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In the title compound, C18H12O6·4H2O, the 2,3,6,7,10,11-hexa­hydroxy­triphenyl­ene mol­ecule is located on a twofold axis and two water mol­ecules occupy general positions. The compound forms (4,4) two-dimensional nets via hydrogen bonds between neighbouring hexa­hydroxy­triphenyl­ene mol­ecules, somewhat similar to the cyclo­penta­none solvates but distinctively different from the monohydrate form. Hydrogen bonds to water mol­ecules connect these layers to form a complicated three-dimensional net, supported also by strong π–π stacking.

Supporting information


Crystallographic Information File (CIF)
Contains datablocks I, global


Structure factor file (CIF format)
Contains datablock I

CCDC reference: 824047

Comment top

2,3,6,7,10,11-Hexahydroxytriphenylene has emerged as an important starting material for making discrete supramolecular units (Fyfe et al. 2000; Waldvogel et al., 2000; Bomkamp et al., 2007) and so-called covalent organic frameworks based on B(Ph)(O)2 trigonal secondary building units (Cote et al., 2005; El-Kaderi et al., 2007). After recovering hexahydroxytriphenylene from unsuccessful reactions we found a new hydrate, 2,3,6,7,10,11-hexahydroxytriphenylene tetrahydrate, (I), different from the other three crystal forms reported for this compound, the monohydrate, (II) [P21/c, a = 11.127 (2) Å, b = 12.797 (3) Å, c = 11.081 (2) Å and β = 119.32 (3)°; Andresen et al., 2000], the tris(cyclopentanone), (III) [P21, a = 7.986 (3) Å, b = 10.161 (2) Å, c = 18.554 (2) Å and β = 99.84 (1)°; Reference?] and the tetrakis(cyclopentanone) monohydrate, (IV) [P21/c, a = 7.603 (7) Å, b = 20.937 (3) Å, c = 22.245 (3) Å and β = 91.85 (3)°; Toda et al., 2000].

This new hydrate, (I), seems to be relatively stable, as the crystal structure presented here was obtained several months after the initial preparation. However, the anisotropy of the solvent water O atoms may indicate that these water molecules are partially lost from the structure and therefore are less well defined.

Tetrahydrate (I) has a hexahydroxytriphenylene unit very similar to those in the three previously reported structures (Fig. 1). As there is some indication that radical species may form (Grange et al., 2010), special attention was paid to the C—O distances in order to rule out a semiquinone molecule. However, all these bond lengths in (I) are consistent with a C—O single bond (Table 1).

A more intricate question is the hydrogen-bond networks in (I)–(IV). Diols of rigid hydrocarbon skeletons are known to form three-dimensional networks of different topologies (Wells, 1954; Wallentin et al., 2009), but hydrated species may be less straightforward to interpret in this way and the large number of hydroxy groups in the case of (I) will add to the complexity.

Analysing the four structures, we find that in the tris(cyclopentanone) solvate, (III), each hexahydroxytriphenylene molecule forms hydrogen bonds to four other units, forming a (4,4) two-dimensional net, with the cyclopentanones hydrogen-bonded and protruding from the network. The situation in (IV) is similar, but with an even thicker layer of cyclopentanones in between the aromatic networks. In the monohydrate, (II), every hexahydroxytriphenylene molecule forms hydrogen bonds to six other hexahydroxytriphenylenes, giving an intricate double layer of two (4,4) nets where every vertex is connected to two other vertices in a neighbouring net. The water molecules further hydrogen-bond these layers to form a complicated three-dimensional net.

In the tetrahydrate reported here, the (4,4) two-dimensional net from (III) and (IV) is reproduced but, instead of hydrocarbon rings separating layers of hexahydroxytriphenylene molecules, this less dense two-dimensional net is further cross-linked by water molecules to form a complex three-dimensional net (Fig. 2). The interpretation of this net in terms of topology would result in a network with at least four different types of vertices, and we do not see any advantage in this type of interpretation in this case. There is also substantial ππ stacking, seemingly more than in the monohydrate, (II) (Fig. 3).

Related literature top

For related literature, see: Allen (2002); Andresen et al. (2000); Bhalla et al. (2009); Bomkamp et al. (2007); Cote et al. (2005); El-Kaderi, Hunt, Mendoza-Cortes, Cote, Taylor, O'Keefe & Yaghi (2007); Fyfe et al. (2000); Grange et al. (2010); Percec et al. (2009); Toda et al. (2000); Waldvogel et al. (2000); Wallentin et al. (2009); Wells (1954); Zniber et al. (2002).

Experimental top

2,3,6,7,10,11-Hexamethoxytriphenylene was prepared according to the literature (Zniber et al., 2002). Other chemicals were purchased from Aldrich and used as received. The syntheses and 1H NMR and mass spectrometry analyses were carried out at Chalmers University of Technology. The X-ray data collection and structure solution were carried out at the University of Eastern Finland.

The hexahydroxytriphenylene has been reported as colourless (Andresen et al., 2000; Toda et al., 2000), grey (Zniber et al., 2002) or brown (Bhalla et al., 2009). Recent reports of the synthesis of hexahydroxytriphenylene using anaerobic conditions lead one to conclude that the darker preparations are contaminated by oxidized forms of the molecule (Percec et al., 2009). The structure of (I) reported herein was obtained independently from one white and one black crystal, with no dramatic crystal quality differences between the two samples.

2,3,6,7,10,11-Hexahydroxytriphenylene monohydrate was prepared as follows. 2,3,6,7,10,11-Hexamethoxytriphenylene (1 g, 2.45 mmol) was added into a solution of glacial acetic acid and hydroiodic acid (aqueous, 57 wt.%) (50:50 v/v, 50 ml) and heated at reflux overnight. A red suspension formed and was filtered off. The product was purified by crystallization with the addition of water [Volume?]. Black crystals formed (yield 500 mg, 60%). 1H NMR and mass spectrometry characterizations of the product were concordant with the literature (Zniber et al., 2002). The crystals formed were characterized by X-ray diffraction as having the published 2,3,6,7,10,11-hexahydroxyterphenylene monohydrate crystal structure [Cambridge Structural Database (CSD; Allen, 2002) entry XEFSIK; Reference?].

2,3,6,7,10,11-Hexahydroxytriphenylene tetrahydrate, (I), was prepared as follows. 2,3,6,7,10,11-Hexahydroxytriphenylene monohydrate (100 mg, 2.9 mmol) and sodium borohydride (10 mg) were added to water (20 ml) and the mixture heated at reflux overnight. The solution was then allowed to evaporate slowly until the formation of colourless crystals of (I) suitable for single-crystal X-ray diffraction.

Refinement top

The hexahydroxyphenylene molecule is located on a twofold axis. The H2O and OH H atoms were located in a difference Fourier map but constrained to ride on their parent atoms, with Uiso(H) = 1.5Ueq(O). The remaining H atoms were positioned geometrically and were also constrained to ride on their parent atoms, with C—H = 0.95 Å, and Uiso(H) = 1.2Ueq(C). The highest peak is located 0.60 Å from atom H3 and the deepest hole is located 0.95 Å from atom O5.

Computing details top

Data collection: APEX2 (Bruker, 2010); cell refinement: SAINT (Bruker, 2009); data reduction: SAINT (Bruker, 2009); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008b); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008b); molecular graphics: CrystalMaker (Palmer, 2010); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008b).

Figures top
[Figure 1] Fig. 1. The molecular structure of (I), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. [Symmetry code: (i) -x, y, -z + 1/2.]
[Figure 2] Fig. 2. The two-dimensional network of (I), built from hexahydroxytriphenylene units hydrogen-bonding to themselves (red in the electronic version of the paper), and the three-dimensional structure, built up by free water molecules hydrogen-bonding to other water molecules or to hexahydroxytriphenylene molecules.
[Figure 3] Fig. 3. A comparison of the ππ stacking in (I) (left) and (II) (right).
2,3,6,7,10,11-Hexahydroxytriphenylene tetrahydrate top
Crystal data top
C18H12O6·4H2OF(000) = 832
Mr = 396.34Dx = 1.542 Mg m3
Orthorhombic, PbcnMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2n 2abCell parameters from 2018 reflections
a = 14.2694 (8) Åθ = 2.5–23.2°
b = 16.5639 (8) ŵ = 0.13 mm1
c = 7.2237 (4) ÅT = 100 K
V = 1707.37 (16) Å3Block, colourless
Z = 40.14 × 0.07 × 0.05 mm
Data collection top
Bruker SMART APEXII CCD area-detector
1567 independent reflections
Radiation source: fine-focus sealed tube928 reflections with I > 2σ(I)
Flat graphite crystal monochromatorRint = 0.083
Detector resolution: 16 pixels mm-1θmax = 25.4°, θmin = 1.9°
ϕ and ω scansh = 1617
Absorption correction: multi-scan
(SADABS; Sheldrick, 2008a)
k = 1919
Tmin = 0.982, Tmax = 0.994l = 88
19113 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)] = 0.050Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.130H-atom parameters constrained
S = 1.02 w = 1/[σ2(Fo2) + (0.0569P)2 + 1.0864P]
where P = (Fo2 + 2Fc2)/3
1567 reflections(Δ/σ)max < 0.001
127 parametersΔρmax = 0.26 e Å3
0 restraintsΔρmin = 0.30 e Å3
Crystal data top
C18H12O6·4H2OV = 1707.37 (16) Å3
Mr = 396.34Z = 4
Orthorhombic, PbcnMo Kα radiation
a = 14.2694 (8) ŵ = 0.13 mm1
b = 16.5639 (8) ÅT = 100 K
c = 7.2237 (4) Å0.14 × 0.07 × 0.05 mm
Data collection top
Bruker SMART APEXII CCD area-detector
1567 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 2008a)
928 reflections with I > 2σ(I)
Tmin = 0.982, Tmax = 0.994Rint = 0.083
19113 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0500 restraints
wR(F2) = 0.130H-atom parameters constrained
S = 1.02Δρmax = 0.26 e Å3
1567 reflectionsΔρmin = 0.30 e Å3
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
O10.58286 (12)0.31180 (10)0.6736 (3)0.0288 (5)
O20.73081 (13)0.20271 (11)0.5655 (3)0.0318 (6)
O30.80822 (13)0.06506 (10)0.4646 (3)0.0326 (5)
C10.54424 (18)0.23791 (15)0.7085 (4)0.0214 (6)
C20.58695 (18)0.16606 (15)0.6680 (4)0.0211 (6)
C30.54461 (17)0.09146 (15)0.7079 (4)0.0195 (6)
C40.59137 (18)0.01502 (14)0.6661 (4)0.0183 (6)
C50.54658 (17)0.05893 (14)0.7105 (4)0.0195 (6)
C60.59475 (18)0.13223 (15)0.6789 (4)0.0226 (7)
C70.68101 (19)0.13342 (15)0.5997 (4)0.0246 (7)
C80.72455 (19)0.06040 (15)0.5474 (4)0.0237 (7)
C90.67939 (18)0.01219 (15)0.5829 (4)0.0218 (6)
O40.57263 (18)0.44283 (13)0.4420 (4)0.0702 (9)
O50.6310 (2)0.32761 (13)0.6929 (4)0.0710 (9)
Atomic displacement parameters (Å2) top
O10.0244 (10)0.0137 (10)0.0482 (14)0.0022 (8)0.0085 (10)0.0030 (9)
O20.0294 (11)0.0154 (10)0.0507 (14)0.0058 (8)0.0076 (10)0.0037 (10)
O30.0346 (11)0.0237 (11)0.0395 (13)0.0037 (9)0.0060 (10)0.0019 (9)
C10.0254 (14)0.0129 (14)0.0258 (16)0.0012 (12)0.0021 (12)0.0006 (13)
C20.0223 (14)0.0218 (16)0.0192 (15)0.0001 (12)0.0002 (12)0.0018 (12)
C30.0244 (13)0.0170 (14)0.0172 (14)0.0027 (12)0.0053 (11)0.0018 (12)
C40.0262 (15)0.0149 (15)0.0139 (14)0.0030 (11)0.0075 (12)0.0005 (11)
C50.0249 (13)0.0179 (15)0.0156 (15)0.0019 (12)0.0090 (11)0.0008 (12)
C60.0238 (15)0.0163 (15)0.0278 (16)0.0006 (12)0.0094 (13)0.0024 (13)
C70.0289 (16)0.0174 (15)0.0275 (16)0.0069 (13)0.0112 (13)0.0029 (12)
C80.0253 (15)0.0239 (16)0.0219 (16)0.0038 (13)0.0050 (12)0.0022 (13)
C90.0297 (16)0.0153 (15)0.0205 (15)0.0028 (12)0.0045 (14)0.0021 (11)
O40.085 (2)0.0355 (14)0.090 (2)0.0037 (13)0.0470 (17)0.0063 (14)
O50.117 (2)0.0325 (14)0.0630 (17)0.0118 (14)0.0330 (17)0.0054 (13)
Geometric parameters (Å, º) top
O1—C11.366 (3)C4—C51.418 (3)
O1—H10.86C5—C61.414 (3)
O2—C71.372 (3)C5—C5i1.447 (5)
O2—H20.88C6—C71.358 (4)
O3—C81.338 (3)C6—H60.95
O3—H30.90C7—C81.411 (4)
C1—C21.369 (3)C8—C91.388 (4)
C1—C1i1.398 (5)C9—H90.95
C2—C31.405 (4)O4—H4A0.84
C3—C3i1.411 (5)O5—H5A0.87
C3—C41.463 (3)O5—H5B0.86
C4—C91.393 (4)
C1—O1—H1110.3C6—C5—C5i120.69 (16)
C7—O2—H2110.8C4—C5—C5i120.22 (15)
C8—O3—H3121.2C7—C6—C5121.4 (2)
O1—C1—C2124.1 (2)C7—C6—H6119.3
O1—C1—C1i116.34 (13)C5—C6—H6119.3
C2—C1—C1i119.60 (15)C6—C7—O2123.9 (2)
C1—C2—C3122.0 (2)C6—C7—C8120.0 (2)
C1—C2—H2A119.0O2—C7—C8116.1 (2)
C3—C2—H2A119.0O3—C8—C9123.2 (2)
C2—C3—C3i118.44 (15)O3—C8—C7117.6 (2)
C2—C3—C4121.5 (2)C9—C8—C7119.2 (2)
C3i—C3—C4120.04 (14)C8—C9—C4121.8 (2)
C9—C4—C5118.3 (2)C8—C9—H9119.1
C9—C4—C3122.0 (2)C4—C9—H9119.1
C5—C4—C3119.7 (2)H4A—O4—H4B112.5
C6—C5—C4119.1 (2)H5A—O5—H5B105.9
Symmetry code: (i) x+1, y, z+3/2.
Hydrogen-bond geometry (Å, º) top
O1—H1···O2ii0.861.922.781 (2)176
O2—H2···O50.881.812.675 (3)170
O3—H3···O4ii0.901.752.649 (3)170
O4—H4A···O4iii0.842.342.930 (5)128
O4—H4B···O1iv0.842.082.914 (3)176
O5—H5A···O3v0.871.962.787 (3)159
O5—H5B···O40.872.382.761 (3)107
Symmetry codes: (ii) x+3/2, y1/2, z; (iii) x+1, y+1, z+1; (iv) x, y, z1/2; (v) x+3/2, y+1/2, z+1/2.

Experimental details

Crystal data
Chemical formulaC18H12O6·4H2O
Crystal system, space groupOrthorhombic, Pbcn
Temperature (K)100
a, b, c (Å)14.2694 (8), 16.5639 (8), 7.2237 (4)
V3)1707.37 (16)
Radiation typeMo Kα
µ (mm1)0.13
Crystal size (mm)0.14 × 0.07 × 0.05
Data collection
DiffractometerBruker SMART APEXII CCD area-detector
Absorption correctionMulti-scan
(SADABS; Sheldrick, 2008a)
Tmin, Tmax0.982, 0.994
No. of measured, independent and
observed [I > 2σ(I)] reflections
19113, 1567, 928
(sin θ/λ)max1)0.602
R[F2 > 2σ(F2)], wR(F2), S 0.050, 0.130, 1.02
No. of reflections1567
No. of parameters127
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.26, 0.30

Computer programs: APEX2 (Bruker, 2010), SAINT (Bruker, 2009), SHELXS97 (Sheldrick, 2008b), SHELXL97 (Sheldrick, 2008b), CrystalMaker (Palmer, 2010).

Selected bond lengths (Å) top
O1—C11.366 (3)O3—C81.338 (3)
O2—C71.372 (3)
Hydrogen-bond geometry (Å, º) top
O1—H1···O2i0.861.922.781 (2)175.9
O2—H2···O50.881.812.675 (3)170.2
O3—H3···O4i0.901.752.649 (3)169.6
O4—H4A···O4ii0.842.342.930 (5)127.9
O4—H4B···O1iii0.842.082.914 (3)175.7
O5—H5A···O3iv0.871.962.787 (3)159.0
O5—H5B···O40.872.382.761 (3)107.2
Symmetry codes: (i) x+3/2, y1/2, z; (ii) x+1, y+1, z+1; (iii) x, y, z1/2; (iv) x+3/2, y+1/2, z+1/2.

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