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The title compound, C
23H
22O, is composed of molecules bonded into linear one-dimensional chains through O—H
π(fluorene) hydrogen bonds, each molecule being both H-atom donor and acceptor. No O—H
O—H hydrogen bonding is exhibited, despite the reasonable donor–acceptor proximity [2.849 (3) Å]. The melted crystals failed to recrystallize on cooling, but solution NMR showed that no decomposition had occurred during the melting.
Supporting information
CCDC reference: 217464
Key indicators
- Single-crystal X-ray study
- T = 296 K
- Mean (C-C) = 0.005 Å
- R factor = 0.046
- wR factor = 0.167
- Data-to-parameter ratio = 14.2
checkCIF results
No syntax errors found
ADDSYM reports no extra symmetry
Alert Level B:
PLAT_420 Alert B D-H Without Acceptor O1 - H1 .. ?
0 Alert Level A = Potentially serious problem
1 Alert Level B = Potential problem
0 Alert Level C = Please check
Freshly distilled tetrahydrofuran (20 ml) and 1,2-dibromoethane (0.30 ml, 3.48 mmol) were added to a flask containing magnesium (0.29 g, 11.82 mmol) and the mixture was gently heated. When bubbles appeared at the surface of the magnesium, meta-tert-butylbromobenzene (Czarnik, 1984; Schaefer & Higgins, 1967) (1.85 g, 12.09 mmol) was added and the mixture was gently heated until all of the magnesium was consumed. A solution of 9-fluorenone (1.01 g, 5.62 mmol) in tetrahydrofuran (15 ml) was added and the mixture, which immediately became yellow-brown, was refluxed for 22 h. A saturated aqueous NH4Cl solution was then added, the mixture was extracted with ether and the combined extracts were dried and concentrated in vacuo leaving a dark yellow oil that solidified on standing; 1.41 g, 79.8% yield. Recrystallization (hexanes) afforded colorless crystals of (I), mp 374.5–376 K. The melt did not recrystallize even on standing for several days, although its 1H NMR spectrum was identical to that of the crystals, showing that they did not decompose on melting. NMR (CDCl3): 1H, δ 1.30 (s, 9 H), 2.43 (s, 1 H), 6.92–6.95 (m, 1 H), 7.10–7.38 (m, 8 H), 7.64–7.71 (m, 3 H); 13C: δ 31.40, 34.81, 83.94, 120.06, 122.33, 122.75, 124.19, 124.81, 127.77, 128.37, 129.00, 139.66, 142.82, 150.57, 151.15.
The rotational orientations of the methyl H atoms of the tert-butyl group and the H atom of the hydroxyl group were refined by the circular Fourier methods available in SHELXL97 (Sheldrick, 1997). The hydroxyl H atom was clearly visible on difference electron density maps. All hydrogen atoms are riding with C—H distances ranging from 0.93 to 0.96 Å and 0.82 Å for O—H.
Data collection: MSC/AFC Diffractometer Control Software
(Molecular Structure Corporation,1996); cell refinement: MSC/AFC Diffractometer Control Software; data reduction: PROCESS in TEXSAN (Molecular Structure Corporation, 1997); program(s) used to solve structure: SIR92 (Burla et al., 1989); program(s) used to refine structure: LS in TEXSAN (Molecular Structure Corporation, 1997) and
SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and PLATON (Spek, 2000).
9-(
meta-
tert-Butylphenyl)-9-fluorenol
top
Crystal data top
C23H22O | Dx = 1.168 Mg m−3 |
Mr = 314.41 | Melting point = 374.5–376 K |
Orthorhombic, Pccn | Mo Kα radiation, λ = 0.71069 Å |
Hall symbol: -P 2ab 2ac | Cell parameters from 25 reflections |
a = 22.123 (5) Å | θ = 11.2–18.8° |
b = 24.203 (3) Å | µ = 0.07 mm−1 |
c = 6.676 (4) Å | T = 296 K |
V = 3575 (2) Å3 | Prism, colorless |
Z = 8 | 0.49 × 0.43 × 0.22 mm |
F(000) = 1344 | |
Data collection top
Rigaku AFC-5S diffractometer | Rint = 0.0 |
Radiation source: fine-focus sealed tube | θmax = 25.0°, θmin = 1.8° |
Graphite monochromator | h = 0→26 |
ω scans | k = 0→28 |
3143 measured reflections | l = 0→7 |
3143 independent reflections | 3 standard reflections every 100 reflections |
1395 reflections with I > 2σ(I) | intensity decay: 0.3% |
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)] = 0.046 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.167 | H-atom parameters constrained |
S = 1.00 | w = 1/[σ2(Fo2) + (0.0762P)2 + 0.4759P] where P = (Fo2 + 2Fc2)/3 |
3143 reflections | (Δ/σ)max < 0.001 |
221 parameters | Δρmax = 0.24 e Å−3 |
0 restraints | Δρmin = −0.18 e Å−3 |
Crystal data top
C23H22O | V = 3575 (2) Å3 |
Mr = 314.41 | Z = 8 |
Orthorhombic, Pccn | Mo Kα radiation |
a = 22.123 (5) Å | µ = 0.07 mm−1 |
b = 24.203 (3) Å | T = 296 K |
c = 6.676 (4) Å | 0.49 × 0.43 × 0.22 mm |
Data collection top
Rigaku AFC-5S diffractometer | Rint = 0.0 |
3143 measured reflections | 3 standard reflections every 100 reflections |
3143 independent reflections | intensity decay: 0.3% |
1395 reflections with I > 2σ(I) | |
Refinement top
R[F2 > 2σ(F2)] = 0.046 | 0 restraints |
wR(F2) = 0.167 | H-atom parameters constrained |
S = 1.00 | Δρmax = 0.24 e Å−3 |
3143 reflections | Δρmin = −0.18 e Å−3 |
221 parameters | |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
O1 | 0.95676 (9) | 0.46596 (7) | 0.5989 (3) | 0.0535 (6) | |
C1 | 0.96983 (17) | 0.42586 (14) | 0.1468 (5) | 0.0717 (10) | |
C2 | 0.98627 (19) | 0.38514 (17) | 0.0105 (6) | 0.0859 (12) | |
C3 | 0.96488 (19) | 0.33206 (18) | 0.0313 (7) | 0.0905 (13) | |
C4 | 0.92542 (17) | 0.31832 (14) | 0.1853 (6) | 0.0788 (11) | |
C4A | 0.90897 (13) | 0.35849 (11) | 0.3216 (5) | 0.0563 (8) | |
C4B | 0.86895 (13) | 0.35678 (11) | 0.4969 (5) | 0.0552 (8) | |
C5 | 0.83508 (15) | 0.31410 (12) | 0.5797 (7) | 0.0716 (10) | |
C6 | 0.80026 (16) | 0.32540 (14) | 0.7470 (7) | 0.0788 (11) | |
C7 | 0.79848 (16) | 0.37760 (13) | 0.8314 (6) | 0.0722 (10) | |
C8 | 0.83184 (14) | 0.41968 (12) | 0.7494 (5) | 0.0612 (8) | |
C8A | 0.86704 (13) | 0.40894 (11) | 0.5836 (5) | 0.0494 (7) | |
C9 | 0.90797 (13) | 0.44872 (10) | 0.4691 (4) | 0.0458 (7) | |
C9A | 0.93151 (14) | 0.41188 (11) | 0.3017 (4) | 0.0518 (7) | |
C10 | 0.87421 (12) | 0.49943 (10) | 0.3960 (4) | 0.0458 (7) | |
C11 | 0.88339 (12) | 0.55126 (10) | 0.4778 (4) | 0.0456 (7) | |
C12 | 0.85135 (13) | 0.59762 (11) | 0.4144 (4) | 0.0478 (7) | |
C13 | 0.80970 (14) | 0.59005 (12) | 0.2614 (5) | 0.0617 (9) | |
C14 | 0.79905 (16) | 0.53857 (13) | 0.1807 (5) | 0.0708 (10) | |
C15 | 0.83040 (15) | 0.49356 (12) | 0.2472 (5) | 0.0613 (8) | |
C16 | 0.86375 (14) | 0.65405 (11) | 0.5097 (5) | 0.0570 (8) | |
C17 | 0.92581 (18) | 0.67422 (14) | 0.4455 (8) | 0.1092 (16) | |
C18 | 0.86236 (17) | 0.64872 (13) | 0.7400 (5) | 0.0826 (11) | |
C19 | 0.81561 (16) | 0.69694 (12) | 0.4531 (6) | 0.0805 (11) | |
H1 | 0.9723 | 0.4387 | 0.6506 | 0.080* | |
H1A | 0.9843 | 0.4617 | 0.1338 | 0.086* | |
H2 | 1.0119 | 0.3938 | −0.0953 | 0.103* | |
H3 | 0.9770 | 0.3050 | −0.0591 | 0.109* | |
H4 | 0.9103 | 0.2826 | 0.1965 | 0.095* | |
H5 | 0.8358 | 0.2789 | 0.5241 | 0.086* | |
H6 | 0.7775 | 0.2972 | 0.8041 | 0.095* | |
H7 | 0.7747 | 0.3841 | 0.9437 | 0.087* | |
H8 | 0.8307 | 0.4549 | 0.8049 | 0.073* | |
H11 | 0.9120 | 0.5553 | 0.5788 | 0.055* | |
H13 | 0.7885 | 0.6204 | 0.2123 | 0.074* | |
H14 | 0.7703 | 0.5344 | 0.0802 | 0.085* | |
H15 | 0.8225 | 0.4589 | 0.1931 | 0.074* | |
H17A | 0.9557 | 0.6472 | 0.4815 | 0.164* | |
H17B | 0.9347 | 0.7085 | 0.5113 | 0.164* | |
H17C | 0.9263 | 0.6796 | 0.3030 | 0.164* | |
H18A | 0.8941 | 0.6244 | 0.7828 | 0.124* | |
H18B | 0.8240 | 0.6340 | 0.7811 | 0.124* | |
H18C | 0.8681 | 0.6845 | 0.7993 | 0.124* | |
H19A | 0.8233 | 0.7308 | 0.5238 | 0.121* | |
H19B | 0.7763 | 0.6832 | 0.4885 | 0.121* | |
H19C | 0.8171 | 0.7037 | 0.3115 | 0.121* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O1 | 0.0667 (13) | 0.0419 (10) | 0.0520 (12) | −0.0040 (10) | −0.0148 (11) | 0.0052 (10) |
C1 | 0.094 (3) | 0.066 (2) | 0.054 (2) | 0.0183 (19) | −0.003 (2) | 0.0011 (17) |
C2 | 0.106 (3) | 0.098 (3) | 0.054 (2) | 0.036 (3) | 0.000 (2) | −0.011 (2) |
C3 | 0.098 (3) | 0.091 (3) | 0.082 (3) | 0.035 (2) | −0.022 (3) | −0.042 (2) |
C4 | 0.078 (2) | 0.060 (2) | 0.099 (3) | 0.0145 (19) | −0.021 (3) | −0.029 (2) |
C4A | 0.0576 (19) | 0.0428 (16) | 0.068 (2) | 0.0110 (14) | −0.0237 (17) | −0.0133 (16) |
C4B | 0.0526 (17) | 0.0431 (16) | 0.070 (2) | 0.0031 (14) | −0.0190 (18) | 0.0004 (15) |
C5 | 0.062 (2) | 0.0391 (16) | 0.114 (3) | −0.0028 (16) | −0.027 (2) | 0.0064 (19) |
C6 | 0.064 (2) | 0.063 (2) | 0.109 (3) | −0.0098 (18) | −0.013 (2) | 0.035 (2) |
C7 | 0.072 (2) | 0.070 (2) | 0.075 (3) | −0.0061 (19) | 0.001 (2) | 0.018 (2) |
C8 | 0.078 (2) | 0.0545 (18) | 0.0515 (19) | −0.0040 (16) | −0.0022 (18) | 0.0071 (17) |
C8A | 0.0574 (17) | 0.0373 (15) | 0.0534 (19) | −0.0006 (13) | −0.0133 (16) | 0.0052 (14) |
C9 | 0.0582 (18) | 0.0382 (14) | 0.0409 (15) | 0.0004 (13) | −0.0093 (15) | −0.0008 (13) |
C9A | 0.0623 (19) | 0.0478 (17) | 0.0455 (17) | 0.0097 (15) | −0.0078 (16) | −0.0022 (15) |
C10 | 0.0571 (17) | 0.0405 (15) | 0.0397 (15) | 0.0010 (13) | −0.0003 (15) | 0.0035 (13) |
C11 | 0.0547 (18) | 0.0408 (15) | 0.0413 (16) | −0.0013 (12) | −0.0009 (14) | 0.0020 (13) |
C12 | 0.0541 (17) | 0.0423 (15) | 0.0470 (17) | 0.0057 (13) | 0.0128 (16) | 0.0080 (13) |
C13 | 0.080 (2) | 0.0497 (18) | 0.055 (2) | 0.0159 (16) | −0.0043 (19) | 0.0079 (16) |
C14 | 0.088 (2) | 0.067 (2) | 0.057 (2) | 0.0147 (19) | −0.0232 (19) | −0.0012 (18) |
C15 | 0.084 (2) | 0.0479 (17) | 0.0522 (18) | 0.0078 (16) | −0.0158 (18) | −0.0075 (15) |
C16 | 0.0608 (19) | 0.0391 (16) | 0.071 (2) | 0.0054 (14) | 0.0117 (17) | −0.0029 (15) |
C17 | 0.088 (3) | 0.060 (2) | 0.180 (5) | −0.018 (2) | 0.035 (3) | −0.023 (3) |
C18 | 0.108 (3) | 0.063 (2) | 0.076 (3) | 0.023 (2) | −0.009 (2) | −0.0222 (19) |
C19 | 0.104 (3) | 0.0460 (17) | 0.092 (3) | 0.0207 (18) | 0.005 (2) | 0.0010 (19) |
Geometric parameters (Å, º) top
O1—C9 | 1.446 (3) | C16—C19 | 1.535 (4) |
C1—C9A | 1.379 (4) | C16—C18 | 1.543 (5) |
C1—C2 | 1.390 (5) | O1—H1 | 0.8200 |
C2—C3 | 1.376 (5) | C1—H1A | 0.9300 |
C3—C4 | 1.389 (5) | C2—H2 | 0.9300 |
C4—C4A | 1.380 (4) | C3—H3 | 0.9300 |
C4A—C9A | 1.391 (4) | C4—H4 | 0.9300 |
C4A—C4B | 1.468 (4) | C5—H5 | 0.9300 |
C4B—C8A | 1.389 (4) | C6—H6 | 0.9300 |
C4B—C5 | 1.391 (4) | C7—H7 | 0.9300 |
C5—C6 | 1.384 (5) | C8—H8 | 0.9300 |
C6—C7 | 1.384 (5) | C11—H11 | 0.9300 |
C7—C8 | 1.372 (4) | C13—H13 | 0.9300 |
C8—C8A | 1.378 (4) | C14—H14 | 0.9300 |
C8A—C9 | 1.526 (4) | C15—H15 | 0.9300 |
C9—C10 | 1.518 (3) | C17—H17A | 0.9600 |
C9—C9A | 1.522 (4) | C17—H17B | 0.9600 |
C10—C11 | 1.383 (3) | C17—H17C | 0.9600 |
C10—C15 | 1.395 (4) | C18—H18A | 0.9600 |
C11—C12 | 1.393 (4) | C18—H18B | 0.9600 |
C12—C13 | 1.388 (4) | C18—H18C | 0.9600 |
C12—C16 | 1.531 (4) | C19—H19A | 0.9600 |
C13—C14 | 1.378 (4) | C19—H19B | 0.9600 |
C14—C15 | 1.365 (4) | C19—H19C | 0.9600 |
C16—C17 | 1.519 (5) | | |
| | | |
C9A—C1—C2 | 118.5 (3) | C9A—C1—H1A | 120.7 |
C3—C2—C1 | 120.4 (4) | C2—C1—H1A | 120.7 |
C2—C3—C4 | 120.9 (3) | C3—C2—H2 | 119.8 |
C4A—C4—C3 | 119.0 (3) | C1—C2—H2 | 119.8 |
C4—C4A—C9A | 119.8 (3) | C2—C3—H3 | 119.5 |
C4—C4A—C4B | 131.6 (3) | C4—C3—H3 | 119.5 |
C9A—C4A—C4B | 108.6 (2) | C4A—C4—H4 | 120.5 |
C8A—C4B—C5 | 119.5 (3) | C3—C4—H4 | 120.5 |
C8A—C4B—C4A | 108.9 (3) | C6—C5—H5 | 120.9 |
C5—C4B—C4A | 131.5 (3) | C4B—C5—H5 | 120.9 |
C6—C5—C4B | 118.3 (3) | C5—C6—H6 | 119.2 |
C5—C6—C7 | 121.7 (3) | C7—C6—H6 | 119.2 |
C8—C7—C6 | 120.0 (4) | C8—C7—H7 | 120.0 |
C7—C8—C8A | 119.0 (3) | C6—C7—H7 | 120.0 |
C8—C8A—C4B | 121.5 (3) | C7—C8—H8 | 120.5 |
C8—C8A—C9 | 128.2 (3) | C8A—C8—H8 | 120.5 |
C4B—C8A—C9 | 110.3 (3) | C10—C11—H11 | 118.8 |
O1—C9—C10 | 109.1 (2) | C12—C11—H11 | 118.8 |
O1—C9—C9A | 110.7 (2) | C14—C13—H13 | 119.3 |
C10—C9—C9A | 114.0 (2) | C12—C13—H13 | 119.3 |
O1—C9—C8A | 109.0 (2) | C15—C14—H14 | 119.8 |
C10—C9—C8A | 112.3 (2) | C13—C14—H14 | 119.8 |
C9A—C9—C8A | 101.6 (2) | C14—C15—H15 | 119.9 |
C1—C9A—C4A | 121.3 (3) | C10—C15—H15 | 119.9 |
C1—C9A—C9 | 128.1 (3) | C16—C17—H17A | 109.5 |
C4A—C9A—C9 | 110.6 (3) | C16—C17—H17B | 109.5 |
C11—C10—C15 | 118.4 (2) | H17A—C17—H17B | 109.5 |
C11—C10—C9 | 122.3 (2) | C16—C17—H17C | 109.5 |
C15—C10—C9 | 119.2 (2) | H17A—C17—H17C | 109.5 |
C10—C11—C12 | 122.4 (3) | H17B—C17—H17C | 109.5 |
C13—C12—C11 | 117.1 (3) | C16—C18—H18A | 109.5 |
C13—C12—C16 | 122.9 (2) | C16—C18—H18B | 109.5 |
C11—C12—C16 | 120.1 (3) | H18A—C18—H18B | 109.5 |
C14—C13—C12 | 121.4 (3) | C16—C18—H18C | 109.5 |
C15—C14—C13 | 120.5 (3) | H18A—C18—H18C | 109.5 |
C14—C15—C10 | 120.2 (3) | H18B—C18—H18C | 109.5 |
C17—C16—C12 | 109.4 (3) | C16—C19—H19A | 109.5 |
C17—C16—C19 | 109.9 (3) | C16—C19—H19B | 109.5 |
C12—C16—C19 | 112.1 (3) | H19A—C19—H19B | 109.5 |
C17—C16—C18 | 109.0 (3) | C16—C19—H19C | 109.5 |
C12—C16—C18 | 109.6 (2) | H19A—C19—H19C | 109.5 |
C19—C16—C18 | 106.7 (3) | H19B—C19—H19C | 109.5 |
C9—O1—H1 | 109.5 | | |
| | | |
C9A—C1—C2—C3 | −0.4 (5) | C4—C4A—C9A—C9 | −179.3 (3) |
C1—C2—C3—C4 | 1.5 (6) | C4B—C4A—C9A—C9 | 1.1 (3) |
C2—C3—C4—C4A | −1.6 (5) | O1—C9—C9A—C1 | −66.0 (4) |
C3—C4—C4A—C9A | 0.6 (5) | C10—C9—C9A—C1 | 57.4 (4) |
C3—C4—C4A—C4B | 180.0 (3) | C8A—C9—C9A—C1 | 178.3 (3) |
C4—C4A—C4B—C8A | −179.4 (3) | O1—C9—C9A—C4A | 113.9 (2) |
C9A—C4A—C4B—C8A | 0.1 (3) | C10—C9—C9A—C4A | −122.7 (3) |
C4—C4A—C4B—C5 | −0.2 (5) | C8A—C9—C9A—C4A | −1.8 (3) |
C9A—C4A—C4B—C5 | 179.2 (3) | O1—C9—C10—C11 | −11.6 (4) |
C8A—C4B—C5—C6 | 0.1 (5) | C9A—C9—C10—C11 | −135.9 (3) |
C4A—C4B—C5—C6 | −179.0 (3) | C8A—C9—C10—C11 | 109.3 (3) |
C4B—C5—C6—C7 | 0.2 (5) | O1—C9—C10—C15 | 171.3 (3) |
C5—C6—C7—C8 | −0.1 (5) | C9A—C9—C10—C15 | 47.0 (4) |
C6—C7—C8—C8A | −0.3 (5) | C8A—C9—C10—C15 | −67.8 (3) |
C7—C8—C8A—C4B | 0.6 (5) | C15—C10—C11—C12 | −1.2 (4) |
C7—C8—C8A—C9 | −179.4 (3) | C9—C10—C11—C12 | −178.3 (2) |
C5—C4B—C8A—C8 | −0.6 (4) | C10—C11—C12—C13 | −0.9 (4) |
C4A—C4B—C8A—C8 | 178.7 (3) | C10—C11—C12—C16 | −179.6 (3) |
C5—C4B—C8A—C9 | 179.5 (3) | C11—C12—C13—C14 | 2.2 (4) |
C4A—C4B—C8A—C9 | −1.2 (3) | C16—C12—C13—C14 | −179.1 (3) |
C8—C8A—C9—O1 | 64.9 (4) | C12—C13—C14—C15 | −1.4 (5) |
C4B—C8A—C9—O1 | −115.1 (2) | C13—C14—C15—C10 | −0.9 (5) |
C8—C8A—C9—C10 | −56.0 (4) | C11—C10—C15—C14 | 2.1 (5) |
C4B—C8A—C9—C10 | 123.9 (3) | C9—C10—C15—C14 | 179.3 (3) |
C8—C8A—C9—C9A | −178.2 (3) | C13—C12—C16—C17 | −108.8 (4) |
C4B—C8A—C9—C9A | 1.8 (3) | C11—C12—C16—C17 | 69.9 (4) |
C2—C1—C9A—C4A | −0.7 (5) | C13—C12—C16—C19 | 13.4 (4) |
C2—C1—C9A—C9 | 179.2 (3) | C11—C12—C16—C19 | −168.0 (3) |
C4—C4A—C9A—C1 | 0.6 (4) | C13—C12—C16—C18 | 131.8 (3) |
C4B—C4A—C9A—C1 | −178.9 (3) | C11—C12—C16—C18 | −49.6 (4) |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···C2i | 0.82 | 2.75 | 3.436 (5) | 143 |
Symmetry code: (i) x, y, z+1. |
Experimental details
Crystal data |
Chemical formula | C23H22O |
Mr | 314.41 |
Crystal system, space group | Orthorhombic, Pccn |
Temperature (K) | 296 |
a, b, c (Å) | 22.123 (5), 24.203 (3), 6.676 (4) |
V (Å3) | 3575 (2) |
Z | 8 |
Radiation type | Mo Kα |
µ (mm−1) | 0.07 |
Crystal size (mm) | 0.49 × 0.43 × 0.22 |
|
Data collection |
Diffractometer | Rigaku AFC-5S diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 3143, 3143, 1395 |
Rint | 0.0 |
(sin θ/λ)max (Å−1) | 0.595 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.046, 0.167, 1.00 |
No. of reflections | 3143 |
No. of parameters | 221 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.24, −0.18 |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1···C2i | 0.82 | 2.75 | 3.436 (5) | 143 |
Symmetry code: (i) x, y, z+1. |
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We recently reported the crystal structure of 9-(para-tert-butylphenyl)-9-fluorenol (II) (McLean et al., 2003), and compared it with that of its isomeric 9-(ortho-tert-butylphenyl)-9-fluorenol (III) (Robinson et al., 1998; see also Meyers et al., 1999) whose NMR spectrum shows it to be rotationally restricted at the 9-position in solution. The similarities and differences between isomers (II) and (III) prompted us to study the crystal structure of the third isomer, 9-(meta-tert-butylphenyl)-9-fluorenol (I), which is freely rotating in solution, like (II), but, like (III), could exhibit conformational preferences in its crystalline structure.
The structure of (I) with atom numbering is shown in Fig. 1. No unusual geometric parameters were noted. The angle between the fluorene least-squares plane and that of the phenyl ring is 84.10 (12)°. Although the meta-tert-butylphenyl group of (I) is freely rotating in solution, it crystallizes in an sp conformation like its ortho-tert-butylphenyl isomer (III) in which this conformation is thermodynamically preferred over the ap conformation because of rotational and steric restrictions. Presumably, the favorability of the sp conformation of (I) is associated with its molecular packing. While the para isomer (II) and ortho isomer (III) crystallized in two somewhat different molecular conformations, respectively, crystalline (I) is composed of a single molecular conformation. The latter molecules are linked into linear one-dimensional chains through O—H···π(fluorene) hydrogen bonds, each molecule being both H-donor and -acceptor. The hydroxyl H atom most closely approaches the fluorene pi-cloud near C2 as depicted in Fig. 2 and the chains propagate in the c-axial direction by simple unit translations. The hydrogen bond geometry is given in Table 1. A view of the molecular packing as viewed down the a axis is shown in Fig. 3 with the previously described molecular chains propagating from right to left. Note that there are two centrosymmetrically related orientations of the chains which form what could be called `layers' of chains parallel to (010); three such layers are apparent in this figure. Another important difference resides in the fact that while (II) as well as (III) exhibit both O—H···O—H and O—H···π(fluorene) hydrogen bonding, only the latter is apparent in (I). It is pertinent to note in this context that within the `layers' of (I), adjacent hydroxyl groups are quite intimately associated, with an O···O distance of only 2.849 (3) Å, a respectable donor-acceptor distance. Despite this fact, no O—H···O hydrogen bonds are formed, because the hydroxyl H atoms are not in reasonable positions to hydrogen bond with the respective O atoms. It is worth noting that the closely associated hydroxyl groups are related by an inversion center and it may be difficult or impossible for O—H···O—H hydrogen bonding to occur under a symmetry constraint of this type.
We have already pointed out that crystalline fluorenols (II) and (III), respectively, have sharp melting points, but their melts fail to recrystallize, even after prolonged standing, although NMR shows that no decomposition had occurred (McLean et al., 2003). Now we find that fluorenol (I) behaves identically. It appears that in the non-packing melt orientation, the molecules of all three of these isomeric 9-(tert-butylphenyl)-9-fluorenols have difficulty reorganizing into the orientation required for their crystalline packing.