Two structures presenting an uncomplexed 2,6-diaminopurine (dap) group are reported, namely 2,6-diamino-9H-purine monohydrate, C5H6N6·H2O, (I), and bis(2,6-diamino-9H-purin-1-ium) 2-(2-carboxylatophenyl)acetate heptahydrate, 2C5H7N6+·C9H6O42−·7H2O, (II). Both structures are rather featureless from a molecular point of view, but present instead an outstanding hydrogen-bonding scheme. In compound (I), this is achieved through a rather simple independent unit content (one neutral dap and one water molecule) and takes the form of two-dimensional layers tightly connected by strong hydrogen bonds, and interlinked by much weaker hydrogen bonds and π–π interactions. In compound (II), the fundamental building blocks are more complex, consisting of two independent 2,6-diamino-9H-purin-1-ium (Hdap+) cations, one homophthalate [2-(2-carboxylatophenyl)acetate] dianion and seven solvent water molecules. The large number of hydrogen-bond donors and acceptors produces 26 independent interactions, leading to an extended and complicated network of hydrogen bonds in a packing organization characterized by the stacking of interleaved anionic and cationic planar arrays. These structural characteristics are compared with those of similar compounds in the literature.
Supporting information
CCDC references: 804129; 804130
A methanolic solution (20 ml) of the ligand 2,6-diaminopurine (0.5 mmol) was
mixed with an aqueous solution containing homophthalic acid (0.5 mmol) and
NaOH (1.0 mmol), and the resulting mixture was heated to reflux with stirring
for 2 h. When trying to obtain suitable crystals for X-ray analysis by slow
evaporation at room temperature, two well differentiated species appeared:
thin colourless plates [Prisms given in CIF tables - please clarify] of
(I), as a minor component, and well developed brownish prisms of (II) as the
major one.
All H atoms were found in a difference Fourier map; they were, however, treated
differently. H atoms attached to C atoms were positioned at their expected
locations and allowed to ride, with C—H = 0.93–0.97 Å and
Uiso(H) = 1.2Ueq(C). H atoms attached to N and O atoms were
initially refined with restrained distances to their hosts [N—H = O—H =
0.85 (1) Å and H···H = 1.35 (1) Å] and restricted to ride after convergence,
with Uiso(H) = 1.2Ueq(N) or 1.5Ueq(O).
For both compounds, data collection: SMART-NT (Bruker, 2001); cell refinement: SAINT-NT (Bruker, 2002); data reduction: SAINT-NT (Bruker, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL-NT (Sheldrick, 2008); software used to prepare material for publication: SHELXTL-NT (Sheldrick, 2008) and PLATON (Spek, 2009).
(I) 2,6-Diamino-9
H-purine monohydrate
top
Crystal data top
C5H6N6·H2O | Z = 2 |
Mr = 168.17 | F(000) = 176 |
Triclinic, P1 | Dx = 1.574 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 6.9331 (15) Å | Cell parameters from 1887 reflections |
b = 7.1079 (16) Å | θ = 3.1–25.7° |
c = 7.5564 (17) Å | µ = 0.12 mm−1 |
α = 99.089 (4)° | T = 298 K |
β = 98.029 (3)° | Plate, colourless |
γ = 101.331 (4)° | 0.28 × 0.25 × 0.08 mm |
V = 354.89 (14) Å3 | |
Data collection top
Bruker SMART CCD area-detector diffractometer | 1521 independent reflections |
Radiation source: fine-focus sealed tube | 1280 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.011 |
ϕ and ω scans | θmax = 27.9°, θmin = 2.8° |
Absorption correction: multi-scan (SADABS in SAINT-NT; Bruker, 2002) | h = −9→8 |
Tmin = 0.96, Tmax = 0.99 | k = −9→9 |
2992 measured reflections | l = −9→9 |
Refinement top
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.047 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.127 | H-atom parameters constrained |
S = 1.03 | w = 1/[σ2(Fo2) + (0.0622P)2 + 0.1765P] where P = (Fo2 + 2Fc2)/3 |
1521 reflections | (Δ/σ)max < 0.001 |
109 parameters | Δρmax = 0.34 e Å−3 |
0 restraints | Δρmin = −0.36 e Å−3 |
Crystal data top
C5H6N6·H2O | γ = 101.331 (4)° |
Mr = 168.17 | V = 354.89 (14) Å3 |
Triclinic, P1 | Z = 2 |
a = 6.9331 (15) Å | Mo Kα radiation |
b = 7.1079 (16) Å | µ = 0.12 mm−1 |
c = 7.5564 (17) Å | T = 298 K |
α = 99.089 (4)° | 0.28 × 0.25 × 0.08 mm |
β = 98.029 (3)° | |
Data collection top
Bruker SMART CCD area-detector diffractometer | 1521 independent reflections |
Absorption correction: multi-scan (SADABS in SAINT-NT; Bruker, 2002) | 1280 reflections with I > 2σ(I) |
Tmin = 0.96, Tmax = 0.99 | Rint = 0.011 |
2992 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.047 | 0 restraints |
wR(F2) = 0.127 | H-atom parameters constrained |
S = 1.03 | Δρmax = 0.34 e Å−3 |
1521 reflections | Δρmin = −0.36 e Å−3 |
109 parameters | |
Special details top
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes)
are estimated using the full covariance matrix. The cell esds are taken
into account individually in the estimation of esds in distances, angles
and torsion angles; correlations between esds in cell parameters are only
used when they are defined by crystal symmetry. An approximate (isotropic)
treatment of cell esds is used for estimating esds involving l.s. planes. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
C1 | 0.3620 (3) | 0.2931 (3) | 0.7865 (2) | 0.0361 (4) | |
H1A | 0.3500 | 0.3314 | 0.9072 | 0.038 (5)* | |
C2 | 0.4791 (2) | 0.2560 (2) | 0.5406 (2) | 0.0286 (4) | |
C3 | 0.5899 (2) | 0.2490 (2) | 0.3984 (2) | 0.0296 (4) | |
C4 | 0.3081 (2) | 0.0475 (2) | 0.2101 (2) | 0.0295 (4) | |
C5 | 0.2831 (2) | 0.1508 (2) | 0.4993 (2) | 0.0279 (4) | |
N1 | 0.2095 (2) | 0.1767 (2) | 0.65794 (19) | 0.0332 (4) | |
H1 | 0.0957 | 0.1177 | 0.6732 | 0.040* | |
N2 | 0.5270 (2) | 0.3460 (2) | 0.7230 (2) | 0.0338 (4) | |
N3 | 0.5019 (2) | 0.1444 (2) | 0.23351 (19) | 0.0308 (4) | |
N4 | 0.1883 (2) | 0.0441 (2) | 0.33584 (19) | 0.0306 (4) | |
N5 | 0.7835 (2) | 0.3421 (2) | 0.4228 (2) | 0.0422 (4) | |
H5B | 0.8414 | 0.3447 | 0.3310 | 0.051* | |
H5A | 0.8384 | 0.4038 | 0.5294 | 0.051* | |
N6 | 0.2269 (2) | −0.0500 (2) | 0.0386 (2) | 0.0382 (4) | |
H6B | 0.1189 | −0.1349 | 0.0286 | 0.046* | |
H6A | 0.3072 | −0.0741 | −0.0328 | 0.046* | |
O1W | 0.9117 (2) | 0.5693 (3) | 0.8411 (2) | 0.0673 (5) | |
H1WA | 0.7987 | 0.4951 | 0.8384 | 0.101* | |
H1WB | 0.8873 | 0.6692 | 0.8014 | 0.101* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
C1 | 0.0343 (9) | 0.0412 (10) | 0.0304 (9) | 0.0028 (8) | 0.0109 (7) | 0.0021 (7) |
C2 | 0.0259 (8) | 0.0291 (8) | 0.0294 (9) | 0.0027 (6) | 0.0073 (7) | 0.0036 (7) |
C3 | 0.0256 (8) | 0.0300 (8) | 0.0327 (9) | 0.0018 (6) | 0.0091 (7) | 0.0062 (7) |
C4 | 0.0260 (8) | 0.0323 (8) | 0.0302 (9) | 0.0045 (7) | 0.0076 (7) | 0.0059 (7) |
C5 | 0.0251 (8) | 0.0299 (8) | 0.0290 (8) | 0.0043 (6) | 0.0082 (6) | 0.0056 (7) |
N1 | 0.0268 (7) | 0.0397 (8) | 0.0304 (8) | 0.0004 (6) | 0.0105 (6) | 0.0030 (6) |
N2 | 0.0304 (8) | 0.0362 (8) | 0.0309 (8) | 0.0005 (6) | 0.0068 (6) | 0.0021 (6) |
N3 | 0.0252 (7) | 0.0350 (8) | 0.0305 (8) | 0.0012 (6) | 0.0097 (6) | 0.0036 (6) |
N4 | 0.0234 (7) | 0.0374 (8) | 0.0287 (7) | 0.0012 (6) | 0.0071 (6) | 0.0038 (6) |
N5 | 0.0284 (8) | 0.0534 (10) | 0.0361 (9) | −0.0083 (7) | 0.0120 (6) | −0.0010 (7) |
N6 | 0.0273 (7) | 0.0508 (9) | 0.0292 (8) | −0.0030 (6) | 0.0069 (6) | −0.0008 (7) |
O1W | 0.0523 (10) | 0.0695 (11) | 0.0622 (11) | −0.0199 (8) | 0.0148 (8) | −0.0020 (8) |
Geometric parameters (Å, º) top
C1—N2 | 1.312 (2) | C4—N3 | 1.357 (2) |
C1—N1 | 1.364 (2) | C5—N4 | 1.347 (2) |
C1—H1A | 0.9300 | C5—N1 | 1.367 (2) |
C2—C5 | 1.383 (2) | N1—H1 | 0.8500 |
C2—N2 | 1.389 (2) | N5—H5B | 0.8500 |
C2—C3 | 1.406 (2) | N5—H5A | 0.8500 |
C3—N3 | 1.339 (2) | N6—H6B | 0.8500 |
C3—N5 | 1.348 (2) | N6—H6A | 0.8500 |
C4—N4 | 1.347 (2) | O1W—H1WA | 0.8500 |
C4—N6 | 1.354 (2) | O1W—H1WB | 0.8500 |
| | | |
N2—C1—N1 | 113.42 (16) | N1—C5—C2 | 105.68 (15) |
N2—C1—H1A | 123.3 | C1—N1—C5 | 106.50 (14) |
N1—C1—H1A | 123.3 | C1—N1—H1 | 128.0 |
C5—C2—N2 | 110.39 (14) | C5—N1—H1 | 125.0 |
C5—C2—C3 | 116.63 (15) | C1—N2—C2 | 104.00 (14) |
N2—C2—C3 | 132.96 (15) | C3—N3—C4 | 118.54 (14) |
N3—C3—N5 | 118.62 (15) | C5—N4—C4 | 112.11 (14) |
N3—C3—C2 | 119.24 (15) | C3—N5—H5B | 119.1 |
N5—C3—C2 | 122.13 (16) | C3—N5—H5A | 117.4 |
N4—C4—N6 | 117.38 (15) | H5B—N5—H5A | 123.2 |
N4—C4—N3 | 127.25 (16) | C4—N6—H6B | 115.5 |
N6—C4—N3 | 115.33 (15) | C4—N6—H6A | 117.2 |
N4—C5—N1 | 128.08 (15) | H6B—N6—H6A | 117.6 |
N4—C5—C2 | 126.23 (15) | H1WA—O1W—H1WB | 106.1 |
| | | |
C5—C2—C3—N3 | 0.5 (2) | N1—C1—N2—C2 | −0.6 (2) |
N2—C2—C3—N3 | 178.60 (16) | C5—C2—N2—C1 | 0.27 (19) |
C5—C2—C3—N5 | −178.57 (16) | C3—C2—N2—C1 | −177.92 (19) |
N2—C2—C3—N5 | −0.5 (3) | N5—C3—N3—C4 | 178.68 (16) |
N2—C2—C5—N4 | −179.17 (15) | C2—C3—N3—C4 | −0.4 (2) |
C3—C2—C5—N4 | −0.7 (3) | N4—C4—N3—C3 | 0.5 (3) |
N2—C2—C5—N1 | 0.15 (19) | N6—C4—N3—C3 | 177.96 (15) |
C3—C2—C5—N1 | 178.67 (15) | N1—C5—N4—C4 | −178.51 (16) |
N2—C1—N1—C5 | 0.7 (2) | C2—C5—N4—C4 | 0.7 (2) |
N4—C5—N1—C1 | 178.81 (17) | N6—C4—N4—C5 | −177.99 (14) |
C2—C5—N1—C1 | −0.49 (19) | N3—C4—N4—C5 | −0.6 (3) |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···N4i | 0.85 | 2.06 | 2.903 (2) | 170 |
N6—H6A···N3ii | 0.85 | 2.21 | 3.059 (2) | 176 |
N6—H6B···O1Wiii | 0.85 | 2.41 | 3.133 (2) | 144 |
N5—H5A···O1W | 0.85 | 2.40 | 3.229 (2) | 166 |
N5—H5B···O1Wiv | 0.85 | 2.34 | 3.145 (2) | 159 |
O1W—H1WA···N2 | 0.85 | 1.97 | 2.767 (2) | 155 |
O1W—H1WB···N4v | 0.85 | 2.54 | 3.387 (2) | 177 |
Symmetry codes: (i) −x, −y, −z+1; (ii) −x+1, −y, −z; (iii) x−1, y−1, z−1; (iv) −x+2, −y+1, −z+1; (v) −x+1, −y+1, −z+1. |
(II) bis(2,6-diamino-9
H-purin-1-ium) 2-(2-carboxylatophenyl)acetate
heptahydrate
top
Crystal data top
2C5H7N6+·C9H6O42−·7H2O | F(000) = 1280 |
Mr = 606.58 | Dx = 1.425 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 9999 reflections |
a = 8.928 (2) Å | θ = 2.9–26.5° |
b = 31.393 (8) Å | µ = 0.12 mm−1 |
c = 10.091 (3) Å | T = 298 K |
β = 90.833 (5)° | Prism, brown |
V = 2828.2 (12) Å3 | 0.22 × 0.16 × 0.12 mm |
Z = 4 | |
Data collection top
Bruker SMART CCD area-detector diffractometer | 6234 independent reflections |
Radiation source: fine-focus sealed tube | 3511 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.058 |
ϕ and ω scans | θmax = 27.8°, θmin = 2.1° |
Absorption correction: multi-scan (SADABS in SAINT-NT; Bruker, 2002) | h = −11→11 |
Tmin = 0.962, Tmax = 0.986 | k = −40→40 |
23079 measured reflections | l = −12→13 |
Refinement top
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.059 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.140 | H-atom parameters constrained |
S = 1.12 | w = 1/[σ2(Fo2) + (0.0515P)2 + 0.5016P] where P = (Fo2 + 2Fc2)/3 |
6234 reflections | (Δ/σ)max = 0.001 |
379 parameters | Δρmax = 0.17 e Å−3 |
0 restraints | Δρmin = −0.18 e Å−3 |
Crystal data top
2C5H7N6+·C9H6O42−·7H2O | V = 2828.2 (12) Å3 |
Mr = 606.58 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 8.928 (2) Å | µ = 0.12 mm−1 |
b = 31.393 (8) Å | T = 298 K |
c = 10.091 (3) Å | 0.22 × 0.16 × 0.12 mm |
β = 90.833 (5)° | |
Data collection top
Bruker SMART CCD area-detector diffractometer | 6234 independent reflections |
Absorption correction: multi-scan (SADABS in SAINT-NT; Bruker, 2002) | 3511 reflections with I > 2σ(I) |
Tmin = 0.962, Tmax = 0.986 | Rint = 0.058 |
23079 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.059 | 0 restraints |
wR(F2) = 0.140 | H-atom parameters constrained |
S = 1.12 | Δρmax = 0.17 e Å−3 |
6234 reflections | Δρmin = −0.18 e Å−3 |
379 parameters | |
Special details top
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes)
are estimated using the full covariance matrix. The cell esds are taken
into account individually in the estimation of esds in distances, angles
and torsion angles; correlations between esds in cell parameters are only
used when they are defined by crystal symmetry. An approximate (isotropic)
treatment of cell esds is used for estimating esds involving l.s. planes. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
O1W | 0.8540 (3) | 0.55442 (9) | 0.9469 (2) | 0.1140 (8) | |
H1WA | 0.8863 | 0.5648 | 0.8750 | 0.171* | |
H1WB | 0.8306 | 0.5286 | 0.9316 | 0.171* | |
O2W | 0.3226 (3) | 0.58889 (9) | 0.9746 (3) | 0.1327 (10) | |
H2WA | 0.3009 | 0.5929 | 0.8932 | 0.199* | |
H2WB | 0.2613 | 0.5706 | 1.0044 | 0.199* | |
O3W | 0.2003 (2) | 0.61023 (5) | 0.73207 (18) | 0.0666 (5) | |
H3WA | 0.2344 | 0.6062 | 0.6548 | 0.100* | |
H3WB | 0.1074 | 0.6047 | 0.7251 | 0.100* | |
O4W | 0.6160 (3) | 0.60760 (8) | 0.9989 (3) | 0.1248 (10) | |
H4WA | 0.6865 | 0.5906 | 0.9796 | 0.187* | |
H4WB | 0.5468 | 0.6017 | 0.9432 | 0.187* | |
O5W | 0.8768 (3) | 0.46547 (9) | 0.9075 (2) | 0.1202 (9) | |
H5WA | 0.9584 | 0.4614 | 0.9501 | 0.180* | |
H5WB | 0.8844 | 0.4563 | 0.8286 | 0.180* | |
O6W | 0.9002 (2) | 0.44366 (9) | 0.6532 (2) | 0.1193 (9) | |
H6WA | 0.8451 | 0.4222 | 0.6359 | 0.179* | |
H6WB | 0.9555 | 0.4471 | 0.5862 | 0.179* | |
O7W | 0.7748 (2) | 0.62405 (7) | 0.2604 (2) | 0.0909 (7) | |
H7WA | 0.7647 | 0.6060 | 0.1981 | 0.136* | |
H7WB | 0.7961 | 0.6113 | 0.3325 | 0.136* | |
O13 | 0.3162 (2) | 0.59642 (6) | 0.48500 (19) | 0.0709 (5) | |
O23 | 0.5334 (2) | 0.61856 (6) | 0.57094 (19) | 0.0681 (5) | |
O33 | 0.8917 (2) | 0.60391 (6) | 0.50298 (19) | 0.0691 (5) | |
O43 | 0.8829 (2) | 0.60191 (6) | 0.7208 (2) | 0.0701 (5) | |
C13 | 0.5388 (3) | 0.55952 (7) | 0.4231 (2) | 0.0484 (6) | |
C23 | 0.6702 (3) | 0.54000 (7) | 0.4707 (2) | 0.0499 (6) | |
C33 | 0.7405 (3) | 0.51037 (8) | 0.3883 (3) | 0.0640 (7) | |
H33 | 0.8273 | 0.4969 | 0.4186 | 0.077* | |
C43 | 0.6861 (4) | 0.50080 (9) | 0.2663 (3) | 0.0761 (9) | |
H43 | 0.7366 | 0.4815 | 0.2133 | 0.091* | |
C53 | 0.5539 (4) | 0.51983 (9) | 0.2195 (3) | 0.0716 (8) | |
H53 | 0.5158 | 0.5135 | 0.1355 | 0.086* | |
C63 | 0.4829 (3) | 0.54769 (8) | 0.2993 (3) | 0.0599 (7) | |
H63 | 0.3927 | 0.5594 | 0.2700 | 0.072* | |
C73 | 0.4580 (3) | 0.59389 (8) | 0.4988 (3) | 0.0550 (6) | |
C83 | 0.7400 (3) | 0.54957 (8) | 0.6034 (3) | 0.0563 (7) | |
H83A | 0.7955 | 0.5247 | 0.6328 | 0.068* | |
H83B | 0.6604 | 0.5543 | 0.6662 | 0.068* | |
C93 | 0.8453 (3) | 0.58796 (8) | 0.6079 (3) | 0.0556 (6) | |
N11 | 0.9412 (2) | 0.68531 (6) | 0.13969 (18) | 0.0496 (5) | |
H11 | 0.8958 | 0.6670 | 0.1866 | 0.060* | |
N21 | 1.0877 (2) | 0.71704 (6) | −0.01009 (18) | 0.0481 (5) | |
N31 | 0.9239 (2) | 0.81043 (6) | 0.15483 (17) | 0.0458 (5) | |
H31 | 0.9226 | 0.8374 | 0.1604 | 0.055* | |
N41 | 0.8328 (2) | 0.74640 (6) | 0.24859 (18) | 0.0451 (5) | |
N51 | 1.0880 (2) | 0.81605 (6) | −0.02174 (19) | 0.0551 (5) | |
H51A | 1.0728 | 0.8428 | −0.0217 | 0.066* | |
H51B | 1.1471 | 0.8051 | −0.0775 | 0.066* | |
N61 | 0.7529 (2) | 0.81180 (7) | 0.3237 (2) | 0.0578 (6) | |
H61A | 0.7026 | 0.7984 | 0.3812 | 0.069* | |
H61B | 0.7571 | 0.8387 | 0.3160 | 0.069* | |
C11 | 1.0417 (3) | 0.68113 (8) | 0.0394 (2) | 0.0522 (6) | |
H11A | 1.0745 | 0.6548 | 0.0092 | 0.063* | |
C21 | 1.0139 (2) | 0.74728 (7) | 0.0674 (2) | 0.0427 (5) | |
C31 | 1.0123 (2) | 0.79190 (7) | 0.0624 (2) | 0.0421 (5) | |
C41 | 0.8363 (2) | 0.78891 (7) | 0.2419 (2) | 0.0426 (5) | |
C51 | 0.9219 (2) | 0.72808 (7) | 0.1583 (2) | 0.0423 (5) | |
N12 | 0.4558 (2) | 0.82560 (6) | 0.62823 (19) | 0.0571 (6) | |
H12 | 0.4914 | 0.8466 | 0.5858 | 0.069* | |
N22 | 0.3081 (2) | 0.79386 (6) | 0.77641 (18) | 0.0496 (5) | |
N32 | 0.46583 (19) | 0.70019 (6) | 0.60898 (17) | 0.0427 (4) | |
H32 | 0.4691 | 0.6732 | 0.6031 | 0.051* | |
N42 | 0.5618 (2) | 0.76468 (6) | 0.51689 (18) | 0.0477 (5) | |
N52 | 0.2953 (2) | 0.69577 (6) | 0.77972 (18) | 0.0494 (5) | |
H52A | 0.2971 | 0.6688 | 0.7726 | 0.059* | |
H52B | 0.2394 | 0.7069 | 0.8377 | 0.059* | |
N62 | 0.6405 (2) | 0.69896 (7) | 0.44262 (19) | 0.0552 (5) | |
H62A | 0.6925 | 0.7118 | 0.3852 | 0.066* | |
H62B | 0.6330 | 0.6721 | 0.4496 | 0.066* | |
C12 | 0.3553 (3) | 0.83013 (8) | 0.7284 (2) | 0.0573 (7) | |
H12A | 0.3234 | 0.8565 | 0.7593 | 0.069* | |
C22 | 0.3853 (2) | 0.76376 (7) | 0.7010 (2) | 0.0395 (5) | |
C32 | 0.3786 (2) | 0.71928 (7) | 0.7006 (2) | 0.0395 (5) | |
C42 | 0.5553 (2) | 0.72234 (8) | 0.5223 (2) | 0.0455 (6) | |
C52 | 0.4737 (2) | 0.78323 (7) | 0.6093 (2) | 0.0434 (5) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O1W | 0.117 (2) | 0.122 (2) | 0.1034 (18) | −0.0091 (16) | −0.0037 (15) | 0.0128 (15) |
O2W | 0.150 (3) | 0.138 (2) | 0.110 (2) | −0.029 (2) | −0.0255 (18) | −0.0001 (17) |
O3W | 0.0585 (11) | 0.0649 (11) | 0.0766 (12) | −0.0065 (9) | 0.0069 (9) | −0.0041 (9) |
O4W | 0.127 (2) | 0.0894 (18) | 0.160 (2) | −0.0049 (15) | 0.0441 (19) | −0.0362 (16) |
O5W | 0.113 (2) | 0.150 (2) | 0.0964 (17) | −0.0032 (18) | −0.0261 (15) | 0.0047 (16) |
O6W | 0.0665 (15) | 0.169 (3) | 0.122 (2) | 0.0102 (15) | −0.0007 (14) | −0.0434 (18) |
O7W | 0.0908 (16) | 0.0836 (15) | 0.0986 (15) | −0.0213 (12) | 0.0072 (12) | 0.0309 (12) |
O13 | 0.0502 (12) | 0.0781 (13) | 0.0845 (13) | 0.0065 (9) | 0.0101 (10) | −0.0059 (10) |
O23 | 0.0616 (12) | 0.0559 (11) | 0.0871 (13) | 0.0017 (9) | 0.0066 (10) | −0.0177 (10) |
O33 | 0.0664 (12) | 0.0597 (11) | 0.0815 (13) | −0.0164 (9) | 0.0169 (10) | 0.0029 (10) |
O43 | 0.0657 (12) | 0.0679 (12) | 0.0768 (13) | −0.0083 (10) | 0.0031 (10) | −0.0128 (10) |
C13 | 0.0461 (15) | 0.0401 (13) | 0.0594 (15) | −0.0097 (11) | 0.0114 (12) | −0.0002 (11) |
C23 | 0.0481 (15) | 0.0374 (13) | 0.0644 (16) | −0.0082 (11) | 0.0094 (12) | −0.0013 (11) |
C33 | 0.0614 (17) | 0.0479 (15) | 0.083 (2) | 0.0042 (13) | 0.0073 (15) | −0.0048 (14) |
C43 | 0.092 (2) | 0.0568 (18) | 0.080 (2) | 0.0012 (17) | 0.0207 (19) | −0.0171 (15) |
C53 | 0.085 (2) | 0.0637 (18) | 0.0659 (18) | −0.0026 (17) | 0.0031 (17) | −0.0106 (15) |
C63 | 0.0593 (17) | 0.0535 (16) | 0.0671 (17) | −0.0067 (13) | 0.0083 (14) | −0.0016 (13) |
C73 | 0.0521 (17) | 0.0495 (15) | 0.0637 (16) | −0.0024 (12) | 0.0085 (13) | 0.0036 (13) |
C83 | 0.0526 (16) | 0.0451 (14) | 0.0715 (17) | −0.0014 (12) | 0.0081 (13) | 0.0063 (12) |
C93 | 0.0484 (15) | 0.0470 (15) | 0.0716 (18) | 0.0005 (12) | 0.0079 (14) | −0.0045 (14) |
N11 | 0.0495 (12) | 0.0491 (12) | 0.0505 (11) | −0.0081 (9) | 0.0144 (10) | 0.0027 (9) |
N21 | 0.0497 (12) | 0.0461 (11) | 0.0488 (11) | −0.0009 (9) | 0.0118 (10) | 0.0011 (9) |
N31 | 0.0420 (11) | 0.0481 (11) | 0.0475 (11) | 0.0043 (9) | 0.0101 (9) | −0.0043 (9) |
N41 | 0.0376 (11) | 0.0510 (12) | 0.0469 (11) | −0.0029 (9) | 0.0084 (9) | −0.0031 (9) |
N51 | 0.0650 (14) | 0.0442 (11) | 0.0566 (12) | −0.0044 (10) | 0.0205 (11) | 0.0012 (9) |
N61 | 0.0535 (13) | 0.0561 (13) | 0.0644 (13) | 0.0025 (10) | 0.0208 (11) | −0.0062 (10) |
C11 | 0.0563 (16) | 0.0461 (14) | 0.0544 (15) | −0.0009 (12) | 0.0125 (13) | −0.0028 (11) |
C21 | 0.0385 (13) | 0.0476 (14) | 0.0423 (13) | −0.0001 (10) | 0.0068 (10) | −0.0012 (10) |
C31 | 0.0380 (13) | 0.0479 (14) | 0.0406 (12) | −0.0010 (10) | 0.0022 (10) | 0.0003 (10) |
C41 | 0.0307 (12) | 0.0563 (15) | 0.0407 (13) | 0.0003 (10) | 0.0022 (10) | −0.0030 (11) |
C51 | 0.0376 (12) | 0.0471 (14) | 0.0423 (12) | −0.0036 (10) | 0.0029 (11) | −0.0018 (10) |
N12 | 0.0650 (14) | 0.0471 (12) | 0.0598 (13) | −0.0095 (10) | 0.0193 (11) | −0.0016 (10) |
N22 | 0.0500 (12) | 0.0495 (12) | 0.0498 (11) | −0.0037 (9) | 0.0145 (9) | −0.0085 (9) |
N32 | 0.0409 (11) | 0.0416 (10) | 0.0459 (11) | 0.0004 (8) | 0.0078 (9) | −0.0025 (8) |
N42 | 0.0448 (11) | 0.0502 (12) | 0.0484 (11) | −0.0008 (9) | 0.0094 (9) | −0.0015 (9) |
N52 | 0.0555 (12) | 0.0418 (11) | 0.0514 (11) | −0.0047 (9) | 0.0184 (10) | −0.0009 (9) |
N62 | 0.0466 (12) | 0.0582 (13) | 0.0612 (13) | 0.0027 (10) | 0.0175 (10) | −0.0034 (10) |
C12 | 0.0634 (17) | 0.0469 (15) | 0.0619 (16) | −0.0066 (12) | 0.0172 (14) | −0.0097 (12) |
C22 | 0.0342 (12) | 0.0445 (13) | 0.0399 (12) | −0.0015 (10) | 0.0050 (10) | −0.0028 (10) |
C32 | 0.0338 (12) | 0.0444 (13) | 0.0403 (12) | −0.0005 (10) | 0.0002 (10) | −0.0030 (10) |
C42 | 0.0364 (13) | 0.0555 (15) | 0.0448 (13) | −0.0003 (11) | 0.0061 (11) | −0.0026 (11) |
C52 | 0.0397 (13) | 0.0462 (14) | 0.0446 (13) | −0.0030 (10) | 0.0042 (11) | −0.0026 (10) |
Geometric parameters (Å, º) top
O1W—H1WA | 0.8500 | N21—C11 | 1.302 (3) |
O1W—H1WB | 0.8501 | N21—C21 | 1.401 (3) |
O2W—H2WA | 0.8500 | N31—C31 | 1.361 (3) |
O2W—H2WB | 0.8499 | N31—C41 | 1.364 (3) |
O3W—H3WA | 0.8501 | N31—H31 | 0.8500 |
O3W—H3WB | 0.8501 | N41—C41 | 1.336 (3) |
O4W—H4WA | 0.8500 | N41—C51 | 1.347 (3) |
O4W—H4WB | 0.8500 | N51—C31 | 1.330 (3) |
O5W—H5WA | 0.8500 | N51—H51A | 0.8500 |
O5W—H5WB | 0.8500 | N51—H51B | 0.8500 |
O6W—H6WA | 0.8499 | N61—C41 | 1.330 (3) |
O6W—H6WB | 0.8500 | N61—H61A | 0.8500 |
O7W—H7WA | 0.8499 | N61—H61B | 0.8500 |
O7W—H7WB | 0.8500 | C11—H11A | 0.9300 |
O13—C73 | 1.274 (3) | C21—C51 | 1.379 (3) |
O23—C73 | 1.252 (3) | C21—C31 | 1.402 (3) |
O33—C93 | 1.247 (3) | N12—C52 | 1.354 (3) |
O43—C93 | 1.262 (3) | N12—C12 | 1.369 (3) |
C13—C63 | 1.389 (3) | N12—H12 | 0.8500 |
C13—C23 | 1.403 (3) | N22—C12 | 1.310 (3) |
C13—C73 | 1.511 (3) | N22—C22 | 1.401 (3) |
C23—C33 | 1.402 (3) | N32—C32 | 1.357 (3) |
C23—C83 | 1.499 (4) | N32—C42 | 1.381 (3) |
C33—C43 | 1.351 (4) | N32—H32 | 0.8500 |
C33—H33 | 0.9300 | N42—C42 | 1.332 (3) |
C43—C53 | 1.399 (4) | N42—C52 | 1.360 (3) |
C43—H43 | 0.9300 | N52—C32 | 1.324 (3) |
C53—C63 | 1.353 (4) | N52—H52A | 0.8500 |
C53—H53 | 0.9300 | N52—H52B | 0.8500 |
C63—H63 | 0.9300 | N62—C42 | 1.335 (3) |
C83—C93 | 1.529 (3) | N62—H62A | 0.8500 |
C83—H83A | 0.9700 | N62—H62B | 0.8500 |
C83—H83B | 0.9700 | C12—H12A | 0.9300 |
N11—C51 | 1.367 (3) | C22—C52 | 1.369 (3) |
N11—C11 | 1.369 (3) | C22—C32 | 1.398 (3) |
N11—H11 | 0.8500 | | |
| | | |
H1WA—O1W—H1WB | 107.3 | C41—N61—H61A | 117.6 |
H2WA—O2W—H2WB | 107.6 | C41—N61—H61B | 117.1 |
H3WA—O3W—H3WB | 104.8 | H61A—N61—H61B | 125.3 |
H4WA—O4W—H4WB | 104.1 | N21—C11—N11 | 114.5 (2) |
H5WA—O5W—H5WB | 110.1 | N21—C11—H11A | 122.8 |
H6WA—O6W—H6WB | 106.2 | N11—C11—H11A | 122.8 |
H7WA—O7W—H7WB | 109.9 | C51—C21—N21 | 111.4 (2) |
C63—C13—C23 | 118.6 (2) | C51—C21—C31 | 117.1 (2) |
C63—C13—C73 | 118.6 (2) | N21—C21—C31 | 131.4 (2) |
C23—C13—C73 | 122.8 (2) | N51—C31—N31 | 119.9 (2) |
C33—C23—C13 | 117.8 (2) | N51—C31—C21 | 126.0 (2) |
C33—C23—C83 | 118.6 (2) | N31—C31—C21 | 114.07 (19) |
C13—C23—C83 | 123.6 (2) | N61—C41—N41 | 119.6 (2) |
C43—C33—C23 | 122.0 (3) | N61—C41—N31 | 117.6 (2) |
C43—C33—H33 | 119.0 | N41—C41—N31 | 122.77 (19) |
C23—C33—H33 | 119.0 | N41—C51—N11 | 126.1 (2) |
C33—C43—C53 | 120.3 (3) | N41—C51—C21 | 128.8 (2) |
C33—C43—H43 | 119.9 | N11—C51—C21 | 105.10 (19) |
C53—C43—H43 | 119.9 | C52—N12—C12 | 106.61 (19) |
C63—C53—C43 | 118.3 (3) | C52—N12—H12 | 130.2 |
C63—C53—H53 | 120.8 | C12—N12—H12 | 123.1 |
C43—C53—H53 | 120.8 | C12—N22—C22 | 102.83 (18) |
C53—C63—C13 | 122.9 (3) | C32—N32—C42 | 123.53 (19) |
C53—C63—H63 | 118.5 | C32—N32—H32 | 120.5 |
C13—C63—H63 | 118.5 | C42—N32—H32 | 115.9 |
O23—C73—O13 | 123.4 (2) | C42—N42—C52 | 111.91 (19) |
O23—C73—C13 | 118.6 (2) | C32—N52—H52A | 119.5 |
O13—C73—C13 | 118.0 (2) | C32—N52—H52B | 121.8 |
C23—C83—C93 | 115.6 (2) | H52A—N52—H52B | 118.7 |
C23—C83—H83A | 108.4 | C42—N62—H62A | 118.1 |
C93—C83—H83A | 108.4 | C42—N62—H62B | 116.7 |
C23—C83—H83B | 108.4 | H62A—N62—H62B | 125.0 |
C93—C83—H83B | 108.4 | N22—C12—N12 | 113.7 (2) |
H83A—C83—H83B | 107.4 | N22—C12—H12A | 123.2 |
O33—C93—O43 | 122.7 (2) | N12—C12—H12A | 123.2 |
O33—C93—C83 | 120.2 (3) | C52—C22—C32 | 117.98 (19) |
O43—C93—C83 | 117.1 (2) | C52—C22—N22 | 111.03 (19) |
C51—N11—C11 | 106.32 (18) | C32—C22—N22 | 130.87 (19) |
C51—N11—H11 | 121.6 | N52—C32—N32 | 119.9 (2) |
C11—N11—H11 | 132.0 | N52—C32—C22 | 125.43 (19) |
C11—N21—C21 | 102.64 (18) | N32—C32—C22 | 114.72 (19) |
C31—N31—C41 | 125.0 (2) | N42—C42—N62 | 119.9 (2) |
C31—N31—H31 | 118.7 | N42—C42—N32 | 123.7 (2) |
C41—N31—H31 | 116.3 | N62—C42—N32 | 116.4 (2) |
C41—N41—C51 | 112.18 (18) | N12—C52—N42 | 126.0 (2) |
C31—N51—H51A | 118.7 | N12—C52—C22 | 105.86 (19) |
C31—N51—H51B | 121.2 | N42—C52—C22 | 128.1 (2) |
H51A—N51—H51B | 120.0 | | |
| | | |
C63—C13—C23—C33 | 1.8 (3) | C31—N31—C41—N41 | 2.6 (3) |
C73—C13—C23—C33 | −176.2 (2) | C41—N41—C51—N11 | −179.4 (2) |
C63—C13—C23—C83 | −179.0 (2) | C41—N41—C51—C21 | 1.8 (3) |
C73—C13—C23—C83 | 3.0 (3) | C11—N11—C51—N41 | −179.4 (2) |
C13—C23—C33—C43 | 0.6 (4) | C11—N11—C51—C21 | −0.4 (2) |
C83—C23—C33—C43 | −178.6 (2) | N21—C21—C51—N41 | −179.5 (2) |
C23—C33—C43—C53 | −1.5 (4) | C31—C21—C51—N41 | −2.9 (4) |
C33—C43—C53—C63 | −0.2 (4) | N21—C21—C51—N11 | 1.5 (3) |
C43—C53—C63—C13 | 2.8 (4) | C31—C21—C51—N11 | 178.1 (2) |
C23—C13—C63—C53 | −3.6 (4) | C22—N22—C12—N12 | 0.2 (3) |
C73—C13—C63—C53 | 174.4 (2) | C52—N12—C12—N22 | 0.7 (3) |
C63—C13—C73—O23 | −146.4 (2) | C12—N22—C22—C52 | −1.0 (3) |
C23—C13—C73—O23 | 31.6 (3) | C12—N22—C22—C32 | −176.9 (2) |
C63—C13—C73—O13 | 33.1 (3) | C42—N32—C32—N52 | 179.6 (2) |
C23—C13—C73—O13 | −148.9 (2) | C42—N32—C32—C22 | 0.2 (3) |
C33—C23—C83—C93 | 93.9 (3) | C52—C22—C32—N52 | −177.8 (2) |
C13—C23—C83—C93 | −85.3 (3) | N22—C22—C32—N52 | −2.2 (4) |
C23—C83—C93—O33 | −14.1 (3) | C52—C22—C32—N32 | 1.6 (3) |
C23—C83—C93—O43 | 166.6 (2) | N22—C22—C32—N32 | 177.2 (2) |
C21—N21—C11—N11 | 1.8 (3) | C52—N42—C42—N62 | −176.8 (2) |
C51—N11—C11—N21 | −1.0 (3) | C52—N42—C42—N32 | 1.9 (3) |
C11—N21—C21—C51 | −2.0 (3) | C32—N32—C42—N42 | −2.1 (3) |
C11—N21—C21—C31 | −178.0 (3) | C32—N32—C42—N62 | 176.6 (2) |
C41—N31—C31—N51 | 176.9 (2) | C12—N12—C52—N42 | 178.5 (2) |
C41—N31—C31—C21 | −3.4 (3) | C12—N12—C52—C22 | −1.2 (3) |
C51—C21—C31—N51 | −177.0 (2) | C42—N42—C52—N12 | −179.6 (2) |
N21—C21—C31—N51 | −1.2 (4) | C42—N42—C52—C22 | 0.1 (3) |
C51—C21—C31—N31 | 3.3 (3) | C32—C22—C52—N12 | 177.9 (2) |
N21—C21—C31—N31 | 179.1 (2) | N22—C22—C52—N12 | 1.4 (3) |
C51—N41—C41—N61 | 179.2 (2) | C32—C22—C52—N42 | −1.8 (4) |
C51—N41—C41—N31 | −1.5 (3) | N22—C22—C52—N42 | −178.3 (2) |
C31—N31—C41—N61 | −178.1 (2) | | |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N61—H61A···N42 | 0.85 | 2.15 | 3.000 (3) | 176 |
N62—H62A···N41 | 0.85 | 2.17 | 3.016 (3) | 177 |
N51—H51B···N22i | 0.85 | 2.10 | 2.934 (3) | 166 |
N52—H52B···N21ii | 0.85 | 2.09 | 2.914 (3) | 165 |
O7W—H7WB···O33 | 0.85 | 1.92 | 2.722 (3) | 156 |
O7W—H7WA···O4Wiii | 0.85 | 2.39 | 3.022 (4) | 131 |
O6W—H6WA···O13iv | 0.85 | 1.96 | 2.680 (3) | 141 |
O6W—H6WB···O33v | 0.85 | 2.30 | 2.872 (3) | 125 |
O5W—H5WB···O6W | 0.85 | 1.82 | 2.667 (4) | 173 |
O5W—H5WA···O1Wvi | 0.85 | 2.02 | 2.867 (4) | 174 |
O4W—H4WB···O2W | 0.85 | 2.07 | 2.693 (4) | 130 |
O4W—H4WA···O1W | 0.85 | 1.91 | 2.758 (4) | 176 |
O3W—H3WA···O13 | 0.85 | 1.90 | 2.748 (3) | 178 |
O3W—H3WB···O43vii | 0.85 | 2.01 | 2.847 (3) | 170 |
O2W—H2WA···O3W | 0.85 | 1.93 | 2.748 (3) | 163 |
O2W—H2WB···O5Wviii | 0.85 | 1.90 | 2.749 (4) | 172 |
O1W—H1WA···O43 | 0.85 | 1.94 | 2.741 (3) | 156 |
O1W—H1WB···O5W | 0.85 | 2.04 | 2.829 (4) | 154 |
N62—H62B···O23 | 0.85 | 2.27 | 3.000 (3) | 144 |
N52—H52A···O3W | 0.85 | 2.07 | 2.855 (3) | 153 |
N32—H32···O23 | 0.85 | 1.84 | 2.662 (3) | 162 |
N12—H12···O4Wix | 0.85 | 2.03 | 2.864 (3) | 169 |
N61—H61B···O43ix | 0.85 | 2.38 | 3.130 (3) | 147 |
N51—H51A···O33ix | 0.85 | 2.34 | 3.076 (3) | 145 |
N31—H31···O43ix | 0.85 | 2.03 | 2.856 (3) | 163 |
N11—H11···O7W | 0.85 | 1.89 | 2.728 (3) | 169 |
Symmetry codes: (i) x+1, y, z−1; (ii) x−1, y, z+1; (iii) x, y, z−1; (iv) −x+1, −y+1, −z+1; (v) −x+2, −y+1, −z+1; (vi) −x+2, −y+1, −z+2; (vii) x−1, y, z; (viii) −x+1, −y+1, −z+2; (ix) x, −y+3/2, z−1/2. |
Experimental details
| (I) | (II) |
Crystal data |
Chemical formula | C5H6N6·H2O | 2C5H7N6+·C9H6O42−·7H2O |
Mr | 168.17 | 606.58 |
Crystal system, space group | Triclinic, P1 | Monoclinic, P21/c |
Temperature (K) | 298 | 298 |
a, b, c (Å) | 6.9331 (15), 7.1079 (16), 7.5564 (17) | 8.928 (2), 31.393 (8), 10.091 (3) |
α, β, γ (°) | 99.089 (4), 98.029 (3), 101.331 (4) | 90, 90.833 (5), 90 |
V (Å3) | 354.89 (14) | 2828.2 (12) |
Z | 2 | 4 |
Radiation type | Mo Kα | Mo Kα |
µ (mm−1) | 0.12 | 0.12 |
Crystal size (mm) | 0.28 × 0.25 × 0.08 | 0.22 × 0.16 × 0.12 |
|
Data collection |
Diffractometer | Bruker SMART CCD area-detector diffractometer | Bruker SMART CCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS in SAINT-NT; Bruker, 2002) | Multi-scan (SADABS in SAINT-NT; Bruker, 2002) |
Tmin, Tmax | 0.96, 0.99 | 0.962, 0.986 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 2992, 1521, 1280 | 23079, 6234, 3511 |
Rint | 0.011 | 0.058 |
(sin θ/λ)max (Å−1) | 0.658 | 0.656 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.047, 0.127, 1.03 | 0.059, 0.140, 1.12 |
No. of reflections | 1521 | 6234 |
No. of parameters | 109 | 379 |
H-atom treatment | H-atom parameters constrained | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.34, −0.36 | 0.17, −0.18 |
Hydrogen-bond geometry (Å, º) for (I) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···N4i | 0.85 | 2.06 | 2.903 (2) | 170.4 |
N6—H6A···N3ii | 0.85 | 2.21 | 3.059 (2) | 176.1 |
N6—H6B···O1Wiii | 0.85 | 2.41 | 3.133 (2) | 143.7 |
N5—H5A···O1W | 0.85 | 2.40 | 3.229 (2) | 166.2 |
N5—H5B···O1Wiv | 0.85 | 2.34 | 3.145 (2) | 159.2 |
O1W—H1WA···N2 | 0.85 | 1.97 | 2.767 (2) | 154.7 |
O1W—H1WB···N4v | 0.85 | 2.54 | 3.387 (2) | 176.6 |
Symmetry codes: (i) −x, −y, −z+1; (ii) −x+1, −y, −z; (iii) x−1, y−1, z−1; (iv) −x+2, −y+1, −z+1; (v) −x+1, −y+1, −z+1. |
π–π contacts (Å, °) for (I) topGroup 1/group 2 | CCD (Å) | IPD (Å) | SA (°) |
Cg1···Cg2i | 3.501 (2) | 3.30 (2) | 19.5 (6) |
Cg2···Cg2ii | 3.514 (1) | 3.307 (1) | 19.72 (1) |
Symmetry codes: (i) -x + 1, -y, -z + 1; (ii) -x + 1, -y + 1, -z + 1.
Notes: Cg1 is the centroid of the N1/C1/N2/C2/C5 ring and
Cg2 is the centroid of the N3/C3/C2/C5/N4/C4 ring.
CCD id the centre-to-centre distance (distance between ring centroids),
IPD is the mean interplanar distance (distance from one plane to the
neighbouring centroid) and SA is the mean slippage angle (angle subtended by
the intercentroid vector to the plane normal). For details, see Janiak
(2000). |
Hydrogen-bond geometry (Å, º) for (II) top
D—H···A | D—H | H···A | D···A | D—H···A |
N61—H61A···N42 | 0.85 | 2.15 | 3.000 (3) | 175.9 |
N62—H62A···N41 | 0.85 | 2.17 | 3.016 (3) | 176.5 |
N51—H51B···N22i | 0.85 | 2.10 | 2.934 (3) | 165.7 |
N52—H52B···N21ii | 0.85 | 2.09 | 2.914 (3) | 164.5 |
O7W—H7WB···O33 | 0.85 | 1.92 | 2.722 (3) | 156.1 |
O7W—H7WA···O4Wiii | 0.85 | 2.39 | 3.022 (4) | 131.2 |
O6W—H6WA···O13iv | 0.85 | 1.96 | 2.680 (3) | 141.3 |
O6W—H6WB···O33v | 0.85 | 2.30 | 2.872 (3) | 125.3 |
O5W—H5WB···O6W | 0.85 | 1.82 | 2.667 (4) | 172.9 |
O5W—H5WA···O1Wvi | 0.85 | 2.02 | 2.867 (4) | 174.4 |
O4W—H4WB···O2W | 0.85 | 2.07 | 2.693 (4) | 129.5 |
O4W—H4WA···O1W | 0.85 | 1.91 | 2.758 (4) | 175.5 |
O3W—H3WA···O13 | 0.85 | 1.90 | 2.748 (3) | 178.1 |
O3W—H3WB···O43vii | 0.85 | 2.01 | 2.847 (3) | 169.9 |
O2W—H2WA···O3W | 0.85 | 1.93 | 2.748 (3) | 162.6 |
O2W—H2WB···O5Wviii | 0.85 | 1.90 | 2.749 (4) | 172.0 |
O1W—H1WA···O43 | 0.85 | 1.94 | 2.741 (3) | 155.8 |
O1W—H1WB···O5W | 0.85 | 2.04 | 2.829 (4) | 153.8 |
N62—H62B···O23 | 0.85 | 2.27 | 3.000 (3) | 144.4 |
N52—H52A···O3W | 0.85 | 2.07 | 2.855 (3) | 153.3 |
N32—H32···O23 | 0.85 | 1.84 | 2.662 (3) | 162.4 |
N12—H12···O4Wix | 0.85 | 2.03 | 2.864 (3) | 168.6 |
N61—H61B···O43ix | 0.85 | 2.38 | 3.130 (3) | 146.7 |
N51—H51A···O33ix | 0.85 | 2.34 | 3.076 (3) | 144.6 |
N31—H31···O43ix | 0.85 | 2.03 | 2.856 (3) | 163.2 |
N11—H11···O7W | 0.85 | 1.89 | 2.728 (3) | 169.0 |
Symmetry codes: (i) x+1, y, z−1; (ii) x−1, y, z+1; (iii) x, y, z−1; (iv) −x+1, −y+1, −z+1; (v) −x+2, −y+1, −z+1; (vi) −x+2, −y+1, −z+2; (vii) x−1, y, z; (viii) −x+1, −y+1, −z+2; (ix) x, −y+3/2, z−1/2. |
π–π contacts (Å, °) for (II) topGroup 1/group 2 | CCD (Å) | IPD (Å) | SA (°) |
Cg1···Cg2i | 3.693 (2) | 3.35 (1) | 24.7 (1) |
Cg3···Cg4ii | 4.083 (2) | 3.34 (1) | 35.1 (3) |
Cg5···Cg5iii | 4.184 (2) | 3.74 (1) | 26.52 (1) |
Symmetry codes: (i) x + 1, -y + 3/2, z - 1/2; (ii) x, -y + 3/2, z - 1/2;
(iii) -x + 1, -y + 1, -z + 1.
Notes: Cg1 is the centroid of the N11/C11/N21/C21/C51 ring,
Cg2 of the N12/C12/N22/C22/C52 ring, Cg3 of the N31/C31/C21/C51/N41/C41 ring,
Cg4 of the N32/C32/C22/C52/N42/C42 ring and Cg5 of the C13/C23/C33/C43/C53/C63
ring.
CCD is the centre-to-centre distance (distance between ring centroids),
IPD is the mean interplanar distance (distance from one plane to the
neighbouring centroid) and SA is the mean slippage angle (angle subtended by
the intercentroid vector to the plane normal). For details, see Janiak
(2000) |
Purines constitute a family of heterocyclic compounds characterized by a fused pair of pyrimidine and imidazole rings. The simplest representative is purine itself, mostly found in nature as methyl-, hydroxyl- and amino-substituted derivatives. These are esential compounds for biological systems, to the extent that many of the building blocks of DNA and RNA are purines of this kind. The relevance of these small molecules resides mainly in their highly interactive hydrogen-bonding capabilities resulting from the many active sites (both donors and acceptors) available in their structures. This conditon is, of course, not restricted to life processes, and renders these compounds extremely appealing from a synthetic point of view when searching for suitable building blocks for complicated supramolecular structures. Accordingly, much structural work has been devoted to some of these purines (adenine and guanine, among others) but many have not been adequately surveyed from a structural point of view. In this latter category, 2,6-diaminopurine (C5H6N6, hereinafter dap) occupies a noted position: only two appearances of compounds containing the molecule could be found in the Cambridge Structural Database (CSD, Version?; Allen, 2002). We shall return to this point in the discussion below.
Since it seemed this was a gap worth filling, we decided to explore the synthesis and crystallographic study of transition metal complexes, surveying dap as the main ligand, through a project which is beginning to provide interesting results (in preparation). As an introductory paper to this intended series of structural reports, we report here two different structures which feature the dap molecule as an uncomplexed group. One of them, dap monohydrate, (I), presents the molecule as a neutral free base, while in the other, bis(2,6-diamino-9H-purin-1-ium) homophthalate heptahydrate or 2Hdap+.hpt2-.7H2O, (II) [where H2hpt is homophthalic acid, 2-(2-carboxylatophenyl)acetic acid], it fulfils the role of a cation. In spite of the obvious differences displayed by these two structures, viz. the protonation state of the dap group, the number of solvent water molecules etc., the molecule provides a similarly complex hydrogen-bonding network, which will be discussed below.
From the molecular point of view both structures are quite simple, since the individual components do not deviate from the expected geometries, with bond distances and angles lying within reported values for these species (CSD; Allen 2002).
Fig. 1 presents an ellipsoid plot of the asymmetric unit contents in structure (I), consisting of a neutral dap molecule and one solvent water molecule. As expected, the dap unit is planar [maximum deviation from the mean plane is 0.015 (1) Å for atom C1], and the mean plane defined by the molecule deviates by just 0.15 Å from the crystallographic centre of symmetry at (0, 0, 1/2), so that a `thin' planar arrangement builds up via this 1 symmetry operation, with an overall deviation from the mean plane of 0.15 (1) Å and a maximum deviation of 0.42 (1) Å for atom N6. In the resulting two-dimensional structure parallel to (121), molecules of dap are interlinked by most of the existing hydrogen-bonding interactions (six out of a total of seven; Fig. 2 and Table 1) which define a number of closed structures, in particular a couple of centrosymmetric loops with graph-set descriptors R22(8) [The general form of a graph-set descriptor is Gda(n), with possible codings for G being S (intramolecular, or self, hydrogen bonds), D (dimeric system), R (cyclic system) or C (chain). The sub- and superscripts d and a define the number of donors and acceptors in the motif, while n stands for number of atoms involved. For more details on graph-set notation as applied to hydrogen-bonding, see Bernstein et al. (1995).] (labelled A1 and A2 in Fig. 2) involving only dap molecules with no intervention of the solvent water molecule (first two entries in Table 1), and which define a zigzag chain along [101]. These parallel chains are in turn connected along [111] by a number of loops where the water molecule plays an active role, being involved in four different hydrogen bonds in the plane, three of them as an acceptor (entries 3–5 in Table 1) and one as a donor (entry 6). The result is the formation of a centrosymmetric R42(8) ring (B1 in Fig. 2), around which another three different loops build up in pairs, with graph-set descriptors R32(8) (B2), R22(7) (B3) and a rather large R66(20) (B4). The planar structures stack parallel to each other at a distance of ca 3.5 Å (Fig. 3), and are weakly linked by a mixture of hydrogen bonds [through an N···H—O—H···N chain involving both water H atoms (entries 6 and 7 in Table 1), which define a centrosymmetric R44(14) loop around the inversion centre at (1/2, 1/2, 1/2)] (labelled C in Fig. 3) and some π–π interactions, presumably involving the whole two-dimensional structure in a generalized fashion. Individual short contacts between parallel rings fulfilling the π–π bonding criteria are presented in Table 2.
Fig. 4 shows a molecular view of (II). The asymmetric unit, noticeably more complex than that in structure (I), consists of two Hdap+ cations (atoms identified by trailing labels 1 and 2, respectively) counterbalanced by one homophthalate hpt2- anion (trailing label 3) and completed by seven solvent water molecules. It is worth mentioning, for future reference, that both independent Hdap+ cations of (II) are identical, with protonation at N taking place at the same sites, viz. N11 and N31, and N12 and N32.
The two independent Hdap+ cations also show very small individual deviations from planarity: 0.029 (1) Å for atom N51 and 0.033 (1) Å for atom C22, respectively. In addition, they lie almost on the same plane, parallel to (101), with a slightly larger deviation from the mean plane (0.069 Å for atom N51) when both cations are considered in bulk. A peculiar result of this disposition is that these molecules and their (x + 1, y, z - 1) and (x - 1, y, z + 1) translation images determine almost perfect and extremely `thin' infinite `strips' running along [101] [overall deviation from the mean plane for the whole assembly 0.02 (1) Å, with a maximum of 0.09 (1) Å for atom N51]. This structure (to be discussed below) somehow resembles the planar disposition of the dap molecules in (I).
The hpt2- anion of (II), in turn, presents a planar inner phenyl core [maximum deviation from the least-squares plane 0.017 (1) Å for atom C63], the deviations from planarity residing instead in the lateral arms due to rotations in both the carboxylate and the ethyl groups. Fig. 4 gives a qualitative view of this out-of-plane geometry, while Table 3 presents a few torsion angles, quantitatively describing the situation.
In contrast with the deceptive simplicity of the structure when only the molecular aspects are considered, the assembly of the elemental units into a three-dimensional supramolecular organization proves to be extremely complex and possesses a great richness of detail, mainly due to the very large number of hydrogen-bonding donors and acceptors present both in anions, cations and solvates.
A detailed analysis of the hydrogen-bonding scheme of (II) reveals that there are 26 potentially active H atoms (14 Hwater and 12 HHdap), all of which are involved, and 15 potential acceptors (seven Owater, four Ohpt and four NHdap), all of them active. This leads to a large ratio of 1.73 hydrogen bonds per acceptor.
As a result of the abundance of hydrogen-bonding interactions (Table 4) and π–π contacts (Table 5), the structure naturally segregates into two well differentiated substructures, one of them cationic, made up of Hdap+ cations only, and the remaining one anionic and composed of hpt2- anions and water molecules. Both substructures present neat well differentiated characteristics, which we shall describe below.
In the cationic substructure, the basic component is the pair of coplanar Hdap+ cations strongly interlinked into a dimeric hydrogen-bonded structure through head-to-tail interactions, forming R22(8) loops (A in Fig. 5) involving atoms H61A and H62A (Table 4, entries 1 and 2). These hydrogen-bonded dimers, in turn, link to their (x + 1, y, z - 1) and (x - 1, y, z + 1) translation images, forming R22(10) loops (B in Fig. 5) involving atoms H51B and H52B (entries 3 and 4 in Table 4), thus defining planar strips running along [101], as shown in Fig. 5. When the c-glide operates on these strips, it generates a parallel image separated from the former, original, ones by a distance of roughly one-quarter of a [101] translation (Fig. 6a), to build up broad two-dimensional structures parallel to (010) at y ~ 1/4, 3/4 (Figs. 6a and 6b). Even if there are in principle particular aromatic rings fulfilling the expected geometric conditions for π–π contacts (Table 5, first and second entries), the interaction between strips should probably be considered as a collective one, with an interplanar distance equal to d(202) = 3.358 (1) Å.
The anionic substructure is of a completely different nature. It is built up of hpt2- anions and water molecules, generating hollow structures parallel to [010] at y ~0, 1/2 and limited by two parallel `walls' completely made out of hydrophilic entities (water molecules and carboxylate groups), linked into a planar hydrogen-bonding network involving 13 out of the 14 available water H atoms (Table 4, entries 5 to 17, and Fig. 7a). These interactions give rise to a variety of ring motifs (Fig. 7a): R66(18) (C), R55(16) (D), R64(12) (E), R43(10) (F) and R54(10) (G). Adjacent walls join together along b through a centrosymmetric R44(8) loop (H in Fig. 7b) including the water H atom not involved in the planar structure described earlier (Table 4, entry 18). The hydrophilic [hydrophobic?] constituents, in turn, represented by the phenyl rings, lean inwards into the space defined by the limiting walls, and interact with one another in pairs via π–π interactions (Table 5, third entry).
Finally, these anionic and cationic substructures are interleaved, defining a compact three-dimensional structure. Fig. 8 shows the way in which this is achieved. Being ionic in nature, the alternating substructures are obviously held together by Coulombian forces, but in addition their interlinkage is reinforced by a number of hydrogen bonds having H atoms from the anionic side as donors and O atoms from the cationic side as acceptors (Table 4, entries 19 to 26, and Fig. 8)
The structures herein reported are singular in a number of aspects. In spite of pertaining to the most populated nitrogenated group in nature, the dap molecule, in either its neutral or any of its ionic forms, has rarely been reported in structural studies: compound (I) constitutes only the second reported case of an isolated neutral dap molecule, the first one being in the form of a cocrystal with a Ln(crotonate) complex (Atria et al., 2009). Similarly, structure (II) is only the second one to be reported with an ionic dap as a constituent, and the first one with an Hdap+ cationic group; there has been an anionic case already reported (Badura & Vahrenkamp, 2002), corresponding to a deprotonated dap- unit in a pyrazolylborate–zinc(II) complex. Finally, to our knowledge no reported appearance of an hpt2- group as an isolated counterion has been reported: the group has always been found coordinating to a metal atom.
The most attractive aspect of both structures resides in their extensive hydrogen-bonding scheme. In order to assess their real complexity compared with similar structures, we searched the CSD for compounds containing any kind of uncomplexed aminopurines (with allowance for substituents of any sort and eventually any number of carboxylate groups), with the restriction that they should not be bonded to any metal centre. To our surprise, this search provided only five entries, the packing schemes of which we analysed. An initial conclusion was that when the compound is ionic, the packing disposition in well differentiated ionic zones, as found in (II), seems to be typical. However, the particular geometries adopted in any particular case (planar, columnar etc.) can be flexible and ligand-dependent. This comparison with related structures also confirmed the, perhaps obvious, observation that the complexity of the hydrogen-bonding scheme sustaining a structure is strongly related to the hydration state of the compound. In this respect (II), with its seven solvent water molecules, giving rise to 26 independent hydrogen bonds, produces a scheme not only far more complex than that in (I), but also than those in related structures found in the literature, for example those structures which, complying with the restrictions of our search, appeared to have the largest number of such interactions, viz. ethyl 2,6-diaminopurine-9-acetate hemihydrate (Sood et al., 1997), with nine independent hydrogen bonds, or 3,4-dihydroxy-2,4-dimethyl-1,2,3,4-tetrahydropyrimido[2,1-f]- 9H-purine-2-carboxylate dihydrate (Routaboul et al., 2002), with seven independent hydrogen bonds.