Urea–N,N-dimethyl­acetamide (1/1)

Fernandes, P.; Florence, A.J.; Fabbiani, F.; David, W.I.F.; Shankland, K.

doi:10.1107/S1600536807067232

organic compounds

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Volume 64| Part 2| February 2008| Page o355

doi:10.1107/S1600536807067232

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Urea–N,N-dimethylacetamide (1/1)

Philippe Fernandes,^a Alastair J. Florence,^a ^* Francesca Fabbiani,^b William I. F. David ^b and Kenneth Shankland ^b

^aSolid-State Research Group, Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 27 Taylor Street, Glasgow G4 0NR, Scotland, and ^bISIS Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX, England
^*Correspondence e-mail: alastair.florence@strath.ac.uk

(Received 16 November 2007; accepted 16 December 2007; online 4 January 2008)

Urea forms a 1:1 solvate with N,N-dimethylacetamide (DMA) [systematic name: diaminomethanal–N,N-dimethylacetamide (1/1), C₄H₉NO·CH₄N₂O] with both molecules positioned on a twofold axis, giving rise to rotational disorder of the DMA molecule. The molecules display a layered structure in which urea molecules form hydrogen-bonded ribbons bounded by molecules of solvent.

Related literature

For details on experimental methods used to obtain this crystalline compound, see: Florence et al. (2003 ). For crystal structures of urea, see: Fernandes et al. (2007 ); Vaughan & Donohue (1952 ), and references therein; Swaminathan et al. (1984 ); Pryor & Sanger (1970 ); Guth et al. (1980 ); Weber et al. (2002 ). For related literature, see: Etter (1990 ).

Experimental

Crystal data

C₄H₉NO·CH₄N₂O
M_r = 147.18
Monoclinic, C 2/c
a = 7.2770 (3) Å
b = 17.5394 (9) Å
c = 7.3789 (4) Å
β = 119.450 (3)°
V = 820.11 (7) Å³
Z = 4
Mo Kα radiation
μ = 0.09 mm⁻¹
T = 120 K
0.40 × 0.12 × 0.04 mm

Data collection

Bruker–Nonius KappaCCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2007 ) T_min = 0.867, T_max = 1 (expected range = 0.864–0.996)
5338 measured reflections
941 independent reflections
552 reflections with I > 2.0σ(I)
R_int = 0.048

Refinement

R[F² > 2σ(F²)] = 0.050
wR(F²) = 0.150
S = 0.89
939 reflections
63 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.31 e Å⁻³
Δρ_min = −0.39 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N3—H31⋯O2ⁱ	0.87 (2)	2.06 (2)	2.930 (2)	180 (3)
N3—H32⋯O9ⁱⁱ	0.87 (2)	2.09 (2)	2.878 (3)	149.7 (19)
Symmetry codes: (i) $[-x+{\script{1\over 2}}, -y+{\script{1\over 2}}, -z+1]$ ; (ii) -x, -y+1, -z+1.

Data collection: COLLECT (Hooft, 1998 ); cell refinement: DENZO (Otwinowski & Minor, 1997 ) and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: SIR92 (Altomare et al., 1994 ); program(s) used to refine structure: CRYSTALS (Betteridge et al., 2003 ); molecular graphics: ORTEP-3 (Farrugia, 1997 ) and Mercury (Macrae et al., 2006 ); software used to prepare material for publication: enCIFer (Allen et al., 2004 ) and publCIF (Westrip, 2008 ).

Supporting information

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536807067232/ga2020sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536807067232/ga2020Isup2.hkl

checkCIF report

Comment top

The crystal structure of urea has been widely studied (see for example, Vaughan and Donohue (1952) and references therein; Swaminathan et al. (1984), Pryor and Sanger (1970), Guth et al. (1980) and Weber et al. (2002)). This previously unreported crystalline solvate of urea was discovered during an investigation into the influence of different crystallization solvents on urea crystal morphology (see also Fernandes et al., 2007). The sample was obtained by slow evaporation from a saturated N,N-dimethylacetamide (DMA) solution at 298 K and identified by using multi-sample foil transmission X-ray powder diffraction analysis (Florence et al., 2003). Subsequent recrystallization produced a single-crystal suitable for X-ray diffraction at 120 K (Fig. 1).

Both molecules lie over a two fold rotation axis resulting in the DMA being disordered (see refinement section for details). Each urea molecule interacts with adjacent urea molecules via contact 1 (Fig. 2, entry 1, Table 1), forming a hydrogen bonded ribbon that runs in the direction [-1 0 1]. Molecules of DMA lie on the edge of the ribbons, connected through a second hydrogen bond (contact 2), (entry 2, Table 1).The DMA-bordered ribbons of urea pack side-by-side to form a two-dimensional sheet.

Related literature top

For details on experimental methods used to obtain this crystal, see: Florence et al. (2003). For crystal structures of urea, see: Fernandes et al. (2007); Vaughan & Donohue (1952), and references therein; Swaminathan et al. (1984); Pryor & Sanger (1970); Guth et al. (1980); Weber et al. (2002). For related literature, see: Etter (1990).

Experimental top

The compound was sourced from Sigma-Aldrich and used as supplied. A single-crystal sample of the 1/1 solvate was recrystallized from a saturated N,N-dimethylacetamide solution by isothermal solvent evaporation at room temperature (298 K).

Computing details top

Data collection: COLLECT (Hooft, 1998); cell refinement: DENZO (Otwinowski & Minor, 1997) and COLLECT (Hooft, 1998); data reduction: DENZO (Otwinowski & Minor, 1997) and COLLECT (Hooft, 1998); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: CRYSTALS (Betteridge et al., 2003); molecular graphics: ORTEP-3 (Farrugia, 1997) and Mercury (Macrae et al., 2006); software used to prepare material for publication: enCIFer (Allen et al., 2004) and publCIF (Westrip, 2007).

Figures top

Fig. 1. The molecular structure of the title compound showing 50% probablility displacement ellipsoids. Hydrogen atoms have been omitted for clarity. A twofold axis runs through C₁, O₂ of urea and O₉, C₇ of DMA, giving rise to the rotational disorder of the DMA molecule. Symmetry codes: (i) -x, y, 1/2 - z. (ii) -x, y, 3/2 - z.

Fig. 2. Selected molecular packing, viewed down the a axis, of the title compound illustrating the hydrogen bonded network. Urea molecules (green) form an R₂²(8) motif (Etter, 1990) involving contact 1 (entry 1, Table 1) that propagates to form an infinite ribbon. DMA molecules (shown in blues with rotational disorder) are hydrogen bonded via N—H···O contacts 2 (entry 2, Table 1) at the edges of the ribbon. Hydrogen bonds are shown as dashed lines and hydrogen atoms have been omitted for clarity. Symmetry codes: (a) -x, 1 - y, 1 - z; (b) 1/2 - x, 1/2 - y, 1 - z.

Diaminomethanal–N,N-dimethylacetamide solvate (1:1) top

Crystal data top

C₄H₉NO·CH₄N₂O	F(000) = 320
M_r = 147.18	D_x = 1.192 Mg m⁻³
Monoclinic, C2/c	Melting point: 406 K
Hall symbol: -C 2yc	Mo Kα radiation, λ = 0.71073 Å
a = 7.2770 (3) Å	Cell parameters from 2218 reflections
b = 17.5394 (9) Å	θ = 3–27°
c = 7.3789 (4) Å	µ = 0.09 mm⁻¹
β = 119.450 (3)°	T = 120 K
V = 820.11 (7) Å³	Lath, colourless
Z = 4	0.40 × 0.12 × 0.04 mm

Data collection top

Bruker–Nonius KappaCCD diffractometer	941 independent reflections
Radiation source: Bruker-Nonius FR591 rotating anode	552 reflections with I > 2.0σ(I)
Graphite monochromator	R_int = 0.048
Detector resolution: 9.091 pixels mm^-1	θ_max = 27.6°, θ_min = 3.4°
ϕ & ω scans	h = −9→9
Absorption correction: multi-scan (SADABS; Bruker, 2007)	k = −22→22
T_min = 0.867, T_max = 1	l = −9→9
5338 measured reflections

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Hydrogen site location: geom + difmap
R[F² > 2σ(F²)] = 0.050	H atoms treated by a mixture of independent and constrained refinement
wR(F²) = 0.150	Method = Modified Sheldrick w = 1/[σ²(F²) + ( 0.07P)²] , where P = (max(F_o²,0) + 2F_c²)/3
S = 0.89	(Δ/σ)_max = 0.000129
939 reflections	Δρ_max = 0.31 e Å⁻³
63 parameters	Δρ_min = −0.39 e Å⁻³
0 restraints

Crystal data top

C₄H₉NO·CH₄N₂O	V = 820.11 (7) Å³
M_r = 147.18	Z = 4
Monoclinic, C2/c	Mo Kα radiation
a = 7.2770 (3) Å	µ = 0.09 mm⁻¹
b = 17.5394 (9) Å	T = 120 K
c = 7.3789 (4) Å	0.40 × 0.12 × 0.04 mm
β = 119.450 (3)°

Data collection top

Bruker–Nonius KappaCCD diffractometer	941 independent reflections
Absorption correction: multi-scan (SADABS; Bruker, 2007)	552 reflections with I > 2.0σ(I)
T_min = 0.867, T_max = 1	R_int = 0.048
5338 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.050	0 restraints
wR(F²) = 0.150	H atoms treated by a mixture of independent and constrained refinement
S = 0.89	Δρ_max = 0.31 e Å⁻³
939 reflections	Δρ_min = −0.39 e Å⁻³
63 parameters

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

	x	y	z	U_iso*/U_eq	Occ. (<1)
C1	0.0000	0.30587 (14)	0.2500	0.0293
O2	0.0000	0.23473 (9)	0.2500	0.0380
N3	0.1649 (2)	0.34642 (10)	0.3935 (3)	0.0360
N4	0.0668 (4)	0.37977 (18)	0.7962 (5)	0.0347	0.5000
C6	0.2835 (3)	0.40670 (13)	0.9670 (4)	0.0525
C7	0.0000	0.29897 (16)	0.7500	0.0508
C8	−0.0735 (5)	0.4351 (2)	0.6946 (6)	0.0347	0.5000
O9	0.0000	0.50307 (11)	0.7500	0.0628
H31	0.264 (3)	0.3224 (11)	0.499 (4)	0.0365*
H32	0.158 (3)	0.3959 (13)	0.393 (3)	0.0360*
H71	−0.1409	0.2969	0.6380	0.0608*	0.5000
H72	0.0074	0.2760	0.8696	0.0608*	0.5000
H73	0.0908	0.2732	0.7124	0.0608*	0.5000
H61	0.2880	0.4608	0.9665	0.0542*	0.5000
H62	0.3056	0.3894	1.0980	0.0542*	0.5000
H63	0.3889	0.3866	0.9409	0.0542*	0.5000
H64	0.2827	0.3526	0.9657	0.0542*	0.5000
H65	0.3108	0.4244	1.0994	0.0542*	0.5000
H66	0.3885	0.4250	0.9377	0.0542*	0.5000

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
C1	0.0239 (11)	0.0284 (14)	0.0251 (13)	0.0000	0.0038 (10)	0.0000
O2	0.0315 (9)	0.0245 (10)	0.0342 (11)	0.0000	−0.0022 (8)	0.0000
N3	0.0289 (8)	0.0261 (9)	0.0325 (10)	−0.0009 (6)	−0.0006 (7)	0.0011 (7)
N4	0.0290 (18)	0.0271 (17)	0.038 (2)	0.0003 (11)	0.0085 (16)	−0.0020 (14)
C6	0.0327 (10)	0.0554 (14)	0.0474 (14)	−0.0003 (9)	0.0026 (10)	0.0046 (11)
C7	0.0663 (19)	0.0236 (14)	0.059 (2)	0.0000	0.0286 (17)	0.0000
C8	0.0332 (19)	0.030 (2)	0.031 (2)	−0.0004 (14)	0.0084 (16)	0.0008 (16)
O9	0.0855 (16)	0.0210 (11)	0.0587 (16)	0.0000	0.0176 (13)	0.0000

Geometric parameters (Å, º) top

O9—C8	1.288 (4)	C6—H63	0.9500
O9—C8ⁱ	1.288 (4)	C6—H64	0.9500
O2—C1	1.248 (3)	C6—H65	0.9500
N4—C6	1.531 (4)	C6—H61	0.9500
N4—C8	1.339 (5)	C6—H66	0.9500
N4—C7	1.483 (4)	C7—H72ⁱ	0.9500
N3—C1	1.348 (2)	C7—H73ⁱ	0.9500
N3—H32	0.87 (2)	C7—H71ⁱ	0.9500
N3—H31	0.87 (2)	C7—H71	0.9500
C6—C8ⁱ	1.488 (5)	C7—H72	0.9500
C6—H62	0.9500	C7—H73	0.9500

C6—N4—C7	124.9 (2)	C8ⁱ—C6—H61	72.00
C6—N4—C8	115.5 (3)	H62—C6—H63	110.00
C7—N4—C8	119.4 (3)	H62—C6—H64	72.00
C1—N3—H32	119.8 (14)	C8ⁱ—C6—H66	109.00
H31—N3—H32	120.7 (19)	N4—C7—H71ⁱ	75.00
C1—N3—H31	118.4 (14)	N4—C7—H72ⁱ	119.00
N4—C8—C6ⁱ	114.0 (3)	N4—C7—H73	109.00
O9—C8—N4	114.2 (3)	H71—C7—H72	110.00
O9—C8—C6ⁱ	131.8 (3)	H71—C7—H73	110.00
N4—C6—H61	109.00	N4—C7—H73ⁱ	126.00
N4—C6—H62	109.00	H71—C7—H71ⁱ	176.00
N4—C6—H63	109.00	H71—C7—H72ⁱ	68.00
N4—C6—H64	72.00	H71—C7—H73ⁱ	68.00
H61—C6—H63	110.00	H72—C7—H73	110.00
H61—C6—H64	178.00	N4ⁱ—C7—H72	119.00
H61—C6—H65	72.00	H71ⁱ—C7—H72	68.00
H61—C6—H66	68.00	N4ⁱ—C7—H71	75.00
N4—C6—H65	124.00	N4ⁱ—C7—H73	126.00
N4—C6—H66	122.00	H71ⁱ—C7—H73	68.00
H61—C6—H62	110.00	N4ⁱ—C7—H71ⁱ	109.00
H62—C6—H66	126.00	N4ⁱ—C7—H72ⁱ	109.00
C8ⁱ—C6—H62	121.00	N4ⁱ—C7—H73ⁱ	109.00
H63—C6—H64	68.00	H71ⁱ—C7—H72ⁱ	110.00
H63—C6—H65	123.00	H71ⁱ—C7—H73ⁱ	110.00
C8ⁱ—C6—H63	125.00	N4—C7—H71	109.00
H64—C6—H65	110.00	N4—C7—H72	109.00
H64—C6—H66	110.00	O2—C1—N3	121.84 (12)
C8ⁱ—C6—H64	109.00	O2—C1—N3ⁱⁱ	121.84 (12)
H65—C6—H66	110.00	N3—C1—N3ⁱⁱ	116.3 (2)
C8ⁱ—C6—H65	109.00

Symmetry codes: (i) −x, y, −z+3/2; (ii) −x, y, −z+1/2.

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N3—H31···O2ⁱⁱⁱ	0.87 (2)	2.06 (2)	2.930 (2)	180 (3)
N3—H32···O9^iv	0.87 (2)	2.09 (2)	2.878 (3)	149.7 (19)

Symmetry codes: (iii) −x+1/2, −y+1/2, −z+1; (iv) −x, −y+1, −z+1.

Experimental details

Crystal data
Chemical formula	C₄H₉NO·CH₄N₂O
M_r	147.18
Crystal system, space group	Monoclinic, C2/c
Temperature (K)	120
a, b, c (Å)	7.2770 (3), 17.5394 (9), 7.3789 (4)
β (°)	119.450 (3)
V (Å³)	820.11 (7)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	0.09
Crystal size (mm)	0.40 × 0.12 × 0.04

Data collection
Diffractometer	Bruker–Nonius KappaCCD diffractometer
Absorption correction	Multi-scan (SADABS; Bruker, 2007)
T_min, T_max	0.867, 1
No. of measured, independent and observed [I > 2.0σ(I)] reflections	5338, 941, 552
R_int	0.048
(sin θ/λ)_max (Å⁻¹)	0.652

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.050, 0.150, 0.89
No. of reflections	939
No. of parameters	63
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.31, −0.39

Computer programs: , DENZO (Otwinowski & Minor, 1997) and COLLECT (Hooft, 1998), SIR92 (Altomare et al., 1994), CRYSTALS (Betteridge et al., 2003), ORTEP-3 (Farrugia, 1997) and Mercury (Macrae et al., 2006), enCIFer (Allen et al., 2004) and publCIF (Westrip, 2007).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N3—H31···O2ⁱ	0.87 (2)	2.06 (2)	2.930 (2)	180 (3)
N3—H32···O9ⁱⁱ	0.87 (2)	2.09 (2)	2.878 (3)	149.7 (19)

Symmetry codes: (i) −x+1/2, −y+1/2, −z+1; (ii) −x, −y+1, −z+1.

Acknowledgements

The authors thank the Basic Technology programme of the UK Research Councils for funding this work under the project Control and Prediction of the Organic Solid State (http://www.cposs.org.uk ). We also thank the EPSRC National X-ray Crystallography Service at the University of Southampton for the data collection.

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