Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807032163/ym2059sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536807032163/ym2059Isup2.hkl |
CCDC reference: 657796
Key indicators
- Single-crystal X-ray study
- T = 170 K
- Mean (C-C) = 0.002 Å
- R factor = 0.045
- wR factor = 0.122
- Data-to-parameter ratio = 18.3
checkCIF/PLATON results
No syntax errors found
Alert level C PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low ....... 0.98
Alert level G PLAT793_ALERT_1_G Check the Absolute Configuration of C1 = ... S PLAT793_ALERT_1_G Check the Absolute Configuration of C2 = ... S PLAT793_ALERT_1_G Check the Absolute Configuration of C5 = ... S PLAT793_ALERT_1_G Check the Absolute Configuration of C6 = ... S
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 1 ALERT level C = Check and explain 4 ALERT level G = General alerts; check 4 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 0 ALERT type 2 Indicator that the structure model may be wrong or deficient 1 ALERT type 3 Indicator that the structure quality may be low 0 ALERT type 4 Improvement, methodology, query or suggestion 0 ALERT type 5 Informative message, check
Compound (I) was synthesized (Carrasco, 2001) within a project related with the synthesis of a universal template for resolution of racemic mixtures of secondary alcohols and was crystallized from a mixture of acetone/n-hexane at 50%. No structural phase transition was detected when cooling the sample from room temperature to 170 K.
Refinements were performed in the Cc and C2/c space groups. In the C2/c group, the H atom of the hydroxyl groups were split into two positions while in the Cc space group refinements were carried out with two independent molecules without disorder. The lack of suitable anomalous scatters did not allow us to reliably determine the absolute structure according to the Flack parameters = 0.3 (14) and, therefore, the Friedel pairs were merged. All hydrogen atoms were located on difference Fourier maps and they were included in the refinement in the riding-model approximation with C—H = 0.98 (CH3), 0.99 (CH2), 1.00 (CH) and O—H = 0.84 Å with Uiso(H) = 1.2Ueq(C,O).
In a project related with the synthesis of a universal template for resolution of racemic mixtures of secondary alcohols, the intermediate title compound was synthesized (Carrasco, 2001). On the other hand, the analogous syn-diols derivatives studied so far have proved to have inclusion behaviour (Kim et al., 2002).
The two independent molecules of (I) in the Cc space group differ from each other only in the orientation of the H atoms of the hydroxyl groups. The molecules are almost related by a twofold axis which is a crystallographic one in the C2/c space group and, therefore, the H atoms are split into two positions (Figure 1). The same situation has been observed (Cambridge Crystallographic Database, Allen, 2002) in the structure of the endo-2,endo-6-dihydroxy-2,6-dimethylbicyclo(3.3.1)nonane compound described in the Pc group (SEWXAT refcode: Hawkins et al., 1990) with a CH2 group instead of the ether bridge while in the thio-bicycle derivative (SEWXEX refcode, P21/c space group: Hawkins et al., 1990) the H of the hydroxyl groups appear to be disordered.
The six-membered rings are in a slightly distorted chair conformation with the hydroxyl groups in equatorial position, anti with respect to the ether atom O1 (Table 1). These OH groups are involved in the formation of the R44(8) hydrogen bonding motif (Bernstein et al., 1995) acting as both donor and acceptor of hydrogen bonds that results into sheets (Table 2, Figure 2 and 3). Weak C—H···Oether contacts link the layers into a three-dimensional network (2.65, 3.613 (1)Å and 162° for the H···A, D···A distances and DH···A angle). This layered structure is similar to that of carbo-bicycle and thio-biclycle analogues (SEWXAT and SEWXEX) but dissimilar to that of the exo diastereoisomer derivative (OH groups in syn disposition with respect to the ether bridge (WASWAO, Pich et al., 1993). These results are in agreement with the rules proposed by Kim et al., (2002) to be fulfilled by the molecular structure of these derivatives to form supramolecular tubulant hydrogen-bonding networks.
For the related structures [Cambridge Structural Database (CSD), Version 5.28; Allen, 2002] of the endo-2,endo-6-dihydroxy-2,6-dimethylbicyclo(3.3.1)nonane (CSD refcode SEWXAT) and endo-2,endo-6-dihydroxy-2,6-thiobicyclo(3.3.1)nonane (CSD refcode SEWXEX) analogues, see: Hawkins et al. (1990). For the exo diastereoisomer (CSD refcode WASWAO) of the title compound, see: Pich et al. (1993). For syn-diol derivatives with inclusion behaviour, see: Kim et al. (2002).
For related literature, see: Bernstein et al. (1995); Carrasco (2001).
Data collection: COLLECT (Nonius, 2000); cell refinement: SCALEPACK (Otwinowski & Minor, 1997); data reduction: SCALEPACK and DENZO (Otwinowski & Minor, 1997); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: WinGX (Farrugia, 1999), PLATON (Spek, 2003) and Mercury (Macrae et al., 2006).
C10H18O3 | F(000) = 816 |
Mr = 186.24 | Dx = 1.252 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71069 Å |
Hall symbol: -C 2yc | Cell parameters from 11200 reflections |
a = 10.8900 (2) Å | θ = 2.2–27.5° |
b = 9.9227 (2) Å | µ = 0.09 mm−1 |
c = 18.8981 (3) Å | T = 170 K |
β = 104.658 (11)° | Plate, colourless |
V = 1975.63 (12) Å3 | 0.40 × 0.23 × 0.17 mm |
Z = 8 |
Nonius KappaCCD area-detector diffractometer | 2113 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.032 |
Horizontally mounted graphite crystal monochromator | θmax = 27.5°, θmin = 2.2° |
Detector resolution: 9 pixels mm-1 | h = −14→14 |
φ and ω scans | k = −12→12 |
11200 measured reflections | l = −23→24 |
2220 independent reflections |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.045 | H-atom parameters constrained |
wR(F2) = 0.122 | w = 1/[σ2(Fo2) + (0.0645P)2 + 1.3903P] where P = (Fo2 + 2Fc2)/3 |
S = 1.08 | (Δ/σ)max = 0.001 |
2220 reflections | Δρmax = 0.37 e Å−3 |
121 parameters | Δρmin = −0.27 e Å−3 |
0 restraints | Extinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.063 (6) |
C10H18O3 | V = 1975.63 (12) Å3 |
Mr = 186.24 | Z = 8 |
Monoclinic, C2/c | Mo Kα radiation |
a = 10.8900 (2) Å | µ = 0.09 mm−1 |
b = 9.9227 (2) Å | T = 170 K |
c = 18.8981 (3) Å | 0.40 × 0.23 × 0.17 mm |
β = 104.658 (11)° |
Nonius KappaCCD area-detector diffractometer | 2113 reflections with I > 2σ(I) |
11200 measured reflections | Rint = 0.032 |
2220 independent reflections |
R[F2 > 2σ(F2)] = 0.045 | 0 restraints |
wR(F2) = 0.122 | H-atom parameters constrained |
S = 1.08 | Δρmax = 0.37 e Å−3 |
2220 reflections | Δρmin = −0.27 e Å−3 |
121 parameters |
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. |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
O1 | 0.14392 (7) | 0.13828 (8) | 0.05218 (4) | 0.0205 (2) | |
O2 | −0.05943 (9) | 0.06522 (9) | 0.17721 (5) | 0.0325 (3) | |
H2 | −0.0068 | 0.0669 | 0.2183 | 0.039* | 0.50 |
H12 | −0.0688 | −0.0156 | 0.1637 | 0.039* | 0.50 |
O3 | 0.39487 (9) | 0.30199 (9) | 0.19209 (5) | 0.0329 (3) | |
H3 | 0.4123 | 0.3624 | 0.1650 | 0.039* | 0.50 |
H13 | 0.4693 | 0.2797 | 0.2137 | 0.039* | 0.50 |
C1 | 0.08890 (10) | 0.05681 (11) | 0.09945 (6) | 0.0197 (3) | |
H1 | 0.0414 | −0.0175 | 0.0685 | 0.024* | |
C2 | −0.01064 (10) | 0.14124 (11) | 0.12572 (6) | 0.0199 (3) | |
C3 | 0.04768 (10) | 0.27108 (11) | 0.16325 (6) | 0.0203 (3) | |
H3A | 0.1006 | 0.2493 | 0.2127 | 0.024* | |
H3B | −0.0211 | 0.3321 | 0.1689 | 0.024* | |
C4 | 0.12935 (11) | 0.34342 (11) | 0.12003 (6) | 0.0209 (3) | |
H4A | 0.0730 | 0.3907 | 0.0780 | 0.025* | |
H4B | 0.1818 | 0.4123 | 0.1518 | 0.025* | |
C5 | 0.21646 (10) | 0.24856 (11) | 0.09164 (6) | 0.0183 (3) | |
H5 | 0.2496 | 0.3010 | 0.0552 | 0.022* | |
C6 | 0.33340 (10) | 0.19199 (11) | 0.14790 (6) | 0.0194 (3) | |
C7 | 0.29534 (11) | 0.08904 (12) | 0.19901 (6) | 0.0214 (3) | |
H7A | 0.3715 | 0.0380 | 0.2250 | 0.026* | |
H7B | 0.2623 | 0.1375 | 0.2361 | 0.026* | |
C8 | 0.19427 (11) | −0.01001 (11) | 0.15796 (6) | 0.0226 (3) | |
H8A | 0.2358 | −0.0796 | 0.1345 | 0.027* | |
H8B | 0.1559 | −0.0559 | 0.1937 | 0.027* | |
C9 | −0.12245 (11) | 0.17108 (14) | 0.06051 (7) | 0.0296 (3) | |
H9A | −0.1577 | 0.0862 | 0.0376 | 0.044* | |
H9B | −0.0934 | 0.2260 | 0.0248 | 0.044* | |
H9C | −0.1880 | 0.2202 | 0.0772 | 0.044* | |
C10 | 0.42431 (11) | 0.13079 (13) | 0.10697 (7) | 0.0278 (3) | |
H10A | 0.4471 | 0.1992 | 0.0751 | 0.042* | |
H10B | 0.3830 | 0.0546 | 0.0773 | 0.042* | |
H10C | 0.5012 | 0.0993 | 0.1423 | 0.042* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O1 | 0.0249 (4) | 0.0206 (4) | 0.0156 (4) | −0.0001 (3) | 0.0046 (3) | −0.0026 (3) |
O2 | 0.0337 (5) | 0.0271 (5) | 0.0423 (5) | 0.0021 (4) | 0.0200 (4) | 0.0106 (4) |
O3 | 0.0296 (5) | 0.0241 (5) | 0.0412 (5) | −0.0056 (3) | 0.0023 (4) | −0.0107 (4) |
C1 | 0.0224 (5) | 0.0162 (5) | 0.0197 (5) | −0.0001 (4) | 0.0037 (4) | −0.0020 (4) |
C2 | 0.0212 (5) | 0.0185 (5) | 0.0201 (5) | 0.0011 (4) | 0.0052 (4) | 0.0016 (4) |
C3 | 0.0245 (5) | 0.0170 (5) | 0.0208 (5) | 0.0025 (4) | 0.0082 (4) | −0.0009 (4) |
C4 | 0.0248 (6) | 0.0147 (5) | 0.0241 (5) | 0.0034 (4) | 0.0079 (4) | 0.0014 (4) |
C5 | 0.0221 (5) | 0.0157 (5) | 0.0174 (5) | 0.0012 (4) | 0.0057 (4) | 0.0012 (4) |
C6 | 0.0212 (5) | 0.0156 (5) | 0.0202 (5) | 0.0002 (4) | 0.0031 (4) | −0.0009 (4) |
C7 | 0.0233 (5) | 0.0200 (5) | 0.0193 (5) | 0.0026 (4) | 0.0024 (4) | 0.0036 (4) |
C8 | 0.0240 (6) | 0.0157 (5) | 0.0273 (6) | 0.0025 (4) | 0.0051 (4) | 0.0028 (4) |
C9 | 0.0232 (6) | 0.0329 (7) | 0.0292 (6) | 0.0049 (5) | 0.0000 (5) | −0.0002 (5) |
C10 | 0.0246 (6) | 0.0287 (6) | 0.0316 (6) | 0.0063 (5) | 0.0100 (5) | 0.0023 (5) |
O1—C5 | 1.4420 (13) | C4—H4A | 0.9900 |
O1—C1 | 1.4427 (13) | C4—H4B | 0.9900 |
O2—C2 | 1.4352 (13) | C5—C6 | 1.5433 (14) |
O2—H2 | 0.8400 | C5—H5 | 1.0000 |
O2—H12 | 0.8400 | C6—C10 | 1.5280 (16) |
O3—C6 | 1.4331 (13) | C6—C7 | 1.5332 (15) |
O3—H3 | 0.8400 | C7—C8 | 1.5320 (16) |
O3—H13 | 0.8400 | C7—H7A | 0.9900 |
C1—C8 | 1.5287 (15) | C7—H7B | 0.9900 |
C1—C2 | 1.5478 (15) | C8—H8A | 0.9900 |
C1—H1 | 1.0000 | C8—H8B | 0.9900 |
C2—C9 | 1.5263 (16) | C9—H9A | 0.9800 |
C2—C3 | 1.5292 (15) | C9—H9B | 0.9800 |
C3—C4 | 1.5300 (15) | C9—H9C | 0.9800 |
C3—H3A | 0.9900 | C10—H10A | 0.9800 |
C3—H3B | 0.9900 | C10—H10B | 0.9800 |
C4—C5 | 1.5269 (14) | C10—H10C | 0.9800 |
C5—O1—C1 | 111.34 (8) | C4—C5—H5 | 106.6 |
C2—O2—H2 | 109.5 | C6—C5—H5 | 106.6 |
C2—O2—H12 | 109.5 | O3—C6—C10 | 109.31 (9) |
C6—O3—H3 | 109.5 | O3—C6—C7 | 107.54 (9) |
C6—O3—H13 | 109.5 | C10—C6—C7 | 111.54 (9) |
O1—C1—C8 | 109.73 (9) | O3—C6—C5 | 107.86 (9) |
O1—C1—C2 | 109.25 (8) | C10—C6—C5 | 108.85 (9) |
C8—C1—C2 | 117.46 (9) | C7—C6—C5 | 111.64 (9) |
O1—C1—H1 | 106.6 | C8—C7—C6 | 112.49 (9) |
C8—C1—H1 | 106.6 | C8—C7—H7A | 109.1 |
C2—C1—H1 | 106.6 | C6—C7—H7A | 109.1 |
O2—C2—C9 | 107.03 (9) | C8—C7—H7B | 109.1 |
O2—C2—C3 | 108.05 (9) | C6—C7—H7B | 109.1 |
C9—C2—C3 | 111.34 (9) | H7A—C7—H7B | 107.8 |
O2—C2—C1 | 110.03 (9) | C1—C8—C7 | 113.55 (9) |
C9—C2—C1 | 109.05 (9) | C1—C8—H8A | 108.9 |
C3—C2—C1 | 111.25 (9) | C7—C8—H8A | 108.9 |
C2—C3—C4 | 112.14 (9) | C1—C8—H8B | 108.9 |
C2—C3—H3A | 109.2 | C7—C8—H8B | 108.9 |
C4—C3—H3A | 109.2 | H8A—C8—H8B | 107.7 |
C2—C3—H3B | 109.2 | C2—C9—H9A | 109.5 |
C4—C3—H3B | 109.2 | C2—C9—H9B | 109.5 |
H3A—C3—H3B | 107.9 | H9A—C9—H9B | 109.5 |
C5—C4—C3 | 113.28 (9) | C2—C9—H9C | 109.5 |
C5—C4—H4A | 108.9 | H9A—C9—H9C | 109.5 |
C3—C4—H4A | 108.9 | H9B—C9—H9C | 109.5 |
C5—C4—H4B | 108.9 | C6—C10—H10A | 109.5 |
C3—C4—H4B | 108.9 | C6—C10—H10B | 109.5 |
H4A—C4—H4B | 107.7 | H10A—C10—H10B | 109.5 |
O1—C5—C4 | 109.98 (8) | C6—C10—H10C | 109.5 |
O1—C5—C6 | 109.20 (8) | H10A—C10—H10C | 109.5 |
C4—C5—C6 | 117.37 (9) | H10B—C10—H10C | 109.5 |
O1—C5—H5 | 106.6 | ||
C5—O1—C1—C8 | −64.28 (10) | O1—C5—C6—O3 | −173.1 (1) |
C5—O1—C1—C2 | 65.83 (11) | C4—C5—C6—O3 | −47.12 (12) |
O1—C1—C2—O2 | −175.6 (1) | O1—C5—C6—C10 | 68.4 (1) |
C8—C1—C2—O2 | −49.86 (13) | C4—C5—C6—C10 | −165.62 (9) |
O1—C1—C2—C9 | 67.3 (1) | O1—C5—C6—C7 | −55.19 (11) |
C8—C1—C2—C9 | −166.96 (10) | C4—C5—C6—C7 | 70.81 (12) |
O1—C1—C2—C3 | −55.91 (11) | O3—C6—C7—C8 | 162.07 (9) |
C8—C1—C2—C3 | 69.86 (12) | C10—C6—C7—C8 | −78.10 (12) |
O2—C2—C3—C4 | 166.59 (9) | C5—C6—C7—C8 | 43.94 (12) |
C9—C2—C3—C4 | −76.15 (12) | O1—C1—C8—C7 | 51.38 (12) |
C1—C2—C3—C4 | 45.70 (12) | C2—C1—C8—C7 | −74.14 (12) |
C2—C3—C4—C5 | −44.26 (12) | C6—C7—C8—C1 | −42.51 (13) |
C1—O1—C5—C4 | −63.63 (10) | C1—C2—O2—H2 | 79 |
C1—O1—C5—C6 | 66.52 (10) | C1—C2—O2—H12 | −39 |
C3—C4—C5—O1 | 52.01 (11) | C5—C6—O3—H3 | −56 |
C3—C4—C5—C6 | −73.60 (12) | C5—C6—O3—H13 | −162 |
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H2···O2i | 0.84 | 1.92 | 2.728 (2) | 160 |
O2—H12···O3ii | 0.84 | 1.96 | 2.687 (1) | 145 |
O3—H3···O2iii | 0.84 | 2.04 | 2.687 (1) | 133 |
O3—H13···O3iv | 0.84 | 2.02 | 2.738 (2) | 143 |
Symmetry codes: (i) −x, y, −z+1/2; (ii) x−1/2, y−1/2, z; (iii) x+1/2, y+1/2, z; (iv) −x+1, y, −z+1/2. |
Experimental details
Crystal data | |
Chemical formula | C10H18O3 |
Mr | 186.24 |
Crystal system, space group | Monoclinic, C2/c |
Temperature (K) | 170 |
a, b, c (Å) | 10.8900 (2), 9.9227 (2), 18.8981 (3) |
β (°) | 104.658 (11) |
V (Å3) | 1975.63 (12) |
Z | 8 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.40 × 0.23 × 0.17 |
Data collection | |
Diffractometer | Nonius KappaCCD area-detector |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 11200, 2220, 2113 |
Rint | 0.032 |
(sin θ/λ)max (Å−1) | 0.650 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.045, 0.122, 1.08 |
No. of reflections | 2220 |
No. of parameters | 121 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.37, −0.27 |
Computer programs: COLLECT (Nonius, 2000), SCALEPACK (Otwinowski & Minor, 1997), SCALEPACK and DENZO (Otwinowski & Minor, 1997), SIR97 (Altomare et al., 1999), SHELXL97 (Sheldrick, 1997), WinGX (Farrugia, 1999), PLATON (Spek, 2003) and Mercury (Macrae et al., 2006).
O1—C1—C2—O2 | −175.6 (1) | C1—C2—O2—H2 | 79 |
O1—C1—C2—C9 | 67.3 (1) | C1—C2—O2—H12 | −39 |
O1—C5—C6—O3 | −173.1 (1) | C5—C6—O3—H3 | −56 |
O1—C5—C6—C10 | 68.4 (1) | C5—C6—O3—H13 | −162 |
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H2···O2i | 0.84 | 1.92 | 2.728 (2) | 160 |
O2—H12···O3ii | 0.84 | 1.96 | 2.687 (1) | 145 |
O3—H3···O2iii | 0.84 | 2.04 | 2.687 (1) | 133 |
O3—H13···O3iv | 0.84 | 2.02 | 2.738 (2) | 143 |
Symmetry codes: (i) −x, y, −z+1/2; (ii) x−1/2, y−1/2, z; (iii) x+1/2, y+1/2, z; (iv) −x+1, y, −z+1/2. |
In a project related with the synthesis of a universal template for resolution of racemic mixtures of secondary alcohols, the intermediate title compound was synthesized (Carrasco, 2001). On the other hand, the analogous syn-diols derivatives studied so far have proved to have inclusion behaviour (Kim et al., 2002).
The two independent molecules of (I) in the Cc space group differ from each other only in the orientation of the H atoms of the hydroxyl groups. The molecules are almost related by a twofold axis which is a crystallographic one in the C2/c space group and, therefore, the H atoms are split into two positions (Figure 1). The same situation has been observed (Cambridge Crystallographic Database, Allen, 2002) in the structure of the endo-2,endo-6-dihydroxy-2,6-dimethylbicyclo(3.3.1)nonane compound described in the Pc group (SEWXAT refcode: Hawkins et al., 1990) with a CH2 group instead of the ether bridge while in the thio-bicycle derivative (SEWXEX refcode, P21/c space group: Hawkins et al., 1990) the H of the hydroxyl groups appear to be disordered.
The six-membered rings are in a slightly distorted chair conformation with the hydroxyl groups in equatorial position, anti with respect to the ether atom O1 (Table 1). These OH groups are involved in the formation of the R44(8) hydrogen bonding motif (Bernstein et al., 1995) acting as both donor and acceptor of hydrogen bonds that results into sheets (Table 2, Figure 2 and 3). Weak C—H···Oether contacts link the layers into a three-dimensional network (2.65, 3.613 (1)Å and 162° for the H···A, D···A distances and DH···A angle). This layered structure is similar to that of carbo-bicycle and thio-biclycle analogues (SEWXAT and SEWXEX) but dissimilar to that of the exo diastereoisomer derivative (OH groups in syn disposition with respect to the ether bridge (WASWAO, Pich et al., 1993). These results are in agreement with the rules proposed by Kim et al., (2002) to be fulfilled by the molecular structure of these derivatives to form supramolecular tubulant hydrogen-bonding networks.