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The title lignin model compound, C16H18O6, resides on a twofold axis parallel with the b axis, with the mid-point of the inter­nal C-C(-x + 1, y, -z + {1\over 2}) bond located on the twofold axis. The exo angles between the meth­oxy groups and the benzene rings deviate significantly from the expected value of 120° [125.15 (7) and 114.27 (6)°]. A 12-coordinated 3-modal three-dimensional net with a new topology was identified on the synthon level. A comparison of the flexibility of related o,o'-disubstituted biphenyl derivatives and biphenyl is presented, with the angles between the ring planes in substituted biphenyls found to be in the range 40-70°.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270110046913/gg3249sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270110046913/gg3249Isup2.hkl
Contains datablock I

CCDC reference: 810024

Comment top

The title compound, (I), is a lignin model compound representative of a type of biphenyl structure in lignins (Ralph et al., 2004). A perspective drawing and the atom-numbering of (I) are shown in Fig. 1 and selected geometric parameters are given in Table 1. The molecule is located with the midpoint of the C1—C1i bond [symmetry code: (i) -x + 1, y, -z + 1/2] on a twofold axis parallel with the b axis. A striking deformation in (I) is the deviation of the O2—C3—C2 and O2—C3—C4 angles from 120° (Table 1). Such deformation was observed earlier by, for example, Lundquist et al. (1987) and Gallagher et al. (2001). There is an intramolecular hydrogen bond between the methoxy group and the adjacent hydroxy group (Fig. 1, Table 2). There are also two strong intermolecular hydrogen bonds of O—H···O type present in the crystal structure of (I); geometric details of these hydrogen bonds are given in Table 2. On the first-level graph-set, as defined by Bernstein et al. (1995) and Grell et al. (1999), an S(5) string is formed by the intramolecular hydrogen bond, while both intermolecular hydrogen bonds form C(8) and C(9) chains. On the second-level graph-set, R44(8) rings are formed by the two intermolecular hydrogen bonds (Fig. 2).

Due to the symmetry of the molecule of (I) and the arrangement in the unit cell, an infinite three-dimensional framework is built, with a body-centred cubic (b.c.u.) topology, using the nomenclature of the Reticular Chemistry Structural Resource (RCSR) database (O'Keeffe et al., 2008). We contracted the molecular residues to synthons, defined by O1, C11 (the midpoint of the C1—C1i bond), C5 and O3, and a 12-coordinated 3-modal three-dimensional net with a new topology was identified using the program TOPOS (Blatov et al., 2000; Blatov & Shevchenko, 2010). This new topology, denoted vla1, has a point (Schläfli) symbol for the net of (123)(4;122)2. This means that each synthon is connected with 11 other synthons through symmetry-related molecules (Fig. 3).

The crystal structures of a number of lignin model compounds of the biphenyl type have previously been reported in the literature (Brunow et al., 1995; Karhunen et al., 1996; Xi et al., 1996; Ferreira et al., 1998; Roblin et al., 2000). Compound (I) is phenolic and only one structurally related compound with phenolic groups has been examined previously, namely 5,5'-bis[(2-hydroxy-3-methoxy-5-methylphenyl)methyl]-3,3'-dimethoxy-2,2'-biphenyldiol (Xi et al., 1996). In these two compounds there are hydrogen bonds between the hydroxy groups and methoxy groups. In biphenyls o,o'-disubstituted with hydroxy groups lacking adjacent methoxy groups (Bedford et al., 2003; Wang et al., 1983; Bocelli et al., 1999; Xi et al., 1996; Byrne et al., 1998), hydrogen bonds are formed between the hydroxy groups.

The angle between the aromatic rings is flexible in the structures of o,o'-disubstituted biphenyl derivatives. For (I) it is 68.88 (2)°. In Table 3, the angles between the aromatic rings and selected torsion angles are presented for a series of such compounds. The non-derivatized biphenyl molecule is planar in crystals at room temperature, but libration around the long axis of the molecule suggests a statistically centrosymmetric arrangement (Charbonneau & Delugeard, 1977). At 41 K, crystals of biphenyl undergo a structural phase transition to an intermediate phase called phase II, and at 21 K another phase III is formed. Surprisingly, Cailleau et al. (1979) found the angle between the phenyl rings to be 10.2° for crystals of phase III, which was later correctly attributed to the existence of a modulated structure by Baudour & Sanquer (1983). In crystal structures where biphenyl is cocrystallized with other molecules or complexes as a solvent, the angle between the phenyl rings is dependent on the type and strength of the interactions, with a maximum of 50.8° for a dichromium complex (Van Order et al., 1987).

Experimental top

Compound (I) was prepared according to the method of Adler & Hernestam (1955) [m.p. 458–459 K (Adler & Hernestam reported m.p. 460–463 K under quick heating)]. Crystals of (I) were obtained by recrystallisation from which solvent?

Refinement top

H atoms were refined isotropically and their positions were constrained to ideal geometry using an appropriate riding model, with C—H = 0.95–0.99 Å. For methyl groups, O—C—H angles (109.5°) were kept fixed, while the torsion angle was allowed to refine with the starting positions based on the circular Fourier synthesis averaged using the local three-fold axis. For the hydroxyl groups, the O—H distances (0.84 Å) and C—O—H angles (109.5°) were kept fixed, while the torsion angles were allowed to refine with the starting positions based on the circular Fourier synthesis. The highest positive peaks in the residual electron-density map with absolute values higher than that of the minimum peak, -0.22 e Å-3, ranging from 0.23 to 0.55 e Å-3, are located in the middle of the bonds and represent the σ electrons.

Computing details top

Data collection: SMART (Bruker, 2003); cell refinement: SAINT (Bruker, 2003); data reduction: SAINT (Bruker, 2003) and SADABS (Sheldrick, 2003); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2010); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. A perspective drawing of (I), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. Intramolecular hydrogen bonds are shown as dashed lines. [Symmetry code: (i) -x + 1, y, -z + 1/2.]
[Figure 2] Fig. 2. The hydrogen-bond pattern (broken lines) in the structure of (I), showing the directed four-membered cooperative hydrogen bonds. H atoms not taking part in the hydrogen-bonding pattern have been omitted for clarity. [Symmetry codes: (ii) -x + 1/2, -y + 1/2, z + 1/2; (iv) 1 - x, -y, 1 - z; (v) x + 1/2, y - 1/2, -z + 1/2.]
[Figure 3] Fig. 3. A representation of the new topology in (I), showing the 12-coordinated 3-modal part of the three-dimensional framework. C11 is the midpoint of the C1—C1i bond. [Symmetry codes: (i) -x + 1, y, -z + 1/2; (ii) -x + 1/2, -y + 1/2, z + 1/2; (iii) x - 1/2, y + 1/2, -z + 1/2; (iv) 1 - x, -y, 1 - z; (v) x + 1/2, y - 1/2, -z + 1/2; (vi) x - 1/2, -y + 1/2, -z + 1; (vii) x, -y + 1, z + 1/2; (viii) -x, y, -z + 1/2; (ix) -x + 1/2, y + 1/2, z; (x) -x + 1/2, -y + 1/2, z - 1/2; (xi) -x, -y + 1, -z.]
5,5'-Bis(hydroxymethyl)-3,3'-dimethoxy-2,2'-biphenyldiol top
Crystal data top
C16H18O6Dx = 1.440 Mg m3
Mr = 306.30Melting point: 458 K
Orthorhombic, PbcnMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2n 2abCell parameters from 8263 reflections
a = 12.4911 (6) Åθ = 5.8–66.1°
b = 8.5100 (4) ŵ = 0.11 mm1
c = 13.2883 (7) ÅT = 153 K
V = 1412.54 (12) Å3Prism, colourless
Z = 40.35 × 0.20 × 0.15 mm
F(000) = 648
Data collection top
Siemens SMART CCD area-detector
diffractometer
2621 independent reflections
Radiation source: fine-focus sealed tube2150 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.046
Detector resolution: 120 pixels mm-1θmax = 33.1°, θmin = 2.9°
ω scansh = 1918
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)
k = 1212
Tmin = 0.594, Tmax = 0.984l = 1920
23325 measured reflections
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)] = 0.038Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.116H-atom parameters constrained
S = 1.00 w = 1/[σ2(Fo2) + (0.0706P)2 + 0.2578P]
where P = (Fo2 + 2Fc2)/3
2621 reflections(Δ/σ)max < 0.001
112 parametersΔρmax = 0.55 e Å3
0 restraintsΔρmin = 0.22 e Å3
Crystal data top
C16H18O6V = 1412.54 (12) Å3
Mr = 306.30Z = 4
Orthorhombic, PbcnMo Kα radiation
a = 12.4911 (6) ŵ = 0.11 mm1
b = 8.5100 (4) ÅT = 153 K
c = 13.2883 (7) Å0.35 × 0.20 × 0.15 mm
Data collection top
Siemens SMART CCD area-detector
diffractometer
2621 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 2003)
2150 reflections with I > 2σ(I)
Tmin = 0.594, Tmax = 0.984Rint = 0.046
23325 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0380 restraints
wR(F2) = 0.116H-atom parameters constrained
S = 1.00Δρmax = 0.55 e Å3
2621 reflectionsΔρmin = 0.22 e Å3
112 parameters
Special details top

Experimental. Data were collected at 153 K using a Siemens SMART CCD diffractometer equipped with an LT-2 A cooling device. A full sphere of reciprocal space was scanned by 0.3° steps in ω with a crystal-to-detector distance of 3.97 cm, 15 s per frame. Preliminary orientation matrix was obtained from the first 100 frames using SMART (Bruker, 2003). The collected frames were integrated using the preliminary orientation matrix which was updated every 100 frames. Final cell parameters were obtained by refinement on the position of 8263 reflections with I>10σ(I) after integration of all the frames data using SAINT (Bruker, 2003).

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
O10.43908 (5)0.18771 (8)0.39864 (5)0.02078 (15)
H10.39630.15710.44330.049 (4)*
O20.22560 (5)0.20158 (8)0.40800 (5)0.02033 (14)
O30.11368 (5)0.46466 (7)0.07418 (5)0.02186 (15)
H30.06340.52480.09080.042 (4)*
C10.44040 (6)0.34720 (8)0.25099 (5)0.01441 (15)
C20.38431 (6)0.27141 (9)0.32729 (5)0.01518 (15)
C30.27174 (6)0.28087 (9)0.32983 (6)0.01550 (15)
C40.21651 (6)0.36524 (9)0.25701 (6)0.01603 (15)
H40.14060.37180.25980.023 (3)*
C50.27235 (6)0.44051 (8)0.17968 (6)0.01514 (15)
C60.38324 (6)0.43095 (9)0.17766 (6)0.01527 (15)
H60.42140.48240.12530.024 (3)*
C70.11152 (7)0.20158 (13)0.41085 (7)0.02543 (19)
H7A0.08550.30980.41710.037 (4)*
H7B0.08700.13990.46870.044 (4)*
H7C0.08360.15500.34870.030 (3)*
C80.21401 (6)0.53500 (9)0.10103 (6)0.01858 (16)
H8A0.20110.64240.12700.024 (3)*
H8B0.25940.54380.04020.033 (3)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0132 (3)0.0300 (3)0.0191 (3)0.0030 (2)0.0007 (2)0.0088 (2)
O20.0135 (3)0.0281 (3)0.0194 (3)0.0005 (2)0.00324 (19)0.0046 (2)
O30.0152 (3)0.0246 (3)0.0257 (3)0.0030 (2)0.0071 (2)0.0043 (2)
C10.0115 (3)0.0164 (3)0.0153 (3)0.0003 (2)0.0008 (2)0.0010 (2)
C20.0126 (3)0.0177 (3)0.0152 (3)0.0017 (2)0.0008 (2)0.0002 (2)
C30.0125 (3)0.0180 (3)0.0161 (3)0.0004 (2)0.0012 (2)0.0011 (2)
C40.0113 (3)0.0181 (3)0.0187 (3)0.0016 (2)0.0009 (2)0.0017 (3)
C50.0141 (3)0.0140 (3)0.0173 (3)0.0013 (2)0.0029 (2)0.0020 (2)
C60.0141 (3)0.0160 (3)0.0157 (3)0.0009 (2)0.0014 (2)0.0003 (2)
C70.0139 (4)0.0386 (5)0.0238 (4)0.0024 (3)0.0041 (3)0.0031 (3)
C80.0166 (3)0.0170 (3)0.0222 (4)0.0008 (3)0.0057 (3)0.0001 (3)
Geometric parameters (Å, º) top
O1—C21.3690 (9)C4—C51.3974 (11)
O1—H10.8400C4—H40.9500
O2—C31.3662 (9)C5—C61.3878 (10)
O2—C71.4255 (10)C5—C81.5066 (11)
O3—C81.4339 (10)C6—H60.9500
O3—H30.8400C7—H7A0.9800
C1—C21.3910 (10)C7—H7B0.9800
C1—C61.4024 (10)C7—H7C0.9800
C1—C1i1.4893 (14)C8—H8A0.9900
C2—C31.4088 (10)C8—H8B0.9900
C3—C41.3886 (10)
C2—O1—H1109.5C4—C5—C8120.88 (7)
C3—O2—C7116.23 (6)C5—C6—C1121.63 (7)
C8—O3—H3109.5C5—C6—H6119.2
C2—C1—C6119.06 (7)C1—C6—H6119.2
C2—C1—C1i121.09 (7)O2—C7—H7A109.5
C6—C1—C1i119.78 (7)O2—C7—H7B109.5
O1—C2—C1119.63 (7)H7A—C7—H7B109.5
O1—C2—C3120.79 (7)O2—C7—H7C109.5
C1—C2—C3119.58 (6)H7A—C7—H7C109.5
O2—C3—C4125.15 (7)H7B—C7—H7C109.5
O2—C3—C2114.27 (6)O3—C8—C5111.87 (6)
C4—C3—C2120.58 (7)O3—C8—H8A109.2
C3—C4—C5120.10 (7)C5—C8—H8A109.2
C3—C4—H4120.0O3—C8—H8B109.2
C5—C4—H4120.0C5—C8—H8B109.2
C6—C5—C4119.04 (7)H8A—C8—H8B107.9
C6—C5—C8120.05 (7)
C6—C1—C2—O1179.23 (7)O2—C3—C4—C5179.31 (7)
C1i—C1—C2—O13.80 (10)C2—C3—C4—C50.63 (11)
C6—C1—C2—C30.37 (10)C3—C4—C5—C60.72 (11)
C1i—C1—C2—C3176.60 (6)C3—C4—C5—C8178.90 (7)
C7—O2—C3—C42.86 (11)C4—C5—C6—C10.26 (11)
C7—O2—C3—C2177.09 (7)C8—C5—C6—C1178.47 (7)
O1—C2—C3—O20.28 (10)C2—C1—C6—C50.28 (11)
C1—C2—C3—O2179.87 (7)C1i—C1—C6—C5176.73 (6)
O1—C2—C3—C4179.67 (7)C6—C5—C8—O3144.81 (7)
C1—C2—C3—C40.08 (11)C4—C5—C8—O337.02 (10)
Symmetry code: (i) x+1, y, z+1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1···O20.842.222.6720 (9)114
O1—H1···O3ii0.842.032.7489 (8)144
O3—H3···O1iii0.842.092.9138 (9)168
Symmetry codes: (ii) x+1/2, y+1/2, z+1/2; (iii) x1/2, y+1/2, z+1/2.

Experimental details

Crystal data
Chemical formulaC16H18O6
Mr306.30
Crystal system, space groupOrthorhombic, Pbcn
Temperature (K)153
a, b, c (Å)12.4911 (6), 8.5100 (4), 13.2883 (7)
V3)1412.54 (12)
Z4
Radiation typeMo Kα
µ (mm1)0.11
Crystal size (mm)0.35 × 0.20 × 0.15
Data collection
DiffractometerSiemens SMART CCD area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 2003)
Tmin, Tmax0.594, 0.984
No. of measured, independent and
observed [I > 2σ(I)] reflections
23325, 2621, 2150
Rint0.046
(sin θ/λ)max1)0.768
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.038, 0.116, 1.00
No. of reflections2621
No. of parameters112
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.55, 0.22

Computer programs: SMART (Bruker, 2003), SAINT (Bruker, 2003) and SADABS (Sheldrick, 2003), SHELXTL (Sheldrick, 2008), DIAMOND (Brandenburg, 2010).

Selected geometric parameters (Å, º) top
O1—C21.3690 (9)O3—C81.4339 (10)
O2—C71.4255 (10)C1—C1i1.4893 (14)
C2—C1—C1i121.09 (7)O2—C3—C4125.15 (7)
C6—C1—C1i119.78 (7)O2—C3—C2114.27 (6)
O1—C2—C1119.63 (7)C6—C5—C4119.04 (7)
O1—C2—C3120.79 (7)C6—C5—C8120.05 (7)
Symmetry code: (i) x+1, y, z+1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1···O20.842.222.6720 (9)114
O1—H1···O3ii0.842.032.7489 (8)144
O3—H3···O1iii0.842.092.9138 (9)168
Symmetry codes: (ii) x+1/2, y+1/2, z+1/2; (iii) x1/2, y+1/2, z+1/2.
Torsion angles C(O)—C—C—C(O) [C2—C1—C1i—C2i in (I)] and C(H)—C—C—C(H) [C6—C11—C1i—C6i in (I)] (°), and angle A between the aromatic rings (°), for (I) and related compounds top
Compound (CSD code)ReferenceRemarkC(O)-C-C-C(O)C(H)-C-C-C(H)A
(I)aBP114.43 (8)108.33 (8)68.88 (2)
AJAPUWaBP53.9647.9551.52
CIPXIIbBP49.0441.9844.86
MEBMIPcBP-55.18-49.4952.77
MEBMOVcBP-46.49-41.0943.81
TECQOHdBP62.1063.1662.12
TECQOHdBP-61.73-61.2261.47
NUTSUQeBP-51.39-45.7548.65
MAYFEXfNP65.8664.4565.11
TUGVUMgNP-53.41-48.0450.87
NOZZUXhNP-63.35-57.0960.15
NOZZUXhNP-115.39-115.3465.09
NOZZORhNP-62.85-56.4159.42
ZIZDIViNP120.70119.4959.83
ZIZDOBiNP128.82125.2353.10
ZIZDOBiNP-123.74-120.3659.10
BP = biphenolic, NP = non-phenolic References: (a) this work; (b) Wang et al. (1983); (c) Bocelli et al. (1999); (d) Xi et al. (1996); (e) Byrne et al. (1998); (f) Roblin et al. (2000); (g) Karhunen et al. (1996); (h) Ferreira et al. (1998); (i) Brunow et al. (1995). For the Cambridge Structural Database (CSD), see: Allen (2002).
 

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