1,4-Diazo­niabicyclo­[2.2.2]octane bis­(3-carboxypyridine-2-carboxyl­ate) 2.17-hydrate

The title compound, C₆H₁₄N₂²⁺·2C₇H₄NO₄⁻·2.17H₂O, is a hydrated mol­ecular salt. The cation has crystallographic twofold rotation symmetry, and the component species inter­act by way of bifurcated N—H...(O, N) hydrogen bonds to result in associations of two anions and one cation. The anion is stabilized by an intra­molecular O—H...O bond. The water mol­ecules are disordered and occupy [001] pseudo channels in the structure.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.002 Å
Some non-H atoms missing
• Disorder in main residue
• R factor = 0.051
• wR factor = 0.155
• Data-to-parameter ratio = 17.5

checkCIF/PLATON results

No syntax errors found



Alert level A
PLAT430_ALERT_2_A Short Inter D...A Contact  O11    ..  O13     ..       1.81 Ang.

Author Response: this is a disorder artefact

PLAT430_ALERT_2_A Short Inter D...A Contact  O11    ..  O13     ..       2.38 Ang.

Author Response: this is a disorder artefact

PLAT430_ALERT_2_A Short Inter D...A Contact  O12    ..  O12     ..       1.95 Ang.

Author Response: this is a disorder artefact

Alert level C
CHEMW01_ALERT_1_C  The difference between the given and expected weight for
            compound is greater 1 mass unit. Check that all hydrogen
            atoms have been taken into account.
PLAT041_ALERT_1_C Calc. and Rep. SumFormula Strings    Differ ....          ?
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ ....          ?
PLAT068_ALERT_1_C Reported F000 Differs from Calcd (or Missing)...          ?
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         C9
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor ....       2.16
PLAT301_ALERT_3_C Main Residue  Disorder .........................       6.00 Perc.
PLAT311_ALERT_2_C Isolated Disordered Oxygen Atom (No H's ?) .....       >O11
PLAT311_ALERT_2_C Isolated Disordered Oxygen Atom (No H's ?) .....       <O12
PLAT369_ALERT_2_C Long   C(sp2)-C(sp2) Bond  C8     -   C10    ...       1.53 Ang.

Alert level G
FORMU01_ALERT_2_G  There is a discrepancy between the atom counts in the
            _chemical_formula_sum and the formula from the _atom_site* data.
            Atom count from _chemical_formula_sum:C20 H26.34 N4 O10.17
            Atom count from the _atom_site data:  C20 H22 N4 O10.342
CELLZ01_ALERT_1_G Difference between formula and atom_site contents detected.
CELLZ01_ALERT_1_G ALERT: Large difference may be due to a
            symmetry error - see SYMMG tests
           From the CIF: _cell_formula_units_Z    4
           From the CIF: _chemical_formula_sum  C20 H26.34 N4 O10.17
           TEST: Compare cell contents of formula and atom_site data

           atom    Z*formula  cif sites diff
           C         80.00     80.00    0.00
           H        105.36     88.00   17.36
           N         16.00     16.00    0.00
           O         40.68     41.37   -0.69
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature .        293 K

   3 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
  10 ALERT level C = Check and explain
   5 ALERT level G = General alerts; check

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

---

S1. Comment

As part of our investigations of supramolecular networks (Harrison et al., 2007), the title compound, (I), a hydrated molecular salt, has been prepared and structurally characterized. The complete C₆H₁₄N₂²⁺ cation is generated by crystallographic 2-fold symmetry, with the rotation axis bisecting the C3—C3ⁱ (i = 1 - x, y, 3/2 - z) bond. The C—O bond distances of the C₇H₄NO₄^- anion suggest charge localization (i.e. well defined single and double bonds) in the deprotonated carboxylate group. The dihedral angles between the mean plane of the pyridine ring (N2/C4—C8) and the planes of the C9/O1/O2 and C10/O3/O4 groups are 3.7 (3)° and 5.0 (2)°, respectively. The anion is stabilized by an intramolecular O—H···O hydrogen bond (Table 2).

In the crystal of (I), associations of two anions and one cation occur, linked by bifurcated N—H···(N,O) hydrogen bonds arising from the symmetry equivalent N—H groupings of the cation. These trimolecular associations form a pseudo framework delimiting [001] channels containing the disordered water molecules (Fig. 2). There are no significant π-π stacking interactions, the shortest centroid-centroid separation involving the pyridine rings being longer than 4.13 Å.

Related literature

For background, see: Harrison et al. (2007).

S2. Experimental

Pyridine-2,3-dicarboxylic acid (0.0835 g, 0.5 mmol) was dissolved in hot water. To the resulting clear solution was added an aqueous solution of diazabicyclo[2.2.2]octane (0.056 g, 0.5 mmol). The mixture was allowed to crystallize at room temperature. Colourless blocks of (I) were obtained after six weeks. The crystals were washed with doubly distilled water and finally with ether and then air dried.

S3. Refinement

The carboxylic acid hydrogen atom was located in a difference map and refined as riding in its as-found relative position. The C– and N-bound H atoms were geometrically placed (C—H = 0.93–0.97 Å, N—H = 0.91 Å) and refined as riding. The constraint U_iso(H) = 1.2U_eq(carrier) was applied in all cases. The H atoms of the disordered water molecules could not be located in difference maps, nor could they be geometrically placed in an unambiguous manner.

Computing details

Data collection: SMART (Bruker, 1999); cell refinement: SAINT (Bruker, 1999); data reduction: SAINT (Bruker, 1999); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

Figures

	Fig. 1. A view of the trimeric association of two anions and one cation in (I), showing displacement ellipsoids at the 50% probability level (arbitrary spheres for the H atoms). Symmetry code: (i) 1 - x, y, 3/2 - z. The disordered water molecule O atoms are not shown.
	Fig. 2. Unit cell packing of (I), viewed along [001]. The C-bound H atoms are omitted for clarity and hydrogen bonds are shown as dashed lines. The disordered water-molecule O atoms are shown as open ellipses.

1,4-Diazoniabicyclo[2.2.2]octane bis(3-carboxypyridine-2-carboxylate) 2.17-hydrate

Crystal data

C6H14N2^2+·2C7H4NO4^−·2.17H2O	F(000) = 1030
Mr = 488.62	Dx = 1.525 Mg m^−3
Orthorhombic, Pbcn	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2n 2ab	Cell parameters from 35550 reflections
a = 19.4117 (6) Å	θ = 1.0–29.5°
b = 8.1486 (3) Å	µ = 0.12 mm^−1
c = 13.4528 (4) Å	T = 293 K
V = 2127.94 (12) Å^3	Block, colourless
Z = 4	0.20 × 0.15 × 0.15 mm

Data collection

Bruker SMART1000 CCD diffractometer	2239 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.034
Graphite monochromator	θmax = 29.5°, θmin = 3.0°
ω scans	h = −26→26
46987 measured reflections	k = −11→11
2958 independent reflections	l = −18→18

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)] = 0.051	Hydrogen site location: difmap and geom
wR(F^2) = 0.155	H-atom parameters constrained
S = 1.03	w = 1/[σ^2(Fo^2) + (0.0738P)^2 + 0.9232P] where P = (Fo^2 + 2Fc^2)/3
2958 reflections	(Δ/σ)max = 0.001
169 parameters	Δρmax = 0.40 e Å^−3
0 restraints	Δρmin = −0.27 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	Occ. (<1)
N1	0.44586 (6)	0.05154 (17)	0.79953 (9)	0.0365 (3)
H1	0.4062	0.0516	0.8357	0.044*
C1	0.50208 (8)	−0.0217 (2)	0.85972 (12)	0.0452 (4)
H1A	0.4877	−0.1272	0.8858	0.054*
H1B	0.5132	0.0496	0.9152	0.054*
C2	0.43507 (8)	−0.0429 (3)	0.70684 (12)	0.0478 (4)
H2A	0.3942	−0.0036	0.6729	0.057*
H2B	0.4286	−0.1581	0.7223	0.057*
C3	0.46380 (10)	0.2233 (2)	0.77198 (16)	0.0548 (5)
H3A	0.4622	0.2932	0.8303	0.066*
H3B	0.4311	0.2650	0.7236	0.066*
C4	0.26026 (9)	−0.0092 (2)	0.78806 (12)	0.0441 (4)
H4	0.2796	−0.0662	0.7351	0.053*
C5	0.18977 (9)	0.0058 (2)	0.79217 (13)	0.0485 (4)
H5	0.1619	−0.0386	0.7427	0.058*
C6	0.16167 (8)	0.0881 (2)	0.87141 (13)	0.0452 (4)
H6	0.1141	0.0991	0.8760	0.054*
C7	0.20344 (7)	0.15523 (19)	0.94498 (11)	0.0362 (3)
C8	0.27499 (7)	0.13568 (18)	0.93433 (10)	0.0322 (3)
C9	0.16358 (9)	0.2440 (2)	1.02636 (15)	0.0509 (4)
C10	0.33207 (8)	0.1987 (2)	1.00263 (11)	0.0385 (3)
N2	0.30195 (6)	0.05417 (17)	0.85635 (9)	0.0382 (3)
O1	0.19488 (7)	0.3047 (2)	1.10082 (11)	0.0672 (4)
H2	0.2447	0.2903	1.0970	0.081*
O2	0.10145 (8)	0.2546 (3)	1.01790 (17)	0.1080 (9)
O3	0.31596 (7)	0.26887 (19)	1.08370 (9)	0.0575 (4)
O4	0.39173 (6)	0.1798 (2)	0.97738 (10)	0.0616 (4)
O11	0.0514 (5)	0.0498 (6)	0.6190 (5)	0.111 (2)	0.555 (12)
O12	0.0227 (3)	0.0523 (6)	0.5563 (8)	0.090 (3)	0.445 (12)
O13	0.0231 (5)	0.0986 (13)	0.7440 (9)	0.083 (5)*	0.171 (6)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
N1	0.0252 (5)	0.0537 (8)	0.0305 (6)	0.0001 (5)	0.0049 (4)	−0.0032 (5)
C1	0.0332 (7)	0.0738 (12)	0.0287 (7)	0.0002 (7)	0.0002 (5)	0.0085 (7)
C2	0.0293 (7)	0.0765 (13)	0.0378 (8)	−0.0089 (7)	−0.0013 (6)	−0.0109 (8)
C3	0.0560 (11)	0.0510 (10)	0.0575 (11)	0.0076 (8)	0.0185 (9)	0.0002 (8)
C4	0.0429 (9)	0.0551 (10)	0.0344 (7)	−0.0073 (7)	0.0047 (6)	−0.0058 (7)
C5	0.0417 (8)	0.0624 (11)	0.0412 (8)	−0.0146 (8)	−0.0032 (7)	−0.0016 (8)
C6	0.0308 (7)	0.0547 (10)	0.0500 (9)	−0.0038 (7)	0.0006 (6)	0.0052 (8)
C7	0.0329 (7)	0.0386 (7)	0.0371 (7)	0.0025 (6)	0.0060 (5)	0.0056 (6)
C8	0.0317 (6)	0.0369 (7)	0.0281 (6)	0.0017 (5)	0.0034 (5)	0.0050 (5)
C9	0.0385 (8)	0.0566 (11)	0.0577 (10)	0.0048 (7)	0.0142 (7)	−0.0071 (8)
C10	0.0356 (7)	0.0502 (9)	0.0296 (7)	0.0030 (6)	0.0012 (5)	0.0006 (6)
N2	0.0336 (6)	0.0495 (8)	0.0314 (6)	0.0000 (5)	0.0046 (5)	−0.0012 (5)
O1	0.0485 (7)	0.1003 (12)	0.0527 (8)	0.0172 (7)	0.0088 (6)	−0.0245 (8)
O2	0.0375 (8)	0.155 (2)	0.1312 (17)	0.0157 (10)	0.0101 (9)	−0.0741 (15)
O3	0.0473 (7)	0.0861 (10)	0.0391 (6)	0.0092 (7)	−0.0016 (5)	−0.0194 (6)
O4	0.0326 (6)	0.1067 (12)	0.0457 (7)	−0.0007 (7)	0.0017 (5)	−0.0208 (7)
O11	0.151 (5)	0.095 (3)	0.085 (3)	−0.052 (3)	0.005 (4)	0.012 (2)
O12	0.052 (2)	0.081 (3)	0.137 (7)	0.0051 (18)	0.017 (3)	0.020 (3)

Geometric parameters (Å, º)

N1—C2	1.480 (2)	C4—H4	0.9300
N1—C1	1.484 (2)	C5—C6	1.372 (3)
N1—C3	1.489 (2)	C5—H5	0.9300
N1—H1	0.9100	C6—C7	1.392 (2)
C1—C2^i	1.523 (2)	C6—H6	0.9300
C1—H1A	0.9700	C7—C8	1.4052 (19)
C1—H1B	0.9700	C7—C9	1.523 (2)
C2—C1^i	1.523 (2)	C8—N2	1.3475 (18)
C2—H2A	0.9700	C8—C10	1.528 (2)
C2—H2B	0.9700	C9—O2	1.214 (2)
C3—C3^i	1.525 (4)	C9—O1	1.272 (2)
C3—H3A	0.9700	C10—O4	1.2168 (19)
C3—H3B	0.9700	C10—O3	1.2704 (18)
C4—N2	1.329 (2)	O1—H2	0.9750
C4—C5	1.375 (2)
C2—N1—C1	110.77 (13)	N2—C4—C5	122.96 (16)
C2—N1—C3	108.18 (14)	N2—C4—H4	118.5
C1—N1—C3	109.98 (14)	C5—C4—H4	118.5
C2—N1—H1	109.3	C6—C5—C4	118.04 (16)
C1—N1—H1	109.3	C6—C5—H5	121.0
C3—N1—H1	109.3	C4—C5—H5	121.0
N1—C1—C2^i	108.29 (12)	C5—C6—C7	120.86 (15)
N1—C1—H1A	110.0	C5—C6—H6	119.6
C2^i—C1—H1A	110.0	C7—C6—H6	119.6
N1—C1—H1B	110.0	C6—C7—C8	117.31 (14)
C2^i—C1—H1B	110.0	C6—C7—C9	113.70 (14)
H1A—C1—H1B	108.4	C8—C7—C9	128.98 (15)
N1—C2—C1^i	108.83 (12)	N2—C8—C7	121.28 (13)
N1—C2—H2A	109.9	N2—C8—C10	110.61 (12)
C1^i—C2—H2A	109.9	C7—C8—C10	128.11 (13)
N1—C2—H2B	109.9	O2—C9—O1	121.37 (18)
C1^i—C2—H2B	109.9	O2—C9—C7	118.09 (19)
H2A—C2—H2B	108.3	O1—C9—C7	120.54 (16)
N1—C3—C3^i	108.18 (9)	O4—C10—O3	122.07 (15)
N1—C3—H3A	110.1	O4—C10—C8	118.66 (13)
C3^i—C3—H3A	110.1	O3—C10—C8	119.27 (13)
N1—C3—H3B	110.1	C4—N2—C8	119.54 (13)
C3^i—C3—H3B	110.1	C9—O1—H2	112.7
H3A—C3—H3B	108.4
C2—N1—C1—C2^i	51.54 (17)	C9—C7—C8—C10	0.2 (3)
C3—N1—C1—C2^i	−68.01 (18)	C6—C7—C9—O2	−3.3 (3)
C1—N1—C2—C1^i	−67.61 (16)	C8—C7—C9—O2	175.6 (2)
C3—N1—C2—C1^i	53.01 (18)	C6—C7—C9—O1	176.68 (18)
C2—N1—C3—C3^i	−71.0 (2)	C8—C7—C9—O1	−4.5 (3)
C1—N1—C3—C3^i	50.1 (2)	N2—C8—C10—O4	4.8 (2)
N2—C4—C5—C6	−0.9 (3)	C7—C8—C10—O4	−174.75 (17)
C4—C5—C6—C7	0.4 (3)	N2—C8—C10—O3	−175.20 (15)
C5—C6—C7—C8	0.2 (2)	C7—C8—C10—O3	5.3 (2)
C5—C6—C7—C9	179.21 (16)	C5—C4—N2—C8	0.7 (3)
C6—C7—C8—N2	−0.4 (2)	C7—C8—N2—C4	0.0 (2)
C9—C7—C8—N2	−179.25 (15)	C10—C8—N2—C4	−179.56 (14)
C6—C7—C8—C10	179.01 (15)

Symmetry code: (i) −x+1, y, −z+3/2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H2···O3	0.98	1.41	2.3796 (18)	176
N1—H1···N2	0.91	2.04	2.8963 (17)	156
N1—H1···O4	0.91	2.19	2.8143 (17)	125