A new polymorph of 1,4-dibenzoylbutane, C
18H
18O
2, has been discovered. Until now only a monoclinic polymorph of the title compound was known. The newly found triclinic polymorph crystallizes in
P with half a molecule in the asymmetric unit. The two polymorphs differ slightly in the torsion angles of the central chain.
Supporting information
CCDC reference: 242333
Key indicators
- Single-crystal X-ray study
- T = 173 K
- Mean (C-C) = 0.002 Å
- R factor = 0.036
- wR factor = 0.096
- Data-to-parameter ratio = 17.7
checkCIF/PLATON results
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Data collection: X-AREA (Stoe & Cie, 2001); cell refinement: X-AREA; data reduction: X-AREA; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP in SHELXTL-Plus (Sheldrick, 1991); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 1990).
Crystal data top
C18H18O2 | Z = 1 |
Mr = 266.32 | F(000) = 142 |
Triclinic, P1 | Dx = 1.274 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 5.7482 (12) Å | Cell parameters from 4194 reflections |
b = 7.6480 (16) Å | θ = 3.8–27.7° |
c = 8.2817 (15) Å | µ = 0.08 mm−1 |
α = 95.413 (16)° | T = 173 K |
β = 105.265 (15)° | Block, colourless |
γ = 95.206 (17)° | 0.52 × 0.29 × 0.27 mm |
V = 347.13 (12) Å3 | |
Data collection top
Stoe IPDS-II two-circle diffractometer | 1203 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.040 |
Graphite monochromator | θmax = 27.8°, θmin = 3.9° |
ω scans | h = −7→7 |
5151 measured reflections | k = −9→9 |
1610 independent reflections | l = −10→10 |
Refinement top
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)] = 0.036 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.096 | H-atom parameters constrained |
S = 1.08 | w = 1/[σ2(Fo2) + (0.0517P)2] where P = (Fo2 + 2Fc2)/3 |
1610 reflections | (Δ/σ)max < 0.001 |
91 parameters | Δρmax = 0.29 e Å−3 |
0 restraints | Δρmin = −0.17 e Å−3 |
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 | x | y | z | Uiso*/Ueq | |
O1 | 0.42467 (14) | 0.26727 (12) | 0.79614 (10) | 0.0371 (2) | |
C1 | 0.46452 (18) | 0.24376 (13) | 0.51876 (12) | 0.0251 (2) | |
C2 | 0.60358 (19) | 0.27709 (15) | 0.40828 (13) | 0.0311 (3) | |
H2 | 0.7612 | 0.3411 | 0.4499 | 0.037* | |
C3 | 0.5131 (2) | 0.21725 (16) | 0.23728 (14) | 0.0367 (3) | |
H3 | 0.6086 | 0.2408 | 0.1623 | 0.044* | |
C4 | 0.2847 (2) | 0.12377 (16) | 0.17644 (14) | 0.0354 (3) | |
H4 | 0.2239 | 0.0817 | 0.0598 | 0.042* | |
C5 | 0.1444 (2) | 0.09121 (15) | 0.28472 (13) | 0.0339 (3) | |
H5 | −0.0133 | 0.0276 | 0.2425 | 0.041* | |
C6 | 0.23372 (19) | 0.15142 (14) | 0.45531 (13) | 0.0292 (2) | |
H6 | 0.1362 | 0.1293 | 0.5293 | 0.035* | |
C7 | 0.55417 (18) | 0.30082 (14) | 0.70579 (12) | 0.0259 (2) | |
C8 | 0.80576 (17) | 0.39905 (14) | 0.77633 (12) | 0.0272 (2) | |
H8A | 0.8150 | 0.5094 | 0.7236 | 0.033* | |
H8B | 0.9245 | 0.3255 | 0.7458 | 0.033* | |
C9 | 0.87631 (18) | 0.44548 (15) | 0.96719 (12) | 0.0282 (2) | |
H9A | 0.7526 | 0.5129 | 0.9990 | 0.034* | |
H9B | 0.8787 | 0.3351 | 1.0208 | 0.034* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O1 | 0.0326 (4) | 0.0489 (5) | 0.0288 (4) | −0.0058 (3) | 0.0122 (3) | −0.0016 (3) |
C1 | 0.0260 (5) | 0.0240 (5) | 0.0248 (5) | 0.0039 (4) | 0.0059 (4) | 0.0028 (4) |
C2 | 0.0263 (5) | 0.0364 (6) | 0.0307 (5) | 0.0010 (4) | 0.0093 (4) | 0.0035 (4) |
C3 | 0.0388 (6) | 0.0452 (7) | 0.0297 (5) | 0.0065 (5) | 0.0150 (5) | 0.0059 (5) |
C4 | 0.0421 (6) | 0.0379 (6) | 0.0233 (5) | 0.0059 (5) | 0.0049 (4) | −0.0002 (4) |
C5 | 0.0321 (5) | 0.0327 (6) | 0.0317 (5) | −0.0018 (4) | 0.0028 (4) | 0.0015 (4) |
C6 | 0.0292 (5) | 0.0292 (6) | 0.0290 (5) | 0.0001 (4) | 0.0089 (4) | 0.0037 (4) |
C7 | 0.0257 (5) | 0.0263 (5) | 0.0259 (5) | 0.0030 (4) | 0.0076 (4) | 0.0022 (4) |
C8 | 0.0239 (5) | 0.0299 (6) | 0.0259 (5) | 0.0003 (4) | 0.0054 (4) | 0.0014 (4) |
C9 | 0.0260 (5) | 0.0321 (5) | 0.0251 (5) | 0.0003 (4) | 0.0055 (4) | 0.0032 (4) |
Geometric parameters (Å, º) top
O1—C7 | 1.2144 (13) | C5—C6 | 1.3870 (15) |
C1—C6 | 1.3884 (15) | C5—H5 | 0.95 |
C1—C2 | 1.3904 (15) | C6—H6 | 0.95 |
C1—C7 | 1.5055 (14) | C7—C8 | 1.5074 (14) |
C2—C3 | 1.3901 (15) | C8—C9 | 1.5229 (13) |
C2—H2 | 0.95 | C8—H8A | 0.99 |
C3—C4 | 1.3790 (18) | C8—H8B | 0.99 |
C3—H3 | 0.95 | C9—C9i | 1.518 (2) |
C4—C5 | 1.3796 (17) | C9—H9A | 0.99 |
C4—H4 | 0.95 | C9—H9B | 0.99 |
| | | |
C6—C1—C2 | 118.97 (9) | C1—C6—H6 | 119.7 |
C6—C1—C7 | 118.05 (9) | O1—C7—C1 | 119.98 (9) |
C2—C1—C7 | 122.97 (9) | O1—C7—C8 | 121.52 (9) |
C3—C2—C1 | 120.33 (10) | C1—C7—C8 | 118.50 (9) |
C3—C2—H2 | 119.8 | C7—C8—C9 | 113.26 (9) |
C1—C2—H2 | 119.8 | C7—C8—H8A | 108.9 |
C4—C3—C2 | 120.04 (11) | C9—C8—H8A | 108.9 |
C4—C3—H3 | 120.0 | C7—C8—H8B | 108.9 |
C2—C3—H3 | 120.0 | C9—C8—H8B | 108.9 |
C3—C4—C5 | 120.12 (10) | H8A—C8—H8B | 107.7 |
C3—C4—H4 | 119.9 | C9i—C9—C8 | 111.91 (11) |
C5—C4—H4 | 119.9 | C9i—C9—H9A | 109.2 |
C4—C5—C6 | 119.99 (10) | C8—C9—H9A | 109.2 |
C4—C5—H5 | 120.0 | C9i—C9—H9B | 109.2 |
C6—C5—H5 | 120.0 | C8—C9—H9B | 109.2 |
C5—C6—C1 | 120.55 (10) | H9A—C9—H9B | 107.9 |
C5—C6—H6 | 119.7 | | |
| | | |
C6—C1—C2—C3 | −0.57 (16) | C6—C1—C7—O1 | −0.70 (15) |
C7—C1—C2—C3 | 178.41 (10) | C2—C1—C7—O1 | −179.69 (10) |
C1—C2—C3—C4 | −0.24 (17) | C6—C1—C7—C8 | 179.20 (10) |
C2—C3—C4—C5 | 0.77 (19) | C2—C1—C7—C8 | 0.21 (14) |
C3—C4—C5—C6 | −0.48 (18) | O1—C7—C8—C9 | 1.19 (15) |
C4—C5—C6—C1 | −0.35 (17) | C1—C7—C8—C9 | −178.72 (9) |
C2—C1—C6—C5 | 0.87 (16) | C7—C8—C9—C9i | −176.29 (11) |
C7—C1—C6—C5 | −178.17 (10) | | |
Symmetry code: (i) −x+2, −y+1, −z+2. |