1-Carboxy­methyl­pyridinium-2-carboxyl­ate

The title compound, C₈H₇NO₄, crystallizes with two independent mol­ecules in the asymmetric unit, displaying different conformations. The mol­ecules are linked into chains via O—H...O hydrogen bonds, and there are C—H...O inter­actions between chains.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.055
• wR factor = 0.158
• Data-to-parameter ratio = 14.8

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT432_ALERT_2_B Short Inter X...Y Contact  O6     ..  C5      ..       2.88 Ang.

Alert level C
PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical .          ?
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor ....       2.02
PLAT369_ALERT_2_C Long   C(sp2)-C(sp2) Bond  C1     -   C8     ...       1.54 Ang.
PLAT369_ALERT_2_C Long   C(sp2)-C(sp2) Bond  C9     -   C16    ...       1.55 Ang.

Alert level G
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature .        293 K

   0 ALERT level A = In general: serious problem
   1 ALERT level B = Potentially serious problem
   4 ALERT level C = Check and explain
   2 ALERT level G = General alerts; check

   3 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   4 ALERT type 2 Indicator that the structure model may be wrong or deficient
   0 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

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Computing details

Data collection: XSCANS (Siemens, 1994); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1997); software used to prepare material for publication: SHELXTL.

1-Carboxymethylpyridinium-2-carboxylate

Crystal data

C8H7NO4	F(000) = 752
Mr = 181.15	Dx = 1.483 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 3516 reflections
a = 7.9459 (12) Å	θ = 2.1–27.0°
b = 11.5115 (18) Å	µ = 0.12 mm^−1
c = 17.826 (5) Å	T = 293 K
β = 95.671 (17)°	Block, colourless
V = 1622.5 (6) Å^3	0.25 × 0.23 × 0.20 mm
Z = 8

Data collection

Siemens P4 diffractometer	2248 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.040
Graphite monochromator	θmax = 27.0°, θmin = 2.1°
ω scans	h = −1→10
Absorption correction: ψ scan (North et al., 1968)	k = −1→14
Tmin = 0.970, Tmax = 0.976	l = −22→22
4683 measured reflections	3 standard reflections every 120 reflections
3516 independent reflections	intensity decay: 8%

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)] = 0.055	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.158	H-atom parameters constrained
S = 0.99	w = 1/[σ^2(Fo^2) + (0.0409P)^2 + 0.3152P] where P = (Fo^2 + 2Fc^2)/3
3516 reflections	(Δ/σ)max < 0.001
237 parameters	Δρmax = 0.30 e Å^−3
0 restraints	Δρmin = −0.23 e Å^−3

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
N1	0.2363 (2)	0.20970 (15)	0.02792 (10)	0.0349 (4)
C1	0.2303 (3)	0.11070 (19)	0.06904 (13)	0.0367 (5)
C2	0.3791 (3)	0.0572 (2)	0.09451 (15)	0.0474 (6)
H2	0.3759	−0.0123	0.1209	0.057*
C3	0.5339 (3)	0.1043 (2)	0.08179 (16)	0.0518 (7)
H3	0.6342	0.0670	0.0989	0.062*
C4	0.5358 (3)	0.2070 (2)	0.04341 (16)	0.0496 (7)
H4	0.6381	0.2423	0.0359	0.060*
C5	0.3866 (3)	0.2577 (2)	0.01621 (14)	0.0441 (6)
H5	0.3885	0.3266	−0.0109	0.053*
C6	0.0822 (3)	0.2677 (2)	−0.00745 (13)	0.0380 (5)
H6A	−0.0036	0.2098	−0.0220	0.046*
H6B	0.1083	0.3083	−0.0526	0.046*
C7	0.0148 (3)	0.35320 (19)	0.04667 (13)	0.0352 (5)
O1	−0.13928 (19)	0.38667 (15)	0.02265 (9)	0.0457 (4)
H1	−0.1723	0.4342	0.0521	0.069*
O2	0.0974 (2)	0.38758 (14)	0.10242 (9)	0.0477 (4)
C8	0.0619 (3)	0.0645 (2)	0.09294 (14)	0.0416 (6)
O3	−0.0551 (2)	0.13250 (16)	0.09761 (11)	0.0542 (5)
O4	0.0684 (3)	−0.04129 (16)	0.11004 (14)	0.0710 (7)
N2	0.9641 (2)	0.21221 (15)	0.26908 (10)	0.0341 (4)
C9	0.9613 (3)	0.11715 (19)	0.31391 (12)	0.0343 (5)
C10	1.1118 (3)	0.0645 (2)	0.33858 (15)	0.0463 (6)
H10	1.1115	−0.0009	0.3692	0.056*
C11	1.2633 (3)	0.1070 (2)	0.31860 (16)	0.0516 (7)
H11	1.3644	0.0701	0.3348	0.062*
C12	1.2629 (3)	0.2045 (2)	0.27450 (16)	0.0522 (7)
H12	1.3638	0.2348	0.2606	0.063*
C13	1.1126 (3)	0.2563 (2)	0.25131 (14)	0.0455 (6)
H13	1.1122	0.3237	0.2225	0.055*
C14	0.8095 (3)	0.2763 (2)	0.24203 (13)	0.0415 (6)
H14A	0.7261	0.2226	0.2185	0.050*
H14B	0.8354	0.3327	0.2045	0.050*
C15	0.7379 (3)	0.33781 (19)	0.30694 (14)	0.0378 (5)
O5	0.5908 (2)	0.38232 (16)	0.28640 (10)	0.0527 (5)
H5A	0.5512	0.4099	0.3233	0.079*
O6	0.8140 (2)	0.34328 (17)	0.36900 (10)	0.0543 (5)
C16	0.7940 (3)	0.0658 (2)	0.33675 (15)	0.0423 (6)
O7	0.6663 (2)	0.0733 (2)	0.29310 (14)	0.0746 (7)
O8	0.8120 (2)	0.01846 (17)	0.40012 (11)	0.0598 (5)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0301 (10)	0.0355 (10)	0.0402 (10)	−0.0030 (8)	0.0094 (8)	−0.0026 (8)
C1	0.0294 (11)	0.0334 (12)	0.0488 (13)	−0.0032 (9)	0.0116 (10)	−0.0020 (10)
C2	0.0388 (13)	0.0407 (13)	0.0641 (16)	0.0003 (11)	0.0125 (11)	0.0077 (12)
C3	0.0322 (13)	0.0540 (16)	0.0697 (17)	0.0026 (12)	0.0080 (12)	0.0009 (14)
C4	0.0272 (12)	0.0546 (16)	0.0684 (17)	−0.0120 (11)	0.0116 (11)	−0.0018 (13)
C5	0.0376 (13)	0.0444 (13)	0.0521 (14)	−0.0110 (11)	0.0134 (11)	0.0024 (11)
C6	0.0318 (11)	0.0440 (13)	0.0389 (12)	0.0006 (10)	0.0063 (9)	0.0009 (10)
C7	0.0338 (12)	0.0316 (11)	0.0415 (13)	−0.0046 (9)	0.0106 (10)	0.0026 (10)
O1	0.0344 (9)	0.0484 (10)	0.0553 (10)	0.0043 (8)	0.0087 (7)	−0.0067 (8)
O2	0.0501 (10)	0.0437 (10)	0.0490 (10)	−0.0020 (8)	0.0033 (8)	−0.0084 (8)
C8	0.0345 (12)	0.0392 (13)	0.0540 (14)	−0.0094 (10)	0.0185 (11)	−0.0068 (11)
O3	0.0360 (9)	0.0530 (10)	0.0776 (13)	−0.0026 (8)	0.0258 (9)	0.0035 (10)
O4	0.0621 (13)	0.0370 (10)	0.1220 (19)	−0.0058 (9)	0.0499 (12)	0.0077 (11)
N2	0.0313 (10)	0.0361 (10)	0.0360 (10)	0.0037 (8)	0.0086 (7)	−0.0003 (8)
C9	0.0299 (11)	0.0314 (11)	0.0428 (12)	−0.0007 (9)	0.0101 (9)	−0.0037 (10)
C10	0.0352 (13)	0.0379 (13)	0.0662 (16)	0.0021 (10)	0.0073 (11)	0.0081 (12)
C11	0.0288 (12)	0.0552 (16)	0.0710 (18)	0.0051 (11)	0.0056 (12)	0.0040 (14)
C12	0.0298 (12)	0.0598 (17)	0.0689 (18)	−0.0085 (12)	0.0141 (12)	0.0039 (14)
C13	0.0457 (14)	0.0454 (13)	0.0475 (14)	−0.0065 (12)	0.0147 (11)	0.0073 (11)
C14	0.0399 (13)	0.0432 (13)	0.0417 (13)	0.0121 (11)	0.0051 (10)	0.0019 (11)
C15	0.0335 (12)	0.0309 (11)	0.0504 (14)	0.0026 (10)	0.0114 (11)	0.0029 (10)
O5	0.0375 (9)	0.0531 (11)	0.0689 (12)	0.0114 (8)	0.0125 (8)	−0.0019 (10)
O6	0.0565 (11)	0.0612 (12)	0.0455 (10)	0.0152 (9)	0.0061 (9)	−0.0088 (9)
C16	0.0301 (12)	0.0348 (12)	0.0644 (16)	−0.0019 (10)	0.0171 (11)	−0.0063 (12)
O7	0.0282 (10)	0.0845 (15)	0.1116 (18)	−0.0034 (10)	0.0091 (10)	0.0229 (13)
O8	0.0585 (12)	0.0619 (12)	0.0619 (12)	−0.0202 (10)	0.0202 (9)	0.0049 (10)

Geometric parameters (Å, º)

N1—C5	1.350 (3)	N2—C13	1.350 (3)
N1—C1	1.358 (3)	N2—C9	1.357 (3)
N1—C6	1.480 (3)	N2—C14	1.472 (3)
C1—C2	1.370 (3)	C9—C10	1.374 (3)
C1—C8	1.539 (3)	C9—C16	1.545 (3)
C2—C3	1.384 (3)	C10—C11	1.379 (3)
C2—H2	0.930	C10—H10	0.930
C3—C4	1.367 (4)	C11—C12	1.370 (4)
C3—H3	0.930	C11—H11	0.930
C4—C5	1.366 (3)	C12—C13	1.362 (3)
C4—H4	0.930	C12—H12	0.930
C5—H5	0.930	C13—H13	0.930
C6—C7	1.513 (3)	C14—C15	1.515 (3)
C6—H6A	0.970	C14—H14A	0.970
C6—H6B	0.970	C14—H14B	0.970
C7—O2	1.202 (3)	C15—O6	1.209 (3)
C7—O1	1.314 (3)	C15—O5	1.295 (3)
O1—H1	0.820	O5—H5A	0.820
C8—O3	1.225 (3)	C16—O7	1.219 (3)
C8—O4	1.255 (3)	C16—O8	1.250 (3)
C5—N1—C1	120.4 (2)	C13—N2—C9	120.46 (19)
C5—N1—C6	117.17 (19)	C13—N2—C14	117.06 (19)
C1—N1—C6	122.45 (18)	C9—N2—C14	122.35 (18)
N1—C1—C2	118.7 (2)	N2—C9—C10	118.7 (2)
N1—C1—C8	121.2 (2)	N2—C9—C16	121.9 (2)
C2—C1—C8	119.9 (2)	C10—C9—C16	119.4 (2)
C1—C2—C3	121.5 (2)	C9—C10—C11	121.0 (2)
C1—C2—H2	119.3	C9—C10—H10	119.5
C3—C2—H2	119.3	C11—C10—H10	119.5
C4—C3—C2	118.3 (2)	C12—C11—C10	119.2 (2)
C4—C3—H3	120.8	C12—C11—H11	120.4
C2—C3—H3	120.8	C10—C11—H11	120.4
C5—C4—C3	119.7 (2)	C13—C12—C11	119.0 (2)
C5—C4—H4	120.2	C13—C12—H12	120.5
C3—C4—H4	120.2	C11—C12—H12	120.5
N1—C5—C4	121.3 (2)	N2—C13—C12	121.6 (2)
N1—C5—H5	119.3	N2—C13—H13	119.2
C4—C5—H5	119.3	C12—C13—H13	119.2
N1—C6—C7	110.62 (18)	N2—C14—C15	110.39 (19)
N1—C6—H6A	109.5	N2—C14—H14A	109.6
C7—C6—H6A	109.5	C15—C14—H14A	109.6
N1—C6—H6B	109.5	N2—C14—H14B	109.6
C7—C6—H6B	109.5	C15—C14—H14B	109.6
H6A—C6—H6B	108.1	H14A—C14—H14B	108.1
O2—C7—O1	126.0 (2)	O6—C15—O5	126.4 (2)
O2—C7—C6	122.8 (2)	O6—C15—C14	122.1 (2)
O1—C7—C6	111.11 (19)	O5—C15—C14	111.5 (2)
C7—O1—H1	109.5	C15—O5—H5A	109.5
O3—C8—O4	128.1 (2)	O7—C16—O8	128.4 (2)
O3—C8—C1	119.0 (2)	O7—C16—C9	119.2 (2)
O4—C8—C1	112.8 (2)	O8—C16—C9	112.4 (2)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···O8^i	0.82	1.76	2.540 (3)	160
O5—H5A···O4^i	0.82	1.69	2.499 (3)	168

Symmetry code: (i) −x+1/2, y+1/2, −z+1/2.