organic compounds
of a second triclinic polymorph of 2-methylpyridinium picrate
aPG and Research Department of Chemistry, Seethalakshmi Ramaswami College, Tiruchirappalli 620 002, Tamil Nadu, India
*Correspondence e-mail: kalaivbalaj@yahoo.co.in
The title molecular salt, C6H8N+·C6H2N3O7− (systematic name: 2-methylpyridinium 2,4,6-trinitrophenolate), crystallizes with two cations and two anions in the In the crystal, the cations are linked to the anions via bifurcated N—H⋯(O,O) hydrogen bonds, generating R12(6) graph-set motifs. Numerous C—H⋯O hydrogen bonds are observed between these cation–anion pairs, which result in a three-dimensional network. In addition, weak aromatic π–π stacking between the 2-methylpyridinium rings [inter-centroid distance = 3.8334 (19) Å] and very weak stacking [inter-centroid distance = 4.0281 (16) Å] between inversion-related pairs of picrate anions is observed. The title salt is a second triclinic polymorph of the structure (also with Z′ = 2) reported earlier [Anita et al. (2006). Acta Cryst. C62, o567–o570; Chan et al. (2014). CrystEngComm, 16, 4508–4538]. In the title compound, the cations and anions display a chequerboard arrangement when viewed down [100], whereas in the first polymorph, (010) layers of alternating cations and anions are apparent in a [100] view. It is interesting that the unit-cell lengths are almost identical for the two polymorphs, although the inter-axial angles are quite different.
Keywords: crystal structure; polymorphism; 2-methylpyridinium picrate; 3-methylpyridinium picrate; 2,4,6-trinitrophenolate.
CCDC reference: 1417625
1. Related literature
For the first triclinic polymorph of 2-methylpyridinium picrate, see: Anitha et al. (2006); Chan et al. (2014). For the of the isomeric 3-methylpyridinium picrate, see: Gomathi & Kalaivani (2015).
2. Experimental
2.1. Crystal data
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2.3. Refinement
|
Data collection: APEX2 (Bruker, 2004); cell SAINT (Bruker, 2004); data reduction: SAINT; program(s) used to solve structure: SIR92 (Altomare et al., 1993); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL2014.
Supporting information
CCDC reference: 1417625
https://doi.org/10.1107/S205698901501912X/hb7512sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S205698901501912X/hb7512Isup2.hkl
Supporting information file. DOI: https://doi.org/10.1107/S205698901501912X/hb7512Isup3.cml
2-Chloro-1,3,5-trinitrobenzene [2.56 g (0.01 mol)] was dissolved in 30 ml of rectified spirit and mixed with hydantoin [1.00 g (0.01 mol)] in 20 ml of the same solvent. After mixing of these two solutions, 3 ml of 2-methylpyridine (0.03 mol) was added and the solution was heated to 318 K. The solution was stirred at this temperature with the help of magnetic stirrer for 5 h. The solution was cooled to room temperature and then filtered carefully. The clear maroon-red colour solution obtained was allowed to evaporate slowly maintaining the temperature at 293 K. After a period of six weeks, maroon-red coloured crystals formed from the solution. The crystals were filtered, powdered and washed with 30 ml of dry ether and recrystallized from rectified spirit. Instead of the expected carbon-bonded anionic sigma complex with hydantoin, crystals of 2-methylpyridinium picrate were obtained (yield: 70%; m.p.: 423 K).
Previous attempt in our laboratories to synthesize carbon-bonded anionic sigma complex with two heterocyclic moieties (substituted imidazole and pyridine) from the ethanolic solution containing 2-chloro-1,3,5-trinitrobenzene, hydantoin and 3-methylpyridine yielded 3-methylpyridinium picrate, a triclinic polymorph (Gomathi & Kalaivani, 2015). In the present work, a similar attempt with 2-methylpyridine instead of 3-methylpyridine in the reaction mixture, yielded 2-methylpyridinium picrate which crystallizes in the triclinic system with 1. Fig. 1 & 2 depict ORTEP and packing view of title molecular salt of present investigation respectively. Anita et al. (Anitha et al., 2006) have synthesized 2-methylpyridinium picrate by slow evaporation of the aqueous solution containing pyridoxine and picric acid in a 1:1 stoichiometric ratio at room temperature. They isolated instead of the expected picric acid complex with pyridoxine, crystals of 2-methylpyridinium picrate. Another group (Chan et al., 2014) has prepared 2-methylpyridinium picrate by adding picric acid to liquid 2-methylpyridine without other organic solvents. 2-Methylpyridinium picrate synthesized by both the groups also crystallize in the triclinic system with P1. The parameters of 2-methylpyridinium picrate of both the groups are nearly similar. However, 2-methypyridinium picrate reported in this article differs in the inter-axial bond angles noticeably. In addition to this observation, no disorder is observed in the title molecule, whereas, 2-methylpyridinium picrate reported by Anita et al. one of the oxygen atoms of the nitro group of picrate anion is disordered, with occupancy factors of 0.71 and 0.29. The dihedral angles between the planes of phenyl ring of picrate anions and that of 2-methylpyridinium cations of two molecules present in the are greater than 80 ° [dihedral angle between (i) planes constituting C1-C2-C3-C4-C5-C6 and N7-C13-C14-C15-C16-C17, 85.54 (11)°; (ii) C1-C2-C3-C4-C5-C6 and N8-C19-C20-C21-C22-C23, 87.60 (11)°; (iii) C7-C8-C9-C10-C11-C12 and N7-C13-C14-C15-C16-C17, 80.60 (11)°; (iv) C7-C8-C9-C10-C11-C12 and N8-C19-C20-C21-C22-C23, 82.49 (10)°], which unambigously reflects the absence of π-bonding between the aromatic rings of anion and cation and supports the fact that the main contributing factor of the formation of the product is proton-transfer reaction. Protonation of the nitrogen atom is further evidenced from the values of the C-N bond distances. N-H···O hydrogen bonding is noticed between the cation and anion parts of two molecules of and the bifurcation at N-H forming N-H···O hydrogen bonds with the oxygen atoms of phenolate and nitro group results in R12(6) ring motif and this sort of linkage is highly responsible for the stability of the molecule. Along with this ring motif, other ring motifs such as R22(7), R33(13) and R43(19) are also stabilizing the The nitro group involved in forming R12(6) ring motif bends only slightly from the plane of the aromatic ring to which it is attached [dihedral angles, 21.68 (16)° and 24.16 (12)°], whereas, the other nitro group lying on the other side of C-O- bond twists from the ring remarkably [dihedral angles, 79.94 (12)° and 53.29 (15)°]. This kind of twisting may probably reduce the strain due to overcrowding around C-O-. The plane of the nitro group para with respect to C-O- lies almost in the plane of the phenyl ring [dihedral angles, 5.02 (19)° and 3.08 (29)°].
PFor the first triclinic polymorph of 2-methylpyridinium picrate, see: Anitha et al. (2006); Chan et al. (2014). For the
of the isomeric 3-methylpyridinium picrate, see: Gomathi & Kalaivani (2015).Data collection: APEX2 (Bruker, 2004); cell
SAINT (Bruker, 2004); data reduction: SAINT (Bruker, 2004); program(s) used to solve structure: SIR92 (Altomare et al., 1993); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and Mercury (Macrae et al., 2008); software used to prepare material for publication: SHELXL2014 (Sheldrick, 2015).Fig. 1. ORTEP view of the title molecular salt with displacement ellipsoids drawn at 40% probability. | |
Fig. 2. A partial view of the crystal packing diagram of the title molecular salt (hydrogen bonds and π–π stacking are shown as dotted lines). |
C6H8N+·C6H2N3O7− | Z = 4 |
Mr = 322.24 | F(000) = 664 |
Triclinic, P1 | Dx = 1.572 Mg m−3 |
a = 8.1524 (4) Å | Mo Kα radiation, λ = 0.71073 Å |
b = 11.8809 (6) Å | Cell parameters from 6819 reflections |
c = 14.6377 (9) Å | θ = 2.5–25.5° |
α = 102.077 (3)° | µ = 0.13 mm−1 |
β = 90.001 (3)° | T = 296 K |
γ = 100.692 (3)° | Block, yellow |
V = 1361.21 (13) Å3 | 0.35 × 0.35 × 0.30 mm |
Bruker Kappa APEXII CCD diffractometer | 4789 independent reflections |
Radiation source: fine-focus sealed tube | 3165 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.034 |
ω and φ scan | θmax = 25.0°, θmin = 2.0° |
Absorption correction: multi-scan (SADABS; Bruker, 2004) | h = −9→9 |
Tmin = 0.952, Tmax = 0.969 | k = −14→14 |
25854 measured reflections | l = −17→17 |
Refinement on F2 | 0 restraints |
Least-squares matrix: full | Hydrogen site location: mixed |
R[F2 > 2σ(F2)] = 0.052 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.159 | w = 1/[σ2(Fo2) + (0.0576P)2 + 1.224P] where P = (Fo2 + 2Fc2)/3 |
S = 1.06 | (Δ/σ)max < 0.001 |
4789 reflections | Δρmax = 0.35 e Å−3 |
423 parameters | Δρmin = −0.27 e Å−3 |
C6H8N+·C6H2N3O7− | γ = 100.692 (3)° |
Mr = 322.24 | V = 1361.21 (13) Å3 |
Triclinic, P1 | Z = 4 |
a = 8.1524 (4) Å | Mo Kα radiation |
b = 11.8809 (6) Å | µ = 0.13 mm−1 |
c = 14.6377 (9) Å | T = 296 K |
α = 102.077 (3)° | 0.35 × 0.35 × 0.30 mm |
β = 90.001 (3)° |
Bruker Kappa APEXII CCD diffractometer | 4789 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2004) | 3165 reflections with I > 2σ(I) |
Tmin = 0.952, Tmax = 0.969 | Rint = 0.034 |
25854 measured reflections |
R[F2 > 2σ(F2)] = 0.052 | 0 restraints |
wR(F2) = 0.159 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.06 | Δρmax = 0.35 e Å−3 |
4789 reflections | Δρmin = −0.27 e Å−3 |
423 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
C1 | 0.2716 (3) | 0.1874 (2) | 0.86637 (19) | 0.0366 (6) | |
C2 | 0.2025 (3) | 0.2910 (2) | 0.8744 (2) | 0.0393 (7) | |
C3 | 0.2970 (3) | 0.4009 (2) | 0.8818 (2) | 0.0411 (7) | |
H3 | 0.2457 | 0.4657 | 0.8877 | 0.049* | |
C4 | 0.4672 (3) | 0.4148 (2) | 0.88062 (19) | 0.0369 (6) | |
C5 | 0.5471 (3) | 0.3206 (2) | 0.87618 (19) | 0.0359 (6) | |
H5 | 0.6630 | 0.3308 | 0.8777 | 0.043* | |
C6 | 0.4504 (3) | 0.2134 (2) | 0.86961 (19) | 0.0345 (6) | |
C7 | 0.6949 (3) | 0.3848 (2) | 0.64217 (19) | 0.0367 (6) | |
C8 | 0.5153 (3) | 0.3557 (2) | 0.62748 (19) | 0.0359 (6) | |
C9 | 0.4225 (3) | 0.2467 (2) | 0.61397 (19) | 0.0372 (6) | |
H9 | 0.3071 | 0.2346 | 0.6047 | 0.045* | |
C10 | 0.5014 (3) | 0.1533 (2) | 0.61406 (19) | 0.0361 (6) | |
C11 | 0.6715 (3) | 0.1706 (2) | 0.62624 (19) | 0.0382 (7) | |
H11 | 0.7239 | 0.1071 | 0.6248 | 0.046* | |
C12 | 0.7637 (3) | 0.2815 (2) | 0.64042 (19) | 0.0370 (6) | |
C13 | 1.1475 (4) | 0.6975 (3) | 0.6877 (2) | 0.0460 (7) | |
C14 | 1.2631 (4) | 0.7880 (3) | 0.7391 (3) | 0.0559 (9) | |
H14 | 1.3302 | 0.8401 | 0.7090 | 0.067* | |
C15 | 1.2802 (4) | 0.8019 (3) | 0.8328 (3) | 0.0592 (9) | |
H15 | 1.3584 | 0.8635 | 0.8667 | 0.071* | |
C16 | 1.1837 (4) | 0.7263 (3) | 0.8779 (3) | 0.0572 (9) | |
H16 | 1.1961 | 0.7346 | 0.9422 | 0.069* | |
C17 | 1.0688 (4) | 0.6385 (3) | 0.8267 (3) | 0.0535 (8) | |
H17 | 1.0012 | 0.5860 | 0.8562 | 0.064* | |
C18 | 1.1222 (5) | 0.6719 (4) | 0.5849 (3) | 0.0747 (11) | |
H18A | 1.1979 | 0.7286 | 0.5597 | 0.112* | |
H18B | 1.1430 | 0.5948 | 0.5592 | 0.112* | |
H18C | 1.0093 | 0.6755 | 0.5691 | 0.112* | |
C19 | −0.1835 (3) | −0.1337 (2) | 0.8099 (2) | 0.0412 (7) | |
C20 | −0.2865 (4) | −0.2209 (3) | 0.7485 (2) | 0.0524 (8) | |
H20 | −0.3591 | −0.2782 | 0.7708 | 0.063* | |
C21 | −0.2835 (4) | −0.2242 (3) | 0.6552 (3) | 0.0627 (10) | |
H21 | −0.3535 | −0.2839 | 0.6138 | 0.075* | |
C22 | −0.1775 (5) | −0.1400 (3) | 0.6221 (3) | 0.0640 (10) | |
H22 | −0.1753 | −0.1408 | 0.5584 | 0.077* | |
C23 | −0.0760 (4) | −0.0555 (3) | 0.6837 (3) | 0.0569 (9) | |
H23 | −0.0024 | 0.0022 | 0.6623 | 0.068* | |
C24 | −0.1811 (5) | −0.1215 (3) | 0.9123 (2) | 0.0641 (9) | |
H24A | −0.2608 | −0.1842 | 0.9281 | 0.096* | |
H24B | −0.0715 | −0.1247 | 0.9343 | 0.096* | |
H24C | −0.2096 | −0.0477 | 0.9412 | 0.096* | |
N1 | 0.0244 (3) | 0.2838 (3) | 0.8789 (2) | 0.0583 (8) | |
N2 | 0.5652 (3) | 0.5307 (2) | 0.88834 (18) | 0.0459 (6) | |
N3 | 0.5319 (3) | 0.1137 (2) | 0.86915 (19) | 0.0420 (6) | |
N4 | 0.9426 (3) | 0.2915 (2) | 0.6504 (2) | 0.0513 (7) | |
N5 | 0.4056 (3) | 0.0360 (2) | 0.59800 (18) | 0.0463 (6) | |
N6 | 0.4285 (3) | 0.4513 (2) | 0.6237 (2) | 0.0485 (7) | |
N7 | 1.0518 (3) | 0.6267 (2) | 0.7348 (2) | 0.0458 (6) | |
N8 | −0.0805 (3) | −0.0542 (2) | 0.7744 (2) | 0.0455 (6) | |
O1 | −0.0686 (3) | 0.1928 (2) | 0.8495 (3) | 0.1149 (13) | |
O2 | −0.0287 (3) | 0.3707 (2) | 0.9134 (3) | 0.0944 (10) | |
O3 | 0.7155 (3) | 0.5408 (2) | 0.8829 (2) | 0.0747 (8) | |
O4 | 0.4947 (3) | 0.61454 (18) | 0.90051 (17) | 0.0594 (6) | |
O5 | 0.5817 (4) | 0.1009 (3) | 0.9423 (2) | 0.0988 (11) | |
O6 | 0.5417 (4) | 0.0464 (2) | 0.79711 (19) | 0.0767 (8) | |
O7 | 0.1934 (2) | 0.08461 (17) | 0.86122 (15) | 0.0512 (6) | |
O8 | 1.0032 (3) | 0.2064 (2) | 0.6182 (2) | 0.0866 (9) | |
O9 | 1.0276 (3) | 0.3819 (2) | 0.6908 (2) | 0.0953 (10) | |
O10 | 0.4784 (3) | −0.04584 (18) | 0.59417 (15) | 0.0536 (6) | |
O11 | 0.2538 (3) | 0.0224 (2) | 0.5862 (2) | 0.0737 (8) | |
O12 | 0.3364 (4) | 0.4393 (3) | 0.5559 (2) | 0.0983 (11) | |
O13 | 0.4468 (3) | 0.5344 (2) | 0.6878 (2) | 0.0752 (8) | |
O14 | 0.7744 (2) | 0.48653 (17) | 0.64961 (16) | 0.0523 (6) | |
H7A | 0.970 (5) | 0.565 (3) | 0.700 (2) | 0.072 (11)* | |
H8A | −0.003 (5) | 0.005 (3) | 0.814 (3) | 0.085 (12)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0308 (14) | 0.0384 (16) | 0.0384 (16) | −0.0002 (12) | −0.0031 (11) | 0.0091 (13) |
C2 | 0.0229 (13) | 0.0440 (17) | 0.0499 (18) | 0.0025 (12) | −0.0006 (11) | 0.0104 (14) |
C3 | 0.0349 (15) | 0.0379 (16) | 0.0528 (19) | 0.0088 (12) | 0.0022 (13) | 0.0132 (14) |
C4 | 0.0305 (14) | 0.0343 (15) | 0.0437 (17) | −0.0009 (11) | 0.0022 (12) | 0.0098 (13) |
C5 | 0.0269 (13) | 0.0381 (15) | 0.0403 (16) | 0.0011 (11) | 0.0017 (11) | 0.0074 (12) |
C6 | 0.0314 (14) | 0.0352 (15) | 0.0366 (16) | 0.0059 (11) | −0.0018 (11) | 0.0071 (12) |
C7 | 0.0318 (14) | 0.0365 (16) | 0.0390 (16) | 0.0017 (12) | −0.0023 (11) | 0.0063 (13) |
C8 | 0.0317 (14) | 0.0326 (15) | 0.0423 (17) | 0.0067 (11) | −0.0019 (11) | 0.0052 (12) |
C9 | 0.0268 (13) | 0.0414 (16) | 0.0409 (17) | 0.0048 (12) | 0.0012 (11) | 0.0046 (13) |
C10 | 0.0329 (14) | 0.0318 (15) | 0.0411 (17) | 0.0019 (11) | 0.0042 (11) | 0.0057 (12) |
C11 | 0.0361 (15) | 0.0349 (15) | 0.0450 (17) | 0.0097 (12) | 0.0056 (12) | 0.0094 (13) |
C12 | 0.0274 (13) | 0.0402 (16) | 0.0428 (17) | 0.0048 (12) | −0.0006 (11) | 0.0086 (13) |
C13 | 0.0430 (16) | 0.0397 (17) | 0.060 (2) | 0.0148 (14) | 0.0040 (14) | 0.0156 (15) |
C14 | 0.0464 (18) | 0.0427 (18) | 0.079 (3) | −0.0026 (14) | 0.0071 (17) | 0.0229 (17) |
C15 | 0.053 (2) | 0.0429 (19) | 0.074 (3) | −0.0037 (15) | −0.0136 (17) | 0.0069 (17) |
C16 | 0.0511 (19) | 0.063 (2) | 0.057 (2) | 0.0121 (17) | −0.0037 (16) | 0.0115 (18) |
C17 | 0.0365 (16) | 0.056 (2) | 0.072 (3) | 0.0031 (14) | 0.0095 (15) | 0.0270 (18) |
C18 | 0.098 (3) | 0.076 (3) | 0.057 (2) | 0.035 (2) | 0.006 (2) | 0.014 (2) |
C19 | 0.0365 (15) | 0.0333 (15) | 0.0545 (19) | 0.0067 (12) | 0.0012 (13) | 0.0106 (14) |
C20 | 0.0489 (18) | 0.0364 (17) | 0.067 (2) | −0.0052 (14) | −0.0052 (16) | 0.0111 (16) |
C21 | 0.063 (2) | 0.048 (2) | 0.069 (3) | 0.0044 (17) | −0.0196 (18) | −0.0004 (18) |
C22 | 0.071 (2) | 0.074 (3) | 0.050 (2) | 0.022 (2) | −0.0042 (18) | 0.0120 (19) |
C23 | 0.0455 (18) | 0.062 (2) | 0.071 (3) | 0.0114 (16) | 0.0139 (17) | 0.0315 (19) |
C24 | 0.073 (2) | 0.063 (2) | 0.055 (2) | 0.0104 (18) | 0.0016 (17) | 0.0122 (18) |
N1 | 0.0306 (14) | 0.0527 (17) | 0.091 (2) | 0.0057 (13) | 0.0026 (13) | 0.0164 (16) |
N2 | 0.0393 (14) | 0.0389 (15) | 0.0577 (17) | −0.0015 (11) | 0.0034 (11) | 0.0140 (12) |
N3 | 0.0369 (13) | 0.0374 (14) | 0.0507 (17) | 0.0042 (10) | −0.0032 (11) | 0.0095 (13) |
N4 | 0.0319 (13) | 0.0450 (16) | 0.078 (2) | 0.0065 (12) | −0.0019 (12) | 0.0159 (14) |
N5 | 0.0416 (15) | 0.0393 (15) | 0.0535 (16) | −0.0004 (12) | 0.0106 (11) | 0.0073 (12) |
N6 | 0.0413 (14) | 0.0418 (15) | 0.0621 (18) | 0.0093 (11) | −0.0072 (13) | 0.0090 (14) |
N7 | 0.0325 (13) | 0.0381 (14) | 0.0644 (19) | 0.0009 (11) | −0.0052 (12) | 0.0107 (13) |
N8 | 0.0334 (13) | 0.0389 (14) | 0.0624 (19) | 0.0024 (11) | −0.0012 (12) | 0.0103 (13) |
O1 | 0.0293 (13) | 0.0564 (17) | 0.239 (4) | −0.0057 (12) | −0.0048 (17) | −0.003 (2) |
O2 | 0.0400 (14) | 0.0627 (17) | 0.181 (3) | 0.0171 (12) | 0.0187 (16) | 0.0202 (19) |
O3 | 0.0350 (13) | 0.0545 (15) | 0.131 (2) | −0.0054 (10) | 0.0125 (13) | 0.0251 (15) |
O4 | 0.0605 (14) | 0.0346 (12) | 0.0830 (17) | 0.0070 (10) | 0.0091 (12) | 0.0143 (11) |
O5 | 0.151 (3) | 0.096 (2) | 0.0671 (19) | 0.072 (2) | −0.0282 (18) | 0.0147 (16) |
O6 | 0.108 (2) | 0.0571 (16) | 0.0671 (18) | 0.0379 (15) | 0.0000 (15) | −0.0016 (14) |
O7 | 0.0380 (11) | 0.0385 (12) | 0.0740 (15) | −0.0062 (9) | −0.0104 (10) | 0.0170 (10) |
O8 | 0.0375 (13) | 0.0568 (16) | 0.165 (3) | 0.0165 (12) | 0.0103 (15) | 0.0163 (17) |
O9 | 0.0410 (14) | 0.0557 (16) | 0.176 (3) | 0.0013 (12) | −0.0321 (16) | 0.0013 (18) |
O10 | 0.0617 (14) | 0.0335 (12) | 0.0650 (15) | 0.0068 (10) | 0.0075 (11) | 0.0113 (10) |
O11 | 0.0383 (13) | 0.0528 (14) | 0.120 (2) | −0.0063 (10) | 0.0119 (13) | 0.0102 (14) |
O12 | 0.122 (2) | 0.091 (2) | 0.089 (2) | 0.0606 (19) | −0.0448 (19) | 0.0001 (16) |
O13 | 0.0726 (17) | 0.0431 (14) | 0.101 (2) | 0.0219 (12) | −0.0229 (14) | −0.0149 (14) |
O14 | 0.0399 (11) | 0.0373 (12) | 0.0764 (16) | −0.0041 (9) | −0.0136 (10) | 0.0151 (11) |
C1—O7 | 1.256 (3) | C17—N7 | 1.328 (4) |
C1—C2 | 1.429 (4) | C17—H17 | 0.9300 |
C1—C6 | 1.431 (4) | C18—H18A | 0.9600 |
C2—C3 | 1.371 (4) | C18—H18B | 0.9600 |
C2—N1 | 1.441 (3) | C18—H18C | 0.9600 |
C3—C4 | 1.367 (4) | C19—N8 | 1.334 (4) |
C3—H3 | 0.9300 | C19—C20 | 1.369 (4) |
C4—C5 | 1.385 (4) | C19—C24 | 1.475 (4) |
C4—N2 | 1.441 (3) | C20—C21 | 1.358 (5) |
C5—C6 | 1.353 (4) | C20—H20 | 0.9300 |
C5—H5 | 0.9300 | C21—C22 | 1.366 (5) |
C6—N3 | 1.459 (3) | C21—H21 | 0.9300 |
C7—O14 | 1.244 (3) | C22—C23 | 1.348 (5) |
C7—C12 | 1.437 (4) | C22—H22 | 0.9300 |
C7—C8 | 1.446 (4) | C23—N8 | 1.325 (4) |
C8—C9 | 1.348 (4) | C23—H23 | 0.9300 |
C8—N6 | 1.455 (4) | C24—H24A | 0.9600 |
C9—C10 | 1.382 (4) | C24—H24B | 0.9600 |
C9—H9 | 0.9300 | C24—H24C | 0.9600 |
C10—C11 | 1.370 (4) | N1—O1 | 1.196 (3) |
C10—N5 | 1.438 (3) | N1—O2 | 1.206 (3) |
C11—C12 | 1.365 (4) | N2—O3 | 1.213 (3) |
C11—H11 | 0.9300 | N2—O4 | 1.222 (3) |
C12—N4 | 1.446 (3) | N3—O5 | 1.193 (3) |
C13—N7 | 1.337 (4) | N3—O6 | 1.195 (3) |
C13—C14 | 1.377 (4) | N4—O9 | 1.200 (3) |
C13—C18 | 1.478 (5) | N4—O8 | 1.215 (3) |
C14—C15 | 1.351 (5) | N5—O10 | 1.222 (3) |
C14—H14 | 0.9300 | N5—O11 | 1.225 (3) |
C15—C16 | 1.358 (5) | N6—O13 | 1.198 (3) |
C15—H15 | 0.9300 | N6—O12 | 1.213 (3) |
C16—C17 | 1.356 (5) | N7—H7A | 0.95 (4) |
C16—H16 | 0.9300 | N8—H8A | 0.94 (4) |
O7—C1—C2 | 127.2 (2) | C13—C18—H18A | 109.5 |
O7—C1—C6 | 121.0 (3) | C13—C18—H18B | 109.5 |
C2—C1—C6 | 111.7 (2) | H18A—C18—H18B | 109.5 |
C3—C2—C1 | 123.7 (2) | C13—C18—H18C | 109.5 |
C3—C2—N1 | 116.3 (3) | H18A—C18—H18C | 109.5 |
C1—C2—N1 | 120.0 (2) | H18B—C18—H18C | 109.5 |
C4—C3—C2 | 119.5 (3) | N8—C19—C20 | 117.5 (3) |
C4—C3—H3 | 120.2 | N8—C19—C24 | 118.3 (3) |
C2—C3—H3 | 120.2 | C20—C19—C24 | 124.2 (3) |
C3—C4—C5 | 121.4 (2) | C21—C20—C19 | 120.5 (3) |
C3—C4—N2 | 119.0 (2) | C21—C20—H20 | 119.8 |
C5—C4—N2 | 119.5 (2) | C19—C20—H20 | 119.8 |
C6—C5—C4 | 117.6 (2) | C20—C21—C22 | 120.0 (3) |
C6—C5—H5 | 121.2 | C20—C21—H21 | 120.0 |
C4—C5—H5 | 121.2 | C22—C21—H21 | 120.0 |
C5—C6—C1 | 126.0 (3) | C23—C22—C21 | 118.6 (3) |
C5—C6—N3 | 118.6 (2) | C23—C22—H22 | 120.7 |
C1—C6—N3 | 115.4 (2) | C21—C22—H22 | 120.7 |
O14—C7—C12 | 126.6 (2) | N8—C23—C22 | 120.4 (3) |
O14—C7—C8 | 122.2 (2) | N8—C23—H23 | 119.8 |
C12—C7—C8 | 111.0 (2) | C22—C23—H23 | 119.8 |
C9—C8—C7 | 125.3 (2) | C19—C24—H24A | 109.5 |
C9—C8—N6 | 117.4 (2) | C19—C24—H24B | 109.5 |
C7—C8—N6 | 117.3 (2) | H24A—C24—H24B | 109.5 |
C8—C9—C10 | 119.0 (2) | C19—C24—H24C | 109.5 |
C8—C9—H9 | 120.5 | H24A—C24—H24C | 109.5 |
C10—C9—H9 | 120.5 | H24B—C24—H24C | 109.5 |
C11—C10—C9 | 120.7 (2) | O1—N1—O2 | 120.9 (3) |
C11—C10—N5 | 119.2 (2) | O1—N1—C2 | 120.3 (3) |
C9—C10—N5 | 120.1 (2) | O2—N1—C2 | 118.9 (3) |
C12—C11—C10 | 119.6 (3) | O3—N2—O4 | 122.7 (2) |
C12—C11—H11 | 120.2 | O3—N2—C4 | 118.2 (2) |
C10—C11—H11 | 120.2 | O4—N2—C4 | 119.1 (2) |
C11—C12—C7 | 124.4 (2) | O5—N3—O6 | 122.5 (3) |
C11—C12—N4 | 116.0 (2) | O5—N3—C6 | 117.9 (3) |
C7—C12—N4 | 119.6 (2) | O6—N3—C6 | 119.6 (3) |
N7—C13—C14 | 117.2 (3) | O9—N4—O8 | 121.5 (3) |
N7—C13—C18 | 117.6 (3) | O9—N4—C12 | 120.1 (3) |
C14—C13—C18 | 125.2 (3) | O8—N4—C12 | 118.4 (3) |
C15—C14—C13 | 120.7 (3) | O10—N5—O11 | 122.8 (2) |
C15—C14—H14 | 119.7 | O10—N5—C10 | 119.1 (2) |
C13—C14—H14 | 119.7 | O11—N5—C10 | 118.1 (2) |
C14—C15—C16 | 120.4 (3) | O13—N6—O12 | 123.8 (3) |
C14—C15—H15 | 119.8 | O13—N6—C8 | 119.2 (3) |
C16—C15—H15 | 119.8 | O12—N6—C8 | 116.9 (3) |
C17—C16—C15 | 118.3 (3) | C17—N7—C13 | 122.7 (3) |
C17—C16—H16 | 120.8 | C17—N7—H7A | 119 (2) |
C15—C16—H16 | 120.8 | C13—N7—H7A | 118 (2) |
N7—C17—C16 | 120.6 (3) | C23—N8—C19 | 123.0 (3) |
N7—C17—H17 | 119.7 | C23—N8—H8A | 116 (2) |
C16—C17—H17 | 119.7 | C19—N8—H8A | 121 (2) |
O7—C1—C2—C3 | 178.5 (3) | C15—C16—C17—N7 | 0.2 (5) |
C6—C1—C2—C3 | 1.6 (4) | N8—C19—C20—C21 | −0.7 (5) |
O7—C1—C2—N1 | 1.0 (5) | C24—C19—C20—C21 | 178.5 (3) |
C6—C1—C2—N1 | −175.8 (3) | C19—C20—C21—C22 | −0.2 (5) |
C1—C2—C3—C4 | 0.8 (5) | C20—C21—C22—C23 | 0.8 (5) |
N1—C2—C3—C4 | 178.3 (3) | C21—C22—C23—N8 | −0.5 (5) |
C2—C3—C4—C5 | −2.9 (4) | C3—C2—N1—O1 | 160.5 (4) |
C2—C3—C4—N2 | 179.9 (3) | C1—C2—N1—O1 | −21.9 (5) |
C3—C4—C5—C6 | 2.4 (4) | C3—C2—N1—O2 | −20.0 (5) |
N2—C4—C5—C6 | 179.6 (2) | C1—C2—N1—O2 | 157.6 (3) |
C4—C5—C6—C1 | 0.3 (4) | C3—C4—N2—O3 | −176.7 (3) |
C4—C5—C6—N3 | −177.2 (2) | C5—C4—N2—O3 | 6.0 (4) |
O7—C1—C6—C5 | −179.2 (3) | C3—C4—N2—O4 | 3.7 (4) |
C2—C1—C6—C5 | −2.1 (4) | C5—C4—N2—O4 | −173.6 (3) |
O7—C1—C6—N3 | −1.6 (4) | C5—C6—N3—O5 | 79.3 (4) |
C2—C1—C6—N3 | 175.5 (2) | C1—C6—N3—O5 | −98.5 (3) |
O14—C7—C8—C9 | 176.3 (3) | C5—C6—N3—O6 | −103.1 (3) |
C12—C7—C8—C9 | 0.1 (4) | C1—C6—N3—O6 | 79.1 (3) |
O14—C7—C8—N6 | −1.4 (4) | C11—C12—N4—O9 | −156.7 (3) |
C12—C7—C8—N6 | −177.6 (2) | C7—C12—N4—O9 | 25.7 (4) |
C7—C8—C9—C10 | 0.2 (4) | C11—C12—N4—O8 | 22.4 (4) |
N6—C8—C9—C10 | 177.9 (3) | C7—C12—N4—O8 | −155.2 (3) |
C8—C9—C10—C11 | −1.0 (4) | C11—C10—N5—O10 | −1.1 (4) |
C8—C9—C10—N5 | −178.8 (3) | C9—C10—N5—O10 | 176.7 (3) |
C9—C10—C11—C12 | 1.4 (4) | C11—C10—N5—O11 | −179.2 (3) |
N5—C10—C11—C12 | 179.2 (2) | C9—C10—N5—O11 | −1.4 (4) |
C10—C11—C12—C7 | −1.1 (4) | C9—C8—N6—O13 | 126.6 (3) |
C10—C11—C12—N4 | −178.6 (3) | C7—C8—N6—O13 | −55.5 (4) |
O14—C7—C12—C11 | −175.7 (3) | C9—C8—N6—O12 | −51.1 (4) |
C8—C7—C12—C11 | 0.3 (4) | C7—C8—N6—O12 | 126.8 (3) |
O14—C7—C12—N4 | 1.7 (4) | C16—C17—N7—C13 | 1.6 (5) |
C8—C7—C12—N4 | 177.8 (2) | C14—C13—N7—C17 | −2.4 (4) |
N7—C13—C14—C15 | 1.4 (5) | C18—C13—N7—C17 | 177.0 (3) |
C18—C13—C14—C15 | −177.9 (3) | C22—C23—N8—C19 | −0.4 (5) |
C13—C14—C15—C16 | 0.2 (5) | C20—C19—N8—C23 | 1.0 (4) |
C14—C15—C16—C17 | −1.1 (5) | C24—C19—N8—C23 | −178.2 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
N7—H7A···O9 | 0.95 (4) | 2.28 (4) | 2.813 (4) | 114 (3) |
N7—H7A···O14 | 0.95 (4) | 1.76 (4) | 2.678 (3) | 160 (3) |
N8—H8A···O1 | 0.94 (4) | 2.35 (4) | 2.894 (4) | 117 (3) |
N8—H8A···O7 | 0.94 (4) | 1.76 (4) | 2.660 (3) | 158 (4) |
C5—H5···O2i | 0.93 | 2.50 | 3.423 (4) | 170 |
C9—H9···O8ii | 0.93 | 2.45 | 3.365 (3) | 167 |
C14—H14···O10iii | 0.93 | 2.54 | 3.456 (4) | 167 |
C17—H17···O3 | 0.93 | 2.34 | 3.078 (4) | 136 |
C18—H18B···O12i | 0.96 | 2.64 | 3.488 (5) | 148 |
C20—H20···O13iv | 0.93 | 2.55 | 3.247 (4) | 132 |
C23—H23···O8ii | 0.93 | 2.63 | 3.394 (4) | 140 |
C23—H23···O11 | 0.93 | 2.36 | 3.122 (4) | 139 |
Symmetry codes: (i) x+1, y, z; (ii) x−1, y, z; (iii) x+1, y+1, z; (iv) x−1, y−1, z. |
D—H···A | D—H | H···A | D···A | D—H···A |
N7—H7A···O9 | 0.95 (4) | 2.28 (4) | 2.813 (4) | 114 (3) |
N7—H7A···O14 | 0.95 (4) | 1.76 (4) | 2.678 (3) | 160 (3) |
N8—H8A···O1 | 0.94 (4) | 2.35 (4) | 2.894 (4) | 117 (3) |
N8—H8A···O7 | 0.94 (4) | 1.76 (4) | 2.660 (3) | 158 (4) |
C5—H5···O2i | 0.93 | 2.50 | 3.423 (4) | 170 |
C9—H9···O8ii | 0.93 | 2.45 | 3.365 (3) | 167 |
C14—H14···O10iii | 0.93 | 2.54 | 3.456 (4) | 167 |
C17—H17···O3 | 0.93 | 2.34 | 3.078 (4) | 136 |
C18—H18B···O12i | 0.96 | 2.64 | 3.488 (5) | 148 |
C20—H20···O13iv | 0.93 | 2.55 | 3.247 (4) | 132 |
C23—H23···O8ii | 0.93 | 2.63 | 3.394 (4) | 140 |
C23—H23···O11 | 0.93 | 2.36 | 3.122 (4) | 139 |
Symmetry codes: (i) x+1, y, z; (ii) x−1, y, z; (iii) x+1, y+1, z; (iv) x−1, y−1, z. |
Acknowledgements
The authors are thankful to UGC, New Delhi, for financial support and the SAIF, IIT Madras, Chennai, for the data collection.
References
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Previous attempt in our laboratories to synthesize carbon-bonded anionic sigma complex with two heterocyclic moieties (substituted imidazole and pyridine) from the ethanolic solution containing 2-chloro-1,3,5-trinitrobenzene, hydantoin and 3-methylpyridine yielded 3-methylpyridinium picrate, a triclinic polymorph (Gomathi & Kalaivani, 2015). In the present work, a similar attempt with 2-methylpyridine instead of 3-methylpyridine in the reaction mixture, yielded 2-methylpyridinium picrate which crystallizes in the triclinic system with space group P1. Fig. 1 & 2 depict ORTEP and packing view of title molecular salt of present investigation respectively. Anita et al. (Anitha et al., 2006) have synthesized 2-methylpyridinium picrate by slow evaporation of the aqueous solution containing pyridoxine and picric acid in a 1:1 stoichiometric ratio at room temperature. They isolated instead of the expected picric acid complex with pyridoxine, crystals of 2-methylpyridinium picrate. Another group (Chan et al., 2014) has prepared 2-methylpyridinium picrate by adding picric acid to liquid 2-methylpyridine without other organic solvents. 2-Methylpyridinium picrate synthesized by both the groups also crystallize in the triclinic system with space group P1. The unit cell parameters of 2-methylpyridinium picrate of both the groups are nearly similar. However, 2-methypyridinium picrate reported in this article differs in the inter-axial bond angles noticeably. In addition to this observation, no disorder is observed in the title molecule, whereas, 2-methylpyridinium picrate reported by Anita et al. one of the oxygen atoms of the nitro group of picrate anion is disordered, with occupancy factors of 0.71 and 0.29. The dihedral angles between the planes of phenyl ring of picrate anions and that of 2-methylpyridinium cations of two molecules present in the asymmetric unit are greater than 80 ° [dihedral angle between (i) planes constituting C1-C2-C3-C4-C5-C6 and N7-C13-C14-C15-C16-C17, 85.54 (11)°; (ii) C1-C2-C3-C4-C5-C6 and N8-C19-C20-C21-C22-C23, 87.60 (11)°; (iii) C7-C8-C9-C10-C11-C12 and N7-C13-C14-C15-C16-C17, 80.60 (11)°; (iv) C7-C8-C9-C10-C11-C12 and N8-C19-C20-C21-C22-C23, 82.49 (10)°], which unambigously reflects the absence of π-bonding between the aromatic rings of anion and cation and supports the fact that the main contributing factor of the formation of the product is proton-transfer reaction. Protonation of the nitrogen atom is further evidenced from the values of the C-N bond distances. N-H···O hydrogen bonding is noticed between the cation and anion parts of two molecules of asymmetric unit and the bifurcation at N-H forming N-H···O hydrogen bonds with the oxygen atoms of phenolate and nitro group results in R12(6) ring motif and this sort of linkage is highly responsible for the stability of the molecule. Along with this ring motif, other ring motifs such as R22(7), R33(13) and R43(19) are also stabilizing the crystal system. The nitro group involved in forming R12(6) ring motif bends only slightly from the plane of the aromatic ring to which it is attached [dihedral angles, 21.68 (16)° and 24.16 (12)°], whereas, the other nitro group lying on the other side of C-O- bond twists from the ring remarkably [dihedral angles, 79.94 (12)° and 53.29 (15)°]. This kind of twisting may probably reduce the strain due to overcrowding around C-O-. The plane of the nitro group para with respect to C-O- lies almost in the plane of the phenyl ring [dihedral angles, 5.02 (19)° and 3.08 (29)°].