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Molecules of 13
H-dibenzo[
a,
i]fluoren-13-one, C
21H
12O, straddle a crystallographic mirror plane and are essentially planar, with a dihedral angle of only 1.9 (1)° between the two naphthalene ring systems. Repulsive intramolecular C=O
H interactions therefore do not explain the larger distortions found in isomeric ketones.
Supporting information
CCDC reference: 145535
Compound (II) was made by coupling the Grignard reagent from 1-bromonaphthalene
(Blicke, 1927) with ethyl formate to give 1,1-dinaphthylmethanol. This was
converted to 13H-dibenzo[a,i]fluorene (m.p. 505–506 K; literature
value 504–506 K; Harvey et al., 1991) by the action of
meta-phosphoric acid at 448 K (other dehydrating agents were
unsuccessful). Reaction of the hydrocarbon with potassium methoxide and
acetone gave compound (II) (m.p. 544–545 K Query; literature value 544 K;
Harvey et al., 1991). The 1H NMR of compound (II) in CDCl3 was
determined with a Bruker DPX 400 spectrometer at 9.4 T, and chemical shifts in
p.p.m. were referenced to chloroform at 7.25. Spectroscopic analysis: 1H
NMR: 8.89 (d, J = 8.44 Hz), 2.89 (d, J = 8.16 Hz), 7.70 (d, J = 8.32 Hz), 7.59
(d, J = 8.20 Hz), 7.50 (d, J = 7.60 Hz), 7.33 (d, J = 7.56 Hz). All
absorptions were equally intense. The low field absorption is assigned to the
protons closest to the lone pairs of the carbonyl O. We have, for convenience,
numbered the C atoms of (II) so that the oxygen-bearing C atom is defined as
C1 (Fig. 1). However, this is at variance with IUPAC nomenclature which
defines C4 in Fig. 1 as C1, with other C atoms numbered in sequence around the
ring away from the carbonyl C atom.
Data collection: CAD-4 EXPRESS (Enraf Nonius, 1992); cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: SHELXL97.
13
H-dibenzo[a,i]fluoren-13-one
top
Crystal data top
C21H12O | Dx = 1.415 Mg m−3 |
Mr = 280.31 | Melting point = 543–544 K |
Orthorhombic, Pnma | Mo Kα radiation, λ = 0.71073 Å |
a = 13.2543 (9) Å | Cell parameters from 25 reflections |
b = 25.7694 (18) Å | θ = 19.0–23.4° |
c = 3.8521 (2) Å | µ = 0.09 mm−1 |
V = 1315.71 (15) Å3 | T = 293 K |
Z = 4 | Plate, red |
F(000) = 584 | 0.63 × 0.34 × 0.13 mm |
Data collection top
Enraf Nonius CAD-4 diffractometer | Rint = 0.018 |
Radiation source: fine-focus sealed tube | θmax = 32.9°, θmin = 3.1° |
Graphite monochromator | h = −20→2 |
ω scans | k = −3→39 |
3713 measured reflections | l = −5→1 |
2502 independent reflections | 3 standard reflections every 120 min |
1371 reflections with I > 2σ(I) | intensity decay: none |
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)] = 0.054 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.167 | All H-atom parameters refined |
S = 1.00 | Calculated w = 1/[σ2(Fo2) + (0.0846P)2 + 0.1556P] where P = (Fo2 + 2Fc2)/3 |
2502 reflections | (Δ/σ)max < 0.001 |
127 parameters | Δρmax = 0.36 e Å−3 |
0 restraints | Δρmin = −0.24 e Å−3 |
Crystal data top
C21H12O | V = 1315.71 (15) Å3 |
Mr = 280.31 | Z = 4 |
Orthorhombic, Pnma | Mo Kα radiation |
a = 13.2543 (9) Å | µ = 0.09 mm−1 |
b = 25.7694 (18) Å | T = 293 K |
c = 3.8521 (2) Å | 0.63 × 0.34 × 0.13 mm |
Data collection top
Enraf Nonius CAD-4 diffractometer | Rint = 0.018 |
3713 measured reflections | 3 standard reflections every 120 min |
2502 independent reflections | intensity decay: none |
1371 reflections with I > 2σ(I) | |
Refinement top
R[F2 > 2σ(F2)] = 0.054 | 0 restraints |
wR(F2) = 0.167 | All H-atom parameters refined |
S = 1.00 | Δρmax = 0.36 e Å−3 |
2502 reflections | Δρmin = −0.24 e Å−3 |
127 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 | x | y | z | Uiso*/Ueq | |
O | −0.00758 (11) | 1/4 | 0.7656 (5) | 0.0454 (4) | |
C1 | −0.09098 (13) | 1/4 | 0.6299 (5) | 0.0317 (4) | |
C2 | −0.15223 (9) | 0.29630 (5) | 0.5289 (4) | 0.0312 (3) | |
C3 | −0.13214 (9) | 0.34980 (5) | 0.5674 (4) | 0.0316 (3) | |
C4 | −0.04258 (11) | 0.36996 (6) | 0.7197 (4) | 0.0369 (3) | |
H4 | 0.0078 (15) | 0.3456 (8) | 0.798 (5) | 0.050 (5)* | |
C5 | −0.02961 (12) | 0.42241 (6) | 0.7480 (5) | 0.0435 (4) | |
H5 | 0.0337 (16) | 0.4350 (8) | 0.843 (5) | 0.062 (6)* | |
C6 | −0.10376 (13) | 0.45715 (6) | 0.6308 (5) | 0.0471 (4) | |
H6 | −0.0908 (14) | 0.4945 (7) | 0.660 (4) | 0.052 (5)* | |
C7 | −0.19056 (12) | 0.43907 (6) | 0.4844 (5) | 0.0437 (4) | |
H7 | −0.2427 (13) | 0.4642 (7) | 0.407 (5) | 0.053 (5)* | |
C8 | −0.20742 (10) | 0.38497 (6) | 0.4463 (4) | 0.0359 (3) | |
C9 | −0.29675 (11) | 0.36547 (6) | 0.2929 (4) | 0.0408 (4) | |
H9 | −0.3454 (14) | 0.3906 (8) | 0.212 (5) | 0.054 (5)* | |
C10 | −0.31426 (10) | 0.31342 (6) | 0.2597 (4) | 0.0385 (4) | |
H10 | −0.3762 (14) | 0.3003 (6) | 0.147 (5) | 0.046 (5)* | |
C11 | −0.24108 (9) | 0.27878 (6) | 0.3801 (4) | 0.0321 (3) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O | 0.0312 (7) | 0.0413 (8) | 0.0636 (11) | 0 | −0.0137 (7) | 0 |
C1 | 0.0257 (8) | 0.0371 (9) | 0.0324 (10) | 0 | 0.0010 (8) | 0 |
C2 | 0.0257 (5) | 0.0383 (7) | 0.0296 (7) | 0.0015 (5) | 0.0014 (5) | 0.0001 (6) |
C3 | 0.0287 (6) | 0.0374 (7) | 0.0288 (7) | 0.0027 (5) | 0.0031 (5) | 0.0007 (6) |
C4 | 0.0336 (6) | 0.0397 (7) | 0.0374 (8) | 0.0009 (6) | 0.0004 (6) | −0.0012 (7) |
C5 | 0.0431 (8) | 0.0417 (8) | 0.0456 (9) | −0.0045 (7) | 0.0010 (7) | −0.0052 (7) |
C6 | 0.0514 (9) | 0.0362 (7) | 0.0536 (11) | 0.0003 (7) | 0.0079 (8) | −0.0020 (8) |
C7 | 0.0461 (8) | 0.0391 (8) | 0.0459 (10) | 0.0084 (7) | 0.0054 (7) | 0.0035 (7) |
C8 | 0.0330 (6) | 0.0406 (7) | 0.0340 (8) | 0.0058 (6) | 0.0041 (6) | 0.0031 (6) |
C9 | 0.0324 (7) | 0.0492 (9) | 0.0406 (9) | 0.0096 (6) | −0.0001 (6) | 0.0052 (7) |
C10 | 0.0274 (6) | 0.0519 (9) | 0.0362 (8) | 0.0035 (6) | −0.0023 (6) | 0.0024 (7) |
C11 | 0.0262 (6) | 0.0423 (7) | 0.0278 (7) | 0.0011 (5) | 0.0013 (5) | 0.0011 (6) |
Geometric parameters (Å, º) top
O—C1 | 1.223 (2) | C8—C3 | 1.427 (2) |
C1—C2i | 1.495 (2) | C7—C6 | 1.363 (2) |
C1—C2 | 1.495 (2) | C7—H7 | 0.992 (19) |
C11—C2 | 1.386 (2) | C6—C5 | 1.404 (2) |
C11—C10 | 1.397 (2) | C6—H6 | 0.984 (18) |
C11—C11i | 1.483 (3) | C5—C4 | 1.367 (2) |
C10—C9 | 1.367 (2) | C5—H5 | 0.97 (2) |
C10—H10 | 0.988 (18) | C4—C3 | 1.422 (2) |
C9—C8 | 1.416 (2) | C4—H4 | 0.97 (2) |
C9—H9 | 0.96 (2) | C3—C2 | 1.412 (2) |
C8—C7 | 1.419 (2) | | |
| | | |
O—C1—C2i | 127.04 (8) | C8—C7—H7 | 120.0 (11) |
O—C1—C2 | 127.04 (8) | C7—C6—C5 | 120.38 (15) |
C2i—C1—C2 | 105.92 (15) | C7—C6—H6 | 122.0 (11) |
C2—C11—C10 | 121.28 (14) | C5—C6—H6 | 117.6 (11) |
C2—C11—C11i | 109.01 (8) | C4—C5—C6 | 121.12 (16) |
C10—C11—C11i | 129.71 (9) | C4—C5—H5 | 118.0 (12) |
C9—C10—C11 | 118.55 (14) | C6—C5—H5 | 120.8 (12) |
C9—C10—H10 | 121.2 (10) | C5—C4—C3 | 119.95 (14) |
C11—C10—H10 | 120.2 (10) | C5—C4—H4 | 122.1 (12) |
C10—C9—C8 | 121.96 (14) | C3—C4—H4 | 117.9 (12) |
C10—C9—H9 | 121.0 (11) | C2—C3—C4 | 123.87 (12) |
C8—C9—H9 | 117.1 (11) | C2—C3—C8 | 117.02 (13) |
C9—C8—C7 | 121.58 (13) | C4—C3—C8 | 119.11 (13) |
C9—C8—C3 | 119.73 (14) | C11—C2—C3 | 121.46 (12) |
C7—C8—C3 | 118.69 (14) | C11—C2—C1 | 108.03 (12) |
C6—C7—C8 | 120.75 (14) | C3—C2—C1 | 130.51 (12) |
C6—C7—H7 | 119.2 (11) | | |
| | | |
C2—C11—C10—C9 | −0.3 (2) | C9—C8—C3—C4 | 179.75 (14) |
C11i—C11—C10—C9 | 179.27 (10) | C7—C8—C3—C4 | −0.4 (2) |
C11—C10—C9—C8 | −0.3 (2) | C10—C11—C2—C3 | 0.4 (2) |
C10—C9—C8—C7 | −179.03 (16) | C11i—C11—C2—C3 | −179.21 (11) |
C10—C9—C8—C3 | 0.8 (2) | C10—C11—C2—C1 | 179.85 (14) |
C9—C8—C7—C6 | −179.57 (16) | C11i—C11—C2—C1 | 0.22 (13) |
C3—C8—C7—C6 | 0.6 (2) | C4—C3—C2—C11 | 179.66 (13) |
C8—C7—C6—C5 | −0.3 (3) | C8—C3—C2—C11 | 0.0 (2) |
C7—C6—C5—C4 | −0.2 (3) | C4—C3—C2—C1 | 0.4 (3) |
C6—C5—C4—C3 | 0.4 (3) | C8—C3—C2—C1 | −179.26 (16) |
C5—C4—C3—C2 | −179.68 (15) | O—C1—C2—C11 | 179.27 (19) |
C5—C4—C3—C8 | −0.1 (2) | C2i—C1—C2—C11 | −0.4 (2) |
C9—C8—C3—C2 | −0.6 (2) | O—C1—C2—C3 | −1.4 (3) |
C7—C8—C3—C2 | 179.20 (14) | C2i—C1—C2—C3 | 179.01 (9) |
Symmetry code: (i) x, −y+1/2, z. |
Experimental details
Crystal data |
Chemical formula | C21H12O |
Mr | 280.31 |
Crystal system, space group | Orthorhombic, Pnma |
Temperature (K) | 293 |
a, b, c (Å) | 13.2543 (9), 25.7694 (18), 3.8521 (2) |
V (Å3) | 1315.71 (15) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.63 × 0.34 × 0.13 |
|
Data collection |
Diffractometer | Enraf Nonius CAD-4 diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 3713, 2502, 1371 |
Rint | 0.018 |
(sin θ/λ)max (Å−1) | 0.764 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.054, 0.167, 1.00 |
No. of reflections | 2502 |
No. of parameters | 127 |
H-atom treatment | All H-atom parameters refined |
Δρmax, Δρmin (e Å−3) | 0.36, −0.24 |
Selected geometric parameters (Å, º) topO—C1 | 1.223 (2) | C11—C2 | 1.386 (2) |
C1—C2 | 1.495 (2) | C11—C11i | 1.483 (3) |
| | | |
O—C1—C2 | 127.04 (8) | C11—C2—C1 | 108.03 (12) |
C2i—C1—C2 | 105.92 (15) | C3—C2—C1 | 130.51 (12) |
C2—C3—C4 | 123.87 (12) | | |
| | | |
C4—C3—C2—C1 | 0.4 (3) | O—C1—C2—C3 | −1.4 (3) |
Symmetry code: (i) x, −y+1/2, z. |
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In a recent publication (Morris et al., 1998) we described the crystal structure of 13H-dibenzo[a,g]fluoren-13-one (C·A·S. Registry No. [63041–47-4]), (I), which had previously been shown by Harvey et al. (1992) to exhibit an anomolously low field resonance in the 1H NMR spectrum for the H atom (H4) closest to the carbonyl O.
Molecules of (I) show small but significant distortions from planarity: the two naphthalene ring systems define a dihedral angle of 6.0 (1)° and are themselves slightly ruffled (r.m.s. deviations for the two C10 planes are 0.019 and 0.012 Å). Repulsive intramolecular C=O···H interactions (O···H 2.48 Å and O···C—H 124°) were considered to be the most likely cause of these distortions (Morris et al., 1998). However, the geometry of the C=O···H sub-unit in (I) falls in the region where it is difficult to discriminate between `repulsive forced interactions' and weak C—H···O hydrogen bonds (Jeffrey, 1997). The bay region of (I) also contains a short intramolecular C10—H···H—C14 contact of 2.07 Å which is indicative of overcrowding. In order to investigate this point we have determined the structure of the isomeric compound 13H-dibenzo[a,i]fluoren-13-one, (II) (C·A·S. Registry No. [86854–01-5]), in which there are no short H···H contacts but two C=O···H interactions of the type found in (I). \scheme
Molecules of (II) straddle a crystallographic mirror plane which is normal to the five-membered ring, passing through C1, O and the midpoint of the C11—C11i bond [symmetry code: (i) x, 1/2 - y, z]. Bond lengths and angles in (II) are unexceptional (Table 1) and agree with comparable values in (I). The single independent naphthalene ring system in (II), defined by C2—C11, has an r.m.s. deviation from planarity of only 0.007 Å and the angle between the two mirror-related ring systems within the same molecule is only 1.9 (1)°. Compound (II) is therefore planar almost to within experimental error; only one skeletal torsion angle deviates from 0° or 180° by more than 1° [C3—C2—C1—O = -1.4 (3)°]. However, the C=O.·H contact in (II) [O···H4 = 2.47 (5) Å and O···H4—C4 = 125 (2)°] is very similar to the corresponding contact in (I). This is consistent with the observation of low field signals in the 1H NMR spectra of both molecules. Taken together, the structural and NMR results for (I) and (II) suggest that the C=O···H interactions in both molecules are not strongly repulsive and indeed may be indicative of weak intramolecular hydrogen bonding. The slight distortion observed in (I) probably helps to relieve H···H steric crowding.