The crystal structure of the title compound, CH
6N

·C
7H
4NO
5-, shows that both intra- and intermolecular proton transfers have occurred. Hydrogen-bonding interactions, in addition to ion-pairing forces, are observed between the cation and anion.
Supporting information
CCDC reference: 251486
Key indicators
- Single-crystal X-ray study
- T = 120 K
- Mean
(C-C) = 0.003 Å
- R factor = 0.056
- wR factor = 0.133
- Data-to-parameter ratio = 14.8
checkCIF/PLATON results
No syntax errors found
Alert level A
PLAT093_ALERT_1_A No su's on H-atoms, but refinement reported as . mixed
Alert level C
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low ....... 0.97
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ .... ?
PLAT062_ALERT_4_C Rescale T(min) & T(max) by ..................... 1.02
PLAT222_ALERT_3_C Large Non-Solvent H Ueq(max)/Ueq(min) ... 3.52 Ratio
PLAT355_ALERT_3_C Long O-H Bond (0.82A) O1 - H1O ... 1.01 Ang.
PLAT369_ALERT_2_C Long C(sp2)-C(sp2) Bond C1 - C6 ... 1.53 Ang.
PLAT432_ALERT_2_C Short Inter X...Y Contact C1C .. C2 .. 3.17 Ang.
PLAT720_ALERT_4_C Number of Unusual/Non-Standard Label(s) ........ 6
1 ALERT level A = In general: serious problem
0 ALERT level B = Potentially serious problem
8 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
2 ALERT type 2 Indicator that the structure model may be wrong or deficient
3 ALERT type 3 Indicator that the structure quality may be low
2 ALERT type 4 Improvement, methodology, query or suggestion
Data collection: SMART (Bruker, 1998); cell refinement: SMART; data reduction: SAINT-Plus (Bruker, 1998); program(s) used to solve structure: SHELXTL (Sheldrick, 1998); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.
Guanidinium 4-hydroxypyridinium-2,6-dicarboxylate
top
Crystal data top
CH6N3+·C7H4NO5− | F(000) = 1008 |
Mr = 242.20 | Dx = 1.572 Mg m−3 |
Orthorhombic, Pbca | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ac 2ab | Cell parameters from 2575 reflections |
a = 6.824 (3) Å | θ = 3.2–17.3° |
b = 11.887 (6) Å | µ = 0.13 mm−1 |
c = 25.224 (10) Å | T = 120 K |
V = 2046.1 (16) Å3 | Prism, yellow |
Z = 8 | 0.50 × 0.20 × 0.20 mm |
Data collection top
Bruker SMART 1000 CCD area-detector diffractometer | 2395 independent reflections |
Radiation source: fine-focus sealed tube | 1568 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.037 |
φ and ω scans | θmax = 28.0°, θmin = 1.6° |
Absorption correction: multi-scan (SADABS; Sheldrick, 1998a) | h = −4→9 |
Tmin = 0.874, Tmax = 0.954 | k = −14→15 |
8560 measured reflections | l = −33→22 |
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)] = 0.056 | Hydrogen site location: difference Fourier map |
wR(F2) = 0.133 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | w = 1/[σ2(Fo2) + (0.05P)2 + 2.2P] where P = (Fo2 + 2Fc2)/3 |
2395 reflections | (Δ/σ)max < 0.001 |
162 parameters | Δρmax = 0.30 e Å−3 |
0 restraints | Δρmin = −0.28 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 | |
O1 | 0.6364 (3) | 0.87413 (13) | 0.34855 (6) | 0.0297 (5) | |
O2 | 0.3461 (2) | 0.57734 (13) | 0.47293 (6) | 0.0263 (5) | |
O3 | 0.3277 (2) | 0.43018 (12) | 0.41672 (6) | 0.0281 (5) | |
O4 | 0.4633 (3) | 0.61156 (14) | 0.19497 (6) | 0.0302 (5) | |
O5 | 0.3170 (2) | 0.46897 (13) | 0.23867 (6) | 0.0263 (5) | |
N1 | 0.3962 (3) | 0.56317 (15) | 0.33297 (7) | 0.0226 (6) | |
C1 | 0.4214 (3) | 0.60700 (18) | 0.38211 (8) | 0.0219 (6) | |
C2 | 0.4992 (3) | 0.71278 (18) | 0.38733 (9) | 0.0227 (7) | |
C3 | 0.5526 (3) | 0.77537 (18) | 0.34244 (9) | 0.0243 (7) | |
C4 | 0.5174 (3) | 0.72749 (18) | 0.29203 (9) | 0.0235 (7) | |
C5 | 0.4396 (3) | 0.62141 (18) | 0.28828 (8) | 0.0216 (6) | |
C6 | 0.3609 (3) | 0.53150 (18) | 0.42837 (8) | 0.0217 (6) | |
C7 | 0.4048 (3) | 0.56330 (18) | 0.23573 (9) | 0.0231 (6) | |
N1C | 0.1535 (3) | 0.30907 (15) | 0.50548 (7) | 0.0265 (6) | |
N2C | 0.1522 (3) | 0.46473 (15) | 0.55951 (8) | 0.0261 (6) | |
N3C | 0.0296 (3) | 0.29540 (16) | 0.59074 (7) | 0.0260 (6) | |
C1C | 0.1114 (3) | 0.35587 (18) | 0.55223 (9) | 0.0231 (6) | |
H1A | 0.34280 | 0.49010 | 0.32900 | 0.028 (6)* | |
H1O | 0.66340 | 0.90850 | 0.31250 | 0.095 (14)* | |
H2 | 0.51670 | 0.74330 | 0.42090 | 0.0270* | |
H4 | 0.54700 | 0.76780 | 0.26150 | 0.0280* | |
H1CB | 0.20230 | 0.35010 | 0.47870 | 0.027 (7)* | |
H1CA | 0.15210 | 0.22750 | 0.50180 | 0.033 (7)* | |
H2CA | 0.20680 | 0.50310 | 0.53330 | 0.045 (8)* | |
H2CB | 0.12350 | 0.49530 | 0.58900 | 0.036 (8)* | |
H3CA | 0.01640 | 0.32710 | 0.62300 | 0.043 (8)* | |
H3CB | −0.00320 | 0.22670 | 0.58410 | 0.028 (7)* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O1 | 0.0457 (10) | 0.0214 (8) | 0.0221 (9) | −0.0075 (7) | 0.0000 (7) | 0.0021 (6) |
O2 | 0.0364 (9) | 0.0232 (8) | 0.0193 (9) | 0.0005 (7) | 0.0008 (7) | 0.0018 (6) |
O3 | 0.0394 (9) | 0.0193 (8) | 0.0255 (9) | −0.0034 (7) | 0.0018 (7) | 0.0003 (7) |
O4 | 0.0406 (10) | 0.0298 (9) | 0.0202 (9) | −0.0005 (7) | 0.0011 (7) | 0.0011 (7) |
O5 | 0.0330 (9) | 0.0223 (8) | 0.0235 (9) | −0.0012 (7) | 0.0017 (7) | −0.0038 (6) |
N1 | 0.0286 (10) | 0.0193 (9) | 0.0200 (10) | −0.0009 (7) | 0.0009 (8) | −0.0020 (7) |
C1 | 0.0271 (11) | 0.0221 (10) | 0.0166 (11) | 0.0038 (9) | 0.0014 (9) | 0.0006 (9) |
C2 | 0.0279 (12) | 0.0237 (11) | 0.0166 (11) | 0.0018 (9) | −0.0007 (9) | 0.0002 (9) |
C3 | 0.0291 (12) | 0.0191 (10) | 0.0248 (13) | 0.0005 (9) | −0.0004 (9) | 0.0004 (9) |
C4 | 0.0281 (12) | 0.0225 (10) | 0.0199 (12) | 0.0008 (9) | 0.0009 (9) | 0.0029 (9) |
C5 | 0.0241 (11) | 0.0220 (10) | 0.0187 (11) | 0.0034 (8) | 0.0015 (9) | 0.0016 (9) |
C6 | 0.0253 (11) | 0.0197 (10) | 0.0200 (12) | 0.0021 (8) | −0.0013 (9) | 0.0018 (9) |
C7 | 0.0258 (11) | 0.0232 (10) | 0.0204 (12) | 0.0040 (9) | −0.0015 (9) | −0.0004 (9) |
N1C | 0.0405 (12) | 0.0183 (9) | 0.0208 (10) | −0.0008 (8) | 0.0019 (9) | 0.0001 (8) |
N2C | 0.0355 (11) | 0.0217 (9) | 0.0210 (11) | −0.0023 (8) | 0.0022 (8) | −0.0020 (8) |
N3C | 0.0349 (11) | 0.0232 (9) | 0.0199 (10) | −0.0011 (8) | 0.0012 (8) | −0.0014 (8) |
C1C | 0.0264 (11) | 0.0229 (10) | 0.0199 (11) | 0.0024 (9) | −0.0009 (9) | 0.0009 (9) |
Geometric parameters (Å, º) top
O1—C3 | 1.315 (3) | N1C—H1CB | 0.9000 |
O2—C6 | 1.253 (3) | N2C—H2CA | 0.8900 |
O3—C6 | 1.260 (3) | N2C—H2CB | 0.8500 |
O4—C7 | 1.243 (3) | N3C—H3CA | 0.9000 |
O5—C7 | 1.274 (3) | N3C—H3CB | 0.8600 |
O1—H1O | 1.0100 | C1—C6 | 1.529 (3) |
N1—C1 | 1.356 (3) | C1—C2 | 1.371 (3) |
N1—C5 | 1.356 (3) | C2—C3 | 1.403 (3) |
N1—H1A | 0.9500 | C3—C4 | 1.414 (3) |
N1C—C1C | 1.335 (3) | C4—C5 | 1.371 (3) |
N2C—C1C | 1.336 (3) | C5—C7 | 1.514 (3) |
N3C—C1C | 1.331 (3) | C2—H2 | 0.9300 |
N1C—H1CA | 0.9700 | C4—H4 | 0.9300 |
| | | |
C3—O1—H1O | 109.00 | O1—C3—C2 | 119.5 (2) |
C1—N1—C5 | 122.44 (18) | C3—C4—C5 | 119.9 (2) |
C1—N1—H1A | 120.00 | N1—C5—C7 | 117.45 (18) |
C5—N1—H1A | 118.00 | N1—C5—C4 | 119.79 (19) |
H1CB—N1C—H1CA | 118.00 | C4—C5—C7 | 122.74 (19) |
C1C—N1C—H1CB | 121.00 | O2—C6—O3 | 127.6 (2) |
C1C—N1C—H1CA | 120.00 | O3—C6—C1 | 115.57 (18) |
H2CA—N2C—H2CB | 122.00 | O2—C6—C1 | 116.81 (18) |
C1C—N2C—H2CB | 119.00 | O4—C7—C5 | 117.60 (19) |
C1C—N2C—H2CA | 119.00 | O5—C7—C5 | 115.13 (19) |
H3CA—N3C—H3CB | 123.00 | O4—C7—O5 | 127.3 (2) |
C1C—N3C—H3CA | 118.00 | C1—C2—H2 | 120.00 |
C1C—N3C—H3CB | 119.00 | C3—C2—H2 | 120.00 |
N1—C1—C2 | 119.30 (19) | C5—C4—H4 | 120.00 |
C2—C1—C6 | 124.72 (19) | C3—C4—H4 | 120.00 |
N1—C1—C6 | 115.98 (18) | N2C—C1C—N3C | 120.7 (2) |
C1—C2—C3 | 120.6 (2) | N1C—C1C—N2C | 118.7 (2) |
C2—C3—C4 | 117.92 (19) | N1C—C1C—N3C | 120.65 (19) |
O1—C3—C4 | 122.6 (2) | | |
| | | |
C5—N1—C1—C6 | 178.60 (19) | C1—C2—C3—C4 | 2.1 (3) |
C5—N1—C1—C2 | −2.1 (3) | C1—C2—C3—O1 | −176.4 (2) |
C1—N1—C5—C4 | 2.0 (3) | C2—C3—C4—C5 | −2.2 (3) |
C1—N1—C5—C7 | −179.9 (2) | O1—C3—C4—C5 | 176.3 (2) |
C6—C1—C2—C3 | 179.23 (19) | C3—C4—C5—N1 | 0.2 (3) |
N1—C1—C6—O2 | −166.30 (19) | C3—C4—C5—C7 | −177.76 (19) |
N1—C1—C6—O3 | 12.3 (3) | N1—C5—C7—O5 | 7.5 (3) |
C2—C1—C6—O2 | 14.4 (3) | C4—C5—C7—O5 | −174.49 (19) |
C2—C1—C6—O3 | −167.0 (2) | C4—C5—C7—O4 | 5.4 (3) |
N1—C1—C2—C3 | −0.1 (3) | N1—C5—C7—O4 | −172.6 (2) |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H1O···O4i | 1.01 | 2.57 | 3.104 (3) | 113 |
O1—H1O···O5i | 1.01 | 1.48 | 2.492 (2) | 173 |
N1—H1A···O3 | 0.95 | 2.33 | 2.680 (3) | 101 |
N1—H1A···O5 | 0.95 | 2.30 | 2.684 (3) | 104 |
N1C—H1CB···O3 | 0.90 | 2.02 | 2.915 (3) | 175 |
N1C—H1CA···O2ii | 0.97 | 1.93 | 2.874 (3) | 163 |
N2C—H2CA···O2 | 0.89 | 2.00 | 2.883 (3) | 175 |
N2C—H2CB···O1iii | 0.85 | 2.21 | 3.010 (3) | 156 |
N3C—H3CA···O4iv | 0.90 | 1.96 | 2.853 (3) | 170 |
N3C—H3CB···O3v | 0.86 | 2.19 | 3.021 (3) | 161 |
C2—H2···N1Cvi | 0.93 | 2.55 | 3.358 (3) | 145 |
C4—H4···O5i | 0.93 | 2.57 | 3.181 (3) | 124 |
Symmetry codes: (i) −x+1, y+1/2, −z+1/2; (ii) −x+1/2, y−1/2, z; (iii) x−1/2, −y+3/2, −z+1; (iv) −x+1/2, −y+1, z+1/2; (v) x−1/2, −y+1/2, −z+1; (vi) −x+1/2, y+1/2, z. |