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The high-pressure crystal structure of phenol (C6H5OH), including the positions of the H atoms, has been determined using a combination of single-crystal X-ray diffraction techniques and ab initio density-functional calculations. It is found that at a pressure of 0.16 GPa, which is just sufficient to cause crystallization of a sample held at a temperature just above its ambient-pressure melting point (313 K), a previously unobserved monoclinic structure with P21 symmetry is formed. The structure is characterized by the formation of hydrogen-bonded molecular chains, and the molecules within each chain adopt a coplanar arrangement so that they are ordered in an alternating 1-1-1 sequence. Although the crystal structure of the ambient-pressure P1121 phase is also characterized by the formation of molecular chains, the molecules adopt an approximate threefold arrangement. A series of ab initio calculations indicates that the rearrangement of the molecules from helical to coplanar results in an energy difference of only 0.162 eV molecule−1 (15.6 kJ mole−1) at 0.16 GPa. The calculations also indicate that there is a slight increase in the dipole moment of the molecules, but, as the high-pressure phase has longer hydrogen-bond distances, it is found that, on average, the hydrogen bonds in the ambient-pressure phase are stronger.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108768102018797/bm0050sup1.cif
Contains datablock phenol

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108768102018797/bm0050sup2.hkl
Contains datablock phenol

pdf

Portable Document Format (PDF) file https://doi.org/10.1107/S0108768102018797/bm0050sup3.pdf
Refined fractional coordinates for the high-pressure structures

CCDC reference: 201623

Computing details top

Data collection: Bruker SMART; cell refinement: Bruker SMART; data reduction: Bruker SHELXTL; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: Bruker SHELXTL; software used to prepare material for publication: Bruker SHELXTL.

Figures top
[Figure 1]
[Figure 2]
[Figure 3]
[Figure 4]
(phenol) top
Crystal data top
PhOHF(000) = 300
Mr = 94.11Dx = 1.240 Mg m3
Monoclinic, P21Mo Kα radiation, λ = 0.71073 Å
a = 11.610 (4) ÅCell parameters from 331 reflections
b = 5.4416 (11) Åθ = 2.5–25.5°
c = 12.217 (5) ŵ = 0.08 mm1
β = 101.47 (3)°T = 293 K
V = 756.4 (4) Å3 × × mm
Z = 6
Data collection top
CCD area detector
diffractometer
455 independent reflections
Radiation source: fine-focus sealed tube269 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.057
phi and ω scansθmax = 24.9°, θmin = 2.7°
Absorption correction: SADABS
?
h = 1212
Tmin = 0.213, Tmax = 1.000k = 66
1129 measured reflectionsl = 77
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.086 w = 1/[σ2(Fo2) + (0.1876P)2]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.278(Δ/σ)max = 0.002
S = 0.98Δρmax = 0.32 e Å3
455 reflectionsΔρmin = 0.20 e Å3
29 parametersAbsolute structure: Flack H D (1983), Acta Cryst. A39, 876-881
14 restraintsAbsolute structure parameter: 0 (10)
Crystal data top
PhOHV = 756.4 (4) Å3
Mr = 94.11Z = 6
Monoclinic, P21Mo Kα radiation
a = 11.610 (4) ŵ = 0.08 mm1
b = 5.4416 (11) ÅT = 293 K
c = 12.217 (5) Å × × mm
β = 101.47 (3)°
Data collection top
CCD area detector
diffractometer
455 independent reflections
Absorption correction: SADABS
?
269 reflections with I > 2σ(I)
Tmin = 0.213, Tmax = 1.000Rint = 0.057
1129 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.08614 restraints
wR(F2) = 0.278Δρmax = 0.32 e Å3
S = 0.98Δρmin = 0.20 e Å3
455 reflectionsAbsolute structure: Flack H D (1983), Acta Cryst. A39, 876-881
29 parametersAbsolute structure parameter: 0 (10)
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
xyzUiso*/Ueq
O1A0.7050 (10)0.4386 (19)0.3000 (15)0.0583 (15)*
H1A0.67160.32300.32350.087*
C2A0.6911 (8)0.4219 (16)0.1876 (15)0.0583 (15)*
C3A0.6275 (9)0.2301 (18)0.1293 (17)0.0583 (15)*
H3A0.59350.11130.16750.070*
C4A0.6146 (10)0.216 (2)0.0139 (17)0.0583 (15)*
H4A0.57210.08770.02510.070*
C5A0.6654 (11)0.394 (3)0.0432 (15)0.0583 (15)*
H5A0.65680.38420.12040.070*
C6A0.7290 (11)0.585 (3)0.0150 (15)0.0583 (15)*
H6A0.76290.70430.02320.070*
C7A0.7418 (9)0.5996 (18)0.1304 (15)0.0583 (15)*
H7A0.78440.72790.16940.070*
O1B0.6823 (10)0.937 (2)0.3864 (14)0.0583 (15)*
H1B0.72090.81930.37200.087*
C2B0.6694 (11)0.923 (2)0.4937 (14)0.0583 (15)*
C3B0.7169 (10)0.726 (2)0.5603 (15)0.0583 (15)*
H3B0.75970.60590.53170.070*
C4B0.7005 (9)0.709 (3)0.6697 (15)0.0583 (15)*
H4B0.73220.57760.71430.070*
C5B0.6366 (10)0.889 (3)0.7124 (14)0.0583 (15)*
H5B0.62560.87730.78560.070*
C6B0.5891 (9)1.085 (3)0.6458 (14)0.0583 (15)*
H6B0.54631.20530.67440.070*
C7B0.6055 (10)1.102 (2)0.5364 (14)0.0583 (15)*
H7B0.57371.23370.49180.070*
O1C1.0164 (12)0.860 (2)0.4541 (16)0.0583 (15)*
H1C0.98180.97140.47910.087*
C2C1.0088 (13)0.893 (2)0.3444 (13)0.0583 (15)*
C3C0.9567 (10)1.0874 (15)0.2791 (17)0.0583 (15)*
H3C0.91671.20840.31030.070*
C4C0.9644 (10)1.101 (2)0.1671 (16)0.0583 (15)*
H4C0.92951.23140.12350.070*
C5C1.0241 (12)0.920 (4)0.1205 (13)0.0583 (15)*
H5C1.02930.92950.04560.070*
C6C1.0762 (10)0.726 (3)0.1858 (17)0.0583 (15)*
H6C1.11620.60460.15460.070*
C7C1.0686 (11)0.7119 (15)0.2977 (16)0.0583 (15)*
H7C1.10340.58170.34140.070*
Geometric parameters (Å, º) top
O1A—C2A1.354 (15)C4B—C5B1.3900
C2A—C3A1.3900C5B—C6B1.3900
C2A—C7A1.3900C6B—C7B1.3900
C3A—C4A1.3900O1C—C2C1.338 (17)
C4A—C5A1.3900C2C—C3C1.3900
C5A—C6A1.3900C2C—C7C1.3900
C6A—C7A1.3900C3C—C4C1.3900
O1B—C2B1.351 (16)C4C—C5C1.3900
C2B—C3B1.3900C5C—C6C1.3900
C2B—C7B1.3900C6C—C7C1.3900
C3B—C4B1.3900
O1A—C2A—C3A120.9 (7)C5B—C4B—C3B120.0
O1A—C2A—C7A119.1 (7)C4B—C5B—C6B120.0
C3A—C2A—C7A120.0C7B—C6B—C5B120.0
C4A—C3A—C2A120.0C6B—C7B—C2B120.0
C3A—C4A—C5A120.0O1C—C2C—C3C127.7 (14)
C6A—C5A—C4A120.0O1C—C2C—C7C112.1 (14)
C7A—C6A—C5A120.0C3C—C2C—C7C120.0
C6A—C7A—C2A120.0C2C—C3C—C4C120.0
O1B—C2B—C3B120.3 (7)C5C—C4C—C3C120.0
O1B—C2B—C7B119.6 (7)C6C—C5C—C4C120.0
C3B—C2B—C7B120.0C5C—C6C—C7C120.0
C2B—C3B—C4B120.0C6C—C7C—C2C120.0

Experimental details

Crystal data
Chemical formulaPhOH
Mr94.11
Crystal system, space groupMonoclinic, P21
Temperature (K)293
a, b, c (Å)11.610 (4), 5.4416 (11), 12.217 (5)
β (°) 101.47 (3)
V3)756.4 (4)
Z6
Radiation typeMo Kα
µ (mm1)0.08
Crystal size (mm) × ×
Data collection
DiffractometerCCD area detector
diffractometer
Absorption correctionSADABS
Tmin, Tmax0.213, 1.000
No. of measured, independent and
observed [I > 2σ(I)] reflections
1129, 455, 269
Rint0.057
(sin θ/λ)max1)0.592
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.086, 0.278, 0.98
No. of reflections455
No. of parameters29
No. of restraints14
Δρmax, Δρmin (e Å3)0.32, 0.20
Absolute structureFlack H D (1983), Acta Cryst. A39, 876-881
Absolute structure parameter0 (10)

Computer programs: Bruker SMART, Bruker SHELXTL, SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997).

 

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