Piperazinediium bis­(2-carboxy­pyridine-3-carboxyl­ate)

Abstract

The asymmetric unit of the title salt, C₄H₁₂N₂ ²⁺·2C₇H₄NO₄ ⁻ or pipzH₂ ²⁺·2(py-2,3-dcH⁻), prepared by a reaction between pyridine-2,3-dicarboxylic acid (py-2,3-dcH₂) and piperazine (pipz), contains a monoanion and half of a centrosymmetric dication. The anionic fragment individually has two intra­molecular hydrogen bonds, an almost linear O—H⋯O bond between two carboxyl­ate groups and a C—H⋯O bond between the aromatic ring and carboxyl­ate group. Other O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds are responsible for three-dimensional expansion of the structure.

Related literature

For related literature, see: Aghabozorg et al. (2006 ▶); Aghabozorg, Daneshvar et al. (2007 ▶); Aghabozorg, Sadr-khanlou et al. (2007 ▶); Khalil & Attia (1999 ▶); Manteghi et al. (2007 ▶).

Experimental

Crystal data

• C₄H₁₂N₂ ²⁺·2C₇H₄NO₄ ⁻

• M _r = 420.38

• Monoclinic,

• a = 8.0116 (6) Å

• b = 11.0588 (9) Å

• c = 10.4621 (7) Å

• β = 106.574 (2)°

• V = 888.42 (11) ų

• Z = 2

• Mo Kα radiation

• μ = 0.13 mm⁻¹

• T = 100 (2) K

• 0.20 × 0.15 × 0.15 mm

Data collection

• Bruker SMART APEXII diffractometer

• Absorption correction: none

• 6962 measured reflections

• 2341 independent reflections

• 2104 reflections with I > 2σ(I)

• R _int = 0.015

Refinement

• R[F ² > 2σ(F ²)] = 0.034

• wR(F ²) = 0.084

• S = 1.03

• 2341 reflections

• 136 parameters

• H-atom parameters constrained

• Δρ_max = 0.43 e Å⁻³

• Δρ_min = −0.22 e Å⁻³

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: APEX2; data reduction: APEX2; program(s) used to solve structure: SHELXTL (Sheldrick, 1998 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL and Mercury (Version 1.4.2; Macrae et al., 2006 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O3—H3O⋯O1	0.85	1.57	2.4219 (11)	175
N2—H2A⋯O2i	0.90	1.94	2.7778 (12)	154
N2—H2B⋯O1	0.90	1.97	2.7571 (11)	146
C3—H3A⋯O4	0.95	2.31	2.6773 (13)	102
C8—H8A⋯O2ii	0.99	2.58	3.2982 (13)	130
C9—H9A⋯O4iii	0.99	2.39	3.3491 (14)	163

Symmetry codes: (i) ; (ii) ; (iii) .

supplementary crystallographic information

Comment

Pyridinedicarboxylic acids are of great interest in medicinal chemistry because of the wide variety of their physiological properties displayed by natural as well as synthetic acids. These acids are present in many natural products, such as alkaloids, vitamins and coenzymes. Pyridinedicarboxylic acid metal complexes are therefore, especially interesting model systems (Khalil & Attia, 1999). Pyridine-2,3-dicarboxylic acid (py-2,3-dcH₂) and piperazine (pipz) with other acids and bases are found in many ion pairs, such as (pipzH₂)₂(pydc) (Aghabozorg et al., 2006) and (pnH₂)(py-2,3-dc).H₂O (Manteghi et al., 2007). Moreover, a polymeric complex {(pipzH₂)[Zn(py-2,3-dc)₂].4H₂O}_n including fragments of the title zwitterion has been synthesized (Aghabozorg, Daneshvar et al., 2007). In all mentioned compounds, piperazine is biprotonated and pyridine-2,3-dicarboxylic acid is doubly deprotonated. But in the title ion pair and a complex formulated as [Zn(py-2,3-dcH)₂(H₂O)₂] (Aghabozorg, Sadr-khanlou et al., 2007), pyridine-2,3-dicarboxylic acid is singly deprotonated. Fig. 1 shows the monoanion and the dication and the strong intramolecular hydrogen bond (see table of hydrogen-bond geometry). Fig. 2 illustrates the hydrogen bonded layers parallel to bc plane. The title ion pair has three C—H···O hydrogen bonds amongst them the C3—H3A···O4 has a short distance (H···O, 2.31 Å) compared with common C—H···O bonds, although its angle is far from linearity. Additionally, as shown in Fig. 3, the ion pair has a π-π stacking at the distance of 3.6623 (7) Å between the π-rings (symmetry code: 1 - x, -y, 1 - z).

Experimental

The title compound was synthesized via reaction of 1.67 g (10 mmol) of pyridine-2,3-dicarboxylic acid with 0.86 g (20 mmol) piperazine in a teterahydrofuran (THF) solution (50 ml). After a while, the obtained white precipitate was filtered out and dissolved in water to recrystallize. Colorless crystals of the title compound were obtained after 1 week.

Refinement

The H(N) and H(O) atoms were found from difference Fourier map. The H(C) atom positions were calculated. All the hydrogen atoms were refined in isotropic approximatiom within riding model with the U_iso(H) parameters equal to 1.2Ueq(Ci), 1.2Ueq(Nj) and 1.5Ueq(O) where U(Ci), U(Cj) and U(O) are the equivalent thermal parameters of the carbon, nitrogen and oxygen atoms correspondingly to which corresponding H atoms are bonded.

Figures

Fig. 1.

A view of the ion pair drawn at 50% probability level. Symmetry related atoms are labeled "i" and are generated by 2 - x, 1 - y, 1 - z. Some of the hydrogen bonds are shown and are depicted by dashed lines.

Fig. 2.

Hydrogen bonded layers parallel to bc plane. Hydrogen atoms are omitted for clarity except those involved in hydrogen bonding.

Fig. 3.

The π-π stacking at the distance of 3.6623 (7) Å (symmetry code: 1 - x, -y, 1 - z).

Crystal data

C4H12N22+·2C7H4NO4−	F(000) = 440
Mr = 420.38	Dx = 1.571 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 2095 reflections
a = 8.0116 (6) Å	θ = 2.7–28.6°
b = 11.0588 (9) Å	µ = 0.13 mm−1
c = 10.4621 (7) Å	T = 100 K
β = 106.574 (2)°	Prism, colourless
V = 888.42 (11) Å3	0.20 × 0.15 × 0.15 mm
Z = 2

Data collection

Bruker SMART APEXII diffractometer	2104 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.015
graphite	θmax = 29.0°, θmin = 2.7°
φ and ω scans	h = −10→10
6962 measured reflections	k = −15→15
2341 independent reflections	l = −14→12

Refinement

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)] = 0.034	Hydrogen site location: mixed
wR(F2) = 0.084	H-atom parameters constrained
S = 1.03	w = 1/[σ2(Fo2) + (0.035P)2 + 0.450P] where P = (Fo2 + 2Fc2)/3
2341 reflections	(Δ/σ)max < 0.001
136 parameters	Δρmax = 0.43 e Å−3
0 restraints	Δρmin = −0.22 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
O1	0.88615 (11)	0.17340 (7)	0.51531 (8)	0.02036 (18)
O2	0.98274 (10)	0.08122 (7)	0.70930 (8)	0.02041 (18)
O3	0.72179 (11)	0.13267 (7)	0.28657 (8)	0.02033 (18)
H3O	0.7842	0.1467	0.3657	0.030*
O4	0.54664 (10)	−0.00934 (8)	0.17740 (8)	0.02126 (18)
N1	0.77161 (11)	−0.10247 (8)	0.63974 (9)	0.01409 (18)
N2	0.98062 (11)	0.40793 (8)	0.59237 (8)	0.01352 (17)
H2A	1.0047	0.4441	0.6726	0.016*
H2B	0.9555	0.3300	0.6036	0.016*
C1	0.76624 (12)	−0.02324 (8)	0.54104 (10)	0.01174 (18)
C2	0.65530 (12)	−0.04141 (9)	0.41030 (10)	0.01209 (19)
C3	0.54476 (13)	−0.14260 (9)	0.39063 (10)	0.0147 (2)
H3A	0.4655	−0.1565	0.3052	0.018*
C4	0.54919 (13)	−0.22223 (9)	0.49329 (11)	0.0161 (2)
H4A	0.4736	−0.2902	0.4802	0.019*
C5	0.66802 (14)	−0.19939 (9)	0.61616 (10)	0.0160 (2)
H5A	0.6760	−0.2552	0.6867	0.019*
C6	0.88903 (13)	0.08412 (9)	0.59330 (10)	0.01317 (19)
C7	0.63871 (13)	0.03075 (9)	0.28268 (10)	0.01448 (19)
C8	1.13286 (13)	0.40868 (9)	0.53727 (10)	0.0146 (2)
H8A	1.1067	0.3580	0.4560	0.018*
H8B	1.2353	0.3736	0.6036	0.018*
C9	0.82508 (13)	0.46401 (9)	0.49653 (10)	0.0147 (2)
H9A	0.7270	0.4659	0.5365	0.018*
H9B	0.7892	0.4149	0.4141	0.018*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
O1	0.0283 (4)	0.0139 (3)	0.0167 (4)	−0.0056 (3)	0.0029 (3)	0.0024 (3)
O2	0.0234 (4)	0.0200 (4)	0.0146 (4)	−0.0074 (3)	0.0003 (3)	0.0013 (3)
O3	0.0268 (4)	0.0184 (4)	0.0135 (3)	−0.0025 (3)	0.0021 (3)	0.0034 (3)
O4	0.0197 (4)	0.0294 (4)	0.0129 (4)	−0.0027 (3)	0.0019 (3)	0.0005 (3)
N1	0.0165 (4)	0.0130 (4)	0.0133 (4)	0.0001 (3)	0.0051 (3)	0.0006 (3)
N2	0.0147 (4)	0.0136 (4)	0.0120 (4)	−0.0018 (3)	0.0033 (3)	0.0006 (3)
C1	0.0120 (4)	0.0110 (4)	0.0129 (4)	0.0007 (3)	0.0047 (3)	−0.0008 (3)
C2	0.0119 (4)	0.0128 (4)	0.0123 (4)	0.0023 (3)	0.0047 (3)	−0.0005 (3)
C3	0.0124 (4)	0.0162 (4)	0.0158 (5)	0.0002 (3)	0.0044 (4)	−0.0040 (4)
C4	0.0160 (4)	0.0131 (4)	0.0209 (5)	−0.0022 (3)	0.0082 (4)	−0.0034 (4)
C5	0.0202 (5)	0.0125 (4)	0.0171 (5)	−0.0004 (4)	0.0084 (4)	0.0011 (4)
C6	0.0136 (4)	0.0123 (4)	0.0145 (4)	−0.0005 (3)	0.0054 (3)	−0.0009 (3)
C7	0.0130 (4)	0.0181 (5)	0.0128 (4)	0.0035 (3)	0.0044 (3)	0.0017 (4)
C8	0.0143 (4)	0.0156 (4)	0.0143 (4)	0.0032 (3)	0.0046 (4)	0.0000 (3)
C9	0.0113 (4)	0.0181 (5)	0.0138 (4)	−0.0013 (3)	0.0023 (3)	0.0003 (4)

Geometric parameters (Å, °)

O1—C6	1.2769 (12)	C2—C3	1.4053 (14)
O2—C6	1.2319 (12)	C2—C7	1.5284 (14)
O3—C7	1.3036 (13)	C3—C4	1.3815 (15)
O3—H3O	0.8501	C3—H3A	0.9500
O4—C7	1.2209 (13)	C4—C5	1.3872 (15)
N1—C5	1.3348 (13)	C4—H4A	0.9500
N1—C1	1.3456 (12)	C5—H5A	0.9500
N2—C8	1.4903 (13)	C8—C9i	1.5129 (14)
N2—C9	1.4933 (13)	C8—H8A	0.9900
N2—H2A	0.9000	C8—H8B	0.9900
N2—H2B	0.9000	C9—C8i	1.5129 (14)
C1—C2	1.4169 (13)	C9—H9A	0.9900
C1—C6	1.5394 (13)	C9—H9B	0.9900
C7—O3—H3O	110.0	N1—C5—H5A	118.5
C5—N1—C1	119.93 (9)	C4—C5—H5A	118.5
C8—N2—C9	110.87 (7)	O2—C6—O1	122.99 (9)
C8—N2—H2A	112.1	O2—C6—C1	118.55 (9)
C9—N2—H2A	110.9	O1—C6—C1	118.44 (9)
C8—N2—H2B	107.1	O4—C7—O3	120.92 (9)
C9—N2—H2B	108.1	O4—C7—C2	118.56 (9)
H2A—N2—H2B	107.5	O3—C7—C2	120.51 (9)
N1—C1—C2	121.50 (9)	N2—C8—C9i	110.92 (8)
N1—C1—C6	110.63 (8)	N2—C8—H8A	109.5
C2—C1—C6	127.85 (9)	C9i—C8—H8A	109.5
C3—C2—C1	116.74 (9)	N2—C8—H8B	109.5
C3—C2—C7	113.19 (8)	C9i—C8—H8B	109.5
C1—C2—C7	130.06 (9)	H8A—C8—H8B	108.0
C4—C3—C2	121.22 (9)	N2—C9—C8i	110.15 (8)
C4—C3—H3A	119.4	N2—C9—H9A	109.6
C2—C3—H3A	119.4	C8i—C9—H9A	109.6
C3—C4—C5	117.58 (9)	N2—C9—H9B	109.6
C3—C4—H4A	121.2	C8i—C9—H9B	109.6
C5—C4—H4A	121.2	H9A—C9—H9B	108.1
N1—C5—C4	122.94 (9)
C5—N1—C1—C2	−1.52 (14)	N1—C1—C6—O2	5.34 (13)
C5—N1—C1—C6	176.91 (9)	C2—C1—C6—O2	−176.36 (10)
N1—C1—C2—C3	3.28 (14)	N1—C1—C6—O1	−173.07 (9)
C6—C1—C2—C3	−174.85 (9)	C2—C1—C6—O1	5.23 (15)
N1—C1—C2—C7	−174.82 (9)	C3—C2—C7—O4	−6.01 (13)
C6—C1—C2—C7	7.04 (16)	C1—C2—C7—O4	172.15 (10)
C1—C2—C3—C4	−2.13 (14)	C3—C2—C7—O3	174.22 (9)
C7—C2—C3—C4	176.30 (9)	C1—C2—C7—O3	−7.62 (16)
C2—C3—C4—C5	−0.66 (15)	C9—N2—C8—C9i	57.28 (11)
C1—N1—C5—C4	−1.56 (15)	C8—N2—C9—C8i	−56.84 (11)
C3—C4—C5—N1	2.64 (15)

Symmetry codes: (i) −x+2, −y+1, −z+1.

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3O···O1	0.85	1.57	2.4219 (11)	175
N2—H2A···O2ii	0.90	1.94	2.7778 (12)	154
N2—H2B···O1	0.90	1.97	2.7571 (11)	146
C3—H3A···O4	0.95	2.31	2.6773 (13)	102
C8—H8A···O2iii	0.99	2.58	3.2982 (13)	130
C9—H9A···O4iv	0.99	2.39	3.3491 (14)	163

Symmetry codes: (ii) −x+2, y+1/2, −z+3/2; (iii) x, −y+1/2, z−1/2; (iv) x, −y+1/2, z+1/2.