Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807045448/fl2163sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536807045448/fl2163Isup2.hkl |
CCDC reference: 663826
Key indicators
- Single-crystal X-ray study
- T = 150 K
- Mean (C-C) = 0.002 Å
- R factor = 0.039
- wR factor = 0.108
- Data-to-parameter ratio = 17.7
checkCIF/PLATON results
No syntax errors found
Alert level C PLAT220_ALERT_2_C Large Non-Solvent C Ueq(max)/Ueq(min) ... 2.52 Ratio
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 1 ALERT level C = Check and explain 0 ALERT level G = General alerts; check 0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 1 ALERT type 2 Indicator that the structure model may be wrong or deficient 0 ALERT type 3 Indicator that the structure quality may be low 0 ALERT type 4 Improvement, methodology, query or suggestion 0 ALERT type 5 Informative message, check
Equimolar amounts of butobarbitone and ammonium carbonate were dissolved in distilled water and heated until boiling. Small colourless crystals of polymorph 1 grew over a period of two days on standing at room temperature in a sealed sample vial. Large colourless crystals of this new polymorph 3 (I) were observed after the sample vial had stood undisturbed for 17 months. Some of the smaller crystals were also still present in the vial.
All H atoms were located in a difference map. CH2 H atoms were then idealized (C—H = 0.99 Å) and refined as riding with Uiso(H) = 1.2Ueq(C). The methyl H atoms were geometrically positioned (C—H = 0.98 Å) and refined as riding with Uiso(H) = 1.5Ueq(C) and free rotation about the C—C bond. Nitrogen-bound H atoms were freely refined, giving N—H distances of 0.882 (19) and 0.883 (16) Å.
We have previously reported a temperature-induced phase transition in butobarbitone, (I), with the room-temperature structure determined in space group C2/c (polymorph 1, originally reported by Bideau, 1971), while at 120 K the space group is P21/n (polymorph 2, Nichol & Clegg, 2005). We report here a third polymorph of (I). The space group of this third polymorph is C2/c with Z' = 1 but the unit-cell parameters are quite different from those of the previous structures.
The unit cell volume in this new polymorph is 2265.5 (8) Å3 and this is lower than the P21/n polymorph at low temperature [which is 2356.2 (4) Å3]. A unit cell determination at 270 K on the same crystal showed only the small expected expansion in the cell parameters and so this third polymorph does not appear to undergo a phase transition within the temperature range from 150 to 270 K.
The molecular structure of (I) is shown in Fig. 1. In common with both reported polymorphs, R22(6) N–H···O hydrogen bonding interactions link the butobarbitone molecules into an infinite hydrogen-bonded tape. Differences are found in the crystal packing. As shown in Fig. 2 the hydrogen-bonded tapes interweave, while in the previously-reported polymorphs the ribbons form roughly parallel stacks.
The higher density of this new polymorph, and the fact that it was formed slowly from a solution from which the first polymorph had already been obtained more quickly, suggest that this is the thermodynamically more stable form.
See Bideau (1971) for the original room-temperature determination of polymorph 1, and Nichol & Clegg (2005) for details of the temperature-induced phase transition to polymorph 2.
Data collection: COLLECT (Nonius, 1998); cell refinement: EVALCCD (Duisenberg et al., 2003); data reduction: EVALCCD (Duisenberg et al., 2003); program(s) used to solve structure: SHELXTL (Sheldrick, 2001); program(s) used to refine structure: SHELXTL (Sheldrick, 2001); molecular graphics: DIAMOND (Brandenburg & Putz, 2004) and Mercury (Bruno et al., 2002); software used to prepare material for publication: SHELXTL (Sheldrick, 2001) and local programs.
Fig. 1. The molecular structure of (I) with displacement ellipsoids at the 50% probability level and hydrogen atoms as small spheres. | |
Fig. 2. The interweaving hydrogen-bonded tapes found in (I). |
C10H16N2O3 | F(000) = 912 |
Mr = 212.25 | Dx = 1.245 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -C 2yc | Cell parameters from 6280 reflections |
a = 19.519 (4) Å | θ = 2.5–27.5° |
b = 7.6868 (15) Å | µ = 0.09 mm−1 |
c = 15.117 (3) Å | T = 150 K |
β = 92.77 (3)° | Block, colourless |
V = 2265.5 (8) Å3 | 0.37 × 0.35 × 0.13 mm |
Z = 8 |
Nonius KappaCCD diffractometer | 2585 independent reflections |
Radiation source: sealed tube | 1958 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.034 |
φ and ω scans | θmax = 27.5°, θmin = 4.8° |
Absorption correction: multi-scan (SADABS; Sheldrick, 2003) | h = −25→25 |
Tmin = 0.917, Tmax = 0.988 | k = −9→9 |
12332 measured reflections | l = −18→19 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.039 | Hydrogen site location: difference Fourier map |
wR(F2) = 0.108 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.08 | w = 1/[σ2(Fo2) + (0.0526P)2 + 1.0348P] where P = (Fo2 + 2Fc2)/3 |
2585 reflections | (Δ/σ)max < 0.001 |
146 parameters | Δρmax = 0.28 e Å−3 |
0 restraints | Δρmin = −0.20 e Å−3 |
C10H16N2O3 | V = 2265.5 (8) Å3 |
Mr = 212.25 | Z = 8 |
Monoclinic, C2/c | Mo Kα radiation |
a = 19.519 (4) Å | µ = 0.09 mm−1 |
b = 7.6868 (15) Å | T = 150 K |
c = 15.117 (3) Å | 0.37 × 0.35 × 0.13 mm |
β = 92.77 (3)° |
Nonius KappaCCD diffractometer | 2585 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 2003) | 1958 reflections with I > 2σ(I) |
Tmin = 0.917, Tmax = 0.988 | Rint = 0.034 |
12332 measured reflections |
R[F2 > 2σ(F2)] = 0.039 | 0 restraints |
wR(F2) = 0.108 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.08 | Δρmax = 0.28 e Å−3 |
2585 reflections | Δρmin = −0.20 e Å−3 |
146 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
O1 | 0.47791 (4) | 0.62343 (12) | 0.40519 (6) | 0.0242 (2) | |
O2 | 0.33382 (5) | 0.26565 (12) | 0.54285 (6) | 0.0262 (2) | |
O3 | 0.24583 (5) | 0.55071 (13) | 0.30083 (6) | 0.0296 (3) | |
N1 | 0.40634 (5) | 0.43550 (14) | 0.46817 (7) | 0.0191 (2) | |
H1N | 0.4389 (9) | 0.411 (2) | 0.5089 (11) | 0.035 (4)* | |
N2 | 0.29072 (6) | 0.40867 (15) | 0.42063 (7) | 0.0218 (3) | |
H2N | 0.2499 (8) | 0.364 (2) | 0.4287 (10) | 0.028 (4)* | |
C1 | 0.42106 (6) | 0.55569 (16) | 0.40434 (8) | 0.0176 (3) | |
C2 | 0.34256 (6) | 0.36347 (16) | 0.48085 (8) | 0.0188 (3) | |
C3 | 0.29594 (6) | 0.51903 (16) | 0.34869 (8) | 0.0199 (3) | |
C4 | 0.36613 (6) | 0.59673 (16) | 0.33256 (8) | 0.0191 (3) | |
C5 | 0.35829 (7) | 0.79708 (18) | 0.32390 (10) | 0.0275 (3) | |
H5A | 0.4040 | 0.8482 | 0.3148 | 0.033* | |
H5B | 0.3287 | 0.8230 | 0.2705 | 0.033* | |
C6 | 0.32798 (10) | 0.8851 (2) | 0.40337 (12) | 0.0442 (4) | |
H6A | 0.2826 | 0.8362 | 0.4128 | 0.066* | |
H6B | 0.3238 | 1.0104 | 0.3922 | 0.066* | |
H6C | 0.3581 | 0.8655 | 0.4562 | 0.066* | |
C7 | 0.38930 (7) | 0.52140 (18) | 0.24327 (8) | 0.0237 (3) | |
H7A | 0.3550 | 0.5555 | 0.1960 | 0.028* | |
H7B | 0.4333 | 0.5768 | 0.2296 | 0.028* | |
C8 | 0.39867 (7) | 0.32317 (18) | 0.23944 (9) | 0.0251 (3) | |
H8A | 0.4367 | 0.2882 | 0.2814 | 0.030* | |
H8B | 0.3563 | 0.2653 | 0.2577 | 0.030* | |
C9 | 0.41447 (8) | 0.2637 (2) | 0.14602 (9) | 0.0295 (3) | |
H9A | 0.3743 | 0.2895 | 0.1057 | 0.035* | |
H9B | 0.4536 | 0.3324 | 0.1257 | 0.035* | |
C10 | 0.43166 (9) | 0.0710 (2) | 0.13864 (10) | 0.0362 (4) | |
H10A | 0.4708 | 0.0433 | 0.1792 | 0.054* | |
H10B | 0.4433 | 0.0444 | 0.0778 | 0.054* | |
H10C | 0.3919 | 0.0014 | 0.1542 | 0.054* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0158 (5) | 0.0300 (5) | 0.0263 (5) | −0.0055 (4) | −0.0038 (4) | 0.0070 (4) |
O2 | 0.0219 (5) | 0.0330 (5) | 0.0233 (5) | −0.0069 (4) | −0.0026 (4) | 0.0092 (4) |
O3 | 0.0184 (5) | 0.0384 (6) | 0.0309 (6) | −0.0024 (4) | −0.0084 (4) | 0.0086 (4) |
N1 | 0.0140 (5) | 0.0235 (6) | 0.0194 (6) | −0.0019 (4) | −0.0039 (4) | 0.0042 (4) |
N2 | 0.0128 (5) | 0.0286 (6) | 0.0237 (6) | −0.0060 (5) | −0.0021 (4) | 0.0050 (5) |
C1 | 0.0148 (6) | 0.0201 (6) | 0.0179 (6) | −0.0002 (5) | 0.0002 (5) | 0.0002 (5) |
C2 | 0.0161 (6) | 0.0200 (6) | 0.0201 (6) | −0.0011 (5) | −0.0012 (5) | −0.0006 (5) |
C3 | 0.0165 (6) | 0.0219 (6) | 0.0209 (6) | −0.0001 (5) | −0.0025 (5) | 0.0005 (5) |
C4 | 0.0159 (6) | 0.0223 (6) | 0.0187 (6) | −0.0015 (5) | −0.0028 (5) | 0.0044 (5) |
C5 | 0.0271 (7) | 0.0232 (7) | 0.0314 (8) | −0.0025 (6) | −0.0083 (6) | 0.0070 (6) |
C6 | 0.0592 (11) | 0.0287 (8) | 0.0438 (10) | 0.0079 (8) | −0.0087 (8) | −0.0040 (7) |
C7 | 0.0215 (7) | 0.0309 (7) | 0.0185 (6) | −0.0037 (6) | −0.0014 (5) | 0.0038 (5) |
C8 | 0.0236 (7) | 0.0318 (7) | 0.0196 (7) | −0.0042 (6) | −0.0012 (5) | 0.0006 (6) |
C9 | 0.0304 (8) | 0.0358 (8) | 0.0222 (7) | −0.0036 (7) | 0.0010 (6) | −0.0013 (6) |
C10 | 0.0400 (9) | 0.0391 (9) | 0.0293 (8) | −0.0026 (7) | 0.0004 (7) | −0.0060 (6) |
O1—C1 | 1.2253 (15) | C6—H6A | 0.980 |
O2—C2 | 1.2201 (15) | C6—H6B | 0.980 |
O3—C3 | 1.2129 (16) | C6—H6C | 0.980 |
N1—H1N | 0.882 (19) | C7—H7A | 0.990 |
N1—C1 | 1.3762 (16) | C7—H7B | 0.990 |
N1—C2 | 1.3842 (16) | C7—C8 | 1.536 (2) |
N2—H2N | 0.883 (16) | C8—H8A | 0.990 |
N2—C2 | 1.3727 (17) | C8—H8B | 0.990 |
N2—C3 | 1.3869 (17) | C8—C9 | 1.5300 (18) |
C1—C4 | 1.5212 (18) | C9—H9A | 0.990 |
C3—C4 | 1.5249 (17) | C9—H9B | 0.990 |
C4—C5 | 1.5526 (18) | C9—C10 | 1.524 (2) |
C4—C7 | 1.5560 (18) | C10—H10A | 0.980 |
C5—H5A | 0.990 | C10—H10B | 0.980 |
C5—H5B | 0.990 | C10—H10C | 0.980 |
C5—C6 | 1.523 (2) | ||
H1N—N1—C1 | 117.5 (11) | C5—C6—H6C | 109.5 |
H1N—N1—C2 | 116.2 (11) | H6A—C6—H6B | 109.5 |
C1—N1—C2 | 125.81 (11) | H6A—C6—H6C | 109.5 |
H2N—N2—C2 | 116.7 (10) | H6B—C6—H6C | 109.5 |
H2N—N2—C3 | 116.7 (10) | C4—C7—H7A | 108.2 |
C2—N2—C3 | 126.52 (11) | C4—C7—H7B | 108.2 |
O1—C1—N1 | 119.84 (12) | C4—C7—C8 | 116.23 (11) |
O1—C1—C4 | 121.74 (11) | H7A—C7—H7B | 107.4 |
N1—C1—C4 | 118.40 (11) | H7A—C7—C8 | 108.2 |
O2—C2—N1 | 120.86 (12) | H7B—C7—C8 | 108.2 |
O2—C2—N2 | 122.65 (11) | C7—C8—H8A | 109.4 |
N1—C2—N2 | 116.49 (11) | C7—C8—H8B | 109.4 |
O3—C3—N2 | 120.19 (12) | C7—C8—C9 | 111.15 (11) |
O3—C3—C4 | 122.06 (11) | H8A—C8—H8B | 108.0 |
N2—C3—C4 | 117.75 (11) | H8A—C8—C9 | 109.4 |
C1—C4—C3 | 114.35 (10) | H8B—C8—C9 | 109.4 |
C1—C4—C5 | 109.21 (11) | C8—C9—H9A | 108.7 |
C1—C4—C7 | 108.50 (10) | C8—C9—H9B | 108.7 |
C3—C4—C5 | 108.45 (10) | C8—C9—C10 | 114.38 (12) |
C3—C4—C7 | 107.10 (11) | H9A—C9—H9B | 107.6 |
C5—C4—C7 | 109.12 (11) | H9A—C9—C10 | 108.7 |
C4—C5—H5A | 108.6 | H9B—C9—C10 | 108.7 |
C4—C5—H5B | 108.6 | C9—C10—H10A | 109.5 |
C4—C5—C6 | 114.50 (12) | C9—C10—H10B | 109.5 |
H5A—C5—H5B | 107.6 | C9—C10—H10C | 109.5 |
H5A—C5—C6 | 108.6 | H10A—C10—H10B | 109.5 |
H5B—C5—C6 | 108.6 | H10A—C10—H10C | 109.5 |
C5—C6—H6A | 109.5 | H10B—C10—H10C | 109.5 |
C5—C6—H6B | 109.5 | ||
C2—N1—C1—O1 | 172.55 (12) | O3—C3—C4—C1 | 174.50 (12) |
C2—N1—C1—C4 | −9.21 (18) | O3—C3—C4—C5 | 52.38 (16) |
C3—N2—C2—O2 | 179.71 (12) | O3—C3—C4—C7 | −65.26 (16) |
C3—N2—C2—N1 | −0.05 (19) | N2—C3—C4—C1 | −5.71 (16) |
C1—N1—C2—O2 | −175.46 (12) | N2—C3—C4—C5 | −127.83 (12) |
C1—N1—C2—N2 | 4.30 (18) | N2—C3—C4—C7 | 114.53 (12) |
C2—N2—C3—O3 | −178.94 (13) | C1—C4—C5—C6 | −68.15 (15) |
C2—N2—C3—C4 | 1.27 (19) | C3—C4—C5—C6 | 57.05 (16) |
O1—C1—C4—C3 | −172.44 (12) | C7—C4—C5—C6 | 173.39 (12) |
O1—C1—C4—C5 | −50.74 (16) | C1—C4—C7—C8 | 61.94 (14) |
O1—C1—C4—C7 | 68.10 (15) | C3—C4—C7—C8 | −61.97 (14) |
N1—C1—C4—C3 | 9.35 (16) | C5—C4—C7—C8 | −179.17 (11) |
N1—C1—C4—C5 | 131.05 (12) | C4—C7—C8—C9 | 174.37 (11) |
N1—C1—C4—C7 | −110.10 (12) | C7—C8—C9—C10 | 174.09 (12) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1N···O1i | 0.882 (19) | 2.048 (19) | 2.9251 (17) | 172.7 (15) |
N2—H2N···O2ii | 0.883 (16) | 1.977 (16) | 2.8530 (15) | 171.2 (15) |
C5—H5B···O3iii | 0.99 | 2.49 | 3.3341 (19) | 143 |
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x+1/2, −y+1/2, −z+1; (iii) −x+1/2, y+1/2, −z+1/2. |
Experimental details
Crystal data | |
Chemical formula | C10H16N2O3 |
Mr | 212.25 |
Crystal system, space group | Monoclinic, C2/c |
Temperature (K) | 150 |
a, b, c (Å) | 19.519 (4), 7.6868 (15), 15.117 (3) |
β (°) | 92.77 (3) |
V (Å3) | 2265.5 (8) |
Z | 8 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.37 × 0.35 × 0.13 |
Data collection | |
Diffractometer | Nonius KappaCCD |
Absorption correction | Multi-scan (SADABS; Sheldrick, 2003) |
Tmin, Tmax | 0.917, 0.988 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 12332, 2585, 1958 |
Rint | 0.034 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.039, 0.108, 1.08 |
No. of reflections | 2585 |
No. of parameters | 146 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.28, −0.20 |
Computer programs: COLLECT (Nonius, 1998), EVALCCD (Duisenberg et al., 2003), DIAMOND (Brandenburg & Putz, 2004) and Mercury (Bruno et al., 2002), SHELXTL (Sheldrick, 2001) and local programs.
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1N···O1i | 0.882 (19) | 2.048 (19) | 2.9251 (17) | 172.7 (15) |
N2—H2N···O2ii | 0.883 (16) | 1.977 (16) | 2.8530 (15) | 171.2 (15) |
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x+1/2, −y+1/2, −z+1. |
We have previously reported a temperature-induced phase transition in butobarbitone, (I), with the room-temperature structure determined in space group C2/c (polymorph 1, originally reported by Bideau, 1971), while at 120 K the space group is P21/n (polymorph 2, Nichol & Clegg, 2005). We report here a third polymorph of (I). The space group of this third polymorph is C2/c with Z' = 1 but the unit-cell parameters are quite different from those of the previous structures.
The unit cell volume in this new polymorph is 2265.5 (8) Å3 and this is lower than the P21/n polymorph at low temperature [which is 2356.2 (4) Å3]. A unit cell determination at 270 K on the same crystal showed only the small expected expansion in the cell parameters and so this third polymorph does not appear to undergo a phase transition within the temperature range from 150 to 270 K.
The molecular structure of (I) is shown in Fig. 1. In common with both reported polymorphs, R22(6) N–H···O hydrogen bonding interactions link the butobarbitone molecules into an infinite hydrogen-bonded tape. Differences are found in the crystal packing. As shown in Fig. 2 the hydrogen-bonded tapes interweave, while in the previously-reported polymorphs the ribbons form roughly parallel stacks.
The higher density of this new polymorph, and the fact that it was formed slowly from a solution from which the first polymorph had already been obtained more quickly, suggest that this is the thermodynamically more stable form.