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In xanthinium nitrate hydrate [systematic name: 2,6-dioxo-1,2,3,6-tetrahydro-9
H-purin-7-ium nitrate monohydrate], C
5H
5N
4O
2+·NO
3−·H
2O, (I), and xanthinium hydrogen sulfate hydrate [systematic name: 2,6-dioxo-1,2,3,6-tetrahydro-9
H-purin-7-ium hydrogen sulfate monohydrate], C
5H
5N
4O
2+·HSO
4−·H
2O, (II), the xanthine molecules are protonated at the imine N atom with the transfer of an H atom from the inorganic acid. The asymmetric unit of (I) contains a xanthinium cation, a nitrate anion and one water molecule, while that of (II) contains two crystallographically independent xanthinium cations, two hydrogen sulfate anions and two water molecules. A pseudo-quadruple hydrogen-bonding motif is formed between the xanthinium cations and the water molecules
via N—H
O and O—H
O hydrogen bonds in both structures, and leads to the formation of one-dimensional polymeric tapes. These cation–water tapes are further connected by the respective anions and aggregate into two-dimensional hydrogen-bonded sheets in (I) and three-dimensional arrangements in (II).
Supporting information
CCDC references: 851737; 851738
A hot aqueous solution (5 ml) of xanthine (0.150 g, 1 mmol) was mixed with
either 65% nitric acid (5 ml) [for the preparation of (I)] or 98% sulfuric
acid (5 ml) [for the preparation of (II)]. Crystals of both compounds were
obtained from their respective solutions after several weeks, by slow
evaporation of the aqueous solvent at room temperature.
All N-bound H atoms of the xanthinium cations of (I) and (II), O-bound H atoms
of the hydrogen sulfate anion of (II) and H atoms of the water molecules of
(I) and (II) were located in difference Fourier maps and their positions and
isotropic displacement parameters refined. All other H atoms were located in
difference density maps, positioned geometrically and included as riding
atoms, with C—H = 0.93 Å and Uiso(H) = 1.2Ueq(C).
Distance restraints were applied with a set value of 0.87 (2) Å for
N7A—H3N and N9B—H8N and 0.82 (2)Å for O1A—H1O.
Compound (I) crystallizes in the noncentrosymmetric space group P21
but the structure shows pseudo-symmetry, which is fulfilled for approximately
82% of the atoms. Systematic absences show the space group to be
P21/c, even though the absence condition for a c-glide
is not strictly satisfied. The structure was solved in both P21 and
P21/c space groups. However, the structure refined in space
group P21/c showed poor residual factors and abnormal
geometric parameters, while the structure refined in space group P21
did not show such problems. The asymmetric unit of (II) also does not show any
inversion centre between the sulfate ions. Refinement in a higher symmetric
space group is not possible. The value of the Flack & Bernardinelli
(2000)
parameter of (II) indicates inversion twinning.
For both compounds, data collection: SMART (Bruker, 2001); cell refinement: SAINT (Bruker, 2001); data reduction: SAINT (Bruker, 2001); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg & Putz, 2005); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).
(I) 2,6-dioxo-1,2,3,6-tetrahydro-9
H-purin-7-ium nitrate monohydrate
top
Crystal data top
C5H5N4O2+·NO3−·H2O | Z = 2 |
Mr = 233.16 | F(000) = 240 |
Triclinic, P1 | Dx = 1.789 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 5.0416 (7) Å | Cell parameters from 3003 reflections |
b = 7.4621 (10) Å | θ = 2.8–27.9° |
c = 12.1396 (16) Å | µ = 0.16 mm−1 |
α = 80.248 (2)° | T = 294 K |
β = 80.800 (2)° | Block, colourless |
γ = 75.657 (2)° | 0.21 × 0.18 × 0.09 mm |
V = 432.74 (10) Å3 | |
Data collection top
Bruker SMART APEX CCD area-detector diffractometer | 1672 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.019 |
Graphite monochromator | θmax = 26.5°, θmin = 1.7° |
ω scans | h = −6→6 |
4689 measured reflections | k = −9→9 |
1801 independent reflections | l = −15→15 |
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)] = 0.037 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.102 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.15 | w = 1/[σ2(Fo2) + (0.0573P)2 + 0.0657P] where P = (Fo2 + 2Fc2)/3 |
1801 reflections | (Δ/σ)max < 0.001 |
169 parameters | Δρmax = 0.19 e Å−3 |
0 restraints | Δρmin = −0.28 e Å−3 |
Crystal data top
C5H5N4O2+·NO3−·H2O | γ = 75.657 (2)° |
Mr = 233.16 | V = 432.74 (10) Å3 |
Triclinic, P1 | Z = 2 |
a = 5.0416 (7) Å | Mo Kα radiation |
b = 7.4621 (10) Å | µ = 0.16 mm−1 |
c = 12.1396 (16) Å | T = 294 K |
α = 80.248 (2)° | 0.21 × 0.18 × 0.09 mm |
β = 80.800 (2)° | |
Data collection top
Bruker SMART APEX CCD area-detector diffractometer | 1672 reflections with I > 2σ(I) |
4689 measured reflections | Rint = 0.019 |
1801 independent reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.037 | 0 restraints |
wR(F2) = 0.102 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.15 | Δρmax = 0.19 e Å−3 |
1801 reflections | Δρmin = −0.28 e Å−3 |
169 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. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
C2 | 0.8839 (3) | 0.67326 (18) | 0.85469 (11) | 0.0317 (3) | |
C4 | 0.9133 (3) | 0.95057 (18) | 0.73263 (10) | 0.0303 (3) | |
C5 | 1.0807 (3) | 0.99502 (18) | 0.79615 (11) | 0.0318 (3) | |
C6 | 1.1646 (3) | 0.87723 (18) | 0.89663 (11) | 0.0306 (3) | |
C8 | 1.0093 (3) | 1.2173 (2) | 0.65574 (12) | 0.0379 (3) | |
H8 | 1.0142 | 1.3270 | 0.6068 | 0.045* | |
N1 | 1.0543 (2) | 0.72169 (16) | 0.91742 (10) | 0.0335 (3) | |
H1N | 1.098 (4) | 0.641 (3) | 0.9773 (17) | 0.044 (5)* | |
N3 | 0.8151 (2) | 0.79268 (16) | 0.75885 (10) | 0.0327 (3) | |
H3N | 0.723 (4) | 0.763 (3) | 0.7147 (17) | 0.050 (5)* | |
N7 | 1.1373 (2) | 1.16338 (17) | 0.74592 (10) | 0.0362 (3) | |
H7N | 1.248 (4) | 1.231 (3) | 0.7721 (16) | 0.049 (5)* | |
N9 | 0.8699 (2) | 1.09049 (16) | 0.64468 (10) | 0.0345 (3) | |
H9N | 0.766 (5) | 1.102 (3) | 0.587 (2) | 0.067 (6)* | |
O10 | 0.7987 (2) | 0.53016 (14) | 0.88339 (9) | 0.0428 (3) | |
O11 | 1.3161 (2) | 0.90595 (15) | 0.95805 (9) | 0.0405 (3) | |
N10 | 0.3861 (2) | 0.67465 (16) | 0.58981 (10) | 0.0347 (3) | |
O1 | 0.5039 (3) | 0.60312 (17) | 0.67433 (10) | 0.0572 (4) | |
O2 | 0.2181 (3) | 0.60354 (19) | 0.56025 (10) | 0.0538 (3) | |
O3 | 0.4391 (3) | 0.82339 (16) | 0.53603 (10) | 0.0506 (3) | |
O1W | 0.4474 (3) | 0.29587 (19) | 0.85104 (12) | 0.0535 (3) | |
H1W | 0.515 (5) | 0.384 (4) | 0.8293 (19) | 0.064 (6)* | |
H2W | 0.501 (5) | 0.231 (4) | 0.906 (2) | 0.077 (8)* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
C2 | 0.0366 (7) | 0.0315 (6) | 0.0301 (6) | −0.0105 (5) | −0.0122 (5) | −0.0013 (5) |
C4 | 0.0325 (6) | 0.0329 (6) | 0.0256 (6) | −0.0058 (5) | −0.0083 (5) | −0.0023 (5) |
C5 | 0.0355 (7) | 0.0321 (6) | 0.0301 (6) | −0.0099 (5) | −0.0100 (5) | −0.0021 (5) |
C6 | 0.0330 (6) | 0.0322 (6) | 0.0284 (6) | −0.0074 (5) | −0.0094 (5) | −0.0040 (5) |
C8 | 0.0435 (7) | 0.0366 (7) | 0.0346 (7) | −0.0123 (6) | −0.0114 (6) | 0.0033 (5) |
N1 | 0.0418 (6) | 0.0333 (6) | 0.0287 (6) | −0.0120 (5) | −0.0161 (5) | 0.0027 (5) |
N3 | 0.0393 (6) | 0.0348 (6) | 0.0289 (6) | −0.0127 (5) | −0.0157 (5) | −0.0006 (4) |
N7 | 0.0417 (6) | 0.0350 (6) | 0.0355 (6) | −0.0142 (5) | −0.0125 (5) | 0.0008 (5) |
N9 | 0.0398 (6) | 0.0365 (6) | 0.0283 (6) | −0.0099 (5) | −0.0128 (5) | 0.0022 (5) |
O10 | 0.0563 (6) | 0.0379 (6) | 0.0425 (6) | −0.0226 (5) | −0.0242 (5) | 0.0062 (4) |
O11 | 0.0467 (6) | 0.0431 (6) | 0.0391 (6) | −0.0168 (5) | −0.0223 (4) | −0.0007 (4) |
N10 | 0.0418 (6) | 0.0349 (6) | 0.0311 (6) | −0.0123 (5) | −0.0122 (5) | −0.0016 (4) |
O1 | 0.0828 (9) | 0.0526 (7) | 0.0462 (7) | −0.0292 (6) | −0.0386 (6) | 0.0150 (5) |
O2 | 0.0597 (7) | 0.0643 (7) | 0.0501 (7) | −0.0322 (6) | −0.0199 (5) | −0.0031 (6) |
O3 | 0.0658 (7) | 0.0421 (6) | 0.0487 (6) | −0.0233 (5) | −0.0212 (5) | 0.0106 (5) |
O1W | 0.0699 (8) | 0.0486 (7) | 0.0548 (7) | −0.0349 (6) | −0.0342 (6) | 0.0145 (6) |
Geometric parameters (Å, º) top
C2—O10 | 1.2247 (17) | C8—N9 | 1.345 (2) |
C2—N3 | 1.3759 (18) | C8—H8 | 0.9300 |
C2—N1 | 1.3799 (17) | N1—H1N | 0.88 (2) |
C4—N3 | 1.3588 (18) | N3—H3N | 0.85 (2) |
C4—C5 | 1.3604 (18) | N7—H7N | 0.96 (2) |
C4—N9 | 1.3645 (17) | N9—H9N | 0.92 (2) |
C5—N7 | 1.3761 (18) | N10—O2 | 1.2298 (16) |
C5—C6 | 1.4342 (18) | N10—O1 | 1.2420 (16) |
C6—O11 | 1.2256 (16) | N10—O3 | 1.2550 (16) |
C6—N1 | 1.3770 (18) | O1W—H1W | 0.80 (3) |
C8—N7 | 1.3134 (18) | O1W—H2W | 0.80 (3) |
| | | |
O10—C2—N3 | 121.77 (12) | C6—N1—H1N | 117.2 (12) |
O10—C2—N1 | 121.24 (12) | C2—N1—H1N | 114.8 (12) |
N3—C2—N1 | 117.00 (12) | C4—N3—C2 | 118.83 (12) |
N3—C4—C5 | 122.92 (12) | C4—N3—H3N | 121.2 (13) |
N3—C4—N9 | 129.65 (12) | C2—N3—H3N | 119.8 (13) |
C5—C4—N9 | 107.43 (12) | C8—N7—C5 | 107.89 (12) |
C4—C5—N7 | 107.28 (12) | C8—N7—H7N | 125.5 (11) |
C4—C5—C6 | 121.78 (13) | C5—N7—H7N | 126.6 (11) |
N7—C5—C6 | 130.94 (12) | C8—N9—C4 | 107.42 (12) |
O11—C6—N1 | 122.53 (12) | C8—N9—H9N | 123.9 (15) |
O11—C6—C5 | 125.99 (13) | C4—N9—H9N | 128.7 (15) |
N1—C6—C5 | 111.49 (11) | O2—N10—O1 | 121.01 (12) |
N7—C8—N9 | 109.99 (13) | O2—N10—O3 | 120.55 (12) |
N7—C8—H8 | 125.0 | O1—N10—O3 | 118.43 (12) |
N9—C8—H8 | 125.0 | H1W—O1W—H2W | 116 (3) |
C6—N1—C2 | 127.98 (11) | | |
| | | |
N3—C4—C5—N7 | −179.41 (12) | N3—C2—N1—C6 | 0.5 (2) |
N9—C4—C5—N7 | 0.20 (15) | C5—C4—N3—C2 | 1.0 (2) |
N3—C4—C5—C6 | −0.3 (2) | N9—C4—N3—C2 | −178.52 (13) |
N9—C4—C5—C6 | 179.26 (12) | O10—C2—N3—C4 | 179.04 (13) |
C4—C5—C6—O11 | 179.42 (13) | N1—C2—N3—C4 | −1.02 (19) |
N7—C5—C6—O11 | −1.8 (2) | N9—C8—N7—C5 | 0.04 (16) |
C4—C5—C6—N1 | −0.21 (18) | C4—C5—N7—C8 | −0.15 (16) |
N7—C5—C6—N1 | 178.61 (13) | C6—C5—N7—C8 | −179.10 (14) |
O11—C6—N1—C2 | −179.51 (13) | N7—C8—N9—C4 | 0.08 (16) |
C5—C6—N1—C2 | 0.1 (2) | N3—C4—N9—C8 | 179.41 (14) |
O10—C2—N1—C6 | −179.57 (13) | C5—C4—N9—C8 | −0.17 (15) |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1N···O10i | 0.88 (2) | 1.99 (2) | 2.8761 (15) | 177 (2) |
N3—H3N···O1 | 0.85 (2) | 1.97 (2) | 2.7604 (17) | 153 (2) |
N7—H7N···O1Wii | 0.96 (2) | 1.69 (2) | 2.6233 (17) | 162 (2) |
N9—H9N···O3iii | 0.92 (2) | 1.88 (3) | 2.7878 (17) | 168 (2) |
O1W—H1W···O10 | 0.80 (3) | 2.24 (3) | 2.8873 (16) | 139 (2) |
O1W—H1W···O1 | 0.80 (3) | 2.27 (3) | 2.8986 (18) | 136 (2) |
O1W—H2W···O11i | 0.80 (3) | 2.02 (3) | 2.8059 (16) | 170 (3) |
C8—H8···O2ii | 0.93 | 2.47 | 3.277 (2) | 145 |
C8—H8···O2iii | 0.93 | 2.42 | 2.999 (2) | 120 |
Symmetry codes: (i) −x+2, −y+1, −z+2; (ii) x+1, y+1, z; (iii) −x+1, −y+2, −z+1. |
(II) 2,6-dioxo-1,2,3,6-tetrahydro-9
H-purin-7-ium hydrogen sulfate monohydrate
top
Crystal data top
C5H5N4O2+·HO4S−·H2O | F(000) = 552 |
Mr = 268.21 | Dx = 1.851 Mg m−3 |
Monoclinic, P21 | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: P 2yb | Cell parameters from 9350 reflections |
a = 5.183 (5) Å | θ = 2.7–28.0° |
b = 24.805 (5) Å | µ = 0.37 mm−1 |
c = 7.701 (5) Å | T = 294 K |
β = 103.510 (5)° | Block, colourless |
V = 962.7 (11) Å3 | 0.18 × 0.15 × 0.07 mm |
Z = 4 | |
Data collection top
Bruker SMART APEX CCD area-detector diffractometer | 3939 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.020 |
Graphite monochromator | θmax = 26.5°, θmin = 1.6° |
ω scans | h = −6→6 |
10396 measured reflections | k = −31→31 |
3998 independent reflections | l = −9→9 |
Refinement top
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)] = 0.030 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.080 | w = 1/[σ2(Fo2) + (0.0586P)2 + 0.1425P] where P = (Fo2 + 2Fc2)/3 |
S = 1.06 | (Δ/σ)max = 0.002 |
3998 reflections | Δρmax = 0.46 e Å−3 |
364 parameters | Δρmin = −0.34 e Å−3 |
4 restraints | Absolute structure: Flack & Bernardinelli (2000), with how many Friedel pairs? |
Primary atom site location: structure-invariant direct methods | Absolute structure parameter: 0.13 (5) |
Crystal data top
C5H5N4O2+·HO4S−·H2O | V = 962.7 (11) Å3 |
Mr = 268.21 | Z = 4 |
Monoclinic, P21 | Mo Kα radiation |
a = 5.183 (5) Å | µ = 0.37 mm−1 |
b = 24.805 (5) Å | T = 294 K |
c = 7.701 (5) Å | 0.18 × 0.15 × 0.07 mm |
β = 103.510 (5)° | |
Data collection top
Bruker SMART APEX CCD area-detector diffractometer | 3939 reflections with I > 2σ(I) |
10396 measured reflections | Rint = 0.020 |
3998 independent reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.030 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.080 | Δρmax = 0.46 e Å−3 |
S = 1.06 | Δρmin = −0.34 e Å−3 |
3998 reflections | Absolute structure: Flack & Bernardinelli (2000), with how many Friedel pairs? |
364 parameters | Absolute structure parameter: 0.13 (5) |
4 restraints | |
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. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
C2A | 1.3429 (4) | 0.46306 (8) | 0.6082 (3) | 0.0278 (4) | |
C4A | 1.3118 (4) | 0.51974 (8) | 0.3606 (3) | 0.0253 (4) | |
C5A | 1.4932 (4) | 0.49060 (8) | 0.2972 (2) | 0.0260 (4) | |
C6A | 1.6203 (4) | 0.44469 (8) | 0.3924 (3) | 0.0279 (4) | |
C8A | 1.3504 (4) | 0.55589 (9) | 0.1094 (3) | 0.0310 (4) | |
H8A | 1.3250 | 0.5785 | 0.0104 | 0.037* | |
N1A | 1.5284 (4) | 0.43415 (7) | 0.5435 (2) | 0.0297 (4) | |
H1N | 1.588 (5) | 0.4084 (10) | 0.609 (3) | 0.027 (6)* | |
N3A | 1.2384 (3) | 0.50759 (7) | 0.5137 (2) | 0.0279 (3) | |
H2N | 1.119 (6) | 0.5245 (12) | 0.558 (4) | 0.040 (7)* | |
N7A | 1.5134 (3) | 0.51486 (7) | 0.1393 (2) | 0.0292 (3) | |
H3N | 1.600 (7) | 0.5018 (15) | 0.068 (4) | 0.072 (11)* | |
N9A | 1.2251 (3) | 0.56058 (7) | 0.2428 (2) | 0.0281 (3) | |
H4N | 1.122 (5) | 0.5866 (11) | 0.258 (3) | 0.029 (6)* | |
O10A | 1.2741 (3) | 0.44953 (7) | 0.7434 (2) | 0.0397 (4) | |
O11A | 1.7897 (3) | 0.41685 (6) | 0.3492 (2) | 0.0379 (4) | |
C2B | 1.6485 (4) | 0.32564 (8) | 0.8867 (3) | 0.0286 (4) | |
C4B | 1.6576 (4) | 0.27282 (7) | 1.1416 (2) | 0.0238 (3) | |
C5B | 1.4802 (4) | 0.30477 (8) | 1.1969 (2) | 0.0260 (4) | |
C6B | 1.3646 (4) | 0.35067 (8) | 1.0958 (3) | 0.0267 (4) | |
C8B | 1.5995 (4) | 0.24141 (9) | 1.3953 (3) | 0.0316 (4) | |
H8B | 1.6133 | 0.2200 | 1.4961 | 0.038* | |
N1B | 1.4657 (4) | 0.35717 (7) | 0.9447 (2) | 0.0313 (4) | |
H5N | 1.402 (7) | 0.3884 (16) | 0.871 (5) | 0.069 (10)* | |
N3B | 1.7438 (3) | 0.28130 (7) | 0.9899 (2) | 0.0277 (3) | |
H6N | 1.825 (5) | 0.2571 (11) | 0.934 (3) | 0.029 (6)* | |
N7B | 1.4475 (4) | 0.28433 (7) | 1.3572 (2) | 0.0299 (3) | |
H7N | 1.332 (6) | 0.2988 (13) | 1.429 (4) | 0.050 (8)* | |
N9B | 1.7320 (3) | 0.23320 (7) | 1.2668 (2) | 0.0287 (3) | |
H8N | 1.812 (5) | 0.2049 (9) | 1.252 (4) | 0.034 (7)* | |
O10B | 1.7199 (3) | 0.33619 (7) | 0.7508 (2) | 0.0396 (4) | |
O11B | 1.1990 (3) | 0.38113 (6) | 1.1301 (2) | 0.0381 (3) | |
S1A | 0.80004 (9) | 0.601453 (18) | 0.72459 (6) | 0.02656 (11) | |
O1A | 0.5882 (3) | 0.62314 (7) | 0.5631 (2) | 0.0412 (4) | |
H1O | 0.660 (6) | 0.6251 (13) | 0.480 (3) | 0.051 (8)* | |
O2A | 0.8671 (4) | 0.54763 (7) | 0.6732 (2) | 0.0469 (4) | |
O3A | 0.6642 (3) | 0.59808 (7) | 0.8682 (2) | 0.0401 (3) | |
O4A | 1.0233 (4) | 0.63669 (9) | 0.7597 (3) | 0.0578 (5) | |
S1B | 0.84164 (9) | 0.686166 (18) | 0.22880 (6) | 0.02849 (12) | |
O1B | 0.6339 (4) | 0.68530 (9) | 0.0490 (2) | 0.0511 (4) | |
H2O | 0.658 (9) | 0.6528 (19) | 0.018 (6) | 0.091 (14)* | |
O2B | 0.8328 (3) | 0.63096 (6) | 0.3027 (2) | 0.0389 (3) | |
O3B | 0.7557 (4) | 0.72644 (8) | 0.3326 (3) | 0.0573 (5) | |
O4B | 1.1010 (4) | 0.69425 (8) | 0.1926 (3) | 0.0554 (5) | |
O1W | 2.0991 (4) | 0.33165 (8) | 0.5118 (3) | 0.0468 (4) | |
H1W | 2.014 (6) | 0.3623 (13) | 0.469 (4) | 0.044 (8)* | |
H2W | 2.066 (8) | 0.3192 (18) | 0.598 (6) | 0.073 (12)* | |
O2W | 0.8743 (4) | 0.47062 (9) | 0.9774 (3) | 0.0450 (4) | |
H3W | 0.923 (9) | 0.4832 (18) | 0.904 (6) | 0.077 (13)* | |
H4W | 0.973 (8) | 0.4471 (17) | 1.019 (5) | 0.063 (10)* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
C2A | 0.0325 (9) | 0.0253 (9) | 0.0271 (10) | 0.0030 (7) | 0.0102 (8) | 0.0004 (7) |
C4A | 0.0252 (8) | 0.0219 (8) | 0.0290 (9) | 0.0010 (6) | 0.0066 (7) | 0.0007 (7) |
C5A | 0.0288 (8) | 0.0267 (9) | 0.0239 (8) | −0.0006 (7) | 0.0088 (7) | −0.0003 (7) |
C6A | 0.0273 (9) | 0.0271 (9) | 0.0302 (9) | 0.0004 (7) | 0.0082 (7) | −0.0024 (7) |
C8A | 0.0329 (9) | 0.0305 (9) | 0.0298 (9) | −0.0027 (7) | 0.0079 (8) | 0.0068 (7) |
N1A | 0.0359 (9) | 0.0234 (7) | 0.0311 (9) | 0.0098 (7) | 0.0105 (7) | 0.0047 (7) |
N3A | 0.0329 (8) | 0.0260 (8) | 0.0281 (8) | 0.0069 (6) | 0.0135 (6) | 0.0010 (6) |
N7A | 0.0304 (8) | 0.0330 (9) | 0.0268 (8) | 0.0004 (7) | 0.0121 (6) | 0.0007 (7) |
N9A | 0.0328 (8) | 0.0235 (8) | 0.0287 (8) | 0.0033 (7) | 0.0085 (6) | 0.0022 (6) |
O10A | 0.0509 (9) | 0.0389 (8) | 0.0357 (8) | 0.0152 (7) | 0.0229 (7) | 0.0137 (7) |
O11A | 0.0384 (8) | 0.0366 (8) | 0.0420 (9) | 0.0148 (6) | 0.0160 (7) | 0.0020 (6) |
C2B | 0.0308 (9) | 0.0284 (10) | 0.0272 (10) | 0.0006 (7) | 0.0081 (8) | 0.0018 (7) |
C4B | 0.0293 (8) | 0.0195 (8) | 0.0220 (8) | −0.0001 (7) | 0.0047 (6) | −0.0012 (6) |
C5B | 0.0304 (9) | 0.0249 (9) | 0.0241 (8) | 0.0025 (7) | 0.0095 (7) | −0.0007 (7) |
C6B | 0.0311 (9) | 0.0232 (8) | 0.0264 (9) | 0.0024 (7) | 0.0082 (7) | −0.0006 (7) |
C8B | 0.0380 (10) | 0.0314 (10) | 0.0259 (9) | 0.0011 (8) | 0.0086 (7) | 0.0037 (8) |
N1B | 0.0390 (9) | 0.0269 (9) | 0.0302 (9) | 0.0080 (7) | 0.0123 (7) | 0.0062 (7) |
N3B | 0.0323 (8) | 0.0256 (8) | 0.0282 (8) | 0.0064 (6) | 0.0131 (6) | 0.0015 (6) |
N7B | 0.0357 (9) | 0.0287 (8) | 0.0271 (8) | 0.0009 (6) | 0.0110 (6) | 0.0006 (6) |
N9B | 0.0325 (8) | 0.0233 (8) | 0.0303 (8) | 0.0051 (6) | 0.0075 (6) | 0.0037 (6) |
O10B | 0.0492 (8) | 0.0413 (9) | 0.0337 (8) | 0.0089 (7) | 0.0208 (7) | 0.0076 (6) |
O11B | 0.0438 (8) | 0.0349 (8) | 0.0388 (8) | 0.0146 (6) | 0.0163 (6) | 0.0034 (6) |
S1A | 0.0297 (2) | 0.0275 (2) | 0.0249 (2) | −0.00132 (17) | 0.01116 (16) | 0.00106 (16) |
O1A | 0.0383 (8) | 0.0525 (10) | 0.0343 (8) | 0.0050 (7) | 0.0115 (6) | 0.0136 (7) |
O2A | 0.0589 (10) | 0.0357 (8) | 0.0546 (10) | 0.0120 (8) | 0.0307 (8) | 0.0023 (7) |
O3A | 0.0559 (9) | 0.0383 (8) | 0.0333 (7) | −0.0014 (7) | 0.0250 (6) | −0.0015 (7) |
O4A | 0.0542 (10) | 0.0590 (12) | 0.0581 (11) | −0.0254 (9) | 0.0087 (8) | 0.0045 (9) |
S1B | 0.0343 (2) | 0.0267 (2) | 0.0263 (2) | −0.00138 (19) | 0.01083 (17) | −0.00025 (17) |
O1B | 0.0615 (10) | 0.0481 (10) | 0.0363 (8) | 0.0256 (9) | −0.0034 (7) | −0.0068 (8) |
O2B | 0.0503 (8) | 0.0338 (8) | 0.0364 (8) | 0.0013 (6) | 0.0176 (6) | 0.0065 (6) |
O3B | 0.0743 (13) | 0.0462 (10) | 0.0537 (10) | 0.0033 (9) | 0.0198 (9) | −0.0223 (8) |
O4B | 0.0523 (9) | 0.0545 (11) | 0.0670 (12) | −0.0115 (8) | 0.0295 (9) | 0.0065 (9) |
O1W | 0.0545 (10) | 0.0447 (9) | 0.0509 (10) | 0.0205 (8) | 0.0316 (8) | 0.0173 (8) |
O2W | 0.0491 (10) | 0.0473 (10) | 0.0467 (10) | 0.0164 (8) | 0.0273 (8) | 0.0150 (8) |
Geometric parameters (Å, º) top
C2A—O10A | 1.223 (3) | C5B—C6B | 1.430 (3) |
C2A—N3A | 1.364 (3) | C6B—O11B | 1.218 (3) |
C2A—N1A | 1.382 (3) | C6B—N1B | 1.393 (3) |
C4A—N3A | 1.355 (3) | C8B—N7B | 1.316 (3) |
C4A—C5A | 1.363 (3) | C8B—N9B | 1.346 (3) |
C4A—N9A | 1.364 (3) | C8B—H8B | 0.9300 |
C5A—N7A | 1.383 (3) | N1B—H5N | 0.97 (4) |
C5A—C6A | 1.429 (3) | N3B—H6N | 0.90 (3) |
C6A—O11A | 1.222 (3) | N7B—H7N | 0.97 (3) |
C6A—N1A | 1.382 (3) | N9B—H8N | 0.835 (17) |
C8A—N7A | 1.309 (3) | S1A—O4A | 1.425 (2) |
C8A—N9A | 1.343 (3) | S1A—O3A | 1.4453 (17) |
C8A—H8A | 0.9300 | S1A—O2A | 1.4574 (17) |
N1A—H1N | 0.83 (3) | S1A—O1A | 1.5504 (18) |
N3A—H2N | 0.88 (3) | O1A—H1O | 0.813 (18) |
N7A—H3N | 0.851 (19) | S1B—O3B | 1.4148 (19) |
N9A—H4N | 0.86 (3) | S1B—O4B | 1.449 (2) |
C2B—O10B | 1.217 (3) | S1B—O2B | 1.4877 (16) |
C2B—N3B | 1.379 (3) | S1B—O1B | 1.5430 (19) |
C2B—N1B | 1.381 (3) | O1B—H2O | 0.86 (5) |
C4B—C5B | 1.356 (3) | O1W—H1W | 0.90 (3) |
C4B—N3B | 1.361 (2) | O1W—H2W | 0.79 (4) |
C4B—N9B | 1.368 (2) | O2W—H3W | 0.74 (5) |
C5B—N7B | 1.381 (3) | O2W—H4W | 0.79 (4) |
| | | |
O10A—C2A—N3A | 121.22 (19) | N7B—C5B—C6B | 130.99 (17) |
O10A—C2A—N1A | 122.00 (19) | O11B—C6B—N1B | 122.10 (18) |
N3A—C2A—N1A | 116.79 (18) | O11B—C6B—C5B | 127.06 (19) |
N3A—C4A—C5A | 123.42 (18) | N1B—C6B—C5B | 110.84 (17) |
N3A—C4A—N9A | 128.90 (18) | N7B—C8B—N9B | 109.88 (19) |
C5A—C4A—N9A | 107.68 (18) | N7B—C8B—H8B | 125.1 |
C4A—C5A—N7A | 106.52 (17) | N9B—C8B—H8B | 125.1 |
C4A—C5A—C6A | 120.87 (18) | C2B—N1B—C6B | 128.69 (17) |
N7A—C5A—C6A | 132.61 (17) | C2B—N1B—H5N | 115 (2) |
O11A—C6A—N1A | 122.22 (19) | C6B—N1B—H5N | 116 (2) |
O11A—C6A—C5A | 125.81 (19) | C4B—N3B—C2B | 118.23 (17) |
N1A—C6A—C5A | 111.97 (17) | C4B—N3B—H6N | 126.1 (16) |
N7A—C8A—N9A | 109.92 (18) | C2B—N3B—H6N | 113.9 (16) |
N7A—C8A—H8A | 125.0 | C8B—N7B—C5B | 107.72 (18) |
N9A—C8A—H8A | 125.0 | C8B—N7B—H7N | 126.1 (19) |
C6A—N1A—C2A | 127.68 (17) | C5B—N7B—H7N | 126.2 (19) |
C6A—N1A—H1N | 120.5 (18) | C8B—N9B—C4B | 107.56 (17) |
C2A—N1A—H1N | 111.8 (18) | C8B—N9B—H8N | 125.5 (19) |
C4A—N3A—C2A | 119.19 (17) | C4B—N9B—H8N | 125.0 (19) |
C4A—N3A—H2N | 126.7 (19) | O4A—S1A—O3A | 114.17 (12) |
C2A—N3A—H2N | 114.0 (19) | O4A—S1A—O2A | 112.27 (13) |
C8A—N7A—C5A | 108.34 (17) | O3A—S1A—O2A | 110.13 (10) |
C8A—N7A—H3N | 127 (3) | O4A—S1A—O1A | 109.33 (11) |
C5A—N7A—H3N | 124 (3) | O3A—S1A—O1A | 104.69 (12) |
C8A—N9A—C4A | 107.53 (18) | O2A—S1A—O1A | 105.62 (11) |
C8A—N9A—H4N | 126.2 (16) | S1A—O1A—H1O | 106 (2) |
C4A—N9A—H4N | 126.0 (16) | O3B—S1B—O4B | 116.08 (13) |
O10B—C2B—N3B | 121.8 (2) | O3B—S1B—O2B | 113.06 (12) |
O10B—C2B—N1B | 121.70 (19) | O4B—S1B—O2B | 108.30 (11) |
N3B—C2B—N1B | 116.47 (18) | O3B—S1B—O1B | 105.74 (13) |
C5B—C4B—N3B | 124.21 (17) | O4B—S1B—O1B | 108.26 (13) |
C5B—C4B—N9B | 107.36 (17) | O2B—S1B—O1B | 104.67 (11) |
N3B—C4B—N9B | 128.41 (18) | S1B—O1B—H2O | 99 (3) |
C4B—C5B—N7B | 107.47 (17) | H1W—O1W—H2W | 117 (4) |
C4B—C5B—C6B | 121.53 (18) | H3W—O2W—H4W | 108 (4) |
| | | |
N3A—C4A—C5A—N7A | 179.50 (18) | N3B—C4B—C5B—N7B | −178.45 (17) |
N9A—C4A—C5A—N7A | 0.1 (2) | N9B—C4B—C5B—N7B | 0.1 (2) |
N3A—C4A—C5A—C6A | −0.5 (3) | N3B—C4B—C5B—C6B | 0.8 (3) |
N9A—C4A—C5A—C6A | −179.92 (17) | N9B—C4B—C5B—C6B | 179.43 (17) |
C4A—C5A—C6A—O11A | −178.08 (19) | C4B—C5B—C6B—O11B | 177.9 (2) |
N7A—C5A—C6A—O11A | 1.9 (4) | N7B—C5B—C6B—O11B | −3.0 (4) |
C4A—C5A—C6A—N1A | 2.3 (3) | C4B—C5B—C6B—N1B | −1.8 (3) |
N7A—C5A—C6A—N1A | −177.7 (2) | N7B—C5B—C6B—N1B | 177.35 (19) |
O11A—C6A—N1A—C2A | 178.6 (2) | O10B—C2B—N1B—C6B | −179.9 (2) |
C5A—C6A—N1A—C2A | −1.8 (3) | N3B—C2B—N1B—C6B | 0.7 (3) |
O10A—C2A—N1A—C6A | 179.2 (2) | O11B—C6B—N1B—C2B | −178.6 (2) |
N3A—C2A—N1A—C6A | −0.6 (3) | C5B—C6B—N1B—C2B | 1.0 (3) |
C5A—C4A—N3A—C2A | −2.2 (3) | C5B—C4B—N3B—C2B | 1.1 (3) |
N9A—C4A—N3A—C2A | 177.10 (19) | N9B—C4B—N3B—C2B | −177.21 (19) |
O10A—C2A—N3A—C4A | −177.16 (19) | O10B—C2B—N3B—C4B | 178.88 (19) |
N1A—C2A—N3A—C4A | 2.6 (3) | N1B—C2B—N3B—C4B | −1.7 (3) |
N9A—C8A—N7A—C5A | 1.1 (2) | N9B—C8B—N7B—C5B | 0.5 (2) |
C4A—C5A—N7A—C8A | −0.7 (2) | C4B—C5B—N7B—C8B | −0.4 (2) |
C6A—C5A—N7A—C8A | 179.3 (2) | C6B—C5B—N7B—C8B | −179.6 (2) |
N7A—C8A—N9A—C4A | −1.0 (2) | N7B—C8B—N9B—C4B | −0.4 (2) |
N3A—C4A—N9A—C8A | −178.83 (19) | C5B—C4B—N9B—C8B | 0.1 (2) |
C5A—C4A—N9A—C8A | 0.5 (2) | N3B—C4B—N9B—C8B | 178.65 (19) |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1A—H1N···O10B | 0.83 (3) | 2.12 (3) | 2.949 (2) | 173 (2) |
N3A—H2N···O2A | 0.88 (3) | 1.83 (3) | 2.703 (3) | 169 (3) |
N7A—H3N···O2Wi | 0.85 (2) | 1.89 (2) | 2.710 (3) | 162 (4) |
N9A—H4N···O2B | 0.86 (3) | 1.96 (3) | 2.799 (3) | 166 (2) |
N1B—H5N···O10A | 0.97 (4) | 1.84 (4) | 2.814 (2) | 177 (3) |
N3B—H6N···O4Bii | 0.90 (3) | 1.93 (3) | 2.795 (3) | 163 (2) |
N7B—H7N···O1Wiii | 0.97 (3) | 1.70 (3) | 2.657 (3) | 167 (3) |
N9B—H8N···O4Aiv | 0.84 (2) | 1.91 (2) | 2.739 (3) | 173 (3) |
O1A—H1O···O2B | 0.81 (2) | 1.81 (2) | 2.618 (3) | 177 (3) |
O1B—H2O···O3Av | 0.86 (5) | 1.78 (5) | 2.597 (2) | 157 (4) |
O1W—H1W···O11A | 0.90 (3) | 1.88 (3) | 2.769 (3) | 169 (3) |
O1W—H2W···O10B | 0.79 (4) | 2.40 (4) | 2.992 (3) | 133 (4) |
O1W—H2W···O3Bii | 0.79 (4) | 2.49 (4) | 2.897 (3) | 114 (4) |
O2W—H3W···O2A | 0.74 (5) | 2.36 (5) | 3.016 (3) | 149 (4) |
O2W—H3W···O10A | 0.74 (5) | 2.57 (5) | 3.092 (3) | 130 (4) |
O2W—H4W···O11B | 0.79 (4) | 2.08 (4) | 2.867 (3) | 174 (4) |
C8A—H8A···O3Ai | 0.93 | 2.33 | 2.933 (3) | 122 |
C8B—H8B···O3Bvi | 0.93 | 2.57 | 3.118 (3) | 118 |
C8B—H8B···O4Biv | 0.93 | 2.59 | 3.398 (3) | 146 |
Symmetry codes: (i) x+1, y, z−1; (ii) −x+3, y−1/2, −z+1; (iii) x−1, y, z+1; (iv) −x+3, y−1/2, −z+2; (v) x, y, z−1; (vi) −x+2, y−1/2, −z+2. |
Experimental details
| (I) | (II) |
Crystal data |
Chemical formula | C5H5N4O2+·NO3−·H2O | C5H5N4O2+·HO4S−·H2O |
Mr | 233.16 | 268.21 |
Crystal system, space group | Triclinic, P1 | Monoclinic, P21 |
Temperature (K) | 294 | 294 |
a, b, c (Å) | 5.0416 (7), 7.4621 (10), 12.1396 (16) | 5.183 (5), 24.805 (5), 7.701 (5) |
α, β, γ (°) | 80.248 (2), 80.800 (2), 75.657 (2) | 90, 103.510 (5), 90 |
V (Å3) | 432.74 (10) | 962.7 (11) |
Z | 2 | 4 |
Radiation type | Mo Kα | Mo Kα |
µ (mm−1) | 0.16 | 0.37 |
Crystal size (mm) | 0.21 × 0.18 × 0.09 | 0.18 × 0.15 × 0.07 |
|
Data collection |
Diffractometer | Bruker SMART APEX CCD area-detector diffractometer | Bruker SMART APEX CCD area-detector diffractometer |
Absorption correction | – | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 4689, 1801, 1672 | 10396, 3998, 3939 |
Rint | 0.019 | 0.020 |
(sin θ/λ)max (Å−1) | 0.628 | 0.628 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.037, 0.102, 1.15 | 0.030, 0.080, 1.06 |
No. of reflections | 1801 | 3998 |
No. of parameters | 169 | 364 |
No. of restraints | 0 | 4 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.19, −0.28 | 0.46, −0.34 |
Absolute structure | ? | Flack & Bernardinelli (2000), with how many Friedel pairs? |
Absolute structure parameter | ? | 0.13 (5) |
Selected bond angles (º) for (I) topC8—N7—C5 | 107.89 (12) | C8—N9—C4 | 107.42 (12) |
Hydrogen-bond geometry (Å, º) for (I) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1N···O10i | 0.88 (2) | 1.99 (2) | 2.8761 (15) | 177 (2) |
N3—H3N···O1 | 0.85 (2) | 1.97 (2) | 2.7604 (17) | 153 (2) |
N7—H7N···O1Wii | 0.96 (2) | 1.69 (2) | 2.6233 (17) | 162 (2) |
N9—H9N···O3iii | 0.92 (2) | 1.88 (3) | 2.7878 (17) | 168 (2) |
O1W—H1W···O10 | 0.80 (3) | 2.24 (3) | 2.8873 (16) | 139 (2) |
O1W—H1W···O1 | 0.80 (3) | 2.27 (3) | 2.8986 (18) | 136 (2) |
O1W—H2W···O11i | 0.80 (3) | 2.02 (3) | 2.8059 (16) | 170 (3) |
C8—H8···O2ii | 0.93 | 2.47 | 3.277 (2) | 145 |
C8—H8···O2iii | 0.93 | 2.42 | 2.999 (2) | 120 |
Symmetry codes: (i) −x+2, −y+1, −z+2; (ii) x+1, y+1, z; (iii) −x+1, −y+2, −z+1. |
Selected geometric parameters (Å, º) for (II) topS1A—O4A | 1.425 (2) | S1B—O3B | 1.4148 (19) |
S1A—O3A | 1.4453 (17) | S1B—O4B | 1.449 (2) |
S1A—O2A | 1.4574 (17) | S1B—O2B | 1.4877 (16) |
S1A—O1A | 1.5504 (18) | S1B—O1B | 1.5430 (19) |
| | | |
C8A—N7A—C5A | 108.34 (17) | O3A—S1A—O1A | 104.69 (12) |
C8A—N9A—C4A | 107.53 (18) | O2A—S1A—O1A | 105.62 (11) |
C8B—N7B—C5B | 107.72 (18) | O3B—S1B—O4B | 116.08 (13) |
C8B—N9B—C4B | 107.56 (17) | O3B—S1B—O2B | 113.06 (12) |
O4A—S1A—O3A | 114.17 (12) | O4B—S1B—O2B | 108.30 (11) |
O4A—S1A—O2A | 112.27 (13) | O3B—S1B—O1B | 105.74 (13) |
O3A—S1A—O2A | 110.13 (10) | O4B—S1B—O1B | 108.26 (13) |
O4A—S1A—O1A | 109.33 (11) | O2B—S1B—O1B | 104.67 (11) |
Hydrogen-bond geometry (Å, º) for (II) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1A—H1N···O10B | 0.83 (3) | 2.12 (3) | 2.949 (2) | 173 (2) |
N3A—H2N···O2A | 0.88 (3) | 1.83 (3) | 2.703 (3) | 169 (3) |
N7A—H3N···O2Wi | 0.851 (19) | 1.89 (2) | 2.710 (3) | 162 (4) |
N9A—H4N···O2B | 0.86 (3) | 1.96 (3) | 2.799 (3) | 166 (2) |
N1B—H5N···O10A | 0.97 (4) | 1.84 (4) | 2.814 (2) | 177 (3) |
N3B—H6N···O4Bii | 0.90 (3) | 1.93 (3) | 2.795 (3) | 163 (2) |
N7B—H7N···O1Wiii | 0.97 (3) | 1.70 (3) | 2.657 (3) | 167 (3) |
N9B—H8N···O4Aiv | 0.835 (17) | 1.908 (18) | 2.739 (3) | 173 (3) |
O1A—H1O···O2B | 0.813 (18) | 1.806 (18) | 2.618 (3) | 177 (3) |
O1B—H2O···O3Av | 0.86 (5) | 1.78 (5) | 2.597 (2) | 157 (4) |
O1W—H1W···O11A | 0.90 (3) | 1.88 (3) | 2.769 (3) | 169 (3) |
O1W—H2W···O10B | 0.79 (4) | 2.40 (4) | 2.992 (3) | 133 (4) |
O1W—H2W···O3Bii | 0.79 (4) | 2.49 (4) | 2.897 (3) | 114 (4) |
O2W—H3W···O2A | 0.74 (5) | 2.36 (5) | 3.016 (3) | 149 (4) |
O2W—H3W···O10A | 0.74 (5) | 2.57 (5) | 3.092 (3) | 130 (4) |
O2W—H4W···O11B | 0.79 (4) | 2.08 (4) | 2.867 (3) | 174 (4) |
C8A—H8A···O3Ai | 0.93 | 2.33 | 2.933 (3) | 122.2 |
C8B—H8B···O3Bvi | 0.93 | 2.57 | 3.118 (3) | 118.1 |
C8B—H8B···O4Biv | 0.93 | 2.59 | 3.398 (3) | 146.1 |
Symmetry codes: (i) x+1, y, z−1; (ii) −x+3, y−1/2, −z+1; (iii) x−1, y, z+1; (iv) −x+3, y−1/2, −z+2; (v) x, y, z−1; (vi) −x+2, y−1/2, −z+2. |
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Quadruple hydrogen-bonding motifs have received considerable attention in recent decades, due to their more stable nature compared with double or triple hydrogen-bonding motifs (Beijer et al., 1998). This binding pattern is widely utilized to construct dynamic supramolecular polymers (Corbin & Zimmerman, 1998, 2000). Recently, Lafitte et al. (2006) reported a new quadruple hydrogen-bonding module based on a ureido-substituted cytosine moiety. Xanthine (3,7-dihydropurine-2,6-dione) is a purine base found in most tissues and fluids in the human body and in other organisms. Xanthine and its nucleotide counterpart xanthosine monophosphate are important intermediates in the metabolism of purines and their nucleotides in cells. A number of mild stimulants are derived from xanthine, including caffeine and theobromine. Xanthine exists as the 2,6-diketone tautomer at neutral pH. It can adopt 14 tautomeric forms through either keto–enol transformation or proton exchange on the ring N atoms. X-ray experiments show that the sodium salt of xanthine is found mainly in the N9H dioxo tautomeric form in the solid state (Mizuno et al., 1969). It was also predicted, on the basis of both semi-empirical and ab initio calculations, that the N7H dioxo tautomeric form of xanthine would be energetically favoured over the N9H tautomer in the gas phase (Nonella et al., 1993). We report here two xanthine–inorganic acid complexes, namely xanthinium nitrate hydrate, (I, and xanthinium hydrogen sulfate hydrate, (II), in continuation of our ongoing studies of hydrogen-bonded interactions and molecular recognition of nucleobases in the solid state (Sridhar & Ravikumar, 2007, 2008, 2010; Sridhar et al., 2009).
In compounds (I) and (II), the bond lengths and angles (Tables 1 and 3) are all normal for their types (Allen et al., 1987). The asymmetric unit of (I) contains a xanthinium cation, a nitrate anion and one water molecule (Fig. 1). In (II), the asymmetric unit contains two crystallographically independent xanthinium cations (A and B), two hydrogen sulfate anions (A and B) and two water molecules (O1W and O2W) (Fig. 2).The sulfate anions of (II) exhibit a slightly distorted tetrahedral geometry, with bond lengths and angles typical of those found in several crystal structures of this kind (Cambridge Structural Database, Version?; Allen, 2002). Within the anion, the S—OH distance (Table 3) and its participation in the hydrogen bond show that the H-atom site is static, rather than mobile between the O atoms. The O—S—O angles (Table 3) are typical of those found in hydrogen sulfate anions in crystalline salts.
As expected, xanthine forms protonated units with the transfer of an H atom from the inorganic acid. Comparison of the bond lengths N7—C8 [1.3125 (19) for (I), and 1.307 (3) and 1.316 (3) for (II)] and C8—N9 [1.345 (2) for (I), and 1.338 (3) and 1.346 (3) for (II)] confirms the protonation of atom N7. A similar trend is also observed in xanthinium perchlorate dihydrate (Biradha et al., 2010)
Details of the hydrogen-bonding geometries in (I) and (II) are listed in Tables 2 and 4. A number of intermolecular hydrogen bonds stabilize the crystal structure of each compound.
In (I) and (II), the xanthinium cation and water molecule are interlinked by six hydrogen bonds (two N—H···O and four O—H···O), forming a pseudo-quadruple hydrogen-bonding motif. This motif can been defined in the form of three fused R32(8), R22(8) and R32(8) rings (Fig. 3), in order, using graph-set notation (Etter, 1990; Etter et al., 1990; Bernstein et al., 1995). The xanthinium cations of (I) are held together by N—H···O hydrogen bonds, forming a centrosymmetric dimer [R22(8) motif]. This centrosymmetric dimer is further connected to the water molecule by O—H···O hydrogen bonds [R32(8) motif]. In (II), the two xanthinium cations are interlinked by two intermolecular N—H···O hydrogen bonds to form a noncentrosymmetric dimer, which is further linked by two water molecules through intermolecular O—H..O hydrogen bonds.
In (I), the pseudo-quadruple hydrogen-bonding motif is further connected to its translation-related motif at (x + 1, y + 1, z) by an N—H···O hydrogen bond involving atom N7 of the xanthinium cation and the water, producing an R44(14) ring motif. This N—H···O hydrogen bond leads to the formation of a one-dimensional polymeric tape parallel to the [110] axis (Fig. 3a). Similarly, in (II), the pseudo-quadruple hydrogen-bonding motif is linked to its neighbouring motif by N—H···O hydrogen bonds [R44(14) motif], generating a one-dimensional polymeric tape parallel to the [101] axis (Fig. 3b).
The crystal packing of (I) reveals the involvement of the nitrate anion in cross-linking the stacks of one-dimensional polymeric tapes into two-dimensional hydrogen-bonded sheets parallel to the (112) plane (Fig. 4). The water molecule is involved in three-centred hydrogen bonding (Jeffrey & Saenger, 1991) with the cation and anion to produce an R22(6) motif. Each pseudo-quadruple hydrogen-bonding motif is interlinked to its inversion-related motif by intermolecular N—H···O hydrogen bonds involving atom N9 of the xanthinium cation and atom O3 of the nitrate anion. This N—H···O hydrogen bond generates a centrosymmetric tetramer and produces a characteristic R44(16) ring motif. Thus, the combination of N—H···O and O—H···O hydrogen bonds involving the xanthinium cation, nitrate anion and water molecule forms a centrosymmetric hexamer to produce another R66(20) ring motif and these aggregate into supramolecular two-dimensional hydrogen-bonded sheets.
In (II), the O—H···O hydrogen bonds interconnect two hydrogen sulfate anions into an [–HOSO-HOSO–]n chain along the c axis with a C22(8) graph set. Each anion is involved in two such hydrogen bonds, acting as an H-atom donor in one of them and as an H-atom acceptor in the other. Atoms N3A and N9A of the xanthinium cation link atoms O2A and O2B of the hydrogen sulfate chain through intermolecular N—H···O interactions, forming an R32(10) motif, while atoms N3B and N9B of the cation link the symmetry-related atoms O4B(-x + 3, y - 1/2, -z + 1) and O4A(-x + 3,y - 1/2, -z + 2) of the hydrogen sulfate anions to form an R33(12) motif. Thus, the infinite anion–anion chain along the crystallographic c axis interlinks the pairs of cation–cation dimers, leading to the formation of a three-dimensional hydrogen-bonded network (Fig. 5). The two water molecules are involved in three-centred hydrogen bonding with the cations and anions to produce an R23(8) motif, thus completing the three-dimensional hydrogen-bonded network (Fig. 6).
In summary, in (I), the stacking of the parallel molecular tapes is aligned parallel to the (112) plane, while in (II), the parallel cation–cation dimers are bridged by sulfate anions to form a three-dimensional structure. It is interesting to note that similar cation–cation dimers are observed in the structure of the dixanthinium tetrachlorozinc(II) complex (Hanggi et al., 1992), in which the cation–cation dimers are bridged by ZnCl4 anions. Weak C—H···O interactions are also observed in both structures.