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6-Methoxy­purine crystallizes from N,N-methyl­form­amide as the hemihydrate, C6H6N4O·0.5H2O, and from water as the trihydrate, C6H6N4O·3H2O. Both forms crystallize in the triclinic crystal system. Upon heating the trihydrate, mol­ecules of water are liberated successively; the hemihydrate is formed at 383 K. In the hemihydrate, the H atom on the imidazole N atom is disordered between the two N atoms. The water mol­ecule in the hemihydrate and the H atoms of a water mol­ecule in the trihydrate are also disordered. In the hemihydrate, the organic moieties are connected by N—H...N hydrogen bonds, while they are connected via water mol­ecules in the trihydrate.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S010827010302314X/av1151sup1.cif
Contains datablocks I, II, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S010827010302314X/av1151Isup2.hkl
Contains datablock I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S010827010302314X/av1151IIsup3.hkl
Contains datablock II

CCDC references: 231066; 231067

Comment top

6-Methoxypurine, (1), has been examined for its ability to undergo methyl rearrangement in the solid or liquid state (Kaftory & Handelsman-Benory, 1994; Handelsman-Benory et al., 2000; Greenberg et al. 2001; Kaftory et al., 2001; Kaftory, 2002). Therefore, the structure and the thermal behavior of the commercially available 6-methoxypurine hemihydrate were investigated. Attempts to crystallize the hemihydrate of (1) from water failed, and a trihydrate form was obtained. Later, it was found that the hemihydrate can be crystallized from N,N-methylformamide. The crystal structures and the thermal behavior of the two hydrates are described below.

The structures of the hemihydrate, (I), and trihydrate, (II), showing the atomic numbering and hydrogen bonding, are given in Figs. 1 and 2, respectively. 6-Methoxypurine was expected to pack in a similar way to aminopurine, (2) (Serra, Dorner & Silver, 1992). Aminopurine forms dimers held by hydrogen bonds, as shown in the scheme. However, 6-methoxypurine crystallizes either with half a molecule or with three molecules of water. 6-Methoxypurine hemihydrate, (I), crystallizes with two symmetry-independent molecules. The water molecule is hydrogen bonded to the organic moiety, while the organic moieties are linked to one another by N—H···N hydrogen bonds (Table 2 and Fig. 1). It should be noted that the water molecule is equally disordered, as well as the amino H atom (H3), which is equally distributed between atoms N3 and N4. The disorder is also expressed by the similar lengths of the N3—C5 and N4—C5 bonds. Formally, one bond should be a single and the other a double bond. However, the experimental distances are 1.339 and 1.328 Å [(in molecule A of (I)], and 1.331 and 1.320 Å (in molecule B), while in 6-methoxypurine trihydrate, (II), those distances are 1.348 and 1.321 Å for the single and double bonds, respectively. In the crystal structure of (II), the water molecules serve as linkers between the organic molecules, via hydrogen bonding. There are nine strong hydrogen bonds, of which six are between the water molecules, and three are between molecules of water and the organic moiety (Table 3 and Fig. 2). One of the water molecules is found to be disordered.

The thermal behavior of (I) is shown by the DSC thermograph given in Fig. 3. The thermograph consists of two single endotherms. The first endothermic peak is assigned to the liberation of molecules of water at 399 K (ΔH = 11.08 kJ mol−1). The second endothermic peak at 466 K (ΔH = 5.27 kJ mol−1) is assigned to the melting, and the last exothermic peak at 470 K (ΔH = −33.06 kJ mol−1) is assigned to the methyl rearrangement in the liquid state. The DSC thermographs of (I) and (II) (Fig. 4) are identical in the temperature range 383–493 K, but that of (II) includes two more endothermic peaks at lower temperatures. The extra two peaks are assigned to the liberation of two crystallographically non-identical molecules of water. One is liberated at 342 K (ΔH1 = 21.84 kJ mol−1) and the second is liberated at 372 K (ΔH2 = 44.71 kJ mol−1).

Experimental top

6-Methoxypurine was obtained from a commercial source (Aldrich) and was used without futher purification. Needle-shaped crystals of (I) were grown from N,N-methylformamide, and plate-like crystals of (II) were obtained from water.

Refinement top

Both structures are disordered and therefore the refinement did not converge very satisfactorily. The most difficult part is the refinement of the disordered water molecules. In (I), the water molecules equally occupy two sites and the O atoms refined satisfactorily. One of the H atoms of each water molecule occupies the same site, and therefore it has a full occupancy and refines well. However, only one of the other two H atoms, with an occupancy of 1/2, could be detected and refined. In (II), there are two water molecules that are rotationally disordered, in which one of the H atoms has a full ocupancy. while the second is disordered between two sites.

Computing details top

Data collection: Collect (Nonius, 2001) for (II). For both compounds, cell refinement: DENZO SMN (Otwinowski & Minor 1997); data reduction: DENZO SMN; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997).

Figures top
[Figure 1]
[Figure 2]
[Figure 3]
[Figure 4]
Figure 1. Packing of molecules of (I) in the unit cell. Displacement ellipsoids for non-H atoms are drawn at the 50% probability level. H atoms are drawn as small circles of arbitrary radius.

Figure 2. Packing of molecules of (II) in the unit cell. Displacement ellipsoids for non-H atoms are drawn at the 50% probability level. H atoms are drawn as small circles of arbitrary radius.

Figure 3. DSC thermogram for (I) (heating rate 5 K min−1, weight 7.8 mg).

Figure 4. DSC thermogram for (II) (heating rate 5 K min−1, weight 3.4 mg).

Table 1. Comparison of selected geometric parameters (Å, °).

Table 2. Hydrogen-bonding geometry (Å, °) for (I:1/2H2O).

Table 3. Hydrogen-bonding geometry (Å, °) for (II:3H2O).
(I) 6-Methoxypurine hemihydrate top
Crystal data top
C6H6N4O·0.5H2OZ = 4
Mr = 158.91F(000) = 331
Triclinic, P1Dx = 1.455 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 3.898 (1) ÅCell parameters from 2579 reflections
b = 11.966 (2) Åθ = 1.3–25.1°
c = 15.945 (3) ŵ = 0.11 mm1
α = 79.08 (2)°T = 293 K
β = 83.54 (2)°Needle, colorless
γ = 87.09 (2)°0.30 × 0.12 × 0.09 mm
V = 725.3 (3) Å3
Data collection top
KappaCCD
diffractometer
1877 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.000
Graphite monochromatorθmax = 25.1°, θmin = 1.3°
Detector resolution: 95 pixels mm-1h = 40
phi scank = 1414
2579 measured reflectionsl = 1818
2574 independent 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) = 0.125H atoms treated by a mixture of independent and constrained refinement
S = 1.03 w = 1/[σ2(Fo2) + (0.0663P)2 + 0.0856P]
where P = (Fo2 + 2Fc2)/3
2574 reflections(Δ/σ)max < 0.001
227 parametersΔρmax = 0.15 e Å3
0 restraintsΔρmin = 0.18 e Å3
Crystal data top
C6H6N4O·0.5H2Oγ = 87.09 (2)°
Mr = 158.91V = 725.3 (3) Å3
Triclinic, P1Z = 4
a = 3.898 (1) ÅMo Kα radiation
b = 11.966 (2) ŵ = 0.11 mm1
c = 15.945 (3) ÅT = 293 K
α = 79.08 (2)°0.30 × 0.12 × 0.09 mm
β = 83.54 (2)°
Data collection top
KappaCCD
diffractometer
1877 reflections with I > 2σ(I)
2579 measured reflectionsRint = 0.000
2574 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0500 restraints
wR(F2) = 0.125H atoms treated by a mixture of independent and constrained refinement
S = 1.03Δρmax = 0.15 e Å3
2574 reflectionsΔρmin = 0.18 e Å3
227 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
xyzUiso*/UeqOcc. (<1)
O1a0.6004 (4)0.17735 (12)0.57623 (9)0.0513 (4)
N1a0.3007 (5)0.10988 (16)0.70881 (12)0.0517 (5)
N2a0.3002 (5)0.09016 (17)0.77123 (11)0.0551 (5)
N3a0.6395 (5)0.20579 (15)0.67980 (11)0.0502 (5)
H3a0.60940.27310.70960.075*0.50
N4a0.8240 (4)0.06582 (14)0.57258 (11)0.0461 (4)
H4a0.92740.03120.52500.069*0.50
C1a0.5031 (5)0.09128 (18)0.64025 (13)0.0429 (5)
C2a0.2139 (6)0.0187 (2)0.76993 (15)0.0588 (6)
H2a0.07410.03430.81780.088*
C3a0.5068 (5)0.10510 (18)0.70015 (13)0.0437 (5)
C4a0.6192 (5)0.01840 (17)0.63365 (12)0.0402 (5)
C5a0.8262 (6)0.17696 (18)0.60357 (14)0.0501 (6)
H5a0.94660.23010.57490.075*
C6a0.4507 (6)0.28837 (19)0.58251 (16)0.0599 (6)
H61a0.53200.34220.53250.090*
H62a0.51660.31130.63280.090*
H63a0.20360.28560.58640.078*
O1b0.3055 (4)0.26814 (13)0.99590 (9)0.0581 (4)
N1b0.6583 (5)0.25610 (16)0.87015 (12)0.0526 (5)
N2b0.7657 (5)0.41991 (16)0.75812 (11)0.0511 (5)
N3b0.4729 (5)0.59235 (15)0.79422 (11)0.0496 (5)
H3b0.53600.64210.74940.074*0.50
N4b0.2148 (4)0.51723 (15)0.92284 (11)0.0481 (5)
H4b0.09080.51160.97150.072*0.50
C1b0.4592 (5)0.31604 (18)0.91809 (13)0.0442 (5)
C2b0.7993 (6)0.3108 (2)0.79300 (15)0.0543 (6)
H2b0.93770.26610.76010.081*
C3b0.5617 (5)0.47891 (18)0.80940 (13)0.0425 (5)
C4b0.4021 (5)0.43178 (17)0.88953 (12)0.0409 (5)
C5b0.2680 (6)0.60951 (19)0.86348 (14)0.0520 (6)
H5b0.17050.68050.86950.078*
C6b0.3549 (7)0.1476 (2)1.02206 (18)0.0779 (8)
H61b0.23040.12331.07750.117*
H62b0.59650.12941.02510.117*
H63b0.27100.10920.98110.117*
O1Wa0.1399 (19)0.5447 (4)0.5806 (3)0.0863 (14)0.50
O1Wb0.0946 (18)0.5416 (4)0.5868 (4)0.0790 (14)0.50
H1W0.034 (13)0.510 (4)0.622 (3)0.121 (16)*
H1Wb0.32 (2)0.550 (7)0.596 (5)0.15 (3)*0.50
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O1a0.0628 (9)0.0363 (9)0.0505 (9)0.0013 (7)0.0042 (7)0.0029 (7)
N1a0.0564 (11)0.0488 (12)0.0474 (11)0.0009 (8)0.0033 (9)0.0078 (9)
N2a0.0633 (12)0.0532 (13)0.0428 (11)0.0045 (9)0.0071 (9)0.0004 (9)
N3a0.0625 (11)0.0381 (11)0.0450 (11)0.0050 (8)0.0026 (9)0.0010 (8)
N4a0.0572 (10)0.0379 (11)0.0404 (10)0.0033 (8)0.0047 (8)0.0055 (8)
C1a0.0459 (11)0.0412 (13)0.0400 (12)0.0057 (9)0.0047 (9)0.0021 (9)
C2a0.0656 (15)0.0618 (17)0.0444 (13)0.0001 (12)0.0108 (11)0.0080 (12)
C3a0.0482 (11)0.0423 (13)0.0386 (11)0.0036 (9)0.0015 (9)0.0032 (9)
C4a0.0457 (11)0.0379 (12)0.0352 (11)0.0031 (9)0.0010 (9)0.0035 (9)
C5a0.0626 (14)0.0380 (13)0.0472 (13)0.0021 (10)0.0014 (11)0.0052 (10)
C6a0.0661 (15)0.0403 (13)0.0698 (16)0.0020 (11)0.0048 (12)0.0042 (12)
O1b0.0726 (10)0.0471 (9)0.0465 (9)0.0057 (7)0.0025 (7)0.0078 (7)
N1b0.0603 (11)0.0451 (11)0.0504 (11)0.0031 (9)0.0031 (9)0.0065 (9)
N2b0.0553 (11)0.0530 (12)0.0420 (10)0.0005 (8)0.0049 (8)0.0076 (9)
N3b0.0614 (11)0.0407 (11)0.0418 (10)0.0047 (8)0.0048 (8)0.0005 (8)
N4b0.0576 (11)0.0431 (11)0.0399 (10)0.0021 (8)0.0074 (8)0.0056 (8)
C1b0.0492 (12)0.0425 (13)0.0393 (12)0.0054 (9)0.0062 (9)0.0016 (10)
C2b0.0597 (14)0.0512 (15)0.0500 (14)0.0073 (11)0.0002 (11)0.0100 (12)
C3b0.0489 (11)0.0389 (12)0.0382 (11)0.0044 (9)0.0012 (9)0.0041 (9)
C4b0.0459 (11)0.0410 (12)0.0344 (11)0.0030 (9)0.0014 (9)0.0049 (9)
C5b0.0638 (14)0.0401 (13)0.0484 (13)0.0005 (10)0.0031 (11)0.0044 (10)
C6b0.0866 (19)0.0533 (16)0.0791 (19)0.0024 (13)0.0033 (15)0.0221 (14)
O1Wa0.130 (5)0.061 (3)0.061 (3)0.002 (3)0.006 (3)0.004 (2)
O1Wb0.087 (3)0.064 (3)0.073 (3)0.004 (3)0.012 (3)0.011 (2)
Geometric parameters (Å, º) top
O1a—C1a1.342 (3)N1b—C1b1.311 (3)
O1a—C6a1.440 (3)N1b—C2b1.350 (3)
N1a—C1a1.322 (3)N2b—C2b1.325 (3)
N1a—C2a1.347 (3)N2b—C3b1.347 (3)
N2a—C2a1.325 (3)N3b—C5b1.331 (3)
N2a—C3a1.350 (3)N3b—C3b1.367 (3)
N3a—C5a1.339 (3)N3b—H3b0.8600
N3a—C3a1.368 (3)N4b—C5b1.320 (3)
N3a—H3a0.8600N4b—C4b1.380 (3)
N4a—C5a1.328 (3)N4b—H4b0.8600
N4a—C4a1.377 (3)C1b—C4b1.388 (3)
N4a—H4a0.8600C2b—H2b0.9300
C1a—C4a1.385 (3)C3b—C4b1.386 (3)
C2a—H2a0.9300C5b—H5b0.9300
C3a—C4a1.385 (3)C6b—H61b0.9600
C5a—H5a0.9300C6b—H62b0.9600
C6a—H61a0.9600C6b—H63b0.9600
C6a—H62a0.9600O1Wa—O1Wb0.929 (6)
C6a—H63a0.9600O1Wa—H1W0.85 (4)
O1b—C1b1.351 (3)O1Wb—H1W0.77 (5)
O1b—C6b1.433 (3)O1Wb—H1Wb0.94 (9)
C1a—O1a—C6a116.87 (18)C2b—N2b—C3b112.37 (19)
C1a—N1a—C2a117.3 (2)C5b—N3b—C3b105.39 (18)
C2a—N2a—C3a111.70 (19)C5b—N3b—H3b127.3
C5a—N3a—C3a105.14 (18)C3b—N3b—H3b127.3
C5a—N3a—H3a127.4C5b—N4b—C4b104.72 (18)
C3a—N3a—H3a127.4C5b—N4b—H4b127.6
C5a—N4a—C4a104.63 (17)C4b—N4b—H4b127.6
C5a—N4a—H4a127.7N1b—C1b—O1b121.63 (19)
C4a—N4a—H4a127.7N1b—C1b—C4b120.17 (19)
N1a—C1a—O1a121.07 (19)O1b—C1b—C4b118.20 (19)
N1a—C1a—C4a120.1 (2)N2b—C2b—N1b128.3 (2)
O1a—C1a—C4a118.86 (19)N2b—C2b—H2b115.8
N2a—C2a—N1a129.0 (2)N1b—C2b—H2b115.8
N2a—C2a—H2a115.5N2b—C3b—N3b128.11 (19)
N1a—C2a—H2a115.5N2b—C3b—C4b124.4 (2)
N2a—C3a—N3a127.3 (2)N3b—C3b—C4b107.54 (18)
N2a—C3a—C4a124.9 (2)N4b—C4b—C3b108.08 (18)
N3a—C3a—C4a107.78 (19)N4b—C4b—C1b134.77 (19)
N4a—C4a—C3a108.42 (18)C3b—C4b—C1b117.15 (19)
N4a—C4a—C1a134.48 (19)N4b—C5b—N3b114.3 (2)
C3a—C4a—C1a117.08 (19)N4b—C5b—H5b122.9
N4a—C5a—N3a114.03 (19)N3b—C5b—H5b122.9
N4a—C5a—H5a123.0O1b—C6b—H61b109.5
N3a—C5a—H5a123.0O1b—C6b—H62b109.5
O1a—C6a—H61a109.5H61b—C6b—H62b109.5
O1a—C6a—H62a109.5O1b—C6b—H63b109.5
H61a—C6a—H62a109.5H61b—C6b—H63b109.5
O1a—C6a—H63a109.5H62b—C6b—H63b109.5
H61a—C6a—H63a109.5O1Wb—O1Wa—H1W51 (3)
H62a—C6a—H63a109.5O1Wa—O1Wb—H1W59 (4)
C1b—O1b—C6b117.08 (19)O1Wa—O1Wb—H1Wb170 (5)
C1b—N1b—C2b117.65 (19)H1W—O1Wb—H1Wb121 (6)
C2A—N1A—C1A—O1A179.69 (18)C2B—N1B—C1B—O1B179.50 (18)
C2A—N1A—C1A—C4A0.5 (3)C2B—N1B—C1B—C4B0.7 (3)
C6A—O1A—C1A—N1A5.2 (3)C6B—O1B—C1B—N1B3.1 (3)
C6A—O1A—C1A—C4A174.96 (18)C6B—O1B—C1B—C4B177.03 (19)
C3A—N2A—C2A—N1A0.9 (3)C3B—N2B—C2B—N1B0.1 (3)
C1A—N1A—C2A—N2A0.9 (4)C1B—N1B—C2B—N2B0.5 (3)
C2A—N2A—C3A—N3A178.9 (2)C2B—N2B—C3B—N3B179.7 (2)
C2A—N2A—C3A—C4A0.4 (3)C2B—N2B—C3B—C4B0.3 (3)
C5A—N3A—C3A—N2A179.9 (2)C5B—N3B—C3B—N2B179.9 (2)
C5A—N3A—C3A—C4A0.5 (2)C5B—N3B—C3B—C4B0.2 (2)
C5A—N4A—C4A—C3A0.3 (2)C5B—N4B—C4B—C3B0.2 (2)
C5A—N4A—C4A—C1A177.7 (2)C5B—N4B—C4B—C1B179.8 (2)
N2A—C3A—C4A—N4A179.92 (18)N2B—C3B—C4B—N4B179.87 (18)
N3A—C3A—C4A—N4A0.5 (2)N3B—C3B—C4B—N4B0.2 (2)
N2A—C3A—C4A—C1A1.6 (3)N2B—C3B—C4B—C1B0.1 (3)
N3A—C3A—C4A—C1A177.87 (17)N3B—C3B—C4B—C1B179.79 (17)
N1A—C1A—C4A—N4A179.4 (2)N1B—C1B—C4B—N4B179.6 (2)
O1A—C1A—C4A—N4A0.8 (3)O1B—C1B—C4B—N4B0.2 (3)
N1A—C1A—C4A—C3A1.5 (3)N1B—C1B—C4B—C3B0.4 (3)
O1A—C1A—C4A—C3A178.60 (17)O1B—C1B—C4B—C3B179.80 (17)
C4A—N4A—C5A—N3A0.0 (2)C4B—N4B—C5B—N3B0.1 (2)
C3A—N3A—C5A—N4A0.3 (2)C3B—N3B—C5B—N4B0.1 (2)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N4a—H4a···N4ai0.861.952.801 (3)171
N3a—H3a···N3bii0.861.952.794 (3)167
N4b—H4b···N4biii0.861.942.791 (3)173
N3b—H3b···N3aiv0.861.982.794 (3)158
O1Wb—H1Wa···N2bv0.772.303.021 (3)157
Symmetry codes: (i) x+2, y, z+1; (ii) x, y1, z; (iii) x, y+1, z+2; (iv) x, y+1, z; (v) x1, y, z.
(II) 6-Methoxypurine trihydrate top
Crystal data top
C6H6N4O·3H2OZ = 2
Mr = 204.20F(000) = 216
Triclinic, P1Dx = 1.361 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 6.837 (1) ÅCell parameters from 3048 reflections
b = 7.819 (2) Åθ = 2.2–25.0°
c = 10.281 (2) ŵ = 0.11 mm1
α = 70.13 (2)°T = 293 K
β = 75.49 (2)°Prism, colorless
γ = 80.29 (2)°0.40 × 0.30 × 0.30 mm
V = 498.29 (18) Å3
Data collection top
KappaCCD
diffractometer
1244 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.022
Graphite monochromatorθmax = 25.0°, θmin = 2.2°
Detector resolution: 95 pixels mm-1h = 87
phi scank = 98
3048 measured reflectionsl = 1211
1765 independent 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)] = 0.037Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.094H atoms treated by a mixture of independent and constrained refinement
S = 0.92 w = 1/[σ2(Fo2) + (0.0599P)2]
where P = (Fo2 + 2Fc2)/3
1765 reflections(Δ/σ)max = 0.024
160 parametersΔρmax = 0.18 e Å3
0 restraintsΔρmin = 0.17 e Å3
Crystal data top
C6H6N4O·3H2Oγ = 80.29 (2)°
Mr = 204.20V = 498.29 (18) Å3
Triclinic, P1Z = 2
a = 6.837 (1) ÅMo Kα radiation
b = 7.819 (2) ŵ = 0.11 mm1
c = 10.281 (2) ÅT = 293 K
α = 70.13 (2)°0.40 × 0.30 × 0.30 mm
β = 75.49 (2)°
Data collection top
KappaCCD
diffractometer
1244 reflections with I > 2σ(I)
3048 measured reflectionsRint = 0.022
1765 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0370 restraints
wR(F2) = 0.094H atoms treated by a mixture of independent and constrained refinement
S = 0.92Δρmax = 0.18 e Å3
1765 reflectionsΔρmin = 0.17 e Å3
160 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
xyzUiso*/UeqOcc. (<1)
O10.19668 (16)0.30631 (14)0.74931 (11)0.0533 (3)
N10.25371 (17)0.29417 (17)0.52070 (13)0.0446 (3)
N20.29658 (17)0.56566 (17)0.31939 (12)0.0447 (3)
N30.26624 (17)0.83905 (17)0.38841 (13)0.0462 (4)
H3N0.28400.92230.30740.069*
N40.20967 (18)0.71038 (17)0.62353 (13)0.0458 (4)
C10.2274 (2)0.3883 (2)0.60997 (15)0.0406 (4)
C20.2869 (2)0.3871 (2)0.38155 (16)0.0481 (4)
H20.30530.31740.32120.072*
C30.26780 (19)0.65585 (19)0.41363 (15)0.0377 (4)
C40.23320 (18)0.57715 (19)0.55911 (14)0.0386 (4)
C50.2312 (2)0.8630 (2)0.51637 (16)0.0497 (4)
H50.22300.97700.52810.075*
C60.1843 (3)0.1112 (2)0.80051 (19)0.0668 (5)
H6a0.06120.08460.78560.100*
H6b0.18500.06640.89970.100*
H6c0.29860.05300.75030.100*
O1W0.06376 (19)0.67067 (18)0.91286 (14)0.0568 (4)
O2W0.60220 (19)0.3358 (2)0.98014 (14)0.0608 (4)
O3W0.2944 (2)0.1132 (2)0.13579 (15)0.0769 (5)
H1Wa0.117 (4)0.674 (3)0.819 (3)0.131 (9)*
H1Wb0.191 (6)0.683 (5)0.956 (4)0.066 (10)*0.50
H1Wc0.029 (6)0.565 (5)0.961 (4)0.071 (14)*0.50
H2Wa0.644 (3)0.352 (3)0.887 (3)0.105 (8)*
H2Wb0.574 (11)0.471 (13)0.995 (9)0.20 (3)*0.50
H2Wc0.683 (16)0.242 (16)1.003 (11)0.32 (6)*0.50
H3Wa0.180 (5)0.178 (4)0.120 (3)0.163 (13)*
H3Wb0.395 (4)0.175 (3)0.082 (2)0.095 (7)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
O10.0736 (7)0.0421 (7)0.0385 (6)0.0142 (5)0.0107 (5)0.0018 (5)
N10.0521 (7)0.0379 (8)0.0443 (8)0.0073 (6)0.0086 (5)0.0130 (6)
N20.0486 (7)0.0465 (9)0.0369 (7)0.0052 (5)0.0078 (5)0.0107 (6)
N30.0531 (8)0.0379 (8)0.0401 (7)0.0059 (5)0.0095 (5)0.0022 (6)
N40.0578 (8)0.0379 (8)0.0398 (7)0.0053 (6)0.0064 (5)0.0119 (6)
C10.0395 (8)0.0397 (10)0.0380 (8)0.0063 (6)0.0076 (6)0.0052 (7)
C20.0551 (9)0.0467 (10)0.0447 (9)0.0056 (7)0.0091 (7)0.0174 (8)
C30.0357 (7)0.0354 (9)0.0389 (8)0.0030 (6)0.0072 (6)0.0080 (7)
C40.0392 (8)0.0376 (9)0.0373 (8)0.0044 (6)0.0072 (6)0.0096 (7)
C50.0589 (10)0.0380 (10)0.0507 (10)0.0028 (7)0.0098 (7)0.0139 (8)
C60.0895 (13)0.0430 (11)0.0562 (11)0.0200 (9)0.0162 (9)0.0067 (8)
O1W0.0659 (8)0.0577 (9)0.0424 (7)0.0096 (6)0.0084 (6)0.0103 (6)
O2W0.0698 (8)0.0679 (10)0.0415 (7)0.0143 (7)0.0068 (5)0.0125 (6)
O3W0.0655 (9)0.0673 (9)0.0683 (9)0.0104 (7)0.0094 (7)0.0153 (7)
Geometric parameters (Å, º) top
O1—C11.3333 (17)C3—C41.385 (2)
O1—C61.444 (2)C5—H50.9300
N1—C11.3220 (19)C6—H6a0.9600
N1—C21.3463 (19)C6—H6b0.9600
N2—C21.3287 (19)C6—H6c0.9600
N2—C31.3405 (18)O1W—H1Wa0.93 (3)
N3—C51.348 (2)O1W—H1Wb1.11 (4)
N3—C31.3649 (19)O1W—H1Wc0.84 (3)
N3—H3N0.8600O2W—H2Wa0.90 (3)
N4—C51.3207 (19)O2W—H2Wb1.10 (10)
N4—C41.3816 (19)O2W—H2Wc0.85 (10)
C1—C41.393 (2)O3W—H3Wa0.87 (3)
C2—H20.9300O3W—H3Wb0.87 (2)
C1—O1—C6117.77 (13)C3—C4—C1116.39 (14)
C1—N1—C2117.71 (13)N4—C5—N3114.07 (14)
C2—N2—C3112.03 (12)N4—C5—H5123.0
C5—N3—C3106.02 (12)N3—C5—H5123.0
C5—N3—H3N127.0O1—C6—H6a109.5
C3—N3—H3N127.0O1—C6—H6b109.5
C5—N4—C4103.67 (12)H6A—C6—H6b109.5
N1—C1—O1121.46 (13)O1—C6—H6c109.5
N1—C1—C4120.06 (13)H6A—C6—H6c109.5
O1—C1—C4118.49 (14)H6B—C6—H6c109.5
N2—C2—N1128.29 (15)H1Wa—O1W—H1Wb107 (2)
N2—C2—H2115.9H1Wa—O1W—H1Wc109 (3)
N1—C2—H2115.9H1Wb—O1W—H1Wc103 (3)
N2—C3—N3128.22 (13)H2Wa—O2W—H2Wb108 (5)
N2—C3—C4125.53 (13)H2Wa—O2W—H2Wc94 (7)
N3—C3—C4106.26 (13)H2Wb—O2W—H2Wc136 (9)
N4—C4—C3109.99 (13)H3Wa—O3W—H3Wb109 (2)
N4—C4—C1133.62 (13)
C2—N1—C1—O1179.04 (12)C5—N4—C4—C1179.61 (14)
C2—N1—C1—C40.41 (19)N2—C3—C4—N4179.81 (12)
C6—O1—C1—N12.6 (2)N3—C3—C4—N40.22 (15)
C6—O1—C1—C4177.97 (12)N2—C3—C4—C10.30 (19)
C3—N2—C2—N10.2 (2)N3—C3—C4—C1179.73 (11)
C1—N1—C2—N20.2 (2)N1—C1—C4—N4179.19 (14)
C2—N2—C3—N3179.56 (13)O1—C1—C4—N41.3 (2)
C2—N2—C3—C40.47 (19)N1—C1—C4—C30.17 (19)
C5—N3—C3—N2179.90 (13)O1—C1—C4—C3179.29 (12)
C5—N3—C3—C40.12 (14)C4—N4—C5—N30.14 (16)
C5—N4—C4—C30.22 (15)C3—N3—C5—N40.01 (16)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N3—H3N···O3Wi0.861.882.735 (2)174
O1W—H1Wa···N40.94 (3)1.89 (3)2.816 (2)173 (2)
O1W—H1Wb···O2Wii1.111.662.759 (2)170
O1W—H1Wc···O1Wiii0.841.962.801 (2)174
O2W—H2Wa···N2iv0.90 (3)1.95 (3)2.838 (2)169
O2W—H2Wb···O2Wii1.101.812.815 (2)150
O3W—H3Wb···O2Wv0.87 (3)1.91 (3)2.770 (2)172
O3W—H3Wa···O1Wvi0.88 (3)1.91 (3)2.783 (2)177
Symmetry codes: (i) x, y+1, z; (ii) x+1, y+1, z+2; (iii) x, y+1, z+2; (iv) x+1, y+1, z+1; (v) x, y, z1; (vi) x, y+1, z+1.

Experimental details

(I)(II)
Crystal data
Chemical formulaC6H6N4O·0.5H2OC6H6N4O·3H2O
Mr158.91204.20
Crystal system, space groupTriclinic, P1Triclinic, P1
Temperature (K)293293
a, b, c (Å)3.898 (1), 11.966 (2), 15.945 (3)6.837 (1), 7.819 (2), 10.281 (2)
α, β, γ (°)79.08 (2), 83.54 (2), 87.09 (2)70.13 (2), 75.49 (2), 80.29 (2)
V3)725.3 (3)498.29 (18)
Z42
Radiation typeMo KαMo Kα
µ (mm1)0.110.11
Crystal size (mm)0.30 × 0.12 × 0.090.40 × 0.30 × 0.30
Data collection
DiffractometerKappaCCD
diffractometer
KappaCCD
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
2579, 2574, 1877 3048, 1765, 1244
Rint0.0000.022
(sin θ/λ)max1)0.5960.596
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.050, 0.125, 1.03 0.037, 0.094, 0.92
No. of reflections25741765
No. of parameters227160
H-atom treatmentH atoms treated by a mixture of independent and constrained refinementH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.15, 0.180.18, 0.17

Computer programs: Collect (Nonius, 2001), DENZO SMN (Otwinowski & Minor 1997), DENZO SMN, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEP-3 for Windows (Farrugia, 1997).

Hydrogen-bond geometry (Å, º) for (I) top
D—H···AD—HH···AD···AD—H···A
N4a—H4a···N4ai0.861.952.801 (3)171
N3a—H3a···N3bii0.861.952.794 (3)167
N4b—H4b···N4biii0.861.942.791 (3)173
N3b—H3b···N3aiv0.861.982.794 (3)158
O1Wb—H1Wa···N2bv0.772.303.021 (3)157
Symmetry codes: (i) x+2, y, z+1; (ii) x, y1, z; (iii) x, y+1, z+2; (iv) x, y+1, z; (v) x1, y, z.
Comparison of selected geometric parameters (Å, °) top
Hemihydrate (I)Hemihydrate (I)Trihydrate (II)
Molecule AMolecule B
O1-C11.342 (3)1.351 (3)1.333 (2)
O1-C61.440 (3)1.433 (3)1.444 (2)
N1-C11.322 (3)1.311 (3)1.322 (2)
N1-C21.347 (3)1.350 (3)1.346 (2)
N2-C21.325 (3)1.325 (3)1.329 (2)
N2-C31.350 (3)1.347 (3)1.341 (2)
N3-C31.368 (3)1.367 (3)1.365 (2)
N4-C51.329 (3)1.320 (3)1.321 (2)
N4-C41.377 (3)1.380 (3)1.382 (2)
C1-C41.385 (3)1.388 (3)1.393 (2)
C3-C41.385 (3)1.386 (3)1.385 (2)
C1-O1-C6116.8 (2)117.1 (2)117.8 (1)
C1-N1-C2117.3 (2)117.7 (2)117.7 (1)
C2-N2-C3111.7 (2)112.4 (2)112.0 (1)
C5-N3-C3105.1 (2)105.4 (2)106.0 (1)
C5-N4-C4104.6 (2)104.7 (2)103.7 (1)
N1-C1-O1121.1 (2)121.6 (2)121.5 (1)
N1-C1-C4120.1 (2)120.2 (2)120.1 (1)
O1-C1-C4118.9 (2)118.2 (2)118.5 (1)
N2-C2-N1129.0 (2)128.3 (2)128.3 (2)
N2-C3-N3127.3 (2)128.1 (2)128.2 (1)
N2-C3-C4124.9 (2)124.4 (2)125.5 (1)
N3-C3-C4107.8 (2)107.5 (2)106.3 (1)
N4-C4-C1134.5 (2)134.8 (2)133.6 (1)
N4-C4-C3108.4 (2)108.1 (2)110.0 (1)
C1-C4-C3117.1 (2)117.2 (2)116.3 (1)
N4-C5-N3114.0 (2)114.2 (2)114.1 (1)
Hydrogen-bond geometry (Å, º) for (II) top
D—H···AD—HH···AD···AD—H···A
N3—H3N···O3Wi0.861.882.735 (2)174
O1W—H1Wa···N40.94 (3)1.89 (3)2.816 (2)173 (2)
O1W—H1Wb···O2Wii1.111.662.759 (2)170
O1W—H1Wc···O1Wiii0.841.962.801 (2)174
O2W—H2Wa···N2iv0.90 (3)1.95 (3)2.838 (2)169
O2W—H2Wb···O2Wii1.101.812.815 (2)150
O3W—H3Wb···O2Wv0.87 (3)1.91 (3)2.770 (2)172
O3W—H3Wa···O1Wvi0.88 (3)1.91 (3)2.783 (2)177
Symmetry codes: (i) x, y+1, z; (ii) x+1, y+1, z+2; (iii) x, y+1, z+2; (iv) x+1, y+1, z+1; (v) x, y, z1; (vi) x, y+1, z+1.
 

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