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The crystal structures for the title compounds reveal fundamentally different hydrogen-bonding patterns. (\pm)-3-Oxo­cyclo­hexanecarboxylic acid, C7H10O3, displays acid-to-ketone catemers having a glide relationship for successive components of the hydrogen-bonding chains which advance simultaneously by two cells in a and one in c [O...O = 2.683 (3) Å and O—H...O = 166°]. A pair of intermolecular close contacts exists involving the acid carbonyl group. The asymmetric unit in (\pm)-3-oxo­cyclo­hexane­acetic acid, C8H12O3, utilizes only one of two available isoenthalpic conformers and its aggregation involves mutual hydrogen bonding by centrosymmetric carboxyl dimerization [O...O = 2.648 (3) Å and O—H...O = 171°]. Intermolecular close contacts exist for both the ketone and the acid carbonyl group.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270101020595/fr1356sup1.cif
Contains datablocks I, II, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270101020595/fr1356Isup2.hkl
Contains datablock I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270101020595/fr1356IIsup3.hkl
Contains datablock II

CCDC references: 183001; 183002

Comment top

Five hydrogen-bonding modes are known for the crystalline keto carboxylic acids our studies concern. Two of these lack ketone involvement, reflecting the common pairing and much rarer chain modes known for simple acids (Leiserowitz, 1976). Acid-to-ketone chains (catemers) constitute a sizable minority of cases, while intramolecular H bonds and acid-to-ketone dimers are rarely observed. Hydrates with more complex H-bonding patterns also exist. We have previously provided examples of many of these, along with discussion of factors that appear to govern choice of mode (Brunskill et al., 1999; Lalancette et al., 1998).

We report here the structure and H-bonding behavior of the title compounds, a γ-keto acid (I) and its δ-homolog (II). Both γ- and δ-keto acids are rich in H-bonding types, embracing not only dimers, but catemers of both the homo- and heterochiral type and internal H bonds, as well as hydrated patterns. Compounds (I) & (II) were both of interest to us due to their relationships to several keto acids whose crystal structures display unusual conformational (Lalancette & Thompson, 2001) or H-bonding arrangements (Barcon et al., 1998).

Fig. 1 shows the asymmetric unit of (I) with its numbering. Given the expected chair conformation, the only rotational option involves the equatorial acid group, which is turned with its carbonyl toward the C1—C2 bond so that torsion angle O2—C7—C1—C2 = 19.1 (3)°. The intramolecular dihedral angle between the carboxyl and ketone planes is 65.60 (12)°. The disordering of C—O bond lengths and C—C—O angles often observed in dimerically H-bonded acids (Leiserowitz, 1976) does not appear in catemers, whose geometry cannot support the averaging mechanisms involved. Hence, in (I), which is catemeric, these C—O bond lengths are 1.191 (3)/1.324 (3) Å, with angles of 125.4 (2)/111.76 (19)°. Our own survey of 56 keto acid structures that are not acid dimers gives average values of 1.200 (11)/1.32 (2) Å and 124.5 (14)/112.7 (17)° for these lengths and angles.

Fig. 2 shows the cell packing, in which alternating glide-related molecules associate in carboxyl-to-ketone H-bonding catemers, with two such chains passing counterdirectionally through the cell. We categorize the relationships of intrachain units in catemers as homochiral (screw- or translationally related) or heterochiral (glide-related), and for keto-acid catemers overall, the observed order of prevalence is: screw > translation > glide. Such heterochiral catemers are often much more flattened and ribbon-like than helices, as they are here, with the rings splayed out alternately to either side of the H-bonding axis. Relative to the cell chosen for (I) the chains follow no crystallographic axis but, with each full H-bonding cycle, advance simultaneously by two cells in a and one in c. The arrangement bears a striking resemblance to that found for the α,β-unsaturated counterpart of (I) (Barcon et al., 1998).

The intermolecular dihedral angle between the carboxyl and ketone planes in H-bonded molecules is 65.05 (12)°. To characterize the geometry of H bonding to carbonyls, we use a combination of the H···O=C angle and the H···O=C—C torsion angle. These describe the approach of the acid H atom to the O in terms of its deviation from, respectively, C=O axiality (ideal = 120°) and planarity with the carbonyl (ideal = 0°). In (I) these angles are 128.5 & 2.6°, respectively.

Within the 2.7 Å range we usually employ for non-bonded H···O packing interactions (Steiner, 1997), a pair of intermolecular C—H···O close contacts exists for the acid carbonyl, involving H1 (2.50 Å) and H5A (2.64 Å) in the same neighbor, glide-related in c. Using compiled data for a large number of C—H···O contacts, Steiner & Desiraju (1998) have found significant statistical directionality even as far out as 3.0 Å, and conclude that these are legitimately viewed as "weak hydrogen bonds," with a greater contribution to packing forces than simple van der Waals attractions.

Among several factors tending to disfavor standard dimeric carboxyl H bonding, we have identified low availability of alternative conformations. The flexibility associated with cyclohexane rings is a solution characteristic; in the crystal, the strong preference for chair conformations and equatorial substituents actually leaves a system like (I) with very few conformational options. As a result (I) joins a number of nominally flexible cyclic molecules we have found that behave much more like rigid systems and adopt catemeric H-bonding modes.

Fig. 3 shows the asymmetric unit for (II) with its numbering. The one-carbon lengthening of the equatorial side-chain produces more conformational options than in (I), notably those involving rotation about C1—C7. The observed conformer has a staggered arrangement about this bond [torsion angle C8—C7—C1—C2 = -174.9 (2)°], with a single gauche interaction involving C6 & C8. Its alternative, differing by 120° of C1—C7 rotation has a comparable gauche interaction juxtaposing C2 & C8, but with a calculated enthalpy negligibly different from the one shown. The packing arrangement for (II) chooses only one of these two isoenthalpic conformations, as opposed to the analogous case of (±)-3-oxocyclohexanepropionic acid (Lalancette & Thompson, 2001), where both appear in the asymmetric unit. The intramolecular dihedral angle between the carboxyl and ketone planes in (II) is 83.43 (9)°.

Values cited as typical for highly ordered dimeric carboxyls are 1.21/1.31 Å and 123/112° (Borthwick, 1980). The carboxyl C—O distances and C—C—O angles found for (II) [1.232 (3)/1.269 (3) Å and 121.0 (2)/116.0 (2)°] suggest significant disordering. Although we were unable to find electron density for partial H atoms consistent with this disorder in electron-density difference maps, a single hydrogen was found in the correct position relative to O3.

Fig. 4 shows the packing arrangement, involving centrosymmetric dimers centered on the ac face and on the b-edge of the chosen cell. Intermolecular C—H···O close contacts were found both for the acid carbonyl (2.70 Å to H5A in a neighbor translationally related in a) and for the ketone (2.67 Å to H4B & 2.58 Å to H7A in separate glide-related contacts to molecules mutually related by translation).

In a pattern typical for catemeric keto acids, the solid-state (KBr) infrared spectrum of (I) has well separated C=O absorptions at 1728 & 1686 cm-1, consistent with shifts produced when H bonding is, respectively, removed from a carboxyl and added to a ketone C=O group. In CHCl3 solution these two peaks coalesce to a single one centered around 1713 cm-1. Consistent with its dimeric character, compound (II) in KBr has a single peak at 1695 cm-1 for both C=O groups; in CHCl3 this single peak appears at 1710 cm-1.

Experimental top

Compound (I) was prepared by Pd-catalyzed hydrogenation of 3-oxo-1-cyclohexene-1-carboxylic acid (Barcon et al., 1998). The crystal used was obtained from Et2O, mp 344 K. For (II), Rh-catalyzed hydrogenation of 3-hydroxyphenylacetic acid, followed by Jones oxidation, yielded material suitable for X-ray after recrystallization from Et2O/hexane, mp 351 K.

Refinement top

All H atoms for both (I) and (II) were found in electron density difference maps. For (I), the Hs were placed in calculated positions and allowed to refine as riding models on their respective C and O atoms, with the methine H fixed at 0.98, methylene Hs at 0.97 and OH at 0.82 Å; the temperature factors for all of the Hs were allowed to refine except for the carboxyl H, which was set at 150% of the temperature factor of its O atom. For (II), the Hs were placed in calculated postions with the methine H fixed at 0.99, the methylene Hs at 0.98 and the OH at 0.83 Å. For (II), the temperature factors for the C-bound Hs were set at 120% of their respective atoms, while the carboxyl H was set at 150% of the temprature factor of its respective O atom.

Computing details top

For both compounds, data collection: XSCANS (Siemens, 1996); cell refinement: XSCANS (Siemens, 1996); data reduction: XSCANS (Siemens, 1996); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXP(??)97 (Sheldrick, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

Figures top
[Figure 1] Fig. 1. The asymmetric unit of (I), with its numbering. Displacement ellipsoids are drawn at the 20% probability level.
[Figure 2] Fig. 2. A packing diagram for (I) with extracellular molecules to show the two heterochiral H-bonding chains passing counterdirectionally through the cell. The handedness of the molecules is differentiated by the shading of the bonds, and all carbon-bound H has been removed for clarity. Displacement ellipsoids are set at the 20% probability level.
[Figure 3] Fig. 3. The asymmetric unit of (II), with its numbering. Displacement ellipsoids are drawn at the 20% probability level.
[Figure 4] Fig. 4. A partial packing diagram for (II), with an extracellular molecule, illustrating the dimers centered on the ac face and on the b-edge of the chosen cell. Carbon-bound Hs have been removed for clarity. Displacement ellipsoids are set at the 20% probability level.
(I) '(±)-3-Oxocyclohexanecarboxylic acid' top
Crystal data top
C7H10O3Dx = 1.262 Mg m3
Mr = 142.15Melting point: 344 K
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
a = 6.3346 (17) ÅCell parameters from 30 reflections
b = 10.758 (3) Åθ = 6.1–15.5°
c = 11.012 (3) ŵ = 0.10 mm1
β = 94.202 (17)°T = 296 K
V = 748.4 (4) Å3Parallelepiped, colourless
Z = 40.40 × 0.30 × 0.20 mm
F(000) = 304
Data collection top
Siemens P4
diffractometer
Rint = 0.051
Radiation source: fine-focus sealed tubeθmax = 25.0°, θmin = 2.7°
Graphite monochromatorh = 77
2θ/θ scansk = 012
1891 measured reflectionsl = 013
1315 independent reflections3 standard reflections every 97 reflections
854 reflections with I > 2σ(I) intensity decay: variation < 2%
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)] = 0.049Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.122H-atom parameters constrained
S = 1.04 w = 1/[σ2(Fo2) + (0.036P)2 + 0.2077P]
where P = (Fo2 + 2Fc2)/3
1315 reflections(Δ/σ)max < 0.001
100 parametersΔρmax = 0.19 e Å3
0 restraintsΔρmin = 0.12 e Å3
Crystal data top
C7H10O3V = 748.4 (4) Å3
Mr = 142.15Z = 4
Monoclinic, P21/cMo Kα radiation
a = 6.3346 (17) ŵ = 0.10 mm1
b = 10.758 (3) ÅT = 296 K
c = 11.012 (3) Å0.40 × 0.30 × 0.20 mm
β = 94.202 (17)°
Data collection top
Siemens P4
diffractometer
Rint = 0.051
1891 measured reflections3 standard reflections every 97 reflections
1315 independent reflections intensity decay: variation < 2%
854 reflections with I > 2σ(I)
Refinement top
R[F2 > 2σ(F2)] = 0.0490 restraints
wR(F2) = 0.122H-atom parameters constrained
S = 1.04Δρmax = 0.19 e Å3
1315 reflectionsΔρmin = 0.12 e Å3
100 parameters
Special details top

Experimental. 'crystal mounted on glass fiber with epoxy resin'

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
O10.9648 (3)0.82762 (18)0.85285 (17)0.0772 (6)
O20.4742 (3)0.7526 (2)0.46565 (16)0.0916 (7)
O30.2145 (3)0.66753 (18)0.56032 (15)0.0756 (6)
C10.5417 (3)0.6873 (2)0.67418 (19)0.0462 (6)
C20.7397 (4)0.7681 (2)0.6814 (2)0.0547 (6)
C30.8843 (4)0.7422 (2)0.7935 (2)0.0567 (6)
C40.9277 (4)0.6081 (2)0.8232 (3)0.0679 (8)
C50.7290 (4)0.5273 (2)0.8102 (2)0.0676 (8)
C60.6022 (4)0.5499 (2)0.6887 (2)0.0631 (7)
C70.4111 (4)0.7079 (2)0.5551 (2)0.0505 (6)
H30.14800.67990.49470.080*
H10.45590.71050.74110.048 (6)*
H2A0.81640.75370.60960.073 (8)*
H2B0.69810.85490.68140.062 (7)*
H4A0.99010.60200.90610.077 (8)*
H4B1.03000.57640.76950.104 (11)*
H5A0.64080.54550.87640.076 (8)*
H5B0.76940.44040.81610.084 (9)*
H6A0.47480.49950.68460.092 (9)*
H6B0.68580.52500.62240.072 (8)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0714 (12)0.0784 (13)0.0764 (13)0.0169 (10)0.0302 (10)0.0056 (10)
O20.0828 (14)0.1439 (19)0.0462 (10)0.0330 (13)0.0081 (9)0.0250 (12)
O30.0498 (10)0.1197 (16)0.0556 (11)0.0071 (11)0.0077 (8)0.0055 (10)
C10.0436 (12)0.0540 (14)0.0409 (12)0.0010 (11)0.0021 (9)0.0025 (10)
C20.0527 (14)0.0538 (15)0.0558 (14)0.0017 (12)0.0078 (12)0.0067 (12)
C30.0438 (13)0.0668 (17)0.0580 (14)0.0018 (13)0.0061 (11)0.0084 (14)
C40.0613 (16)0.0720 (18)0.0673 (17)0.0117 (14)0.0154 (14)0.0112 (14)
C50.0793 (19)0.0558 (17)0.0668 (17)0.0066 (14)0.0000 (14)0.0125 (13)
C60.0689 (18)0.0589 (17)0.0608 (15)0.0036 (14)0.0003 (13)0.0021 (13)
C70.0502 (14)0.0598 (15)0.0410 (12)0.0002 (12)0.0007 (10)0.0043 (11)
Geometric parameters (Å, º) top
O1—C31.218 (3)O3—H30.8200
O2—C71.191 (3)C1—H10.9800
O3—C71.324 (3)C2—H2A0.9700
C1—C71.515 (3)C2—H2B0.9700
C1—C21.523 (3)C4—H4A0.9700
C1—C61.533 (3)C4—H4B0.9700
C2—C31.508 (3)C5—H5A0.9700
C3—C41.500 (3)C5—H5B0.9700
C4—C51.528 (4)C6—H6A0.9700
C5—C61.529 (3)C6—H6B0.9700
C7—C1—C2110.94 (18)C3—C2—H2B109.1
C7—C1—C6110.33 (18)C1—C2—H2B109.1
C2—C1—C6110.28 (19)H2A—C2—H2B107.8
C3—C2—C1112.69 (19)C3—C4—H4A109.0
O1—C3—C4123.1 (2)C5—C4—H4A109.0
O1—C3—C2120.4 (2)C3—C4—H4B109.0
C4—C3—C2116.5 (2)C5—C4—H4B109.0
C3—C4—C5113.0 (2)H4A—C4—H4B107.8
C4—C5—C6111.6 (2)C4—C5—H5A109.3
C5—C6—C1110.8 (2)C6—C5—H5A109.3
O2—C7—O3122.8 (2)C4—C5—H5B109.3
O2—C7—C1125.4 (2)C6—C5—H5B109.3
O3—C7—C1111.76 (19)H5A—C5—H5B108.0
C7—O3—H3109.5C5—C6—H6A109.5
C7—C1—H1108.4C1—C6—H6A109.5
C2—C1—H1108.4C5—C6—H6B109.5
C6—C1—H1108.4C1—C6—H6B109.5
C3—C2—H2A109.1H6A—C6—H6B108.1
C1—C2—H2A109.1
C7—C1—C2—C3174.9 (2)C4—C5—C6—C157.1 (3)
C6—C1—C2—C352.3 (3)C7—C1—C6—C5178.4 (2)
C1—C2—C3—O1136.2 (2)C2—C1—C6—C558.7 (3)
C1—C2—C3—C446.1 (3)C2—C1—C7—O219.1 (3)
O1—C3—C4—C5138.3 (3)C6—C1—C7—O2103.4 (3)
C2—C3—C4—C544.0 (3)C2—C1—C7—O3162.2 (2)
C3—C4—C5—C648.9 (3)C6—C1—C7—O375.3 (2)
(II) '(±)-3-Oxocyclohexaneacetic acid' top
Crystal data top
C8H12O3Dx = 1.265 Mg m3
Mr = 156.18Melting point: 351 K
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
a = 6.625 (2) ÅCell parameters from 33 reflections
b = 5.669 (1) Åθ = 7.5–13.0°
c = 21.841 (5) ŵ = 0.10 mm1
β = 90.33 (2)°T = 241 K
V = 820.3 (3) Å3Parallelepiped, colourless
Z = 40.50 × 0.40 × 0.33 mm
F(000) = 336
Data collection top
Siemens P4
diffractometer
Rint = 0.032
Radiation source: normal-focus sealed tubeθmax = 25.0°, θmin = 1.9°
Graphite monochromatorh = 77
2θ/θ scansk = 06
2238 measured reflectionsl = 025
1447 independent reflections3 standard reflections every 97 reflections
989 reflections with I > 2σ(I) intensity decay: variation < 2%
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)] = 0.054Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.143H atoms treated by a mixture of independent and constrained refinement
S = 1.01 w = 1/[σ2(Fo2) + (0.0654P)2 + 0.2424P]
where P = (Fo2 + 2Fc2)/3
1447 reflections(Δ/σ)max = 0.02
101 parametersΔρmax = 0.23 e Å3
0 restraintsΔρmin = 0.12 e Å3
Crystal data top
C8H12O3V = 820.3 (3) Å3
Mr = 156.18Z = 4
Monoclinic, P21/nMo Kα radiation
a = 6.625 (2) ŵ = 0.10 mm1
b = 5.669 (1) ÅT = 241 K
c = 21.841 (5) Å0.50 × 0.40 × 0.33 mm
β = 90.33 (2)°
Data collection top
Siemens P4
diffractometer
Rint = 0.032
2238 measured reflections3 standard reflections every 97 reflections
1447 independent reflections intensity decay: variation < 2%
989 reflections with I > 2σ(I)
Refinement top
R[F2 > 2σ(F2)] = 0.0540 restraints
wR(F2) = 0.143H atoms treated by a mixture of independent and constrained refinement
S = 1.01Δρmax = 0.23 e Å3
1447 reflectionsΔρmin = 0.12 e Å3
101 parameters
Special details top

Experimental. 'crystal mounted on glass fiber using epoxy resin'

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
O10.4354 (3)1.2427 (4)0.24060 (8)0.0728 (6)
O20.9507 (3)0.7174 (3)0.04788 (8)0.0726 (7)
O30.8410 (3)0.3523 (3)0.05366 (9)0.0759 (7)
C10.6287 (3)0.8371 (4)0.13399 (9)0.0438 (6)
C20.5437 (4)0.8791 (5)0.19864 (10)0.0521 (7)
C30.4123 (3)1.0940 (5)0.20135 (10)0.0507 (7)
C40.2548 (4)1.1152 (5)0.15228 (11)0.0588 (7)
C50.3413 (4)1.0669 (5)0.08862 (10)0.0561 (7)
C60.4571 (4)0.8376 (5)0.08710 (10)0.0538 (7)
C70.7492 (4)0.6092 (5)0.13351 (10)0.0508 (6)
C80.8545 (3)0.5613 (5)0.07400 (10)0.0445 (6)
H30.91670.33660.02380.114*
H10.72130.96870.12410.053*
H2A0.46500.74100.21110.063*
H2B0.65600.89720.22770.063*
H4A0.19741.27450.15310.071*
H4B0.14571.00310.16040.071*
H5A0.23081.06050.05870.067*
H5B0.43121.19660.07710.067*
H6A0.51250.81380.04610.065*
H6B0.36500.70660.09570.065*
H7A0.85030.61530.16640.061*
H7B0.65790.47760.14230.061*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0752 (13)0.0841 (15)0.0592 (11)0.0082 (11)0.0059 (10)0.0206 (11)
O20.0850 (14)0.0670 (13)0.0661 (12)0.0178 (11)0.0378 (11)0.0142 (10)
O30.0927 (15)0.0632 (13)0.0723 (13)0.0152 (11)0.0451 (11)0.0174 (10)
C10.0439 (12)0.0553 (14)0.0323 (11)0.0045 (11)0.0063 (9)0.0024 (10)
C20.0553 (14)0.0696 (17)0.0315 (12)0.0056 (13)0.0058 (10)0.0041 (11)
C30.0472 (13)0.0688 (17)0.0364 (12)0.0027 (13)0.0134 (10)0.0047 (12)
C40.0501 (14)0.0725 (19)0.0537 (15)0.0078 (14)0.0057 (12)0.0009 (13)
C50.0512 (14)0.0739 (18)0.0433 (13)0.0007 (14)0.0011 (11)0.0030 (13)
C60.0541 (14)0.0704 (18)0.0371 (12)0.0019 (13)0.0017 (11)0.0058 (12)
C70.0518 (14)0.0629 (16)0.0379 (12)0.0015 (13)0.0066 (11)0.0006 (11)
C80.0389 (12)0.0550 (15)0.0397 (12)0.0037 (12)0.0057 (10)0.0019 (12)
Geometric parameters (Å, º) top
O1—C31.211 (3)C1—H10.9900
O2—C81.232 (3)C2—H2A0.9800
O3—C81.269 (3)C2—H2B0.9800
C1—C71.519 (3)C4—H4A0.9800
C1—C61.526 (3)C4—H4B0.9800
C1—C21.542 (3)C5—H5A0.9800
C2—C31.499 (4)C5—H5B0.9800
C3—C41.496 (3)C6—H6A0.9800
C4—C51.532 (3)C6—H6B0.9800
C5—C61.510 (4)C7—H7A0.9800
C7—C81.504 (3)C7—H7B0.9800
O3—H30.8300
C7—C1—C6112.7 (2)H2A—C2—H2B107.9
C7—C1—C2109.43 (19)C3—C4—H4A109.2
C6—C1—C2109.85 (18)C5—C4—H4A109.2
C3—C2—C1112.16 (19)C3—C4—H4B109.2
O1—C3—C4122.4 (3)C5—C4—H4B109.2
O1—C3—C2121.5 (2)H4A—C4—H4B107.9
C4—C3—C2116.1 (2)C6—C5—H5A109.3
C3—C4—C5111.9 (2)C4—C5—H5A109.3
C6—C5—C4111.5 (2)C6—C5—H5B109.3
C5—C6—C1111.3 (2)C4—C5—H5B109.3
C8—C7—C1113.97 (19)H5A—C5—H5B108.0
O2—C8—O3123.0 (2)C5—C6—H6A109.4
O2—C8—C7121.0 (2)C1—C6—H6A109.4
O3—C8—C7116.0 (2)C5—C6—H6B109.4
C8—O3—H3109.5C1—C6—H6B109.4
C7—C1—H1108.2H6A—C6—H6B108.0
C6—C1—H1108.2C8—C7—H7A108.8
C2—C1—H1108.2C1—C7—H7A108.8
C3—C2—H2A109.2C8—C7—H7B108.8
C1—C2—H2A109.2C1—C7—H7B108.8
C3—C2—H2B109.2H7A—C7—H7B107.7
C1—C2—H2B109.2
C7—C1—C2—C3176.5 (2)C4—C5—C6—C157.9 (3)
C6—C1—C2—C352.2 (3)C7—C1—C6—C5179.71 (19)
C1—C2—C3—O1130.5 (2)C2—C1—C6—C558.0 (3)
C1—C2—C3—C448.4 (3)C6—C1—C7—C862.5 (3)
O1—C3—C4—C5131.6 (3)C2—C1—C7—C8174.9 (2)
C2—C3—C4—C547.2 (3)C1—C7—C8—O246.1 (3)
C3—C4—C5—C651.1 (3)C1—C7—C8—O3135.2 (2)

Experimental details

(I)(II)
Crystal data
Chemical formulaC7H10O3C8H12O3
Mr142.15156.18
Crystal system, space groupMonoclinic, P21/cMonoclinic, P21/n
Temperature (K)296241
a, b, c (Å)6.3346 (17), 10.758 (3), 11.012 (3)6.625 (2), 5.669 (1), 21.841 (5)
β (°) 94.202 (17) 90.33 (2)
V3)748.4 (4)820.3 (3)
Z44
Radiation typeMo KαMo Kα
µ (mm1)0.100.10
Crystal size (mm)0.40 × 0.30 × 0.200.50 × 0.40 × 0.33
Data collection
DiffractometerSiemens P4
diffractometer
Siemens P4
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
1891, 1315, 854 2238, 1447, 989
Rint0.0510.032
(sin θ/λ)max1)0.5940.594
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.049, 0.122, 1.04 0.054, 0.143, 1.01
No. of reflections13151447
No. of parameters100101
H-atom treatmentH-atom parameters constrainedH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.19, 0.120.23, 0.12

Computer programs: XSCANS (Siemens, 1996), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXP(??)97 (Sheldrick, 1997).

Selected geometric parameters (Å, º) for (I) top
O2—C71.191 (3)O3—C71.324 (3)
O2—C7—C1125.4 (2)O3—C7—C1111.76 (19)
C2—C1—C7—O219.1 (3)
Selected geometric parameters (Å, º) for (II) top
O2—C81.232 (3)O3—C81.269 (3)
O2—C8—C7121.0 (2)O3—C8—C7116.0 (2)
C2—C1—C7—C8174.9 (2)
 

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