3,4-Dihydroxy-1,6-bis(4-methoxyphenyl)hexa-2,4-diene-1,6-dione, its 4-methylphenyl analogue, and a potassium salt of 2-hydroxy-4-(4-methoxyphenyl)- 4-oxobut-2-enoic acid

metal-organic compounds

Acta Crystallographica Section C

Crystal Structure

Communications

metal ions. Multiple tautomers are possible for this compound,

including the 1,3,4,6-tetrone form, but in the solid state the di-

enol-dione form is observed. Substituted phenyl derivatives

have also been reported, including the 4-methyl derivative, (2)

[structure previously published from room-temperature data

by Kaitner et al. (1992)] and the 4-chloro derivative (Chetkina,

1992), both of which also exhibit the di-enol-dione form, as

does the parent molecule. We were interested in the effects of

these substituents on the packing strucuture of the molecules

and undertook the synthesis and structural analysis of the

4-methoxyphenyl derivative, (1). In the process, we serendi-

pitously produced a potassium salt of the related 2-hydroxy-4-

methoxyphenyl-4-oxobut-2-enoic acid complex, i.e. catena-

poly[[ꢀ₂-2-hydroxy-4-(4-methoxyphenyl)-4-oxobut-2-enoato]-

[ꢀ₂-2-hydroxy-4-(4-methoxyphenyl)-4-oxobut-2-enoic acid]-

potassium], (3). We report here the structures of 3,4-dihy-

droxy-1,6-bis(4-methoxyphenyl)hexa-2,4-diene-1,6-dione, (1),

and (3), and the low-temperature redetermination of the

structure of 3,4-dihydroxy-1,6-bis(4-methylphenyl)hexa-2,4-

diene-1,6-dione, (2).

ISSN 0108-2701

3,4-Dihydroxy-1,6-bis(4-methoxy-

phenyl)hexa-2,4-diene-1,6-dione, its

4-methylphenyl analogue, and a

potassium salt of 2-hydroxy-4-(4-

methoxyphenyl)-4-oxobut-2-enoic

acid

Luke Nye,^aMark M. Turnbull^a* and Jan L. Wikaira^b

^aDepartment of Chemistry, Clark University, 950 Main Street, Worcester, MA 01610,

USA, and ^bDepartment of Chemistry, University of Canterbury, Private Bag 4800,

Christchurch, New Zealand

Correspondence e-mail: mturnbull@clarku.edu

Received 3 June 2013

Accepted 19 September 2013

Reaction of 4-methoxyacetophenone with diethyl oxalate

under basic conditions produced 3,4-dihydroxy-1,6-bis(4-

methoxyphenyl)hexa-2,4-diene-1,6-dione, C₂₀H₁₈O₆, (1). The

molecules lie across a crystallographic inversion centre and

intramolecular hydrogen bonding, similar to acetylacetone, is

observed, conﬁrming that the molecule is in the di-enol-dione

tautomeric form. Additional O—Hꢀ ꢀ ꢀO hydrogen bonds link

the molecules into chains parallel to the b axis. The structure is

compared with that of redetermined 4-methylphenyl com-

pound 3,4-dihydroxy-1,6-bis(4-methylphenyl)hexa-2,4-diene-

1,6-dione, C₂₀H₁₈O₄, (2), which crystallizes in a similar fashion.

The salt, catena-poly[[ꢀ₂-2-hydroxy-4-(4-methoxyphenyl)-4-

oxobut-2-enoato-ꢁ³O¹,O²:O⁴][ꢀ₂-2-hydroxy-4-(4-methoxy-

phenyl)-4-oxobut-2-enoic acid-ꢁ²O¹:O⁴]potassium], [K(C₁₁-

H₉O₅)(C₁₁H₁₀O₅)]_n, (3), was isolated as a by-product of the

synthesis of (1). The two organic species are linked by a strong

hydrogen bond between the carboxylic acid and carboxylate

groups. They are further stabilized and linked into a double-

chain structure via the seven-coordinate potassium ion.

2. Experimental

Keywords: crystal structure; 2,4-hexadiene-1,6-diones;

potassium salt; di-enol-dione tautomers; metal-ion O₂-chelating

sites.

2.1. Synthesis and crystallization

For the preparation of (1), ethyl oxalate (0.5898 g,

4.0 mmol) and 4-methoxyacetophenone (1.2614 g, 8.4 mmol)

were dissolved in tetrahydrofuran (THF), and the resulting

solution was added dropwise to a suspension of potassium tert-

butoxide (1.371 g, 12.2 mmol) in THF. The resulting mixture

was then reﬂuxed for 21 h. The reaction mixture was cooled to

room temperature, diluted with low-boiling petroleum ether

(30 ml) and allowed to stand for 5 min. The mixture was

ﬁltered and the precipitate washed twice with 10 ml portions

of petroleum ether, yielding a dark-orange powder and a dark-

red ﬁltrate. The orange powder was added to 85% acetic acid

1. Introduction

We have been examining organic compounds as templates for

low-dimensional coordination polymers, and have been

looking at polyones and pentane-2,4-dione (acac) derivatives

in particular. The structure of the compound 3,4-dihydroxy-

1,6-diphenylhexa-2,4-diene-1,6-dione (Kaitner et al., 1992;

Nawar, 1994) lends itself to such structures and in its depro-

tonated form possesses two equivalent O₂-chelating sites for

Acta Cryst. (2013). C69, 1317–1321

doi:10.1107/S0108270113025973

# 2013 International Union of Crystallography 1317

metal-organic compounds

Table 1

Experimental details.

(1)

(2)

(3)

Crystal data

Chemical formula

M_r

C₂₀H₁₈O₆

354.34

C₂₀H₁₈O₄

322.34

[K(C₁₁H₉O₅)(C₁₁H₁₀O₅)]

482.47

Crystal system, space group

Temperature (K)

Monoclinic, P2₁/c

116

15.4385 (6), 6.1475 (2), 8.7281 (3)

105.029 (2)

800.03 (5)

2

Mo Kꢄ

0.11

0.55 ꢄ 0.33 ꢄ 0.12

Monoclinic, P2₁/c

116

14.7710 (6), 6.1622 (2), 8.6184 (3)

91.896 (2)

784.03 (5)

2

Mo Kꢄ

0.10

Monoclinic, P2₁/n

116

15.3832 (4), 6.3481 (1), 21.1606 (5)

90.582 (1)

2066.31 (8)

4

Mo Kꢄ

0.32

0.57 ꢄ 0.55 ꢄ 0.39

˚

a, b, c (A)

ꢃ (^ꢂ)

3

˚

V (A )

Z

Radiation type

ꢀ (mm^ꢁ1

Crystal size (mm)

)

0.62 ꢄ 0.46 ꢄ 0.06

Data collection

Diffractometer

Bruker APEXII CCD area-detector

diffractometer

Bruker APEXII CCD area-detector

diffractometer

Bruker APEXII CCD area-detector

diffractometer

Absorption correction

Multi-scan (SADABS; Sheldrick,

1996)

0.943, 0.987

Multi-scan (SADABS; Sheldrick,

1996)

0.944, 0.994

Multi-scan (SADABS; Sheldrick,

1996)

0.840, 0.886

T_min, T_max

No. of measured, independent and

observed [I > 2ꢅ(I)] reﬂections

R_int

16170, 2313, 2155

19282, 2288, 2150

52473, 6026, 5402

0.029

0.704

0.045

0.704

0.034

0.704

ꢁ1

˚

(sin ꢆ/ꢇ)_max(A

)

Reﬁnement

R[F²> 2ꢅ(F²)], wR(F²), S

No. of reﬂections

No. of parameters

0.043, 0.113, 1.12

2313

122

0.067, 0.151, 1.25

2288

116

0.032, 0.090, 1.06

6026

316

H-atom treatment

H atoms treated by a mixture of

independent and constrained

reﬁnement

H atoms treated by a mixture of

independent and constrained

reﬁnement

0.41, ꢁ0.32

H atoms treated by a mixture of

independent and constrained

reﬁnement

0.47, ꢁ0.42

ꢁ3

˚

Áꢈ_max, Áꢈ_min(e A

)

0.36, ꢁ0.32

Computer programs: SHELXS97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008), Mercury (Macrae et al., 2008), SHELXL97 (Sheldrick, 2008), enCIFer (Allen et al., 2004) and publCIF

(Westrip 2010).

(20 ml). The resulting mixture was stirred for 3 h, ﬁltered and

the solid obtained was washed with three 10 ml portions of

cold water, yielding a pale-yellow–green powder isolated in

34.4% yield. IR (KBr pellet, ꢂ, cm^ꢁ1): O—H 3436, C C 1601,

cm^ꢁ1): O—H 3435, C—H 3112, C C 1599, C O 1571. The

product was recrystallized from chloroform to yield pale-

yellow prisms of (2) suitable for X-ray diffraction.

C

O 1571. The product was recrystallized from chloroform

2.2. Refinement

to yield pale-yellow prisms of (1) suitable for X-ray diffrac-

tion.

Crystal data, data collection and structure reﬁnement

details are summarized in Table 1. Except as indicated below,

all H atoms bound to C atoms were reﬁned using a riding

model, with methyl C—H = 0.98 A, and aromatic and vinylic

˚

C—H = 0.95 A, and with U_iso(H) = 1.2U_eq(C). H atoms

bonded to O atoms, as well as the vinylic H atoms in (2) and

(3), were located in a difference map and their positions

reﬁned using ﬁxed U_isovalues [U_iso(H) = 1.2U_eq(O)].

The potassium salt, (3), formed from the acidic ﬁltrate after

several days. The precipitate was recovered by ﬁltration and

washed with acetone to yield X-ray-quality orange crystals.

For the preparation of (2), ethyl oxalate (0.5828 g,

4.0 mmol) and 4-methylacetophenone (1.0861 g, 8.0 mmol)

were dissolved in THF, and the resulting solution was added

dropwise to a suspension of potassium tert-butoxide (1.329 g,

11.8 mmol, pink) in THF. During the addition, the reaction

mixture changed color from pink to peach to orange to red.

The reaction was then reﬂuxed for 21 h, turning a dark cloudy

red after 15 min and then dark orange after 45 min. After

reﬂux, the reaction mixture was cooled to room temperature

and diluted with low-boiling petroleum ether (30 ml), allowed

to stand for 5 min and then ﬁltered. The precipitate was

washed twice with 10 ml portions of petroleum ether. The

powder salt product was added to 85% acetic acid (20 ml)

which had been previously used to wash the reaction ﬂask. The

salt mixture was stirred for 1.5 h, ﬁltered, and the precipitate

washed with three 10 ml portions of cold water, yielding a

pale-yellow powder (yield 0.388 g, 30.3%). IR (KBr pellet, ꢂ,

˚

3. Results and discussion

Compound (1) crystallizes as a centrosymmetric molecule in

the di-enol-dione form with two intramolecular hydrogen

bonds (Fig. 1). The H atoms on atoms O1 and C2 were located

unambiguously in the difference Fourier map and the position

of H1 was allowed to reﬁne with a ﬁxed isotropic displacement

parameter. The intramolecular hydrogen bond (O1—

H1ꢀ ꢀ ꢀO2) and C—O bond lengths (see Table 2 and Supple-

mentary materials) conﬁrm the tautomer assignment. The

˚

atoms in the central chain are planar to within 0.006 (3) A,

while the benzene ring is canted by 18.33 (10)^ꢂrelative to that

ꢃ

1318 Nye et al. C₂₀H₁₈O₆, C₂₀H₁₈O₄and [K(C₁₁H₉O₅)(C₁₁H₁₀O₅)]

Acta Cryst. (2013). C69, 1317–1321

metal-organic compounds

Figure 1

Figure 3

The molecular unit of (1), showing the atom-numbering scheme.

Displacement ellipsoids are drawn at the 50% probability level. The

asymmetric unit is labelled, along with the hydrogen-bonding H atom

(H1) and symmetry-equivalent atom C1A [symmetry code: (A) ꢁx, ꢁy,

ꢁz + 1]. Dashed lines represent hydrogen bonds.

The molecular unit of (2), showing the atom-numbering scheme.

Displacement ellipsoids are drawn at the 50% probability level. The

asymmetric unit is labelled, along with the hydrogen-bonding H atom

(H1) and symmetry-equivalent atom C1A [symmetry code: (A) ꢁx, ꢁy,

ꢁz + 1]. Dashed lines represent hydrogen bonds.

Table 2

Hydrogen-bond geometry (A, ) for (1).

ꢂ

˚

D—Hꢀ ꢀ ꢀA

D—H

Hꢀ ꢀ ꢀA

Dꢀ ꢀ ꢀA

D—Hꢀ ꢀ ꢀA

O1—H1ꢀ ꢀ ꢀO2

0.951 (15)

1.631 (15)

2.526 (15)

2.5224 (11)

2.6760 (15)

154.4 (14)

88.5 (9)

O1—H1ꢀ ꢀ ꢀO1ⁱ

Symmetry code: (i) ꢁx; ꢁy þ 1; ꢁz þ 2.

Figure 4

The packing of (2), viewed perpendicular to the chain mean plane.

Dashed lines represent hydrogen bonds. The atoms labels are general and

O1A is related to O1 by the symmetry code (ꢁx, ꢁy + 1, ꢁz ꢁ 1).

the changes in packing between the methoxy- and methyl-

substituted compounds, and to investigate the effects of

temperature on the structure. The molecular unit is compar-

able in structure with (1), with the central chain atoms

Figure 2

The packing of (1), viewed perpendicular to the chain mean plane.

Dashed lines represent hydrogen bonds. The atoms labels are general and

O1A is related to O1 by inversion; symmetry code: ꢁx + 1, ꢁy + 1, ꢁz + 3.

˚

coplanar to within 0.0045 (19) A and an equivalent hydrogen

bond (see Table 3) (Fig. 3).

The same layer structure is observed in (2) as in (1), with

intermolecular hydrogen bonds generating chains parallel to

the b axis (Fig. 4). The smaller methyl groups (compared with

methoxy) allow a closer approach of the benzene rings

(intercentroid) parallel to the ac-face diagonal.

plane. The C10—O3—C7—C8 torsion angle of ꢁ10.96 (17)^ꢂ

shows that the methoxy substituent is closer to coplanar with

the central chain.

The molecules of (1) pack in sheets parallel to the b axis and

the ac-face diagonal, and chains are formed within those

sheets via bifurcated hydrogen bonds [O1—H1ꢀ ꢀ ꢀO1A; Fig. 2;

symmetry code: (A) ꢁx, ꢁy + 1, ꢁz + 2]. Although the O—

Hꢀ ꢀ ꢀO angles are near 90^ꢂand the Oꢀ ꢀ ꢀH distances somewhat

long, the relative positions of the molecules is clearly not

coincidental. The methoxy groups are oriented between the

chains in such a way as to minimize the void space. No

signiﬁcant ꢉ-stacking is observed between layers.

The low-temperature structure for the 4-methylphenyl

derivative, (2), was also obtained to allow direct comparison of

Table 3

Hydrogen-bond geometry (A, ) for (2).

ꢂ

˚

D—Hꢀ ꢀ ꢀA

D—H

Hꢀ ꢀ ꢀA

Dꢀ ꢀ ꢀA

D—Hꢀ ꢀ ꢀA

Figure 5

O1—H1ꢀ ꢀ ꢀO2

0.92 (2)

1.68 (2)

2.54 (2)

2.5351 (17)

2.698 (2)

153 (2)

89.7 (14)

(Top) Superposition of the room-temperature and low-temperature

structures of (2). (Bottom) Superposition of the low-temperature

structures of (1) and (2).

O1—H1ꢀ ꢀ ꢀO1ⁱ

Symmetry code: (i) ꢁx; ꢁy þ 1; ꢁz þ 1.

Acta Cryst. (2013). C69, 1317–1321

ꢃ

Nye et al.

C₂₀H₁₈O₆, C₂₀H₁₈O₄and [K(C₁₁H₉O₅)(C₁₁H₁₀O₅)] 1319

metal-organic compounds

˚

is 0.0345 A). The two benzene rings are canted out of that

plane [the C5 ring by 19.4 (2)^ꢂand the C25 ring by 11.5 (2)^ꢂ].

The hydrogen-bond-bridged carboxylate/carboxylic acid

structure is also observed in a variety of structures. In some,

such as the structures of the potassium salts of 4-ﬂuorobenzoic

acid (Longo & Richardson, 1982) and 4-hydroxybenzoic acid

´

(Manojlovic, 1968), or the sodium salt of malic acid (Moore et

Figure 6

The asymmetric unit of (3), showing the atom-numbering scheme.

Displacement ellipsoids are drawn at the 50% probability level. Dashed

lines represent hydrogen bonds.

al., 1980), the central H atom lies on a crystallographic

inversion centre and, as a result, the O—H bonds are

constrained to be identical. However, there are numerous

examples where the H atom does not lie on a symmetry centre

and its position has been allowed to reﬁne, resulting in

unequal O—H bond lengths, as observed in the present

compound. These include salts of hexanedioic acid (Meng et

al., 2009), butanedioic acid (Hsu & Schlemper, 1978), 3,5-di-

nitrobenzoic acid (Madej & Oleksyn, 1986), phthalic acid

(Kuppers et al., 1985), a subsituted imidazoledicarboxylic acid

(Gao & Gu, 2011), pyrazine-2,3-dicarboxylic acid (Smith et al.,

1995), 4,4⁰-bi(benzene-1,2-carboxylic acid) (Wang et al., 2006)

and maleic acid (Madsen & Larsen, 1998). The difference in

the O—H bond lengths for these compounds ranges from

Table 4

Hydrogen-bond geometry (A, ) for (3).

ꢂ

˚

D—Hꢀ ꢀ ꢀA

D—H

Hꢀ ꢀ ꢀA

Dꢀ ꢀ ꢀA

D—Hꢀ ꢀ ꢀA

O1—H1ꢀ ꢀ ꢀO21

O3—H2ꢀ ꢀ ꢀO4

1.071 (15)

0.875 (16)

0.836 (16)

1.361 (15)

1.731 (16)

1.800 (16)

2.4322 (10)

2.5326 (11)

2.5599 (11)

178.2 (15)

151.1 (15)

150.4 (15)

O23—H22ꢀ ꢀ ꢀO24

The effects of temperature and the nature of the benzene-

ring substituents on the molecular structure can most easily be

seen from an overlay of the respective structures. The struc-

ture of (2) has previously been reported at room temperature

(Kaitner et al., 1992). The expected decrease in cell volume

˚

0.018 (Madsen & Larsen, 1998) to 0.225 A (Smith et al., 1995).

The carboxylate/carboxylic acid pairs are further linked via

the K⁺cation, which also bridges them to form a dimeric

structure (Fig. 7). The seven-coordinate K⁺cation lies some-

3

˚

with decreasing temperature is observed [806.7 (2) A at

3

295 K versus 784.03 (5) A at 116 K, a decrease of approxi-

˚

what above [0.6600 (8) A] the plane generated by ﬁve O atoms

[O2, O1B, O3B, O21 and O23; the deviation from the mean

mately 3%], but the structure and conformation of the mol-

ecule itself are virtually unchanged, as shown in Fig. 5,

indicating that the thermal contraction is absorbed by changes

in intermolecular contacts. In spite of the difference in the size

of the substituents in the 4-positions, the conformations of the

molecular units of (1) and (2) are remarkably similar (Fig. 5),

indicating the degree to which the conjugation and intra-

molecular hydrogen bonding dictate the structure.

Salt (3) crystallized as a by-product of the synthesis of (1)

and is best described as a 1:1 complex of 2-hydroxy-4-(4-

methoxyphenyl)-4-oxobut-2-enoic acid and its mono-potas-

sium salt (Fig. 6). The organic entities are linked via a very

strong hydrogen bond between the carboxylic acid and

carboxylate groups (see Table 4). These groups can be

assigned unambiguously via the differences in the C—O bond

lengths (see Supplementary materials). The central hydrogen-

bond-bridged chain structure is nearly planar (the mean

deviation from the plane for the non-H atoms from C5 to C25

˚

plane is 0.07 (2) A; symmetry code: (B) x, y + 1, z] and is then

further linked to two additional O atoms [O22C and O24A;

symmetry codes: (A) ꢁx, ꢁy + 1, ꢁz; (C) ꢁx, ꢁy, ꢁz] at

˚

distances of 3.0350 (12) and 3.1779 (13) A, respectively, above

the plane. This generates potassium-bridged chains parallel to

the b axis.

A copper complex of the anion of 2-hydroxy-4-oxo-4-

phenylbut-2-enoic acid has been reported (Landry et al., 2007)

and exhibits a distinctly different coordination mode. Here,

the enol has been deprotonated to generate an acac-like

structure which chelates the Cu^IIcation, while the carboxylic

acid function remains protonated (ancillary ligands prevent

the formation of a Cu-bridged chain structure). This suggests,

not unexpectedly, varying coordination modes for these

ligands as a function of the metal ion. The similarity of the

current structures to the parent phenyl compound, and the

robust nature of the molecular conformation at varying

Figure 7

(Left) The potassium-bridged dimer structure of (3) and (right) the K⁺cation coordination environment. Symmetry codes A, B, C are as deﬁned in x3.

ꢃ

1320 Nye et al. C₂₀H₁₈O₆, C₂₀H₁₈O₄and [K(C₁₁H₉O₅)(C₁₁H₁₀O₅)]

Acta Cryst. (2013). C69, 1317–1321

metal-organic compounds

Kuppers, H., Takusagawa, F . & Koetzle, T. F. (1985). J. Chem. Phys. 82 , 5636–

5647.

Landry, B. M., Turnbull, M. M. & T w amley, B. (2007). J. Chem. Crystallogr. 37 ,

81–86.

temperatures, should allow for the preparation of families of

coordination complexes and such work is in progress.

LN is grateful for support from a Frederick and Alice

Murdock Summer Research Fellowship.

Longo, J. & Richardson, M. F . (1982). Acta Cryst. B 38 , 2482–2483.

Macrae, C. F ., Bruno, I. J., Chisholm, J. A., Edgington, P . R ., McCabe, P .,

Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood,

P. A . (2008). J. Appl. Cryst. 41 , 466–470.

Madej, A. A. & Oleksyn, B. J. (1986). Pol. J. Chem. 60 , 193–203.

Madsen, D. & Larsen, S. (1998). Acta Cryst. C 54 , 1507–1511.

Supplementary data for this paper are available from the IUCr electronic

archives (Reference: MX3105). Services for accessing these data are

described at the back of the journal.

´

Manojlovic, L. (1968). Acta Cryst. B 24 , 326–330.

Meng, X.-G., Cheng, C.-X. & Yan, G. (2009). Acta Cryst. C 65 , o217–o221.

Moore, P . B ., Pluth, J. J., Molin-Norris, J. A., Weinstein, D. A. & Compere, E. L.

(1980). Acta Cryst. B 36 , 47–50.

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Acta Cryst. (2013). C69, 1317–1321

Nye et al.

C₂₀H₁₈O₆, C₂₀H₁₈O₄and [K(C₁₁H₉O₅)(C₁₁H₁₀O₅)] 1321

supplementary materials

Acta Cryst. (2013). C69, 1317-1321 [doi:10.1107/S0108270113025973]

3,4-Dihydroxy-1,6-bis(4-methoxyphenyl)hexa-2,4-diene-1,6-dione, its 4-methyl-

phenyl analogue, and a potassium salt of 2-hydroxy-4-(4-methoxyphenyl)-4-

oxobut-2-enoic acid

Luke Nye, Mark M. Turnbull and Jan L. Wikaira

Computing details

For all compounds, data collection: SHELXTL (Sheldrick, 2008); cell refinement: SHELXTL (Sheldrick, 2008); data

reduction: SHELXTL (Sheldrick, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s)

used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008) and Mercury

(Macrae et al., 2008). Software used to prepare material for publication: SHELXL97 (Sheldrick, 2008), enCIFer (Allen et

al., 2004) and publCIF (Westrip 2010) for compound1, compound3; SHELXL97 (Sheldrick, 2008), enCIFer (Allen et al.,

2004) and publCIF (Westrip, 2010) for compound2.

(compound1) 3,4-Dihydroxy-1,6-bis(4-methoxyphenyl)hexa-2,4-diene-1,6-dione

Crystal data

C₂₀H₁₈O₆

M_r= 354.34

F(000) = 372

D_x= 1.471 Mg m⁻³

Mo Kα radiation, λ = 0.71073 Å

Cell parameters from 6419 reflections

θ = 2.7–30.4°

Monoclinic, P2₁/c

Hall symbol: -P 2ybc

a = 15.4385 (6) Å

b = 6.1475 (2) Å

c = 8.7281 (3) Å

β = 105.029 (2)°

V = 800.03 (5) Å³

Z = 2

µ = 0.11 mm⁻¹

T = 116 K

Plate, yellow

0.55 × 0.33 × 0.12 mm

Data collection

Bruker APEXII CCD area-detector

diffractometer

Radiation source: fine-focus sealed tube

Graphite monochromator

φ and ω scans

16170 measured reflections

2313 independent reflections

2155 reflections with I > 2σ(I)

R_int= 0.029

θ

_max= 30.0°, θ_min= 2.7°

Absorption correction: multi-scan

(SADABS; Sheldrick, 1996)

h = −20→21

k = −8→8

T

_min= 0.943, T_max= 0.987

l = −12→12

Refinement

Refinement on F²

S = 1.12

Least-squares matrix: full

R[F²> 2σ(F²)] = 0.043

wR(F²) = 0.113

2313 reflections

122 parameters

0 restraints

Acta Cryst. (2013). C69, 1317-1321

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supplementary materials

Primary atom site location: structure-invariant

direct methods

Secondary atom site location: difference Fourier

map

H atoms treated by a mixture of independent

and constrained refinement

w = 1/[σ²(F_o²) + (0.0523P)²+ 0.2726P]

where P = (F_o²+ 2F_c²)/3

(Δ/σ)_max< 0.001

Δρ_max= 0.36 e Å⁻³

Δρ_min= −0.32 e Å⁻³

Hydrogen site location: difference Fourier map

Special details

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 F²against 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)

x

y

z

U_iso*/U_eq

O1

−0.00663 (6)

−0.0476 (10)

−0.12517 (5)

−0.41635 (6)

−0.02613 (7)

−0.08909 (7)

−0.1000

0.71487 (12)

0.642 (2)

0.97532 (10)

0.8907 (18)

0.72353 (9)

0.16040 (10)

0.94117 (12)

0.80906 (12)

0.7894

0.02027 (19)

0.024*

H1

O2

0.63048 (12)

1.05028 (14)

0.92265 (16)

0.98991 (17)

1.1407

0.01960 (18)

0.0264 (2)

0.0153 (2)

0.0168 (2)

0.020*

O3

C1

C2

H2

C3

−0.13895 (7)

−0.20934 (7)

−0.27195 (8)

−0.2677

0.83071 (17)

0.90088 (17)

0.74536 (17)

0.6003

0.69928 (12)

0.55747 (12)

0.48004 (13)

0.5188

0.0162 (2)

0.0166 (2)

0.0195 (2)

0.023*

C4

C5

H5

C6

−0.33969 (8)

−0.3820

0.80018 (18)

0.6936

0.34814 (13)

0.2974

0.0221 (2)

0.026*

H6

C7

−0.34583 (8)

−0.28320 (7)

−0.2863

1.01304 (18)

1.16862 (17)

1.3120

0.28942 (13)

0.36206 (12)

0.3205

0.0196 (2)

0.0192 (2)

0.023*

C8

H8

C9

−0.21571 (7)

−0.1736

1.11223 (17)

1.2191

0.49676 (12)

0.5478

0.0182 (2)

0.022*

H9

C10

H10A

H10B

H10C

−0.43629 (8)

−0.4505

1.27080 (19)

1.3524

0.11246 (15)

0.1993

0.0256 (3)

0.031*

−0.4879

1.2747

0.0192

0.031*

−0.3842

1.3366

0.0859

0.031*

Atomic displacement parameters (Å²)

U¹¹

U²²

U³³

U¹²

U¹³

U²³

O1

O2

O3

C1

0.0253 (4)

0.0235 (4)

0.0272 (5)

0.0176 (5)

0.0111 (3)

0.0139 (3)

0.0211 (4)

0.0125 (4)

0.0207 (4)

0.0012 (3)

0.0000 (3)

0.0017 (3)

0.0001 (3)

−0.0008 (3)

0.0037 (3)

−0.0069 (3)

0.0038 (4)

−0.0001 (3)

0.0001 (3)

−0.0026 (3)

0.0000 (4)

0.0202 (4)

0.0235 (4)

0.0156 (4)

Acta Cryst. (2013). C69, 1317-1321

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supplementary materials

C2

C3

C4

C5

C6

C7

C8

C9

C10

0.0197 (5)

0.0175 (5)

0.0174 (5)

0.0223 (5)

0.0231 (6)

0.0200 (5)

0.0211 (5)

0.0186 (5)

0.0250 (6)

0.0137 (4)

0.0160 (4)

0.0168 (4)

0.0149 (4)

0.0178 (5)

0.0202 (5)

0.0171 (5)

0.0172 (5)

0.0243 (5)

0.0158 (4)

0.0155 (4)

0.0149 (4)

0.0198 (5)

0.0218 (5)

0.0165 (5)

0.0181 (5)

0.0177 (5)

0.0240 (5)

0.0002 (3)

0.0001 (3)

−0.0005 (4)

−0.0011 (4)

−0.0025 (4)

0.0013 (4)

−0.0008 (4)

−0.0024 (4)

0.0025 (4)

0.0022 (4)

0.0047 (3)

0.0029 (4)

0.0026 (4)

−0.0003 (4)

0.0011 (4)

0.0025 (4)

0.0024 (4)

0.0002 (4)

0.0003 (4)

0.0004 (4)

−0.0016 (4)

−0.0011 (4)

−0.0048 (4)

−0.0030 (4)

0.0004 (4)

−0.0007 (4)

0.0032 (4)

Geometric parameters (Å, º)

O1—C1

O1—H1

O2—C3

O3—C7

O3—C10

C1—C2

C1—C1ⁱ

C2—C3

C2—H2

C3—C4

C4—C9

C4—C5

1.3284 (12)

C5—C6

1.3813 (15)

0.951 (15)

1.2577 (12)

1.3675 (13)

1.4285 (14)

1.3653 (14)

1.476 (2)

C5—H5

0.9500

C6—C7

1.3996 (15)

0.9500

C6—H6

C7—C8

1.3906 (15)

1.3974 (14)

0.9500

C8—C9

C8—H8

1.4443 (14)

0.9500

C9—H9

0.9500

C10—H10A

C10—H10B

C10—H10C

0.9800

1.4837 (14)

1.3970 (15)

1.4023 (14)

0.9800

C1—O1—H1

C7—O3—C10

O1—C1—C2

O1—C1—C1ⁱ

C2—C1—C1ⁱ

C1—C2—C3

C1—C2—H2

C3—C2—H2

O2—C3—C2

O2—C3—C4

C2—C3—C4

C9—C4—C5

C9—C4—C3

C5—C4—C3

C6—C5—C4

C6—C5—H5

C4—C5—H5

C5—C6—C7

102.2 (9)

117.72 (9)

123.44 (9)

114.34 (11)

122.23 (11)

119.69 (9)

120.2

C5—C6—H6

120.1

C7—C6—H6

120.1

O3—C7—C8

124.84 (10)

114.96 (10)

120.20 (10)

119.44 (10)

120.3

O3—C7—C6

C8—C7—C6

C7—C8—C9

C7—C8—H8

120.2

C9—C8—H8

120.3

120.91 (9)

118.70 (9)

120.37 (9)

118.65 (10)

123.44 (9)

117.91 (9)

120.90 (10)

119.5

C4—C9—C8

120.91 (10)

119.5

C4—C9—H9

C8—C9—H9

119.5

O3—C10—H10A

O3—C10—H10B

H10A—C10—H10B

O3—C10—H10C

H10A—C10—H10C

H10B—C10—H10C

109.5

119.5

109.5

119.87 (10)

O1—C1—C2—C3

C1ⁱ—C1—C2—C3

C1—C2—C3—O2

C1—C2—C3—C4

O2—C3—C4—C9

C2—C3—C4—C9

0.73 (16)

C4—C5—C6—C7

C10—O3—C7—C8

C10—O3—C7—C6

C5—C6—C7—O3

C5—C6—C7—C8

O3—C7—C8—C9

0.61 (18)

−179.17 (12)

−0.05 (16)

178.32 (10)

−163.46 (10)

18.13 (16)

−10.96 (17)

168.78 (10)

−178.81 (10)

0.94 (18)

177.88 (10)

Acta Cryst. (2013). C69, 1317-1321

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supplementary materials

O2—C3—C4—C5

C2—C3—C4—C5

C9—C4—C5—C6

C3—C4—C5—C6

15.87 (15)

−162.54 (10)

−1.20 (17)

179.44 (10)

C6—C7—C8—C9

C5—C4—C9—C8

C3—C4—C9—C8

C7—C8—C9—C4

−1.84 (17)

0.27 (16)

179.59 (10)

1.24 (16)

Symmetry code: (i) −x, −y+2, −z+2.

Hydrogen-bond geometry (Å, º)

D—H···A

D—H

H···A

D···A

D—H···A

O1—H1···O2

O1—H1···O1ⁱⁱ

0.951 (15)

1.631 (15)

2.526 (15)

2.5224 (11)

2.6760 (15)

154.4 (14)

88.5 (9)

Symmetry code: (ii) −x, −y+1, −z+2.

(compound2) 3,4-Dihydroxy-1,6-bis(4-methylphenyl)hexa-2,4-diene-1,6-dione

Crystal data

C₂₀H₁₈O₄

M_r= 322.34

F(000) = 340

D_x= 1.365 Mg m⁻³

Monoclinic, P2₁/c

Hall symbol: -P 2ybc

a = 14.7710 (6) Å

b = 6.1622 (2) Å

c = 8.6184 (3) Å

β = 91.896 (2)°

V = 784.03 (5) Å³

Z = 2

Mo Kα radiation, λ = 0.71073 Å

Cell parameters from 5544 reflections

θ = 2.8–30.7°

µ = 0.10 mm⁻¹

T = 116 K

Plate, yellow

0.62 × 0.46 × 0.06 mm

Data collection

Bruker APEXII CCD area-detector

diffractometer

Radiation source: fine-focus sealed tube

Graphite monochromator

φ and ω scans

19282 measured reflections

2288 independent reflections

2150 reflections with I > 2σ(I)

R_int= 0.045

θ

_max= 30.0°, θ_min= 2.8°

Absorption correction: multi-scan

(SADABS; Sheldrick, 1996)

h = −20→20

k = −8→8

T

_min= 0.944, T_max= 0.994

l = −12→12

Refinement

Refinement on F²

Least-squares matrix: full

R[F²> 2σ(F²)] = 0.067

wR(F²) = 0.151

S = 1.25

2288 reflections

Secondary atom site location: difference Fourier

map

Hydrogen site location: difference Fourier map

H atoms treated by a mixture of independent

and constrained refinement

w = 1/[σ²(F_o²) + (0.0474P)²+ 0.5796P]

where P = (F_o²+ 2F_c²)/3

116 parameters

0 restraints

(Δ/σ)_max< 0.001

Primary atom site location: structure-invariant

direct methods

Δρ_max= 0.41 e Å⁻³

Δρ_min= −0.31 e Å⁻³

Acta Cryst. (2013). C69, 1317-1321

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