Guanidinium 4-hydroxy­pyridinium-2,6-dicarboxyl­ate

The crystal structure of the title compound, CH₆N·C₇H₄NO₅^-, 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.

Key indicators

• Single-crystal X-ray study
• T = 120 K
• Mean [sigma](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

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Computing details

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

Crystal data

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) Å^3	Prism, yellow
Z = 8	0.50 × 0.20 × 0.20 mm

Data collection

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

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.056	Hydrogen site location: difference Fourier map
wR(F^2) = 0.133	H atoms treated by a mixture of independent and constrained refinement
S = 1.03	w = 1/[σ^2(Fo^2) + (0.05P)^2 + 2.2P] where P = (Fo^2 + 2Fc^2)/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

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 (Ų)

	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 (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
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)

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)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1O···O4^i	1.01	2.57	3.104 (3)	113
O1—H1O···O5^i	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···O2^ii	0.97	1.93	2.874 (3)	163
N2C—H2CA···O2	0.89	2.00	2.883 (3)	175
N2C—H2CB···O1^iii	0.85	2.21	3.010 (3)	156
N3C—H3CA···O4^iv	0.90	1.96	2.853 (3)	170
N3C—H3CB···O3^v	0.86	2.19	3.021 (3)	161
C2—H2···N1C^vi	0.93	2.55	3.358 (3)	145
C4—H4···O5^i	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.