2-(Eth­oxy­carbon­yl)pyridinium nitrate

In the title compound, C₈H₁₀NO₂⁺·NO₃⁻, the cation is essentially planar with C—O—C—C and C—O—C—O torsion angles of −178.1 (2) and 2.1 (4)°, respectively. In the crystal, N—H...O and C—H...O hydrogen-bond inter­actions stabilize the structure.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.064
• wR factor = 0.178
• Data-to-parameter ratio = 16.4

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         N2
PLAT430_ALERT_2_C Short Inter D...A Contact  O1     ..  O4      ..       2.86 Ang.
PLAT910_ALERT_3_C Missing # of FCF Reflections Below Th(Min) .....          2
PLAT913_ALERT_3_C Missing # of Very Strong Reflections in FCF ....          1

Alert level G
PLAT128_ALERT_4_G Alternate Setting of Space-group P21/c   .......      P21/n
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
   0 ALERT level B = Potentially serious problem
   4 ALERT level C = Check and explain
   3 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
   2 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check


checkCIF publication errors

Alert level A
PUBL022_ALERT_1_A There is a mismatched ~ on line 136
              pyridine single salts of the PyHX type (<i>X</i>=ICl~4~, ClO~4~, IO~4~, ReO~4,
              If you require a ~ then it should be escaped
              with a \, i.e. \~
              Otherwise there must be a matching closing ~, e.g. C~2~H~4~
PUBL022_ALERT_1_A There is a mismatched ~ on line 137
              ~<i>etc</i>.) ( Asaji <i>et al.</i>(2007); Wasicki <i>et al.</i> (1997)). As
              If you require a ~ then it should be escaped
              with a \, i.e. \~
              Otherwise there must be a matching closing ~, e.g. C~2~H~4~

   2 ALERT level A = Data missing that is essential or data in wrong format
   0 ALERT level G = General alerts. Data that may be required is missing

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S1. Comment

The study of seignette-electrics materials has received much attention. Some materials exhibit predominant dielectric-ferroelectric properties such as pyridine single salts of the PyHX type (X=ICl₄, ClO₄, IO₄, ReO_4, etc.) ( Asaji et al.(2007); Wasicki et al. (1997)). As one part of our continuing studies on looking for materials with these properties, we have used 2-ethyl picolinate as the ligand and synthesized salts similar to PyHX. The title compound (I) is one of these salts. It exhibits no phase-transition in dielectric measurement going from 93 K to 340 K (m.p 348 K).

The asymmetric unit of (I) contains one picolinate cation and one nitrate radical (Fig 1). The pyridine ring is planar and the carbethoxy is in the plane of the ring with an O2—C6—C5—C4 torsion angle of 0.1 (4)°. The torsion angles C7—O1—C6—C5 and C7—O1—C6—O2 at -178.1 (2)° and 2.1 (4)° respectively also show the overall planarity of the cation. Intramolecular N1—H···O4 and C1—H1B···O3 interactions link the cation and the anion while intermolecular C8—H8A···O3 interactions link the molecules into chains (Table 1, Fig 2).

Related literature

For phase transition of pyridinium salts studied by X-ray analysis and dielectric and heat capacity measurements, see: Asaji et al. (2007). For their ferroelecric properties, see: Wasicki et al. (1997).

S2. Experimental

A solution of 2-ethyl picolinate (10 mmol) in ethanol (20 ml) was added to a solution of equimolar amount of aqua fortis aqueous solution (1 mol/L). Crystals suitable for structure determination were grown by slow evaporation of the mixture at room temperature.

S3. Refinement

Positional parameters of all the H atoms were calculated geometrically and were allowed to ride on the C atoms to which they are bonded, with C—H = 0.93 Å, N—H = 0.75–0.86 Å; with U_iso(H) = 1.2Ueq(C), with U_iso(H) = 1.2–1.5Ueq(N).

Computing details

Data collection: CrystalClear (Rigaku, 2005); cell refinement: CrystalClear (Rigaku, 2005); data reduction: CrystalClear (Rigaku, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures

	Fig. 1. The molecular structure of the title compound with the atomic numbering scheme. Displacement ellipsoids are drawn at the 30% probability level, and all H atoms have been omitted for clarity.
	Fig. 2. A view of the packing of the title compound, stacking along the b axis. Dashed lines indicate hydrogen bonds.

2-(Ethoxycarbonyl)pyridinium nitrate

Crystal data

C8H10NO2^+·NO3^−	F(000) = 448
Mr = 214.18	Dx = 1.456 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 3542 reflections
a = 6.8221 (14) Å	θ = 3.1–27.6°
b = 16.208 (3) Å	µ = 0.12 mm^−1
c = 9.2195 (18) Å	T = 293 K
β = 106.55 (3)°	Prism, colourless
V = 977.2 (3) Å^3	0.20 × 0.20 × 0.20 mm
Z = 4

Data collection

Rigaku SCXmini diffractometer	2226 independent reflections
Radiation source: fine-focus sealed tube	1287 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.089
Detector resolution: 13.6612 pixels mm^-1	θmax = 27.5°, θmin = 3.3°
ω scans	h = −8→8
Absorption correction: multi-scan (CrystalClear; Rigaku, 2005)	k = −21→21
Tmin = 0.976, Tmax = 0.976	l = −11→11
9694 measured reflections

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)] = 0.064	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.178	H-atom parameters constrained
S = 1.04	w = 1/[σ^2(Fo^2) + (0.072P)^2 + 0.2351P] where P = (Fo^2 + 2Fc^2)/3
2226 reflections	(Δ/σ)max < 0.001
136 parameters	Δρmax = 0.22 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	0.2450 (3)	0.15158 (11)	0.4900 (2)	0.0500 (6)
O5	0.1957 (4)	−0.10679 (14)	0.7615 (2)	0.0641 (7)
N1	0.2593 (3)	0.01904 (14)	0.3286 (2)	0.0410 (6)
H1A	0.2558	0.0168	0.4210	0.049*
O4	0.2397 (4)	−0.00834 (13)	0.6195 (3)	0.0730 (8)
O3	0.2805 (4)	−0.13303 (14)	0.5588 (2)	0.0727 (7)
N2	0.2370 (3)	−0.08353 (15)	0.6463 (3)	0.0445 (6)
C6	0.2474 (4)	0.16983 (18)	0.3508 (3)	0.0445 (7)
C5	0.2573 (4)	0.09338 (17)	0.2627 (3)	0.0406 (7)
O2	0.2430 (3)	0.23734 (13)	0.2988 (2)	0.0611 (7)
C3	0.2670 (5)	0.0251 (2)	0.0360 (3)	0.0540 (8)
H3A	0.2693	0.0270	−0.0643	0.065*
C4	0.2621 (4)	0.09761 (19)	0.1144 (3)	0.0503 (8)
H4A	0.2621	0.1485	0.0677	0.060*
C1	0.2664 (4)	−0.05092 (18)	0.2550 (3)	0.0472 (8)
H1B	0.2701	−0.1012	0.3043	0.057*
C7	0.2289 (5)	0.22041 (19)	0.5875 (3)	0.0567 (9)
H7A	0.1064	0.2522	0.5417	0.068*
H7B	0.3465	0.2565	0.6026	0.068*
C2	0.2684 (5)	−0.04929 (19)	0.1065 (4)	0.0513 (8)
H2A	0.2707	−0.0982	0.0544	0.062*
C8	0.2201 (6)	0.1856 (2)	0.7339 (4)	0.0611 (9)
H8A	0.2077	0.2297	0.8004	0.092*
H8B	0.3429	0.1550	0.7788	0.092*
H8C	0.1040	0.1497	0.7175	0.092*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0731 (15)	0.0370 (11)	0.0431 (11)	−0.0019 (9)	0.0217 (10)	−0.0039 (9)
O5	0.0931 (17)	0.0609 (14)	0.0470 (12)	−0.0035 (12)	0.0340 (12)	0.0060 (10)
N1	0.0460 (14)	0.0425 (14)	0.0376 (12)	−0.0003 (11)	0.0172 (11)	0.0002 (10)
O4	0.124 (2)	0.0409 (13)	0.0617 (14)	−0.0030 (12)	0.0388 (14)	0.0056 (11)
O3	0.116 (2)	0.0547 (14)	0.0573 (14)	0.0149 (13)	0.0415 (14)	0.0021 (12)
N2	0.0493 (15)	0.0443 (15)	0.0406 (14)	−0.0017 (11)	0.0138 (11)	0.0039 (11)
C6	0.0479 (18)	0.0420 (16)	0.0449 (16)	−0.0037 (13)	0.0154 (14)	0.0046 (13)
C5	0.0422 (16)	0.0431 (17)	0.0384 (15)	−0.0007 (12)	0.0145 (12)	0.0033 (12)
O2	0.0861 (17)	0.0428 (13)	0.0580 (14)	0.0003 (11)	0.0261 (12)	0.0106 (10)
C3	0.059 (2)	0.066 (2)	0.0412 (17)	−0.0029 (16)	0.0199 (15)	−0.0040 (15)
C4	0.058 (2)	0.0517 (18)	0.0442 (16)	−0.0006 (15)	0.0188 (14)	0.0087 (14)
C1	0.0542 (19)	0.0420 (18)	0.0474 (17)	0.0005 (13)	0.0176 (14)	−0.0042 (13)
C7	0.082 (2)	0.0418 (17)	0.0463 (18)	−0.0006 (16)	0.0181 (16)	−0.0061 (14)
C2	0.053 (2)	0.0539 (19)	0.0464 (17)	0.0032 (15)	0.0139 (14)	−0.0073 (14)
C8	0.086 (2)	0.0526 (19)	0.0507 (18)	−0.0035 (17)	0.0289 (17)	−0.0091 (15)

Geometric parameters (Å, º)

O1—C6	1.321 (3)	C3—C4	1.385 (4)
O1—C7	1.457 (3)	C3—H3A	0.9300
O5—N2	1.233 (3)	C4—H4A	0.9300
N1—C1	1.329 (3)	C1—C2	1.373 (4)
N1—C5	1.348 (3)	C1—H1B	0.9300
N1—H1A	0.8600	C7—C8	1.480 (4)
O4—N2	1.245 (3)	C7—H7A	0.9700
O3—N2	1.232 (3)	C7—H7B	0.9700
C6—O2	1.192 (3)	C2—H2A	0.9300
C6—C5	1.494 (4)	C8—H8A	0.9600
C5—C4	1.378 (4)	C8—H8B	0.9600
C3—C2	1.369 (4)	C8—H8C	0.9600
C6—O1—C7	116.9 (2)	N1—C1—C2	120.3 (3)
C1—N1—C5	122.0 (2)	N1—C1—H1B	119.8
C1—N1—H1A	119.0	C2—C1—H1B	119.8
C5—N1—H1A	119.0	O1—C7—C8	107.5 (2)
O3—N2—O5	121.4 (2)	O1—C7—H7A	110.2
O3—N2—O4	119.2 (2)	C8—C7—H7A	110.2
O5—N2—O4	119.4 (2)	O1—C7—H7B	110.2
O2—C6—O1	126.2 (3)	C8—C7—H7B	110.2
O2—C6—C5	122.9 (3)	H7A—C7—H7B	108.5
O1—C6—C5	110.9 (2)	C3—C2—C1	119.3 (3)
N1—C5—C4	119.4 (3)	C3—C2—H2A	120.3
N1—C5—C6	119.5 (2)	C1—C2—H2A	120.3
C4—C5—C6	121.0 (2)	C7—C8—H8A	109.5
C2—C3—C4	119.8 (3)	C7—C8—H8B	109.5
C2—C3—H3A	120.1	H8A—C8—H8B	109.5
C4—C3—H3A	120.1	C7—C8—H8C	109.5
C5—C4—C3	119.1 (3)	H8A—C8—H8C	109.5
C5—C4—H4A	120.4	H8B—C8—H8C	109.5
C3—C4—H4A	120.4
C7—O1—C6—O2	2.1 (4)	N1—C5—C4—C3	0.6 (4)
C7—O1—C6—C5	−178.1 (2)	C6—C5—C4—C3	−178.7 (3)
C1—N1—C5—C4	0.2 (4)	C2—C3—C4—C5	−0.4 (4)
C1—N1—C5—C6	179.5 (3)	C5—N1—C1—C2	−1.2 (4)
O2—C6—C5—N1	−179.2 (3)	C6—O1—C7—C8	177.6 (3)
O1—C6—C5—N1	1.0 (4)	C4—C3—C2—C1	−0.5 (5)
O2—C6—C5—C4	0.1 (4)	N1—C1—C2—C3	1.3 (4)
O1—C6—C5—C4	−179.8 (2)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O4	0.86	1.91	2.759 (3)	170
C1—H1B···O3	0.93	2.38	3.078 (4)	131
C8—H8A···O3^i	0.96	2.57	3.506 (4)	166

Symmetry code: (i) −x+1/2, y+1/2, −z+3/2.