30.0439 (8)0.0824 (10)0.0832 (10)0.0021 (7)0.0045 (7)0.0281 (8)
C10.0899 (15)0.0771 (14)0.0814 (13)0.0077 (11)0.0013 (10)0.0222 (11)
C20.0683 (11)0.0668 (12)0.0612 (10)0.0097 (9)0.0014 (8)0.0029 (9)
C30.0613 (11)0.0577 (10)0.0525 (8)0.0066 (8)0.0013 (7)0.0027 (8)
C40.0501 (10)0.0674 (11)0.0724 (10)0.0016 (8)0.0040 (8)0.0068 (9)
C50.0473 (10)0.0647 (11)0.0716 (10)0.0090 (7)0.0009 (7)0.0074 (8)
C60.0484 (9)0.0567 (10)0.0507 (8)0.0004 (7)0.0016 (7)0.0057 (7)
C70.0466 (9)0.0670 (11)0.0616 (10)0.0075 (7)0.0015 (7)0.0043 (8)
C80.0596 (11)0.0625 (11)0.0627 (10)0.0137 (8)0.0064 (8)0.0018 (8)
C90.0448 (9)0.0625 (11)0.0498 (8)0.0004 (7)0.0014 (7)0.0092 (7)
C100.0412 (9)0.0819 (12)0.0763 (11)0.0047 (8)0.0061 (7)0.0012 (9)
C110.0402 (9)0.0687 (10)0.0509 (8)0.0046 (7)0.0035 (7)0.0054 (8)
C120.0613 (12)0.0988 (16)0.1354 (18)0.0114 (10)0.0029 (12)0.0533 (14)
Geometric parameters (Å, °) top
C9—O11.2220 (18)C3—C41.391 (2)
C11—O21.2328 (17)C4—C51.376 (2)
N1—C91.3444 (19)C4—H40.9300
N1—C61.4026 (19)C5—C61.389 (2)
N1—H10.8600C5—H50.9300
N2—C111.404 (2)C6—C71.389 (2)
N2—C91.412 (2)C7—C81.385 (2)
N2—C101.4677 (18)C7—H70.9300
N3—C111.326 (2)C8—H80.9300
N3—C121.451 (2)C10—H10A0.9600
N3—H30.8600C10—H10B0.9600
C1—C21.173 (2)C10—H10C0.9600
C1—H1A0.9300C12—H12A0.9600
C2—C31.443 (2)C12—H12B0.9600
C3—C81.381 (2)C12—H12C0.9600
C9—N1—C6128.52 (13)C8—C7—H7120.2
C9—N1—H1115.7C6—C7—H7120.2
C6—N1—H1115.7C3—C8—C7121.61 (15)
C11—N2—C9124.21 (12)C3—C8—H8119.2
C11—N2—C10119.76 (14)C7—C8—H8119.2
C9—N2—C10116.02 (12)O1—C9—N1124.52 (16)
C11—N3—C12119.84 (15)O1—C9—N2119.63 (14)
C11—N3—H3120.1N1—C9—N2115.85 (13)
C12—N3—H3120.1N2—C10—H10A109.5
C2—C1—H1A180.0N2—C10—H10B109.5
C1—C2—C3178.2 (2)H10A—C10—H10B109.5
C8—C3—C4118.44 (15)N2—C10—H10C109.5
C8—C3—C2121.54 (15)H10A—C10—H10C109.5
C4—C3—C2120.01 (15)H10B—C10—H10C109.5
C5—C4—C3120.42 (15)O2—C11—N3120.71 (14)
C5—C4—H4119.8O2—C11—N2122.42 (15)
C3—C4—H4119.8N3—C11—N2116.87 (13)
C4—C5—C6120.97 (14)N3—C12—H12A109.5
C4—C5—H5119.5N3—C12—H12B109.5
C6—C5—H5119.5H12A—C12—H12B109.5
C5—C6—C7118.91 (15)N3—C12—H12C109.5
C5—C6—N1116.33 (13)H12A—C12—H12C109.5
C7—C6—N1124.74 (14)H12B—C12—H12C109.5
C8—C7—C6119.64 (15)
N1—C9—N2—C115.7 (2)O2—C11—N2—C10175.88 (14)
C9—N2—C11—N3176.34 (13)O1—C9—N2—C11174.09 (14)
N2—C11—N3—C12176.20 (16)C9—N2—C11—O23.2 (2)
N1—C9—N2—C10173.37 (12)O2—C11—N3—C124.3 (3)
O1—C9—N2—C106.8 (2)
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O20.861.822.5451 (17)141
N3—H3···O1i0.862.202.9245 (17)141
Symmetry codes: (i) −x+1/2, y−1/2, −z+1/2.
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
N1—H1···O20.861.822.5451 (17)141
N3—H3···O1i0.862.202.9245 (17)141
Symmetry codes: (i) −x+1/2, y−1/2, −z+1/2.
Acknowledgements top

We thank Stuart Aiken and M. John Plater for supplying the sample.

references
References top

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Farrugia, L. J. (1997). J. Appl. Cryst. 30, 565–?.

Sheldrick, G. M. (1997). SHELXS97 and SHELXL97. University of Göttingen, Germany.

Spek, A. L. (2003). J. Appl. Cryst. 36, 7–13.