In the title compound, C
4H
6N
3O
+·C
2HO
4−·H
2O, the cytosine molecule is protonated and oxalic acid is in the monoionized state. The structure is stabilized by O—H
O and N—H
O hydrogen bonds, and van der Waals interactions. The water molecules are also found to mediate interactions between oxalate anions and cytosinium cations.
Supporting information
CCDC reference: 282342
Key indicators
- Single-crystal X-ray study
- T = 293 K
- Mean (C-C) = 0.002 Å
- R factor = 0.050
- wR factor = 0.120
- Data-to-parameter ratio = 22.0
checkCIF/PLATON results
No syntax errors found
Alert level C
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low ....... 0.97
PLAT143_ALERT_4_C su on c - Axis Small or Missing (x 100000) ..... 20 Ang.
PLAT199_ALERT_1_C Check the Reported _cell_measurement_temperature 293 K
PLAT200_ALERT_1_C Check the Reported _diffrn_ambient_temperature . 293 K
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor .... 2.01
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor .... 3.14
PLAT369_ALERT_2_C Long C(sp2)-C(sp2) Bond C1 - C3 ... 1.55 Ang.
0 ALERT level A = In general: serious problem
0 ALERT level B = Potentially serious problem
7 ALERT level C = Check and explain
0 ALERT level G = General alerts; check
2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
3 ALERT type 2 Indicator that the structure model may be wrong or deficient
1 ALERT type 3 Indicator that the structure quality may be low
1 ALERT type 4 Improvement, methodology, query or suggestion
Data collection: KappaCCD Reference Manual (Nonius, 1998); cell refinement: DENZO and SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO and SCALEPACK; program(s) used to solve structure: SIR2002 (Burla et al., 2003); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997) and PLATON (Spek, 2003); software used to prepare material for publication: WinGX (Farrugia, 1999).
cytosinium oxalate monohydrate
top
Crystal data top
C4H6N3O+·C2HO4−·H2O | F(000) = 456 |
Mr = 219.16 | Dx = 1.657 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 3139 reflections |
a = 3.6230 (3) Å | θ = 1.0–32.7° |
b = 11.9750 (2) Å | µ = 0.15 mm−1 |
c = 20.2509 (2) Å | T = 293 K |
β = 91.484 (3)° | Prism, colorless |
V = 878.30 (7) Å3 | 0.20 × 0.20 × 0.15 mm |
Z = 4 | |
Data collection top
Nonius KappaCCD diffractometer | 2226 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.021 |
Graphite monochromator | θmax = 32.7°, θmin = 4.0° |
φ scans | h = −5→5 |
12842 measured reflections | k = −18→18 |
3139 independent reflections | l = −30→30 |
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)] = 0.050 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.120 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | w = 1/[σ2(Fo2) + (0.0394P)2 + 0.627P] where P = (Fo2 + 2Fc2)/3 |
3139 reflections | (Δ/σ)max < 0.001 |
143 parameters | Δρmax = 0.37 e Å−3 |
3 restraints | Δρmin = −0.28 e Å−3 |
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 | x | y | z | Uiso*/Ueq | |
N3 | 0.2230 (3) | 0.47014 (9) | 0.18987 (5) | 0.0173 (2) | |
H3 | 0.2796 | 0.5336 | 0.1731 | 0.021* | |
O7 | 0.4662 (3) | 0.52454 (10) | 0.28914 (5) | 0.0324 (3) | |
N8 | −0.0146 (4) | 0.42070 (11) | 0.08798 (6) | 0.0266 (3) | |
H8A | 0.0451 | 0.4859 | 0.0739 | 0.032* | |
H8B | −0.1201 | 0.3737 | 0.0615 | 0.032* | |
C4 | 0.0551 (4) | 0.39322 (11) | 0.14941 (6) | 0.0173 (2) | |
C2 | 0.3082 (4) | 0.45284 (12) | 0.25608 (6) | 0.0196 (3) | |
N1 | 0.2059 (4) | 0.35086 (11) | 0.27977 (6) | 0.0249 (3) | |
H1 | 0.2446 | 0.3369 | 0.3210 | 0.030* | |
C5 | −0.0339 (4) | 0.28750 (12) | 0.17688 (7) | 0.0231 (3) | |
H5 | −0.1439 | 0.2319 | 0.1511 | 0.028* | |
C6 | 0.0461 (4) | 0.27051 (13) | 0.24131 (8) | 0.0262 (3) | |
H6 | −0.0096 | 0.2018 | 0.2600 | 0.031* | |
O3 | 0.2298 (3) | 0.61975 (9) | 0.04048 (5) | 0.0306 (3) | |
O2 | 0.7719 (3) | 0.85295 (9) | 0.07635 (5) | 0.0292 (3) | |
O4 | 0.4943 (3) | 0.66824 (9) | 0.13756 (5) | 0.0276 (2) | |
O1 | 0.5287 (3) | 0.78944 (10) | −0.01919 (5) | 0.0310 (3) | |
H1A | 0.6358 | 0.8435 | −0.0345 | 0.046* | |
C3 | 0.4238 (4) | 0.68047 (11) | 0.07723 (6) | 0.0184 (3) | |
C1 | 0.5946 (4) | 0.78444 (11) | 0.04447 (6) | 0.0187 (2) | |
O1w | 0.8229 (4) | 0.94524 (11) | −0.08647 (6) | 0.0375 (3) | |
H2w | 0.937 (6) | 1.0033 (12) | −0.0728 (10) | 0.045* | |
H1w | 0.704 (5) | 0.9616 (17) | −0.1221 (7) | 0.045* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
N3 | 0.0251 (5) | 0.0162 (5) | 0.0106 (4) | −0.0024 (4) | −0.0024 (4) | 0.0014 (4) |
O7 | 0.0440 (7) | 0.0360 (6) | 0.0165 (5) | −0.0068 (5) | −0.0098 (4) | −0.0041 (4) |
N8 | 0.0406 (7) | 0.0264 (6) | 0.0124 (5) | −0.0084 (5) | −0.0059 (5) | −0.0008 (4) |
C4 | 0.0183 (6) | 0.0195 (6) | 0.0140 (5) | −0.0001 (5) | 0.0000 (4) | −0.0025 (4) |
C2 | 0.0226 (6) | 0.0248 (6) | 0.0114 (5) | 0.0018 (5) | −0.0018 (4) | 0.0005 (5) |
N1 | 0.0306 (6) | 0.0294 (6) | 0.0145 (5) | 0.0006 (5) | −0.0023 (4) | 0.0082 (5) |
C5 | 0.0262 (7) | 0.0185 (6) | 0.0245 (7) | −0.0026 (5) | −0.0010 (5) | −0.0002 (5) |
C6 | 0.0284 (7) | 0.0220 (7) | 0.0282 (7) | −0.0021 (6) | 0.0008 (6) | 0.0089 (6) |
O3 | 0.0456 (7) | 0.0296 (6) | 0.0159 (5) | −0.0170 (5) | −0.0095 (4) | 0.0014 (4) |
O2 | 0.0428 (6) | 0.0236 (5) | 0.0211 (5) | −0.0128 (5) | −0.0048 (4) | −0.0011 (4) |
O4 | 0.0397 (6) | 0.0298 (6) | 0.0129 (4) | −0.0110 (5) | −0.0055 (4) | 0.0026 (4) |
O1 | 0.0476 (7) | 0.0303 (6) | 0.0147 (4) | −0.0140 (5) | −0.0062 (4) | 0.0066 (4) |
C3 | 0.0232 (6) | 0.0194 (6) | 0.0126 (5) | −0.0024 (5) | −0.0013 (5) | −0.0004 (4) |
C1 | 0.0233 (6) | 0.0194 (6) | 0.0133 (5) | −0.0001 (5) | −0.0013 (5) | 0.0006 (5) |
O1w | 0.0541 (8) | 0.0314 (6) | 0.0263 (6) | −0.0153 (6) | −0.0123 (5) | 0.0122 (5) |
Geometric parameters (Å, º) top
N3—C4 | 1.3653 (16) | C5—C6 | 1.345 (2) |
N3—C2 | 1.3836 (16) | C5—H5 | 0.9300 |
N3—H3 | 0.8600 | C6—H6 | 0.9300 |
O7—C2 | 1.2219 (17) | O3—C3 | 1.2448 (16) |
N8—C4 | 1.3051 (17) | O2—C1 | 1.2170 (16) |
N8—H8A | 0.8600 | O4—C3 | 1.2503 (15) |
N8—H8B | 0.8600 | O1—C1 | 1.3064 (16) |
C4—C5 | 1.4232 (19) | O1—H1A | 0.8200 |
C2—N1 | 1.3669 (18) | C3—C1 | 1.5472 (19) |
N1—C6 | 1.358 (2) | O1w—H2w | 0.851 (9) |
N1—H1 | 0.8600 | O1w—H1w | 0.853 (9) |
| | | |
C4—N3—C2 | 124.43 (11) | C6—C5—C4 | 117.95 (13) |
C4—N3—H3 | 117.8 | C6—C5—H5 | 121.0 |
C2—N3—H3 | 117.8 | C4—C5—H5 | 121.0 |
C4—N8—H8A | 120.0 | C5—C6—N1 | 121.82 (13) |
C4—N8—H8B | 120.0 | C5—C6—H6 | 119.1 |
H8A—N8—H8B | 120.0 | N1—C6—H6 | 119.1 |
N8—C4—N3 | 118.30 (12) | C1—O1—H1A | 109.5 |
N8—C4—C5 | 123.83 (13) | O3—C3—O4 | 127.84 (13) |
N3—C4—C5 | 117.87 (12) | O3—C3—C1 | 116.08 (11) |
O7—C2—N1 | 124.25 (12) | O4—C3—C1 | 116.07 (11) |
O7—C2—N3 | 121.02 (13) | O2—C1—O1 | 124.96 (13) |
N1—C2—N3 | 114.72 (12) | O2—C1—C3 | 121.76 (11) |
C6—N1—C2 | 123.17 (12) | O1—C1—C3 | 113.27 (11) |
C6—N1—H1 | 118.4 | H2w—O1w—H1w | 108.6 (17) |
C2—N1—H1 | 118.4 | | |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N3—H3···O4 | 0.86 | 1.94 | 2.7874 (15) | 170 |
N8—H8A···O3 | 0.86 | 1.87 | 2.7267 (17) | 173 |
N8—H8B···O3i | 0.86 | 2.10 | 2.7397 (15) | 131 |
N8—H8B···O1i | 0.86 | 2.58 | 3.4071 (17) | 161 |
N1—H1···O2ii | 0.86 | 2.09 | 2.9127 (16) | 160 |
N1—H1···O4ii | 0.86 | 2.37 | 2.9445 (16) | 124 |
O1—H1A···O1w | 0.82 | 1.76 | 2.5592 (16) | 165 |
O1w—H2w···O2iii | 0.85 (1) | 2.02 (1) | 2.8322 (16) | 159 (2) |
O1w—H1w···O7iv | 0.85 (1) | 1.98 (1) | 2.8247 (16) | 170 (2) |
Symmetry codes: (i) −x, −y+1, −z; (ii) −x+1, y−1/2, −z+1/2; (iii) −x+2, −y+2, −z; (iv) x, −y+3/2, z−1/2. |