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Crystals of bis(2-ethyl-3-hydroxy-6-methylpyridinium) succinate-succinic acid (1/1), C
8H
12NO
+·0.5C
4H
4O
42-·0.5C
4H
6O
4, (I), and 2-ethyl-3-hydroxy-6-methylpyridinium hydrogen succinate, C
8H
12NO
+·C
4H
5O
4-, (II), were obtained by reaction of 2-ethyl-6-methylpyridin-3-ol with succinic acid. The succinate anion and succinic acid molecule in (I) are located about centres of inversion. Intermolecular O-H
O, N-H
O and C-H
O hydrogen bonds are responsible for the formation of a three-dimensional network in the crystal structure of (I) and a two-dimensional network in the crystal structure of (II). Both structures are additionally stabilized by
-
interactions between symmetry-related pyridine rings, forming a rod-like cationic arrangement for (I) and cationic dimers for (II).
Supporting information
CCDC references: 866762; 866763
For the synthesis of (I), 2-ethyl-6-methylpyridin-3-ol (10.0 g, 73 mmol) and
succinic acid (8.6 g, 73 mmol) were heated in propan-2-ol under reflux for 1 h. The reaction mixture was filtered and the solution obtained was cooled to
room temperature. The precipitated crystals of (I) were collected, washed
twice with acetone (10 ml) and dried in air (yield 11.2 g, 44%; m.p. 385–386 K). 1H NMR (500 MHz, D2O, δ, p.p.m.): 1.16 (t, 3H, J = 7.5 Hz, CH2CH3), 2.43 (s, 4H, CH2CH2), 2.48 (s, 3H, CH3),
2.84 (q, 2H, J = 7.5 Hz, CH2CH3), 7.34 (d, 1H,
J = 9 Hz, aryl), 7.66 (d, 1H, J = 9 Hz, aryl). Single
crystals of (I) suitable for X-ray analysis were selected from the reaction
product.
For the synthesis of (II), compound (I) (5.0 g) was dissolved in a
propan-2-ol–acetone mixture (9:1 v/v, 70 ml) under reflux.
After refluxing for 30 min, the solution obtained was cooled to room
temperature. The precipitated crystals were collected and dried in air to give
a mixture of (I) and (II), with a melting interval of 385–393 K. To prepare a
pure sample of (II), the obtained mixture was heated at 388–391 K in an oil
bath for 30 min. The resulting slurry was left to cool to room temperature
overnight. The resulting crystalline solid of (II) was ground to a fine
polycrystalline powder (yield 3.2 g, 64%; m.p. 392–393 K). The 1H NMR
spectrum of (II) was identical to that of (I). Single crystals of (II)
suitable for X-ray analysis can be prepared by crystallization from acetone
solutions of (I) or (II), using seed crystals of (II). In the present work, a
solution of (I) was used for this purpose.
H atoms were included in geometrically calculated positions, with N—H = 0.86 Å, O—H = 0.82 Å and C—H = 0.93–0.97 Å, and refined using a riding
model, with Uiso(H) = 1.5Ueq(C,O) for methyl and hydroxy H
or 1.2Ueq(C,N) for other H atoms.
For both compounds, data collection: APEX2 (Bruker, 2010); cell refinement: SAINT (Bruker, 2010); data reduction: SAINT (Bruker, 2010); program(s) used to solve structure: SIR2004 (Burla et al., 2005); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008) and PLATON (Spek, 2009).
(I) bis(2-ethyl-6-methyl-3-hydroxypyridinium) succinate–succinic acid (1/1)
top
Crystal data top
C8H12NO+·0.5C4H4O42−·0.5C4H6O4 | Z = 2 |
Mr = 255.27 | F(000) = 272 |
Triclinic, P1 | Dx = 1.284 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 7.3047 (6) Å | Cell parameters from 2735 reflections |
b = 8.4660 (7) Å | θ = 2.6–28.3° |
c = 11.7559 (10) Å | µ = 0.10 mm−1 |
α = 95.747 (1)° | T = 296 K |
β = 103.926 (1)° | Prism, colourless |
γ = 107.716 (1)° | 0.40 × 0.20 × 0.15 mm |
V = 660.25 (10) Å3 | |
Data collection top
Bruker APEXII CCD area-detector diffractometer | 2717 independent reflections |
Radiation source: fine-focus sealed tube | 2189 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.014 |
ϕ and ω scans | θmax = 26.5°, θmin = 2.6° |
Absorption correction: multi-scan (SADABS; Bruker, 2008) | h = −9→9 |
Tmin = 0.961, Tmax = 0.985 | k = −10→10 |
6220 measured reflections | l = −14→14 |
Refinement top
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)] = 0.045 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.128 | H-atom parameters constrained |
S = 1.03 | w = 1/[σ2(Fo2) + (0.0665P)2 + 0.161P] where P = (Fo2 + 2Fc2)/3 |
2717 reflections | (Δ/σ)max < 0.001 |
167 parameters | Δρmax = 0.28 e Å−3 |
0 restraints | Δρmin = −0.24 e Å−3 |
Crystal data top
C8H12NO+·0.5C4H4O42−·0.5C4H6O4 | γ = 107.716 (1)° |
Mr = 255.27 | V = 660.25 (10) Å3 |
Triclinic, P1 | Z = 2 |
a = 7.3047 (6) Å | Mo Kα radiation |
b = 8.4660 (7) Å | µ = 0.10 mm−1 |
c = 11.7559 (10) Å | T = 296 K |
α = 95.747 (1)° | 0.40 × 0.20 × 0.15 mm |
β = 103.926 (1)° | |
Data collection top
Bruker APEXII CCD area-detector diffractometer | 2717 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2008) | 2189 reflections with I > 2σ(I) |
Tmin = 0.961, Tmax = 0.985 | Rint = 0.014 |
6220 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.045 | 0 restraints |
wR(F2) = 0.128 | H-atom parameters constrained |
S = 1.03 | Δρmax = 0.28 e Å−3 |
2717 reflections | Δρmin = −0.24 e Å−3 |
167 parameters | |
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 | x | y | z | Uiso*/Ueq | |
N1 | 0.14960 (17) | 0.42043 (15) | 0.37481 (10) | 0.0384 (3) | |
H1 | 0.0912 | 0.3733 | 0.3012 | 0.046* | |
C2 | 0.16956 (19) | 0.58313 (18) | 0.40600 (12) | 0.0346 (3) | |
C3 | 0.2574 (2) | 0.65950 (19) | 0.52588 (12) | 0.0372 (3) | |
O3 | 0.26961 (18) | 0.82004 (14) | 0.55682 (9) | 0.0498 (3) | |
H3 | 0.2980 | 0.8452 | 0.6296 | 0.075* | |
C4 | 0.3273 (2) | 0.5662 (2) | 0.60597 (13) | 0.0449 (4) | |
H4 | 0.3888 | 0.6157 | 0.6860 | 0.054* | |
C5 | 0.3060 (2) | 0.4013 (2) | 0.56741 (15) | 0.0477 (4) | |
H5 | 0.3544 | 0.3404 | 0.6216 | 0.057* | |
C6 | 0.2138 (2) | 0.3249 (2) | 0.44960 (15) | 0.0441 (4) | |
C7 | 0.1032 (2) | 0.6755 (2) | 0.31137 (13) | 0.0422 (4) | |
H7A | 0.0326 | 0.7440 | 0.3400 | 0.051* | |
H7B | 0.0105 | 0.5945 | 0.2415 | 0.051* | |
C8 | 0.2791 (3) | 0.7883 (2) | 0.27663 (16) | 0.0550 (4) | |
H8A | 0.3747 | 0.8646 | 0.3464 | 0.082* | |
H8B | 0.2318 | 0.8516 | 0.2201 | 0.082* | |
H8C | 0.3418 | 0.7199 | 0.2415 | 0.082* | |
C9 | 0.1797 (3) | 0.1469 (2) | 0.3983 (2) | 0.0670 (5) | |
H9A | 0.0382 | 0.0862 | 0.3684 | 0.100* | |
H9B | 0.2389 | 0.0949 | 0.4592 | 0.100* | |
H9C | 0.2400 | 0.1447 | 0.3344 | 0.100* | |
C10 | 0.7209 (2) | 0.1343 (2) | 0.13892 (13) | 0.0439 (4) | |
O101 | 0.88897 (18) | 0.24738 (16) | 0.15792 (10) | 0.0618 (4) | |
O102 | 0.6442 (2) | 0.08687 (18) | 0.21770 (10) | 0.0704 (4) | |
C11 | 0.6081 (2) | 0.0530 (2) | 0.01004 (13) | 0.0506 (4) | |
H11A | 0.6128 | 0.1412 | −0.0371 | 0.061* | |
H11B | 0.6763 | −0.0173 | −0.0189 | 0.061* | |
C12 | 0.2711 (2) | 0.3927 (2) | 0.05304 (14) | 0.0498 (4) | |
O121 | 0.0812 (2) | 0.3133 (2) | −0.00103 (12) | 0.0906 (6) | |
H121 | 0.0200 | 0.2922 | 0.0487 | 0.136* | |
O122 | 0.33909 (19) | 0.4171 (2) | 0.15904 (11) | 0.0766 (5) | |
C13 | 0.3903 (2) | 0.4524 (3) | −0.03110 (15) | 0.0582 (5) | |
H13A | 0.3338 | 0.5251 | −0.0758 | 0.070* | |
H13B | 0.3788 | 0.3556 | −0.0876 | 0.070* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
N1 | 0.0359 (6) | 0.0425 (7) | 0.0299 (6) | 0.0063 (5) | 0.0072 (5) | 0.0042 (5) |
C2 | 0.0286 (6) | 0.0409 (8) | 0.0285 (7) | 0.0039 (5) | 0.0076 (5) | 0.0066 (5) |
C3 | 0.0312 (7) | 0.0454 (8) | 0.0274 (7) | 0.0029 (6) | 0.0075 (5) | 0.0068 (6) |
O3 | 0.0613 (7) | 0.0467 (6) | 0.0292 (5) | 0.0071 (5) | 0.0079 (5) | 0.0006 (4) |
C4 | 0.0346 (7) | 0.0654 (10) | 0.0280 (7) | 0.0093 (7) | 0.0050 (6) | 0.0124 (7) |
C5 | 0.0385 (8) | 0.0649 (11) | 0.0445 (9) | 0.0193 (7) | 0.0116 (6) | 0.0262 (8) |
C6 | 0.0377 (7) | 0.0478 (9) | 0.0501 (9) | 0.0142 (6) | 0.0162 (7) | 0.0162 (7) |
C7 | 0.0441 (8) | 0.0454 (8) | 0.0293 (7) | 0.0099 (6) | 0.0033 (6) | 0.0075 (6) |
C8 | 0.0660 (11) | 0.0588 (10) | 0.0465 (9) | 0.0193 (9) | 0.0251 (8) | 0.0220 (8) |
C9 | 0.0682 (12) | 0.0523 (11) | 0.0832 (14) | 0.0235 (9) | 0.0218 (11) | 0.0154 (10) |
C10 | 0.0417 (8) | 0.0462 (8) | 0.0293 (7) | −0.0007 (6) | 0.0080 (6) | −0.0033 (6) |
O101 | 0.0458 (7) | 0.0700 (8) | 0.0377 (6) | −0.0152 (6) | 0.0050 (5) | −0.0046 (5) |
O102 | 0.0657 (8) | 0.0830 (9) | 0.0285 (6) | −0.0174 (7) | 0.0142 (5) | −0.0073 (6) |
C11 | 0.0428 (9) | 0.0586 (10) | 0.0296 (7) | −0.0074 (7) | 0.0099 (6) | −0.0049 (7) |
C12 | 0.0432 (8) | 0.0590 (10) | 0.0368 (8) | 0.0101 (7) | 0.0033 (6) | 0.0058 (7) |
O121 | 0.0473 (7) | 0.1430 (15) | 0.0401 (7) | −0.0157 (8) | 0.0040 (6) | 0.0067 (8) |
O122 | 0.0505 (7) | 0.1230 (13) | 0.0389 (7) | 0.0111 (8) | 0.0039 (6) | 0.0187 (7) |
C13 | 0.0441 (9) | 0.0788 (13) | 0.0378 (8) | 0.0068 (9) | 0.0047 (7) | 0.0109 (8) |
Geometric parameters (Å, º) top
N1—C2 | 1.3431 (19) | C8—H8C | 0.9600 |
N1—C6 | 1.350 (2) | C9—H9A | 0.9600 |
N1—H1 | 0.8600 | C9—H9B | 0.9600 |
C2—C3 | 1.3948 (19) | C9—H9C | 0.9600 |
C2—C7 | 1.493 (2) | C10—O102 | 1.2327 (19) |
C3—O3 | 1.3413 (19) | C10—O101 | 1.2587 (18) |
C3—C4 | 1.391 (2) | C10—C11 | 1.5142 (19) |
O3—H3 | 0.8200 | C11—C11i | 1.507 (3) |
C4—C5 | 1.374 (2) | C11—H11A | 0.9700 |
C4—H4 | 0.9300 | C11—H11B | 0.9700 |
C5—C6 | 1.377 (2) | C12—O122 | 1.196 (2) |
C5—H5 | 0.9300 | C12—O121 | 1.305 (2) |
C6—C9 | 1.488 (3) | C12—C13 | 1.497 (2) |
C7—C8 | 1.521 (2) | O121—H121 | 0.8200 |
C7—H7A | 0.9700 | C13—C13ii | 1.511 (3) |
C7—H7B | 0.9700 | C13—H13A | 0.9700 |
C8—H8A | 0.9600 | C13—H13B | 0.9700 |
C8—H8B | 0.9600 | | |
| | | |
C2—N1—C6 | 125.30 (13) | C7—C8—H8C | 109.5 |
C2—N1—H1 | 117.3 | H8A—C8—H8C | 109.5 |
C6—N1—H1 | 117.3 | H8B—C8—H8C | 109.5 |
N1—C2—C3 | 117.99 (13) | C6—C9—H9A | 109.5 |
N1—C2—C7 | 119.05 (12) | C6—C9—H9B | 109.5 |
C3—C2—C7 | 122.93 (13) | H9A—C9—H9B | 109.5 |
O3—C3—C4 | 123.86 (13) | C6—C9—H9C | 109.5 |
O3—C3—C2 | 117.51 (13) | H9A—C9—H9C | 109.5 |
C4—C3—C2 | 118.64 (14) | H9B—C9—H9C | 109.5 |
C3—O3—H3 | 109.5 | O102—C10—O101 | 124.34 (14) |
C5—C4—C3 | 120.26 (14) | O102—C10—C11 | 118.87 (13) |
C5—C4—H4 | 119.9 | O101—C10—C11 | 116.79 (13) |
C3—C4—H4 | 119.9 | C11i—C11—C10 | 114.49 (16) |
C4—C5—C6 | 120.86 (14) | C11i—C11—H11A | 108.6 |
C4—C5—H5 | 119.6 | C10—C11—H11A | 108.6 |
C6—C5—H5 | 119.6 | C11i—C11—H11B | 108.6 |
N1—C6—C5 | 116.89 (15) | C10—C11—H11B | 108.6 |
N1—C6—C9 | 117.60 (16) | H11A—C11—H11B | 107.6 |
C5—C6—C9 | 125.51 (16) | O122—C12—O121 | 122.67 (16) |
C2—C7—C8 | 111.91 (13) | O122—C12—C13 | 124.44 (15) |
C2—C7—H7A | 109.2 | O121—C12—C13 | 112.87 (14) |
C8—C7—H7A | 109.2 | C12—O121—H121 | 109.5 |
C2—C7—H7B | 109.2 | C12—C13—C13ii | 113.19 (17) |
C8—C7—H7B | 109.2 | C12—C13—H13A | 108.9 |
H7A—C7—H7B | 107.9 | C13ii—C13—H13A | 108.9 |
C7—C8—H8A | 109.5 | C12—C13—H13B | 108.9 |
C7—C8—H8B | 109.5 | C13ii—C13—H13B | 108.9 |
H8A—C8—H8B | 109.5 | H13A—C13—H13B | 107.8 |
| | | |
C6—N1—C2—C3 | −2.3 (2) | C2—N1—C6—C9 | −179.50 (14) |
C6—N1—C2—C7 | 175.89 (13) | C4—C5—C6—N1 | 1.1 (2) |
N1—C2—C3—O3 | −177.50 (12) | C4—C5—C6—C9 | −179.01 (15) |
C7—C2—C3—O3 | 4.4 (2) | N1—C2—C7—C8 | −101.27 (16) |
N1—C2—C3—C4 | 2.68 (19) | C3—C2—C7—C8 | 76.84 (18) |
C7—C2—C3—C4 | −175.44 (13) | O102—C10—C11—C11i | 12.4 (3) |
O3—C3—C4—C5 | 178.88 (13) | O101—C10—C11—C11i | −167.5 (2) |
C2—C3—C4—C5 | −1.3 (2) | O122—C12—C13—C13ii | 0.3 (4) |
C3—C4—C5—C6 | −0.6 (2) | O121—C12—C13—C13ii | 178.8 (2) |
C2—N1—C6—C5 | 0.4 (2) | | |
Symmetry codes: (i) −x+1, −y, −z; (ii) −x+1, −y+1, −z. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O101iii | 0.86 | 1.91 | 2.7367 (16) | 161 |
O3—H3···O102iv | 0.82 | 1.74 | 2.5534 (15) | 176 |
O121—H121···O101iii | 0.82 | 1.78 | 2.6020 (18) | 180 |
C4—H4···O122iv | 0.93 | 2.46 | 3.1719 (19) | 134 |
Symmetry codes: (iii) x−1, y, z; (iv) −x+1, −y+1, −z+1. |
(II) 2-ethyl-6-methyl-3-hydroxypyridinium 3-carboxypropionate
top
Crystal data top
C8H12NO+·C4H5O4− | F(000) = 544 |
Mr = 255.27 | Dx = 1.288 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 6600 reflections |
a = 11.4951 (2) Å | θ = 2.4–29.9° |
b = 12.4787 (2) Å | µ = 0.10 mm−1 |
c = 9.1986 (1) Å | T = 296 K |
β = 93.886 (1)° | Prism, colourless |
V = 1316.45 (3) Å3 | 0.50 × 0.15 × 0.15 mm |
Z = 4 | |
Data collection top
Bruker APEXII CCD area-detector diffractometer | 2733 independent reflections |
Radiation source: fine-focus sealed tube | 2226 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.020 |
ϕ and ω scans | θmax = 26.5°, θmin = 1.8° |
Absorption correction: multi-scan (SADABS; Bruker, 2008) | h = −14→14 |
Tmin = 0.952, Tmax = 0.985 | k = −15→13 |
12765 measured reflections | l = −11→9 |
Refinement top
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)] = 0.047 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.141 | H-atom parameters constrained |
S = 1.03 | w = 1/[σ2(Fo2) + (0.0728P)2 + 0.4496P] where P = (Fo2 + 2Fc2)/3 |
2733 reflections | (Δ/σ)max = 0.001 |
167 parameters | Δρmax = 0.28 e Å−3 |
0 restraints | Δρmin = −0.24 e Å−3 |
Crystal data top
C8H12NO+·C4H5O4− | V = 1316.45 (3) Å3 |
Mr = 255.27 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 11.4951 (2) Å | µ = 0.10 mm−1 |
b = 12.4787 (2) Å | T = 296 K |
c = 9.1986 (1) Å | 0.50 × 0.15 × 0.15 mm |
β = 93.886 (1)° | |
Data collection top
Bruker APEXII CCD area-detector diffractometer | 2733 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2008) | 2226 reflections with I > 2σ(I) |
Tmin = 0.952, Tmax = 0.985 | Rint = 0.020 |
12765 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.047 | 0 restraints |
wR(F2) = 0.141 | H-atom parameters constrained |
S = 1.03 | Δρmax = 0.28 e Å−3 |
2733 reflections | Δρmin = −0.24 e Å−3 |
167 parameters | |
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 | x | y | z | Uiso*/Ueq | |
N1 | 0.66493 (11) | 0.06511 (11) | 0.66318 (14) | 0.0410 (3) | |
H1 | 0.7368 | 0.0479 | 0.6824 | 0.049* | |
C2 | 0.64131 (13) | 0.13587 (13) | 0.55524 (17) | 0.0412 (4) | |
C3 | 0.52507 (13) | 0.16437 (13) | 0.52291 (17) | 0.0390 (4) | |
O3 | 0.50401 (10) | 0.23467 (11) | 0.41467 (14) | 0.0547 (4) | |
H3 | 0.4343 | 0.2490 | 0.4071 | 0.082* | |
C4 | 0.44045 (13) | 0.11887 (13) | 0.60292 (18) | 0.0410 (4) | |
H4 | 0.3626 | 0.1371 | 0.5829 | 0.049* | |
C5 | 0.47068 (14) | 0.04696 (13) | 0.71169 (18) | 0.0427 (4) | |
H5 | 0.4129 | 0.0167 | 0.7646 | 0.051* | |
C6 | 0.58527 (14) | 0.01897 (13) | 0.74378 (17) | 0.0406 (4) | |
C7 | 0.73940 (15) | 0.18238 (18) | 0.4772 (2) | 0.0606 (5) | |
H7A | 0.7141 | 0.1925 | 0.3753 | 0.073* | |
H7B | 0.8040 | 0.1322 | 0.4820 | 0.073* | |
C8 | 0.7806 (2) | 0.2884 (2) | 0.5412 (3) | 0.0891 (8) | |
H8A | 0.7151 | 0.3353 | 0.5484 | 0.134* | |
H8B | 0.8350 | 0.3204 | 0.4794 | 0.134* | |
H8C | 0.8180 | 0.2769 | 0.6364 | 0.134* | |
C9 | 0.62727 (18) | −0.05805 (16) | 0.8593 (2) | 0.0579 (5) | |
H9A | 0.6535 | −0.1225 | 0.8149 | 0.087* | |
H9B | 0.5648 | −0.0747 | 0.9197 | 0.087* | |
H9C | 0.6907 | −0.0266 | 0.9178 | 0.087* | |
C10 | 1.20083 (12) | 0.24473 (13) | 0.86375 (18) | 0.0408 (4) | |
O101 | 1.29504 (9) | 0.19678 (9) | 0.86634 (14) | 0.0484 (3) | |
O102 | 1.19101 (10) | 0.34224 (9) | 0.89723 (16) | 0.0571 (4) | |
C11 | 1.09050 (15) | 0.18459 (15) | 0.8192 (3) | 0.0726 (7) | |
H11A | 1.0433 | 0.1813 | 0.9025 | 0.087* | |
H11B | 1.0473 | 0.2257 | 0.7441 | 0.087* | |
C12 | 1.10454 (14) | 0.07488 (15) | 0.7645 (3) | 0.0611 (6) | |
H12A | 1.1486 | 0.0333 | 0.8384 | 0.073* | |
H12B | 1.1495 | 0.0775 | 0.6791 | 0.073* | |
C13 | 0.99071 (13) | 0.01871 (13) | 0.7251 (2) | 0.0485 (4) | |
O131 | 1.00185 (11) | −0.07147 (11) | 0.6597 (2) | 0.0748 (5) | |
H131 | 0.9373 | −0.0978 | 0.6406 | 0.112* | |
O132 | 0.89791 (10) | 0.05696 (11) | 0.75272 (18) | 0.0654 (4) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
N1 | 0.0271 (6) | 0.0491 (8) | 0.0461 (7) | 0.0078 (5) | −0.0034 (5) | −0.0010 (6) |
C2 | 0.0306 (7) | 0.0498 (9) | 0.0429 (8) | 0.0057 (6) | 0.0018 (6) | −0.0011 (7) |
C3 | 0.0324 (7) | 0.0415 (8) | 0.0424 (8) | 0.0059 (6) | −0.0020 (6) | −0.0016 (7) |
O3 | 0.0357 (6) | 0.0660 (8) | 0.0620 (8) | 0.0104 (6) | −0.0005 (5) | 0.0189 (6) |
C4 | 0.0266 (7) | 0.0449 (9) | 0.0513 (9) | 0.0049 (6) | −0.0002 (6) | −0.0050 (7) |
C5 | 0.0347 (8) | 0.0438 (9) | 0.0500 (9) | −0.0011 (6) | 0.0051 (6) | −0.0025 (7) |
C6 | 0.0391 (8) | 0.0406 (8) | 0.0417 (8) | 0.0027 (6) | 0.0003 (6) | −0.0036 (7) |
C7 | 0.0357 (9) | 0.0881 (15) | 0.0589 (11) | 0.0082 (9) | 0.0108 (8) | 0.0149 (10) |
C8 | 0.0697 (15) | 0.0845 (17) | 0.116 (2) | −0.0226 (13) | 0.0268 (14) | 0.0199 (16) |
C9 | 0.0583 (11) | 0.0596 (12) | 0.0551 (11) | 0.0089 (9) | −0.0028 (8) | 0.0100 (9) |
C10 | 0.0281 (7) | 0.0372 (8) | 0.0561 (9) | −0.0002 (6) | −0.0044 (6) | 0.0032 (7) |
O101 | 0.0278 (5) | 0.0432 (7) | 0.0730 (8) | 0.0021 (5) | −0.0065 (5) | −0.0072 (6) |
O102 | 0.0361 (6) | 0.0358 (6) | 0.0968 (10) | 0.0031 (5) | −0.0136 (6) | −0.0049 (6) |
C11 | 0.0297 (9) | 0.0487 (11) | 0.137 (2) | −0.0018 (8) | −0.0076 (10) | −0.0228 (12) |
C12 | 0.0287 (8) | 0.0462 (10) | 0.1072 (17) | −0.0027 (7) | −0.0049 (9) | −0.0119 (10) |
C13 | 0.0284 (8) | 0.0381 (9) | 0.0775 (12) | −0.0003 (6) | −0.0071 (7) | 0.0001 (8) |
O131 | 0.0349 (7) | 0.0441 (8) | 0.1447 (15) | −0.0047 (5) | 0.0001 (8) | −0.0253 (8) |
O132 | 0.0279 (6) | 0.0638 (9) | 0.1031 (11) | 0.0001 (5) | −0.0060 (6) | −0.0251 (8) |
Geometric parameters (Å, º) top
N1—C2 | 1.343 (2) | C8—H8B | 0.9600 |
N1—C6 | 1.346 (2) | C8—H8C | 0.9600 |
N1—H1 | 0.8600 | C9—H9A | 0.9600 |
C2—C3 | 1.395 (2) | C9—H9B | 0.9600 |
C2—C7 | 1.495 (2) | C9—H9C | 0.9600 |
C3—O3 | 1.337 (2) | C10—O101 | 1.2360 (18) |
C3—C4 | 1.381 (2) | C10—O102 | 1.262 (2) |
O3—H3 | 0.8200 | C10—C11 | 1.506 (2) |
C4—C5 | 1.371 (2) | C11—C12 | 1.471 (3) |
C4—H4 | 0.9300 | C11—H11A | 0.9700 |
C5—C6 | 1.375 (2) | C11—H11B | 0.9700 |
C5—H5 | 0.9300 | C12—C13 | 1.507 (2) |
C6—C9 | 1.489 (2) | C12—H12A | 0.9700 |
C7—C8 | 1.512 (3) | C12—H12B | 0.9700 |
C7—H7A | 0.9700 | C13—O132 | 1.211 (2) |
C7—H7B | 0.9700 | C13—O131 | 1.287 (2) |
C8—H8A | 0.9600 | O131—H131 | 0.8200 |
| | | |
C2—N1—C6 | 125.29 (13) | C7—C8—H8C | 109.5 |
C2—N1—H1 | 117.4 | H8A—C8—H8C | 109.5 |
C6—N1—H1 | 117.4 | H8B—C8—H8C | 109.5 |
N1—C2—C3 | 117.90 (14) | C6—C9—H9A | 109.5 |
N1—C2—C7 | 119.30 (14) | C6—C9—H9B | 109.5 |
C3—C2—C7 | 122.79 (16) | H9A—C9—H9B | 109.5 |
O3—C3—C4 | 124.62 (13) | C6—C9—H9C | 109.5 |
O3—C3—C2 | 116.65 (14) | H9A—C9—H9C | 109.5 |
C4—C3—C2 | 118.73 (15) | H9B—C9—H9C | 109.5 |
C3—O3—H3 | 109.5 | O101—C10—O102 | 123.69 (14) |
C5—C4—C3 | 120.33 (14) | O101—C10—C11 | 118.97 (15) |
C5—C4—H4 | 119.8 | O102—C10—C11 | 117.33 (14) |
C3—C4—H4 | 119.8 | C12—C11—C10 | 116.54 (15) |
C4—C5—C6 | 120.97 (15) | C12—C11—H11A | 108.2 |
C4—C5—H5 | 119.5 | C10—C11—H11A | 108.2 |
C6—C5—H5 | 119.5 | C12—C11—H11B | 108.2 |
N1—C6—C5 | 116.78 (15) | C10—C11—H11B | 108.2 |
N1—C6—C9 | 118.00 (14) | H11A—C11—H11B | 107.3 |
C5—C6—C9 | 125.22 (16) | C11—C12—C13 | 113.68 (15) |
C2—C7—C8 | 112.30 (17) | C11—C12—H12A | 108.8 |
C2—C7—H7A | 109.1 | C13—C12—H12A | 108.8 |
C8—C7—H7A | 109.1 | C11—C12—H12B | 108.8 |
C2—C7—H7B | 109.1 | C13—C12—H12B | 108.8 |
C8—C7—H7B | 109.1 | H12A—C12—H12B | 107.7 |
H7A—C7—H7B | 107.9 | O132—C13—O131 | 124.03 (15) |
C7—C8—H8A | 109.5 | O132—C13—C12 | 121.94 (16) |
C7—C8—H8B | 109.5 | O131—C13—C12 | 114.02 (15) |
H8A—C8—H8B | 109.5 | C13—O131—H131 | 109.5 |
| | | |
C6—N1—C2—C3 | −0.1 (2) | C2—N1—C6—C9 | 179.95 (16) |
C6—N1—C2—C7 | 178.66 (16) | C4—C5—C6—N1 | −0.3 (2) |
N1—C2—C3—O3 | −179.78 (14) | C4—C5—C6—C9 | 180.00 (16) |
C7—C2—C3—O3 | 1.5 (3) | N1—C2—C7—C8 | −94.2 (2) |
N1—C2—C3—C4 | 0.1 (2) | C3—C2—C7—C8 | 84.5 (2) |
C7—C2—C3—C4 | −178.65 (16) | O101—C10—C11—C12 | −7.1 (3) |
O3—C3—C4—C5 | 179.69 (16) | O102—C10—C11—C12 | 173.2 (2) |
C2—C3—C4—C5 | −0.1 (2) | C10—C11—C12—C13 | 178.72 (19) |
C3—C4—C5—C6 | 0.2 (2) | C11—C12—C13—O132 | −8.1 (3) |
C2—N1—C6—C5 | 0.2 (2) | C11—C12—C13—O131 | 171.4 (2) |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O132 | 0.86 | 1.92 | 2.7499 (17) | 161 |
O3—H3···O101i | 0.82 | 1.75 | 2.5603 (15) | 167 |
O131—H131···O102ii | 0.82 | 1.67 | 2.4882 (16) | 177 |
C4—H4···O102i | 0.93 | 2.53 | 3.3617 (19) | 149 |
Symmetry codes: (i) x−1, −y+1/2, z−1/2; (ii) −x+2, y−1/2, −z+3/2. |
Experimental details
| (I) | (II) |
Crystal data |
Chemical formula | C8H12NO+·0.5C4H4O42−·0.5C4H6O4 | C8H12NO+·C4H5O4− |
Mr | 255.27 | 255.27 |
Crystal system, space group | Triclinic, P1 | Monoclinic, P21/c |
Temperature (K) | 296 | 296 |
a, b, c (Å) | 7.3047 (6), 8.4660 (7), 11.7559 (10) | 11.4951 (2), 12.4787 (2), 9.1986 (1) |
α, β, γ (°) | 95.747 (1), 103.926 (1), 107.716 (1) | 90, 93.886 (1), 90 |
V (Å3) | 660.25 (10) | 1316.45 (3) |
Z | 2 | 4 |
Radiation type | Mo Kα | Mo Kα |
µ (mm−1) | 0.10 | 0.10 |
Crystal size (mm) | 0.40 × 0.20 × 0.15 | 0.50 × 0.15 × 0.15 |
|
Data collection |
Diffractometer | Bruker APEXII CCD area-detector diffractometer | Bruker APEXII CCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Bruker, 2008) | Multi-scan (SADABS; Bruker, 2008) |
Tmin, Tmax | 0.961, 0.985 | 0.952, 0.985 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 6220, 2717, 2189 | 12765, 2733, 2226 |
Rint | 0.014 | 0.020 |
(sin θ/λ)max (Å−1) | 0.628 | 0.628 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.045, 0.128, 1.03 | 0.047, 0.141, 1.03 |
No. of reflections | 2717 | 2733 |
No. of parameters | 167 | 167 |
H-atom treatment | H-atom parameters constrained | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.28, −0.24 | 0.28, −0.24 |
Selected bond lengths (Å) for (I) topN1—C2 | 1.3431 (19) | C7—C8 | 1.521 (2) |
N1—C6 | 1.350 (2) | C10—O102 | 1.2327 (19) |
N1—H1 | 0.8600 | C10—O101 | 1.2587 (18) |
C2—C3 | 1.3948 (19) | C10—C11 | 1.5142 (19) |
C2—C7 | 1.493 (2) | C11—C11i | 1.507 (3) |
C3—O3 | 1.3413 (19) | C12—O122 | 1.196 (2) |
C3—C4 | 1.391 (2) | C12—O121 | 1.305 (2) |
C4—C5 | 1.374 (2) | C12—C13 | 1.497 (2) |
C5—C6 | 1.377 (2) | C13—C13ii | 1.511 (3) |
C6—C9 | 1.488 (3) | | |
Symmetry codes: (i) −x+1, −y, −z; (ii) −x+1, −y+1, −z. |
Hydrogen-bond geometry (Å, º) for (I) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O101iii | 0.86 | 1.91 | 2.7367 (16) | 161 |
O3—H3···O102iv | 0.82 | 1.74 | 2.5534 (15) | 176 |
O121—H121···O101iii | 0.82 | 1.78 | 2.6020 (18) | 180 |
C4—H4···O122iv | 0.93 | 2.46 | 3.1719 (19) | 134 |
Symmetry codes: (iii) x−1, y, z; (iv) −x+1, −y+1, −z+1. |
Selected bond lengths (Å) for (II) topN1—C2 | 1.343 (2) | C7—C8 | 1.512 (3) |
N1—C6 | 1.346 (2) | C10—O101 | 1.2360 (18) |
C2—C3 | 1.395 (2) | C10—O102 | 1.262 (2) |
C2—C7 | 1.495 (2) | C10—C11 | 1.506 (2) |
C3—O3 | 1.337 (2) | C11—C12 | 1.471 (3) |
C3—C4 | 1.381 (2) | C12—C13 | 1.507 (2) |
C4—C5 | 1.371 (2) | C13—O132 | 1.211 (2) |
C5—C6 | 1.375 (2) | C13—O131 | 1.287 (2) |
C6—C9 | 1.489 (2) | | |
Hydrogen-bond geometry (Å, º) for (II) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O132 | 0.86 | 1.92 | 2.7499 (17) | 161 |
O3—H3···O101i | 0.82 | 1.75 | 2.5603 (15) | 167 |
O131—H131···O102ii | 0.82 | 1.67 | 2.4882 (16) | 177 |
C4—H4···O102i | 0.93 | 2.53 | 3.3617 (19) | 149 |
Symmetry codes: (i) x−1, −y+1/2, z−1/2; (ii) −x+2, y−1/2, −z+3/2. |
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A succinic acid derivative of 2-ethyl-6-methylpyridin-3-ol is used as a nootropic drug in medical practice (Voronina, 1992, and references therein). It is also known for its antioxidant (Klebanov et al., 2001), antihypoxant (Luk'yanova et al., 1990), cardioprotective (Golikov et al., 2004; Sidorenko et al., 2011) and antistressor (Tilekeyeva & Sitina, 2005; Sariev & Kravtsova, 2005) effects. As no crystal data are available for any succinic acid derivatives of 2-ethyl-6-methylpyridin-3-ol [Cambridge Structural Database (CSD), Version 5.32, November 2010; Allen, 2002], in the present work we intended to obtain structural information.
Our preliminary investigation, carried out by X-ray powder diffraction, revealed that the reaction of 2-ethyl-6-methylpyridin-3-ol with succinic acid (1:1 molar ratio) could give either one crystalline compound or its mixture with another one (the ratio of these products depends on the reaction conditions). The aim of the present work was to obtain pure crystalline samples of the compounds and investigate their crystal structures using single-crystal X-ray diffraction.
One of the above-mentioned crystalline compounds, bis(2-ethyl-3-hydroxy-6-methylpyridinium) succinate–succinic acid (1/1), (I) (Fig. 1), was obtained directly as a result of the reaction of 2-ethyl-6-methylpyridin-3-ol with succinic acid. A pure sample of another compound, 2-ethyl-3-hydroxy-6-methylpyridinium hydrogen succinate, (II) (Fig. 2), can be prepared by transformation of (I) (see Experimental).
The asymmetric unit of (I) comprises one 2-ethyl-6-methyl-3-hydroxypyridinium cation, half a succinate anion (fully deprotonated) and half a succinic acid molecule. All atoms occupy general positions. The succinate anion and succinic acid molecule are located about centres of inversion, imposing Ci symmetry on both moieties. However, their non-H-atom skeletons show almost planar configurations corresponding to noncrystallographic symmetry C2h, with r.m.s. deviations from planarity of 0.0056 Å for the succinic acid molecule and 0.0612 Å for the succinate anion (Pilati & Forni, 1998).
In (I), the bond lengths and valence angles are in the expected ranges for all moieties of the compound (Table 1) [Standard reference?]. In the carboxyl group of the succinic acid molecule, the C12—O121(H) bond length of 1.304 (2) Å is longer than the carbonyl group C12—O122 bond length of 1.196 (2) Å. The C10—O101 and C10—O102 bond lengths of the carboxylate groups of the succinate anion are close to each other, being 1.2587 (18) and 1.2327 (19) Å, respectively.
There are hydrogen bonds in the crystal structure of (I) (Table 2 and Fig. 3). Intermolecular O—H···O hydrogen bonds between the succinic acid molecules and the succinate anions connect the components into polymeric chains extending along the [210] direction. Each 2-ethyl-6-methyl-3-hydroxypyridinium cation is bonded to three such polymeric chains through three hydrogen bonds, namely N—H···O, O—H···O and C—H···O, forming a three-dimensional polymeric network. There are additional π–π interactions between the pyridine rings, with centroid–centroid (Cg···Cg) distances of about 3.58 Å [Cg···Cgi; symmetry code: (i) -x, -y + 1, -z + 1] and of about 3.74 Å [Cg···Cgii; symmetry code: (ii) -x + 1, -y + 1, -z + 1]. These π–π interactions result in the formation of a rod-like cationic arrangement extending along the a axis (Fig. 3).
The asymmetric unit of (II) includes one 2-ethyl-6-methyl-3-hydroxypyridinium cation and one hydrogen succinate anion having only one deprotonated carboxyl group. All atoms lie on general positions. The non-H-atom skeleton of the hydrogen succinate anion is almost planar, with a mean deviation of the atoms from the least-squares plane of 0.0076 (12) Å. Bond lengths in the 2-ethyl-6-methyl-3-hydroxypyridinium cation and hydrogen succinate anion are similar to the corresponding values in (I) (Table 3).
Hydrogen bonds in the crystal structure of (II) (Table 4 and Fig. 4) are similar to those in (I), including intermolecular O—H···O, N—H···O and C—H···O hydrogen bonds. However, the supramolecular structure is somewhat different from that of (I). O—H···O hydrogen bonds between the succinate anions form infinite chains running along the b axis. Each 2-ethyl-6-methyl-3-hydroxypyridinium cation is connected to two anionic chains, to one via O—H···O and C—H···O hydrogen bonds and to another through N—H···O hydrogen bonds, forming a two-dimensional network parallel to the (102) plane. There are also π–π interactions between the pyridine rings, with centroid–centroid distances of about 3.52 Å [Cg···Cgiii; symmetry code: (iii) -x + 1, -y, -z + 1]. These are responsible for the formation of cationic dimers, shown in Fig. 5. The crystal packing of (II) is shown in Fig. 6.