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Acta Cryst. (2012). E68, o3310    [ doi:10.1107/S1600536812045497 ]

Piperidine-1-carboxamidinium ethyl carbonate

I. Tiritiris

Abstract top

In the title salt, C6H14N3+·C3H5O3-, the C-N bond lengths in the central CN3 unit of the carboxamidinium cation are 1.3262 (18), 1.3359 (18) and 1.3498 (18) Å, indicating partial double-bond character. The central C atom is bonded to the three N atoms in a nearly ideal trigonal-planar geometry and the positive charge is delocalized in the CN3 plane. The piperidine ring is in a chair conformation. The C-O bond lengths in the ethyl carbonate anion are characteristic for a delocalized double bond and a typical single bond. In the crystal, N-H...O hydrogen bonds between cations and anions generate a two-dimensional network in the direction of the ab plane, whereas adjacent ion pairs form chains running along the b axis.

Comment top

By reacting guanidines with CO2 in undried aprotic solvents, the corresponding guanidinium hydrogen carbonate salts are formed exclusively (Tiritiris et al., 2011). To investigate the reaction of carboxamidines with CO2, we used both aprotic and protic solvents. Due to the water content in the common aprotic solvents, the hydrogen carbonate salts were formed too. Most of them are sparingly soluble and could therefore not be obtained in crystalline form. By using ethanol as a solvent for the reaction, the crystalline title compound emerged. According to the structure analysis, the C1–N1 bond in the title compound is 1.3262 (18) Å, C1–N2 = 1.3359 (18) Å and C1–N3 = 1.3498 (18) Å, showing partial double-bond character (Fig. 1). The N–C1–N angles are: 117.59 (13)° (N1–C1–N2), 121.04 (12)° (N1–C1–N3) and 121.36 (12)° (N2–C1–N3), which indicate a nearly ideal trigonal-planar surrounding of the carbon centre by the nitrogen atoms. The positive charge is completely delocalized on the CN3 plane. The structural parameters of the piperidine ring in the here presented title compound agree very well with the data obtained from the X-ray analysis of the starting compound piperidine-1-carboximidamide (Tiritiris, 2012). The piperidine ring adopt a chair conformation. In the ethyl carbonate ion the C7–O1 and C7–O2 bond lengths indicate an evenly distributed double bond character (C7–O1, 1.2485 (16) Å; C7–O2, 1.2509 (17) Å) and a typical single bond (C7–O3, 1.3706 (18) Å). The data fit with the C–O bond lengths of the anion in sodium methyl carbonate (Kunert et al., 1998). In the crystal structure, strong N—H···O hydrogen bonds between hydrogen atoms of carboxamidinium ions and oxygen atoms of neighboring ethyl carbonate ions are observed, generating an infinite two-dimensional network [d(H···O) = 1.88 (2)–2.19 (2) Å] (Tab. 1) with base vectors [1 0 - 1] and [0 1 0] (Fig. 2). Furthermore, the hydrogen bonds are arranged in a way, that adjacent ion pairs are forming chains running along the b axis (Fig. 3).

Related literature top

For the synthesis and crystal structures of guanidinium hydrogencarbonates, see: Tiritiris et al. (2011). For the crystal structure of 1-piperidinecarboximdamide, see: Tiritiris (2012) and for the crystal structure of sodium methylcarbonate, see: Kunert et al. (1998).

Experimental top

The title compound was prepared by bubbling excess CO2 gas into an ethanolic solution of 2.04 g (16 mmol) piperidine-1-carboximidamide (Tiritiris, 2012). The resulting colourless precipitate was recrystallized from a small amount of ethanol and single crystals suitable for X-ray analysis were obtained. Yield: 3.25 g (93.3%). 1H NMR (500 MHz, D2O/DSS): δ = 1.17–1.20 [t, 3 H, –CH3], 1.61–1.70 [m, 6 H, –CH2], 3.40–3.43 [m, 4 H, –CH2], 3.64–3.68 [q, 2 H, –CH2]. Because of the H/D exchange, the hydrogen atoms of the –NH2 groups were not observed. 13C NMR (125 MHz, D2O/DSS): δ = 16.8 (–CH3), 23.1 (–CH2), 24.7 (–CH2), 46.7 (–CH2), 57.4 (–CH2), 155.5 (N3C+), 160.3 (CO).

Refinement top

The N-bound H atoms were located in a difference Fourier map and were refined freely [N—H = 0.84 (2)–0.88 (2) Å]. The hydrogen atoms of the methyl group were allowed to rotate with a fixed angle around the C–C bond to best fit the experimental electron density, with U(H) set to 1.5 Ueq(C) and d(C—H) = 0.98 Å. The H atoms of the methylene groups were placed in calculated positions with d(C—H) = 0.99 Å. They were included in the refinement in the riding model approximation, with U(H) set to 1.2 Ueq(C).

Computing details top

Data collection: COLLECT (Hooft, 2004); cell refinement: SCALEPACK (Otwinowski & Minor, 1997); data reduction: SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg & Putz, 2005); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The structure of the title compound with displacement ellipsoids at the 50% probability level.
[Figure 2] Fig. 2. N–H···O hydrogen bonds generating a two-dimensional network, ab-view. The hydrogen bonds are indicated by dashed lines.
[Figure 3] Fig. 3. N–H···O hydrogen bond arrangement forming chains running along the b axis. The hydrogen bonds are indicated by dashed lines.
Piperidine-1-carboxamidinium ethyl carbonate top
Crystal data top
C6H14N3+·C3H5O3F(000) = 472
Mr = 217.27Dx = 1.306 Mg m3
Monoclinic, P21/nMelting point: 397 K
Hall symbol: -P 2ynMo Kα radiation, λ = 0.71073 Å
a = 11.8320 (6) ÅCell parameters from 2732 reflections
b = 7.2407 (4) Åθ = 0.4–27.9°
c = 13.3755 (9) ŵ = 0.10 mm1
β = 105.292 (3)°T = 100 K
V = 1105.33 (11) Å3Plate, colourless
Z = 40.25 × 0.20 × 0.05 mm
Data collection top
Bruker–Nonius KappaCCD
diffractometer
1982 reflections with I > 2σ(I)
Radiation source: sealed tubeRint = 0.047
Graphite monochromatorθmax = 27.9°, θmin = 2.1°
φ scans, and ω scansh = 1515
4452 measured reflectionsk = 98
2638 independent reflectionsl = 1717
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.042Hydrogen site location: difference Fourier map
wR(F2) = 0.106H atoms treated by a mixture of independent and constrained refinement
S = 1.02 w = 1/[σ2(Fo2) + (0.0412P)2 + 0.424P]
where P = (Fo2 + 2Fc2)/3
2638 reflections(Δ/σ)max < 0.001
153 parametersΔρmax = 0.28 e Å3
0 restraintsΔρmin = 0.23 e Å3
Crystal data top
C6H14N3+·C3H5O3V = 1105.33 (11) Å3
Mr = 217.27Z = 4
Monoclinic, P21/nMo Kα radiation
a = 11.8320 (6) ŵ = 0.10 mm1
b = 7.2407 (4) ÅT = 100 K
c = 13.3755 (9) Å0.25 × 0.20 × 0.05 mm
β = 105.292 (3)°
Data collection top
Bruker–Nonius KappaCCD
diffractometer
1982 reflections with I > 2σ(I)
4452 measured reflectionsRint = 0.047
2638 independent reflectionsθmax = 27.9°
Refinement top
R[F2 > 2σ(F2)] = 0.042H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.106Δρmax = 0.28 e Å3
S = 1.02Δρmin = 0.23 e Å3
2638 reflectionsAbsolute structure: ?
153 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Special details top

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 (Å2) top
xyzUiso*/Ueq
N10.01610 (11)0.84504 (19)0.10282 (10)0.0182 (3)
H110.0373 (17)0.810 (3)0.0712 (16)0.030 (5)*
H120.0527 (16)0.949 (3)0.0829 (15)0.029 (5)*
N20.11973 (10)0.83590 (18)0.22402 (10)0.0162 (3)
H210.1508 (14)0.936 (3)0.1994 (14)0.019 (4)*
H220.1552 (15)0.779 (3)0.2649 (15)0.023 (5)*
N30.01511 (10)0.60093 (16)0.22039 (9)0.0140 (2)
C10.04041 (11)0.75874 (19)0.18211 (11)0.0138 (3)
C20.02711 (12)0.4939 (2)0.29709 (11)0.0163 (3)
H2A0.09690.42140.26100.020*
H2B0.05080.57980.34550.020*
C30.06700 (13)0.3636 (2)0.35824 (11)0.0192 (3)
H3A0.13220.43690.40190.023*
H3B0.03380.28660.40460.023*
C40.11384 (13)0.2397 (2)0.28736 (12)0.0191 (3)
H4A0.04980.16320.24460.023*
H4B0.17480.15640.32880.023*
C50.16564 (13)0.3613 (2)0.21824 (12)0.0219 (3)
H5A0.23200.43260.26170.026*
H5B0.19630.28250.17090.026*
C60.07529 (12)0.4939 (2)0.15493 (11)0.0188 (3)
H6A0.11440.58050.11750.023*
H6B0.01630.42320.10270.023*
O10.25289 (8)0.31135 (14)0.63820 (8)0.0173 (2)
O20.36182 (9)0.34098 (15)0.52507 (8)0.0210 (2)
O30.26553 (8)0.08408 (14)0.52492 (8)0.0175 (2)
C70.29380 (11)0.2563 (2)0.56646 (11)0.0144 (3)
C80.18221 (12)0.0237 (2)0.56032 (11)0.0169 (3)
H8A0.10790.04510.55110.020*
H8B0.21320.05480.63460.020*
C90.16276 (14)0.1971 (2)0.49492 (12)0.0232 (3)
H9A0.12350.16520.42290.035*
H9B0.11370.28320.52150.035*
H9C0.23840.25510.49800.035*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
N10.0210 (6)0.0191 (6)0.0183 (6)0.0056 (5)0.0120 (5)0.0059 (5)
N20.0193 (6)0.0147 (6)0.0175 (6)0.0039 (5)0.0100 (5)0.0048 (5)
N30.0151 (5)0.0161 (6)0.0124 (5)0.0021 (4)0.0064 (4)0.0022 (5)
C10.0155 (6)0.0145 (6)0.0115 (6)0.0020 (5)0.0037 (5)0.0012 (5)
C20.0177 (6)0.0194 (7)0.0141 (7)0.0018 (6)0.0086 (5)0.0035 (6)
C30.0228 (7)0.0207 (7)0.0154 (7)0.0043 (6)0.0072 (6)0.0048 (6)
C40.0243 (7)0.0145 (7)0.0207 (7)0.0026 (6)0.0098 (6)0.0027 (6)
C50.0232 (7)0.0229 (8)0.0240 (8)0.0081 (6)0.0137 (6)0.0062 (6)
C60.0229 (7)0.0206 (7)0.0168 (7)0.0060 (6)0.0122 (6)0.0028 (6)
O10.0201 (5)0.0178 (5)0.0171 (5)0.0018 (4)0.0104 (4)0.0027 (4)
O20.0244 (5)0.0221 (6)0.0209 (5)0.0078 (4)0.0139 (4)0.0052 (4)
O30.0188 (5)0.0184 (5)0.0181 (5)0.0050 (4)0.0099 (4)0.0041 (4)
C70.0123 (6)0.0181 (7)0.0131 (7)0.0006 (5)0.0037 (5)0.0003 (5)
C80.0169 (6)0.0186 (7)0.0174 (7)0.0021 (5)0.0081 (6)0.0004 (6)
C90.0250 (7)0.0238 (8)0.0241 (8)0.0083 (6)0.0121 (6)0.0052 (7)
Geometric parameters (Å, º) top
N1—C11.3262 (18)C4—H4B0.9900
N1—H110.88 (2)C5—C61.518 (2)
N1—H120.88 (2)C5—H5A0.9900
N2—C11.3359 (18)C5—H5B0.9900
N2—H210.84 (2)C6—H6A0.9900
N2—H220.87 (2)C6—H6B0.9900
N3—C11.3498 (18)O1—C71.2485 (16)
N3—C21.4742 (17)O2—C71.2509 (17)
N3—C61.4842 (17)O3—C71.3706 (18)
C2—C31.5227 (19)O3—C81.4323 (16)
C2—H2A0.9900C8—C91.512 (2)
C2—H2B0.9900C8—H8A0.9900
C3—C41.512 (2)C8—H8B0.9900
C3—H3A0.9900C9—H9A0.9800
C3—H3B0.9900C9—H9B0.9800
C4—C51.518 (2)C9—H9C0.9800
C4—H4A0.9900
C1—N1—H11125.4 (13)H4A—C4—H4B108.4
C1—N1—H12117.1 (12)C6—C5—C4111.62 (12)
H11—N1—H12117.4 (18)C6—C5—H5A109.3
C1—N2—H21118.6 (11)C4—C5—H5A109.3
C1—N2—H22125.0 (12)C6—C5—H5B109.3
H21—N2—H22114.7 (16)C4—C5—H5B109.3
C1—N3—C2119.25 (11)H5A—C5—H5B108.0
C1—N3—C6118.65 (11)N3—C6—C5112.21 (11)
C2—N3—C6116.07 (11)N3—C6—H6A109.2
N1—C1—N2117.59 (13)C5—C6—H6A109.2
N1—C1—N3121.04 (12)N3—C6—H6B109.2
N2—C1—N3121.36 (12)C5—C6—H6B109.2
N3—C2—C3111.43 (10)H6A—C6—H6B107.9
N3—C2—H2A109.3C7—O3—C8118.52 (10)
C3—C2—H2A109.3O1—C7—O2127.52 (13)
N3—C2—H2B109.3O1—C7—O3119.95 (12)
C3—C2—H2B109.3O2—C7—O3112.53 (12)
H2A—C2—H2B108.0O3—C8—C9105.90 (11)
C4—C3—C2111.57 (12)O3—C8—H8A110.6
C4—C3—H3A109.3C9—C8—H8A110.6
C2—C3—H3A109.3O3—C8—H8B110.6
C4—C3—H3B109.3C9—C8—H8B110.6
C2—C3—H3B109.3H8A—C8—H8B108.7
H3A—C3—H3B108.0C8—C9—H9A109.5
C3—C4—C5108.14 (12)C8—C9—H9B109.5
C3—C4—H4A110.1H9A—C9—H9B109.5
C5—C4—H4A110.1C8—C9—H9C109.5
C3—C4—H4B110.1H9A—C9—H9C109.5
C5—C4—H4B110.1H9B—C9—H9C109.5
C2—N3—C1—N1170.39 (13)C3—C4—C5—C658.57 (17)
C6—N3—C1—N118.76 (19)C1—N3—C6—C5160.64 (12)
C2—N3—C1—N211.15 (19)C2—N3—C6—C546.85 (16)
C6—N3—C1—N2162.78 (13)C4—C5—C6—N352.04 (17)
C1—N3—C2—C3160.06 (12)C8—O3—C7—O14.51 (19)
C6—N3—C2—C347.59 (16)C8—O3—C7—O2175.98 (12)
N3—C2—C3—C454.20 (16)C7—O3—C8—C9175.66 (12)
C2—C3—C4—C559.74 (16)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H11···O2i0.88 (2)1.99 (2)2.812 (1)155 (1)
N1—H12···O2ii0.88 (2)1.88 (2)2.747 (1)173 (1)
N2—H21···O1ii0.84 (2)2.19 (2)3.033 (1)175 (1)
N2—H22···O1iii0.87 (2)2.06 (2)2.923 (1)170 (1)
Symmetry codes: (i) x+1/2, y+1/2, z+1/2; (ii) x1/2, y+3/2, z1/2; (iii) x, y+1, z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
N1—H11···O2i0.88 (2)1.99 (2)2.812 (1)155 (1)
N1—H12···O2ii0.88 (2)1.88 (2)2.747 (1)173 (1)
N2—H21···O1ii0.84 (2)2.19 (2)3.033 (1)175 (1)
N2—H22···O1iii0.87 (2)2.06 (2)2.923 (1)170 (1)
Symmetry codes: (i) x+1/2, y+1/2, z+1/2; (ii) x1/2, y+3/2, z1/2; (iii) x, y+1, z+1.
Acknowledgements top

The author thanks Dr F. Lissner (Institut für Anorganische Chemie, Universität Stuttgart) for measuring the crystal data.

references
References top

Brandenburg, K. & Putz, H. (2005). DIAMOND. Crystal Impact GbR, D-53002 Bonn, Germany.

Hooft, R. W. W. (2004). COLLECT. Bruker–Nonius BV, Delft, The Netherlands.

Kunert, M., Wiegeleben, P., Görls, H. & Dinjus, E. (1998). Inorg. Chem. Commun. 1, 131–133.

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Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.

Tiritiris, I. (2012). Acta Cryst. E68, o3253.

Tiritiris, I., Mezger, J., Stoyanov, E. V. & Kantlehner, W. (2011). Z. Naturforsch. Teil B, 66, 407–418.