3,5-Pyrazole­di­carboxyl­ic acid monohydrate

In the title compound, C₅H₄N₂O₄·H₂O, the 3,5-pyrazoledicarboxylic acid (H₃pdc) molecules are joined into one-dimensional chains by O—H...O and N—H...O hydrogen bonds, with distances of 2.671 (2) and 2.776 (2) Å, respectively. The one-dimensional chains form a three-dimensional structure via O—H...OW and OW—HW...N hydrogen bonds, with distances of 2.597 (3) and 2.780 (3) Å, respectively. In addition to the potential for forming open-channel frameworks, access to the six coordination atoms of H₃pdc can be directly controlled by varying the pH of the reaction environment, allowing further control over the design and synthesis of novel coordination polymers using various metal centers.

Computing details

Data collection: CAD-4-PC (Enraf-Nonius, 1992); cell refinement: CAD-4-PC; data reduction: XCAD4/PC (Harms, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SCHAKAL92; software used to prepare material for publication: CIF.

3,5-pyrazoledicarboxylic acid monohydrate

Crystal data

C5H4N2O4·H2O	F(000) = 360
Mr = 174.12	Dx = 1.641 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
a = 13.386 (3) Å	Cell parameters from 20 reflections
b = 3.750 (1) Å	θ = 7.1–12.1°
c = 14.350 (3) Å	µ = 0.15 mm^−1
β = 101.88 (3)°	T = 293 K
V = 704.9 (3) Å^3	Columnar, colorless
Z = 4	0.30 × 0.10 × 0.08 mm

Data collection

Enraf-Nonius CAD4 diffractometer	856 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.044
Graphite monochromator	θmax = 26.0°, θmin = 2.3°
ω scans	h = 0→16
Absorption correction: ψ scan (Kopfman & Hubber, 1968)	k = −4→4
Tmin = 0.959, Tmax = 1.000	l = −17→17
2883 measured reflections	3 standard reflections every 250 min
1388 independent reflections	intensity decay: −2.8%

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.040	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.079	Calculated w = 1/[σ^2(Fo^2) + 0.250P] where P = (Fo^2 + 2Fc^2)/3
S = 1.18	(Δ/σ)max < 0.001
1388 reflections	Δρmax = 0.17 e Å^−3
128 parameters	Δρmin = −0.23 e Å^−3
1 restraint	Extinction correction: SHELXL97 (Sheldrick, 1997), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0109 (12)

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
O1	0.04455 (12)	0.2049 (6)	0.41802 (10)	0.0640 (6)
O2	−0.10649 (12)	−0.0709 (6)	0.39626 (11)	0.0613 (6)
H1	−0.0840 (17)	−0.114 (8)	0.4625 (18)	0.074*
O3	−0.11526 (11)	0.2663 (5)	−0.05303 (10)	0.0558 (6)
O4	−0.24032 (12)	−0.0402 (6)	−0.00896 (11)	0.0553 (5)
H2	−0.2596 (17)	−0.077 (8)	−0.0766 (17)	0.066*
O5	−0.29513 (15)	−0.1326 (7)	−0.19175 (14)	0.0753 (7)
H3	−0.360 (2)	−0.065 (9)	−0.212 (2)	0.090*
H4	−0.284 (2)	−0.318 (8)	−0.218 (2)	0.090*
N1	0.01692 (13)	0.3323 (6)	0.22830 (11)	0.0443 (5)
N2	−0.01893 (13)	0.3347 (6)	0.13467 (12)	0.0424 (5)
H5	0.0195 (16)	0.434 (7)	0.0970 (15)	0.051*
C1	−0.03493 (18)	0.1021 (7)	0.36728 (15)	0.0459 (6)
C2	−0.05516 (16)	0.1631 (7)	0.26339 (14)	0.0395 (6)
C3	−0.13674 (17)	0.0613 (7)	0.19199 (15)	0.0405 (6)
H6	−0.1937 (15)	−0.071 (7)	0.1979 (15)	0.049*
C4	−0.11019 (15)	0.1748 (7)	0.10941 (14)	0.0383 (6)
C5	−0.15587 (16)	0.1420 (7)	0.00769 (14)	0.0409 (6)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0621 (11)	0.0937 (16)	0.0326 (9)	−0.0169 (12)	0.0016 (8)	0.0089 (10)
O2	0.0631 (11)	0.0884 (15)	0.0329 (8)	−0.0157 (12)	0.0108 (8)	0.0113 (10)
O3	0.0559 (9)	0.0819 (15)	0.0302 (8)	−0.0125 (10)	0.0101 (8)	0.0047 (9)
O4	0.0504 (9)	0.0793 (14)	0.0339 (8)	−0.0134 (10)	0.0035 (7)	0.0004 (10)
O5	0.0548 (11)	0.1051 (19)	0.0570 (12)	0.0109 (14)	−0.0096 (9)	−0.0227 (13)
N1	0.0481 (10)	0.0581 (14)	0.0258 (9)	−0.0007 (11)	0.0055 (8)	0.0033 (10)
N2	0.0453 (11)	0.0573 (14)	0.0256 (9)	0.0000 (11)	0.0092 (8)	0.0058 (10)
C1	0.0504 (13)	0.0543 (17)	0.0333 (12)	−0.0009 (14)	0.0096 (11)	0.0032 (13)
C2	0.0463 (12)	0.0433 (14)	0.0299 (10)	0.0035 (12)	0.0102 (10)	0.0045 (11)
C3	0.0430 (12)	0.0458 (16)	0.0331 (11)	0.0014 (12)	0.0087 (10)	0.0028 (11)
C4	0.0400 (11)	0.0413 (14)	0.0330 (11)	0.0034 (12)	0.0062 (9)	0.0008 (11)
C5	0.0414 (12)	0.0482 (15)	0.0322 (11)	0.0055 (13)	0.0052 (10)	0.0024 (12)

Geometric parameters (Å, º)

O1—C1	1.221 (3)	N1—C2	1.337 (3)
O2—C1	1.294 (3)	N2—C4	1.342 (3)
O2—H1	0.95 (3)	N2—H5	0.90 (2)
O3—C5	1.211 (2)	C1—C2	1.477 (3)
O4—C5	1.300 (3)	C2—C3	1.388 (3)
O4—H2	0.96 (2)	C3—C4	1.373 (3)
O5—H3	0.90 (3)	C3—H6	0.93 (2)
O5—H4	0.82 (3)	C4—C5	1.467 (3)
N1—N2	1.330 (2)
C1—O2—H1	107.7 (15)	N1—C2—C1	117.2 (2)
C5—O4—H2	107.7 (14)	C3—C2—C1	130.9 (2)
H3—O5—H4	111 (3)	C4—C3—C2	104.3 (2)
N2—N1—C2	104.20 (18)	C4—C3—H6	127.5 (13)
N1—N2—C4	112.88 (18)	C2—C3—H6	128.0 (13)
N1—N2—H5	118.6 (14)	N2—C4—C3	106.77 (19)
C4—N2—H5	128.5 (14)	N2—C4—C5	118.43 (18)
O1—C1—O2	125.3 (2)	C3—C4—C5	134.7 (2)
O1—C1—C2	120.6 (2)	O3—C5—O4	124.9 (2)
O2—C1—C2	114.1 (2)	O3—C5—C4	121.8 (2)
N1—C2—C3	111.82 (18)	O4—C5—C4	113.30 (19)
C2—N1—N2—C4	0.0 (3)	N1—N2—C4—C3	0.4 (3)
N2—N1—C2—C3	−0.5 (3)	N1—N2—C4—C5	−176.8 (2)
N2—N1—C2—C1	177.2 (2)	C2—C3—C4—N2	−0.7 (3)
O1—C1—C2—N1	0.3 (4)	C2—C3—C4—C5	175.9 (3)
O2—C1—C2—N1	−178.3 (2)	N2—C4—C5—O3	−2.8 (4)
O1—C1—C2—C3	177.4 (3)	C3—C4—C5—O3	−179.0 (3)
O2—C1—C2—C3	−1.2 (4)	N2—C4—C5—O4	175.1 (2)
N1—C2—C3—C4	0.7 (3)	C3—C4—C5—O4	−1.1 (4)
C1—C2—C3—C4	−176.5 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H1···O1^i	0.95 (3)	1.72 (3)	2.671 (2)	178 (3)
O4—H2···O5	0.96 (2)	1.64 (2)	2.597 (3)	178 (2)
O5—H3···N1^ii	0.90 (3)	1.90 (3)	2.780 (3)	165 (3)
O5—H4···O5^iii	0.82 (3)	2.18 (3)	2.933 (3)	153 (3)
N2—H5···O3^iv	0.90 (2)	1.91 (2)	2.776 (2)	162 (2)

Symmetry codes: (i) −x, −y, −z+1; (ii) x−1/2, −y+1/2, z−1/2; (iii) −x−1/2, y−1/2, −z−1/2; (iv) −x, −y+1, −z.