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The title compound, 2CH6N3+·C6H2N2O42-·3H2O, forms a three-dimensional hydrogen-bonded framework structure involving all six protons of the guanidinium cation as donors to the carboxylate O and hetero N atoms of the anions, as well as to the water molecules of solvation. The anions and one of the water molecules lie on crystallographic twofold rotational axes.
Supporting information
CCDC reference: 621308
Key indicators
- Single-crystal X-ray study
- T = 130 K
- Mean (C-C) = 0.002 Å
- R factor = 0.031
- wR factor = 0.085
- Data-to-parameter ratio = 9.6
checkCIF/PLATON results
No syntax errors found
Alert level C
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ .... ?
PLAT088_ALERT_3_C Poor Data / Parameter Ratio .................... 9.65
0 ALERT level A = In general: serious problem
0 ALERT level B = Potentially serious problem
2 ALERT level C = Check and explain
0 ALERT level G = General alerts; check
1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
0 ALERT type 2 Indicator that the structure model may be wrong or deficient
1 ALERT type 3 Indicator that the structure quality may be low
0 ALERT type 4 Improvement, methodology, query or suggestion
0 ALERT type 5 Informative message, check
Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 1999); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: PLATON.
Bis(guanidinium) pyrazine-2,3-dicarboxylate trihydrate
top
Crystal data top
2CH6N3+·C6H2N2O42−·3H2O | F(000) = 360 |
Mr = 340.32 | Dx = 1.458 Mg m−3 |
Monoclinic, P2/c | Melting point: 565 K |
Hall symbol: -P 2yc | Mo Kα radiation, λ = 0.71073 Å |
a = 7.7141 (8) Å | Cell parameters from 1956 reflections |
b = 7.7252 (8) Å | θ = 2.6–27.5° |
c = 13.0299 (13) Å | µ = 0.13 mm−1 |
β = 93.403 (2)° | T = 130 K |
V = 775.12 (14) Å3 | Block, colourless |
Z = 2 | 0.35 × 0.30 × 0.25 mm |
Data collection top
Bruker CCD area-detector diffractometer | 1202 reflections with I > 2σ(I) |
Radiation source: sealed tube | Rint = 0.039 |
Graphite monochromator | θmax = 25.0°, θmin = 2.6° |
φ and ω scans | h = −9→9 |
3904 measured reflections | k = −9→8 |
1360 independent reflections | l = −15→8 |
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)] = 0.031 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.085 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.10 | w = 1/[σ2(Fo2) + (0.0474P)2 + 0.0086P] where P = (Fo2 + 2Fc2)/3 |
1360 reflections | (Δ/σ)max < 0.001 |
141 parameters | Δρmax = 0.21 e Å−3 |
0 restraints | Δρmin = −0.16 e Å−3 |
Special details top
Geometry. Bond distances, angles etc. have been calculated using the rounded
fractional coordinates. All su's are estimated from the variances of the
(full) variance-covariance matrix. The cell e.s.d.'s are taken into account in
the estimation of distances, angles and torsion angles |
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 | |
O21 | 0.75174 (12) | 0.55020 (11) | 0.10249 (7) | 0.0209 (3) | |
O22 | 0.80649 (12) | 0.43969 (12) | 0.25967 (7) | 0.0231 (3) | |
N1 | 0.83813 (14) | 0.86590 (14) | 0.19627 (8) | 0.0171 (3) | |
C2 | 0.91909 (16) | 0.71685 (16) | 0.22302 (10) | 0.0154 (4) | |
C6 | 0.91933 (17) | 1.01324 (18) | 0.22345 (10) | 0.0179 (4) | |
C21 | 0.81946 (16) | 0.55376 (17) | 0.19303 (11) | 0.0165 (4) | |
N1G | 0.47431 (16) | 0.94365 (17) | 0.12223 (9) | 0.0196 (4) | |
N2G | 0.40920 (18) | 0.69045 (16) | 0.03843 (10) | 0.0248 (4) | |
N3G | 0.20799 (15) | 0.90970 (17) | 0.03598 (9) | 0.0203 (4) | |
C1G | 0.36409 (17) | 0.84835 (17) | 0.06520 (10) | 0.0169 (4) | |
O1W | 0.10220 (13) | 0.26837 (13) | 0.05415 (9) | 0.0234 (3) | |
O2W | 0.50000 | 0.24843 (18) | 0.25000 | 0.0235 (5) | |
H6 | 0.865 | 1.120 | 0.205 | 0.022* | |
H11G | 0.4487 (19) | 1.046 (2) | 0.1450 (13) | 0.025 (4)* | |
H12G | 0.576 (2) | 0.9006 (19) | 0.1406 (12) | 0.028 (4)* | |
H21G | 0.514 (2) | 0.645 (2) | 0.0647 (14) | 0.044 (5)* | |
H22G | 0.343 (2) | 0.634 (2) | −0.0088 (14) | 0.037 (5)* | |
H31G | 0.1868 (18) | 1.029 (2) | 0.0464 (12) | 0.024 (4)* | |
H32G | 0.133 (2) | 0.843 (2) | 0.0051 (12) | 0.024 (4)* | |
H11W | 0.125 (3) | 0.334 (3) | 0.1038 (18) | 0.064 (7)* | |
H12W | 0.154 (2) | 0.331 (3) | 0.0023 (17) | 0.061 (6)* | |
H21W | 0.406 (2) | 0.324 (3) | 0.2487 (16) | 0.057 (6)* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O21 | 0.0239 (5) | 0.0202 (6) | 0.0177 (5) | −0.0025 (4) | −0.0056 (4) | −0.0006 (4) |
O22 | 0.0263 (6) | 0.0203 (5) | 0.0222 (6) | −0.0044 (4) | −0.0030 (4) | 0.0054 (4) |
N1 | 0.0203 (6) | 0.0174 (6) | 0.0135 (6) | 0.0016 (5) | 0.0002 (5) | 0.0004 (5) |
C2 | 0.0181 (7) | 0.0181 (7) | 0.0101 (7) | 0.0008 (5) | 0.0014 (5) | 0.0009 (5) |
C6 | 0.0236 (7) | 0.0158 (7) | 0.0143 (7) | 0.0026 (6) | 0.0025 (6) | 0.0006 (6) |
C21 | 0.0136 (7) | 0.0169 (7) | 0.0188 (7) | 0.0035 (5) | −0.0002 (6) | −0.0008 (6) |
N1G | 0.0186 (7) | 0.0187 (7) | 0.0209 (7) | 0.0021 (5) | −0.0034 (5) | −0.0044 (5) |
N2G | 0.0246 (7) | 0.0212 (7) | 0.0273 (7) | 0.0035 (6) | −0.0086 (6) | −0.0076 (6) |
N3G | 0.0182 (6) | 0.0198 (7) | 0.0224 (7) | 0.0001 (5) | −0.0038 (5) | −0.0021 (5) |
C1G | 0.0192 (7) | 0.0183 (7) | 0.0132 (7) | −0.0002 (6) | 0.0015 (6) | 0.0018 (6) |
O1W | 0.0278 (6) | 0.0222 (6) | 0.0199 (6) | −0.0036 (4) | −0.0004 (5) | −0.0022 (5) |
O2W | 0.0222 (8) | 0.0159 (7) | 0.0323 (9) | 0.0000 | 0.0013 (7) | 0.0000 |
Geometric parameters (Å, º) top
O21—C21 | 1.2618 (17) | N1G—H12G | 0.872 (15) |
O22—C21 | 1.2453 (17) | N1G—H11G | 0.871 (16) |
O1W—H11W | 0.83 (2) | N2G—H22G | 0.890 (17) |
O1W—H12W | 0.94 (2) | N2G—H21G | 0.928 (16) |
O2W—H21W | 0.930 (19) | N3G—H32G | 0.857 (15) |
O2W—H21Wi | 0.930 (19) | N3G—H31G | 0.947 (15) |
N1—C2 | 1.3459 (16) | C2—C2ii | 1.3959 (18) |
N1—C6 | 1.3368 (17) | C2—C21 | 1.5150 (18) |
N1G—C1G | 1.3199 (18) | C6—C6ii | 1.3876 (19) |
N2G—C1G | 1.3210 (18) | C6—H6 | 0.950 |
N3G—C1G | 1.3286 (18) | | |
| | | |
H11W—O1W—H12W | 100 (2) | N1—C2—C21 | 115.10 (11) |
H21W—O2W—H21Wi | 102.3 (18) | N1—C2—C2ii | 121.18 (11) |
C2—N1—C6 | 117.19 (11) | C2ii—C2—C21 | 123.69 (11) |
H11G—N1G—H12G | 118.1 (14) | N1—C6—C6ii | 121.63 (12) |
C1G—N1G—H11G | 123.1 (10) | O22—C21—C2 | 117.98 (12) |
C1G—N1G—H12G | 118.7 (10) | O21—C21—O22 | 126.19 (12) |
H21G—N2G—H22G | 121.4 (14) | O21—C21—C2 | 115.77 (11) |
C1G—N2G—H22G | 119.1 (10) | C6ii—C6—H6 | 120 |
C1G—N2G—H21G | 119.3 (10) | N1—C6—H6 | 119 |
C1G—N3G—H31G | 117.9 (9) | N1G—C1G—N3G | 120.33 (13) |
H31G—N3G—H32G | 122.3 (14) | N2G—C1G—N3G | 120.15 (13) |
C1G—N3G—H32G | 119.7 (11) | N1G—C1G—N2G | 119.52 (13) |
| | | |
C6—N1—C2—C21 | 178.38 (11) | C2iii—C2—C21—O22 | −57.13 (10) |
C6—N1—C2—C2ii | 0.1 (2) | N1—C2—C2ii—N1ii | −0.3 (2) |
C2—N1—C6—C6ii | 0.32 (18) | N1—C2—C2ii—C21ii | −178.43 (12) |
N1—C2—C21—O21 | 45.86 (16) | C21—C2—C2ii—C21ii | 3.4 (2) |
N1—C2—C21—O22 | −131.67 (12) | N1—C6—C6ii—N1ii | −0.5 (2) |
C2iii—C2—C21—O21 | 120.47 (11) | | |
Symmetry codes: (i) −x+1, y, −z+1/2; (ii) −x+2, y, −z+1/2; (iii) −x, y, −z+3/2. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O1W—H11W···O22i | 0.83 (2) | 2.00 (2) | 2.8160 (15) | 167 (2) |
O1W—H12W···O21iv | 0.94 (2) | 1.83 (2) | 2.7700 (14) | 178 (2) |
O2W—H21W···O22i | 0.930 (19) | 1.865 (18) | 2.7845 (12) | 170 (2) |
N1G—H11G···O2Wv | 0.871 (16) | 2.100 (16) | 2.8836 (17) | 149.3 (14) |
N1G—H11G···O2Wvi | 0.871 (16) | 2.100 (16) | 2.8836 (17) | 149.3 (14) |
N1G—H12G···N1 | 0.872 (15) | 2.124 (15) | 2.9743 (17) | 164.6 (13) |
N2G—H21G···O21 | 0.928 (16) | 2.009 (16) | 2.9310 (17) | 172.3 (16) |
N2G—H22G···O21iv | 0.890 (17) | 1.986 (17) | 2.8458 (16) | 162.0 (14) |
N3G—H31G···O1Wv | 0.947 (15) | 1.966 (15) | 2.9021 (17) | 169.6 (13) |
N3G—H32G···O1Wvii | 0.857 (15) | 2.112 (16) | 2.9434 (16) | 163.3 (14) |
Symmetry codes: (i) −x+1, y, −z+1/2; (iv) −x+1, −y+1, −z; (v) x, y+1, z; (vi) −x+1, y+1, −z+1/2; (vii) −x, −y+1, −z. |
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