organic compounds
6-Amino-2-(pivaloylamino)pyridinium benzoate
aStructural Chemistry and Crystallography Group, University of Lodz, Pomorska 163/165, PL-90-236 Łódź, Poland, bFaculty of Technology and Chemical Engineering, University of Technology and Life Sciences, Seminaryjna 3, PL-85-326 Bydgoszcz, Poland, and cDepartment of Chemistry, University of Jyväskylä, PO Box 35, FI-40014 Jyväskylä, Finland
*Correspondence e-mail: lilach@uni.lodz.pl
In the 10H16N3O+·C7H5O2−, the cations and anions are linked to each other via N—H⋯O hydrogen bonds, forming infinite chains running along [010]. The also features C—H⋯O and π–π stacking interactions, which assemble the chains into supramolecular layers parallel to (100). The π–π stacking interactions are observed between the pyridine rings of inversion-related cations with a centroid–centroid distance of 3.867 (2) Å.
of the title salt, CRelated literature
For co-crystallization of pharmaceuticals, see: Vishweshwar et al. (2006); Lemmerer (2012). For the crystal structures of related compounds, see: Ośmiałowski et al. (2010b); Aakeröy et al. (2006, 2010). For the role of steric effects in hydrogen-bonded compounds, see Ośmiałowski et al. (2012a,b, 2010a,b). For the synthesis of 2-pivaloylamino-6-aminopyridine, see: Ośmiałowski et al. (2010a).
Experimental
Crystal data
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Data collection: COLLECT (Bruker, 2008); cell DENZO-SMN (Otwinowski & Minor, 1997); data reduction: DENZO-SMN; program(s) used to solve structure: SIR2004 (Burla et al., 2005); program(s) used to refine structure: SHELXL2013 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: SHELXL2013 and publCIF (Westrip, 2010).
Supporting information
10.1107/S1600536813023787/fy2103sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536813023787/fy2103Isup2.hkl
Supporting information file. DOI: 10.1107/S1600536813023787/fy2103Isup3.cml
For the synthesis of the title compound, equimolar ammounts of 2-pivaloylamino-6-aminopyridine and benzoic acid were mixed in methanol. The solution was left for a couple of days for slow evaporation and produced single crystals. The parent 2-pivaloylamino-6-aminopyridine was prepared according to a literature procedure (Ośmiałowski et al., 2010a).
All non-hydrogen atoms were refined anisotropically. H atoms bonded to N atoms were located in a difference map and refined with distance restraints of N1—H1 (and N7—H7) = 0.88 (2) Å, N6—H6A (and N6—H6B) = 0.91 (2) Å and with Uiso(H) = 1.2Ueq(N). Other H atoms were positioned geometrically and refined using a riding model with C—H = 0.95–0.98 Å and with Uiso(H) = 1.2 Ueq(C) or 1.5 Ueq(methyl C).
Data collection: COLLECT (Bruker, 2008); cell
DENZO-SMN (Otwinowski & Minor, 1997); data reduction: DENZO-SMN (Otwinowski & Minor, 1997); program(s) used to solve structure: SIR2004 (Burla et al., 2005); program(s) used to refine structure: SHELXL2013 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: SHELXL2013 (Sheldrick, 2008) and publCIF (Westrip, 2010).Fig. 1. The molecular structure of (I), with atom labels and 50% probability displacement ellipsoids for non-H atoms. | |
Fig. 2. A part of the crystal structure of (I), showing the intermolecular interactions as dashed lines [symmetry codes: (i) x,y + 1,z; (ii)-x + 1,y + 1/2,-z + 1/2; (iii)-x + 1,- y,-z + 1]. |
C10H16N3O+·C7H5O2− | F(000) = 672 |
Mr = 315.37 | Dx = 1.293 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
a = 15.1438 (4) Å | Cell parameters from 4257 reflections |
b = 5.7099 (2) Å | θ = 0.4–28.3° |
c = 18.7388 (6) Å | µ = 0.09 mm−1 |
β = 91.967 (2)° | T = 123 K |
V = 1619.38 (9) Å3 | Block, colourless |
Z = 4 | 0.13 × 0.10 × 0.08 mm |
Bruker–Nonius KappaCCD diffractometer with APEXII detector | 3724 independent reflections |
Radiation source: fine-focus sealed tube | 2054 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.094 |
Detector resolution: 9 pixels mm-1 | θmax = 27.5°, θmin = 2.5° |
ϕ and ω scans | h = −19→18 |
Absorption correction: multi-scan (SADABS; Sheldrick, 2004) | k = −7→7 |
Tmin = 0.988, Tmax = 0.993 | l = −24→20 |
10993 measured reflections |
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)] = 0.066 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.141 | H-atom parameters constrained |
S = 1.00 | w = 1/[σ2(Fo2) + (0.0496P)2] where P = (Fo2 + 2Fc2)/3 |
3724 reflections | (Δ/σ)max < 0.001 |
220 parameters | Δρmax = 0.24 e Å−3 |
4 restraints | Δρmin = −0.28 e Å−3 |
C10H16N3O+·C7H5O2− | V = 1619.38 (9) Å3 |
Mr = 315.37 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 15.1438 (4) Å | µ = 0.09 mm−1 |
b = 5.7099 (2) Å | T = 123 K |
c = 18.7388 (6) Å | 0.13 × 0.10 × 0.08 mm |
β = 91.967 (2)° |
Bruker–Nonius KappaCCD diffractometer with APEXII detector | 3724 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 2004) | 2054 reflections with I > 2σ(I) |
Tmin = 0.988, Tmax = 0.993 | Rint = 0.094 |
10993 measured reflections |
R[F2 > 2σ(F2)] = 0.066 | 4 restraints |
wR(F2) = 0.141 | H-atom parameters constrained |
S = 1.00 | Δρmax = 0.24 e Å−3 |
3724 reflections | Δρmin = −0.28 e Å−3 |
220 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 | ||
O8 | 0.69413 (12) | 0.1535 (3) | 0.54656 (10) | 0.0370 (5) | |
N1 | 0.57982 (12) | 0.6015 (4) | 0.39112 (11) | 0.0205 (5) | |
H1 | 0.6221 (14) | 0.710 (4) | 0.3842 (13) | 0.025* | |
N6 | 0.48943 (14) | 0.7758 (4) | 0.30603 (12) | 0.0278 (5) | |
H6A | 0.5311 (15) | 0.882 (4) | 0.2960 (14) | 0.033* | |
H6B | 0.4404 (14) | 0.774 (4) | 0.2764 (13) | 0.033* | |
N7 | 0.68521 (13) | 0.4637 (4) | 0.47095 (11) | 0.0231 (5) | |
H7 | 0.7141 (15) | 0.580 (4) | 0.4546 (13) | 0.028* | |
C2 | 0.60154 (15) | 0.4307 (4) | 0.43895 (13) | 0.0223 (6) | |
C3 | 0.54405 (15) | 0.2505 (4) | 0.45137 (14) | 0.0249 (6) | |
H3 | 0.5582 | 0.1307 | 0.4850 | 0.030* | |
C4 | 0.46378 (16) | 0.2513 (4) | 0.41222 (14) | 0.0261 (6) | |
H4 | 0.4225 | 0.1295 | 0.4200 | 0.031* | |
C5 | 0.44278 (15) | 0.4204 (4) | 0.36334 (13) | 0.0227 (6) | |
H5 | 0.3881 | 0.4149 | 0.3369 | 0.027* | |
C6 | 0.50276 (15) | 0.6023 (4) | 0.35252 (13) | 0.0209 (6) | |
C8 | 0.72715 (16) | 0.3289 (4) | 0.52242 (14) | 0.0234 (6) | |
C9 | 0.81731 (15) | 0.4228 (4) | 0.54969 (13) | 0.0219 (6) | |
C10 | 0.79992 (16) | 0.5515 (5) | 0.61949 (14) | 0.0293 (6) | |
H10A | 0.7718 | 0.4443 | 0.6526 | 0.044* | |
H10B | 0.7608 | 0.6852 | 0.6096 | 0.044* | |
H10C | 0.8560 | 0.6072 | 0.6409 | 0.044* | |
C11 | 0.87823 (17) | 0.2125 (4) | 0.56515 (16) | 0.0326 (7) | |
H11A | 0.8896 | 0.1308 | 0.5204 | 0.049* | |
H11B | 0.8497 | 0.1049 | 0.5980 | 0.049* | |
H11C | 0.9342 | 0.2675 | 0.5869 | 0.049* | |
C12 | 0.86140 (15) | 0.5877 (5) | 0.49737 (14) | 0.0263 (6) | |
H12A | 0.8723 | 0.5037 | 0.4529 | 0.040* | |
H12B | 0.9176 | 0.6436 | 0.5185 | 0.040* | |
H12C | 0.8225 | 0.7216 | 0.4871 | 0.040* | |
O13A | 0.71169 (10) | −0.1201 (3) | 0.37777 (10) | 0.0287 (5) | |
O13B | 0.64016 (11) | 0.0950 (3) | 0.29481 (10) | 0.0289 (5) | |
C13 | 0.70775 (15) | 0.0432 (4) | 0.33191 (13) | 0.0215 (6) | |
C14 | 0.79105 (15) | 0.1829 (4) | 0.32285 (13) | 0.0203 (6) | |
C15 | 0.87128 (15) | 0.0994 (4) | 0.35068 (13) | 0.0220 (6) | |
H15 | 0.8731 | −0.0436 | 0.3766 | 0.026* | |
C16 | 0.94848 (16) | 0.2232 (4) | 0.34092 (14) | 0.0255 (6) | |
H16 | 1.0031 | 0.1649 | 0.3600 | 0.031* | |
C17 | 0.94615 (16) | 0.4311 (4) | 0.30351 (14) | 0.0271 (6) | |
H17 | 0.9992 | 0.5155 | 0.2966 | 0.033* | |
C18 | 0.86638 (16) | 0.5174 (5) | 0.27596 (14) | 0.0279 (6) | |
H18 | 0.8647 | 0.6621 | 0.2509 | 0.033* | |
C19 | 0.78894 (16) | 0.3920 (4) | 0.28499 (13) | 0.0245 (6) | |
H19 | 0.7345 | 0.4494 | 0.2652 | 0.029* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O8 | 0.0319 (11) | 0.0331 (11) | 0.0450 (13) | −0.0155 (8) | −0.0117 (9) | 0.0167 (10) |
N1 | 0.0153 (11) | 0.0213 (11) | 0.0248 (12) | −0.0069 (8) | 0.0000 (8) | 0.0002 (9) |
N6 | 0.0206 (12) | 0.0284 (13) | 0.0339 (14) | −0.0070 (9) | −0.0076 (10) | 0.0059 (11) |
N7 | 0.0175 (11) | 0.0242 (12) | 0.0275 (13) | −0.0068 (9) | −0.0028 (9) | 0.0046 (10) |
C2 | 0.0197 (13) | 0.0264 (14) | 0.0208 (14) | −0.0036 (10) | 0.0006 (10) | −0.0012 (11) |
C3 | 0.0208 (13) | 0.0273 (15) | 0.0266 (15) | −0.0069 (10) | 0.0002 (11) | 0.0067 (11) |
C4 | 0.0202 (14) | 0.0284 (14) | 0.0297 (16) | −0.0106 (11) | 0.0016 (11) | −0.0020 (12) |
C5 | 0.0166 (12) | 0.0281 (14) | 0.0234 (14) | −0.0049 (10) | −0.0005 (10) | −0.0004 (11) |
C6 | 0.0165 (12) | 0.0254 (14) | 0.0210 (14) | −0.0004 (10) | 0.0029 (10) | −0.0029 (11) |
C8 | 0.0235 (13) | 0.0221 (14) | 0.0246 (15) | −0.0043 (11) | −0.0006 (11) | 0.0012 (11) |
C9 | 0.0172 (12) | 0.0227 (13) | 0.0255 (14) | −0.0018 (10) | −0.0039 (10) | −0.0019 (11) |
C10 | 0.0215 (13) | 0.0354 (16) | 0.0309 (15) | −0.0046 (11) | −0.0012 (11) | −0.0032 (13) |
C11 | 0.0264 (15) | 0.0257 (16) | 0.0449 (19) | 0.0005 (11) | −0.0076 (12) | 0.0017 (13) |
C12 | 0.0171 (13) | 0.0323 (15) | 0.0295 (15) | −0.0046 (11) | −0.0007 (10) | −0.0001 (12) |
O13A | 0.0198 (9) | 0.0276 (10) | 0.0384 (12) | −0.0058 (7) | −0.0032 (8) | 0.0102 (9) |
O13B | 0.0199 (9) | 0.0326 (11) | 0.0335 (11) | −0.0030 (7) | −0.0069 (8) | 0.0078 (9) |
C13 | 0.0201 (13) | 0.0225 (14) | 0.0220 (14) | −0.0029 (10) | 0.0016 (10) | −0.0010 (12) |
C14 | 0.0186 (13) | 0.0227 (14) | 0.0197 (14) | −0.0027 (10) | 0.0022 (10) | −0.0021 (11) |
C15 | 0.0214 (13) | 0.0219 (13) | 0.0227 (14) | −0.0017 (10) | 0.0019 (10) | 0.0010 (11) |
C16 | 0.0192 (13) | 0.0288 (15) | 0.0287 (15) | −0.0016 (10) | 0.0012 (10) | −0.0017 (12) |
C17 | 0.0251 (14) | 0.0302 (15) | 0.0264 (15) | −0.0118 (11) | 0.0062 (11) | −0.0010 (12) |
C18 | 0.0329 (15) | 0.0231 (14) | 0.0278 (15) | −0.0058 (11) | 0.0025 (12) | 0.0051 (12) |
C19 | 0.0264 (14) | 0.0230 (14) | 0.0242 (14) | −0.0012 (11) | −0.0008 (11) | 0.0010 (12) |
O8—C8 | 1.214 (3) | C10—H10B | 0.9800 |
N1—C6 | 1.352 (3) | C10—H10C | 0.9800 |
N1—C2 | 1.358 (3) | C11—H11A | 0.9800 |
N1—H1 | 0.905 (16) | C11—H11B | 0.9800 |
N6—C6 | 1.330 (3) | C11—H11C | 0.9800 |
N6—H6A | 0.899 (17) | C12—H12A | 0.9800 |
N6—H6B | 0.913 (16) | C12—H12B | 0.9800 |
N7—C8 | 1.373 (3) | C12—H12C | 0.9800 |
N7—C2 | 1.396 (3) | O13A—C13 | 1.268 (3) |
N7—H7 | 0.859 (17) | O13B—C13 | 1.253 (3) |
C2—C3 | 1.373 (3) | C13—C14 | 1.507 (3) |
C3—C4 | 1.398 (3) | C14—C19 | 1.389 (3) |
C3—H3 | 0.9500 | C14—C15 | 1.390 (3) |
C4—C5 | 1.361 (3) | C15—C16 | 1.384 (3) |
C4—H4 | 0.9500 | C15—H15 | 0.9500 |
C5—C6 | 1.400 (3) | C16—C17 | 1.379 (4) |
C5—H5 | 0.9500 | C16—H16 | 0.9500 |
C8—C9 | 1.538 (3) | C17—C18 | 1.388 (4) |
C9—C12 | 1.529 (3) | C17—H17 | 0.9500 |
C9—C10 | 1.531 (3) | C18—C19 | 1.389 (3) |
C9—C11 | 1.536 (3) | C18—H18 | 0.9500 |
C10—H10A | 0.9800 | C19—H19 | 0.9500 |
C6—N1—C2 | 122.7 (2) | C9—C10—H10C | 109.5 |
C6—N1—H1 | 121.5 (16) | H10A—C10—H10C | 109.5 |
C2—N1—H1 | 115.6 (16) | H10B—C10—H10C | 109.5 |
C6—N6—H6A | 123.2 (17) | C9—C11—H11A | 109.5 |
C6—N6—H6B | 119.4 (17) | C9—C11—H11B | 109.5 |
H6A—N6—H6B | 116 (2) | H11A—C11—H11B | 109.5 |
C8—N7—C2 | 128.1 (2) | C9—C11—H11C | 109.5 |
C8—N7—H7 | 117.2 (17) | H11A—C11—H11C | 109.5 |
C2—N7—H7 | 114.7 (17) | H11B—C11—H11C | 109.5 |
N1—C2—C3 | 120.7 (2) | C9—C12—H12A | 109.5 |
N1—C2—N7 | 112.5 (2) | C9—C12—H12B | 109.5 |
C3—C2—N7 | 126.9 (2) | H12A—C12—H12B | 109.5 |
C2—C3—C4 | 117.0 (2) | C9—C12—H12C | 109.5 |
C2—C3—H3 | 121.5 | H12A—C12—H12C | 109.5 |
C4—C3—H3 | 121.5 | H12B—C12—H12C | 109.5 |
C5—C4—C3 | 122.3 (2) | O13B—C13—O13A | 124.6 (2) |
C5—C4—H4 | 118.9 | O13B—C13—C14 | 118.9 (2) |
C3—C4—H4 | 118.9 | O13A—C13—C14 | 116.5 (2) |
C4—C5—C6 | 119.1 (2) | C19—C14—C15 | 119.4 (2) |
C4—C5—H5 | 120.4 | C19—C14—C13 | 120.5 (2) |
C6—C5—H5 | 120.4 | C15—C14—C13 | 120.0 (2) |
N6—C6—N1 | 117.5 (2) | C16—C15—C14 | 120.4 (2) |
N6—C6—C5 | 124.3 (2) | C16—C15—H15 | 119.8 |
N1—C6—C5 | 118.2 (2) | C14—C15—H15 | 119.8 |
O8—C8—N7 | 122.5 (2) | C17—C16—C15 | 120.0 (2) |
O8—C8—C9 | 122.4 (2) | C17—C16—H16 | 120.0 |
N7—C8—C9 | 115.0 (2) | C15—C16—H16 | 120.0 |
C12—C9—C10 | 110.1 (2) | C16—C17—C18 | 120.1 (2) |
C12—C9—C11 | 109.3 (2) | C16—C17—H17 | 119.9 |
C10—C9—C11 | 109.5 (2) | C18—C17—H17 | 119.9 |
C12—C9—C8 | 113.8 (2) | C17—C18—C19 | 120.0 (2) |
C10—C9—C8 | 105.9 (2) | C17—C18—H18 | 120.0 |
C11—C9—C8 | 108.1 (2) | C19—C18—H18 | 120.0 |
C9—C10—H10A | 109.5 | C14—C19—C18 | 120.0 (2) |
C9—C10—H10B | 109.5 | C14—C19—H19 | 120.0 |
H10A—C10—H10B | 109.5 | C18—C19—H19 | 120.0 |
C6—N1—C2—C3 | −1.4 (4) | O8—C8—C9—C10 | −79.0 (3) |
C6—N1—C2—N7 | 178.4 (2) | N7—C8—C9—C10 | 98.3 (3) |
C8—N7—C2—N1 | 178.5 (2) | O8—C8—C9—C11 | 38.3 (3) |
C8—N7—C2—C3 | −1.8 (4) | N7—C8—C9—C11 | −144.3 (2) |
N1—C2—C3—C4 | 0.7 (4) | O13B—C13—C14—C19 | 12.4 (4) |
N7—C2—C3—C4 | −179.1 (2) | O13A—C13—C14—C19 | −167.2 (2) |
C2—C3—C4—C5 | 0.6 (4) | O13B—C13—C14—C15 | −165.7 (2) |
C3—C4—C5—C6 | −1.1 (4) | O13A—C13—C14—C15 | 14.7 (3) |
C2—N1—C6—N6 | −178.5 (2) | C19—C14—C15—C16 | 0.1 (4) |
C2—N1—C6—C5 | 0.8 (4) | C13—C14—C15—C16 | 178.2 (2) |
C4—C5—C6—N6 | 179.6 (3) | C14—C15—C16—C17 | 0.1 (4) |
C4—C5—C6—N1 | 0.4 (4) | C15—C16—C17—C18 | 0.4 (4) |
C2—N7—C8—O8 | 1.0 (4) | C16—C17—C18—C19 | −1.1 (4) |
C2—N7—C8—C9 | −176.4 (2) | C15—C14—C19—C18 | −0.8 (4) |
O8—C8—C9—C12 | 159.9 (2) | C13—C14—C19—C18 | −178.9 (2) |
N7—C8—C9—C12 | −22.8 (3) | C17—C18—C19—C14 | 1.3 (4) |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O13Ai | 0.91 (2) | 1.67 (2) | 2.571 (2) | 170 (2) |
N6—H6A···O13Bi | 0.90 (2) | 2.05 (2) | 2.934 (3) | 167 (2) |
N6—H6B···O13Bii | 0.91 (2) | 2.05 (2) | 2.869 (3) | 149 (2) |
N7—H7···O13Ai | 0.86 (2) | 2.24 (2) | 2.984 (3) | 146 (2) |
C4—H4···O8iii | 0.95 | 2.49 | 3.433 (3) | 172 |
Symmetry codes: (i) x, y+1, z; (ii) −x+1, y+1/2, −z+1/2; (iii) −x+1, −y, −z+1. |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1···O13Ai | 0.905 (16) | 1.674 (17) | 2.571 (2) | 170 (2) |
N6—H6A···O13Bi | 0.899 (17) | 2.053 (18) | 2.934 (3) | 167 (2) |
N6—H6B···O13Bii | 0.913 (16) | 2.05 (2) | 2.869 (3) | 149 (2) |
N7—H7···O13Ai | 0.859 (17) | 2.24 (2) | 2.984 (3) | 146 (2) |
C4—H4···O8iii | 0.95 | 2.49 | 3.433 (3) | 172 |
Symmetry codes: (i) x, y+1, z; (ii) −x+1, y+1/2, −z+1/2; (iii) −x+1, −y, −z+1. |
Acknowledgements
Financial support from the National Science Centre in Kraków (grant No. NCN204 356840) is gratefully acknowledged. Academy Professor Kari Rissanen (Academy of Finland grant Nos. 122350, 140718, 265328 and 263256) and the University of Jyväskylä (postdoc grant to AV) are also gratefully acknowledged for financial support.
References
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Co-crystallization is used in the pharmaceutical industry to improve the shelf life of drugs (Vishweshwar et al., 2006; Lemmerer, 2012). It is also used in many fields of chemistry, including material science. It is known that 2-acylaminopyridine forms co-crystals with acids, while in 2-aminopyridine acid complexes proton transfer takes place, yielding salts (Aakeröy et al., 2010; 2006). The current report deals with the competition between formation of a salt and co-crystal. It is worth pointing out that the 2-acylamino moiety prefers to form co-crystals, while the 6-amino moiety prefers salt formation. In 2-pivaloylamino pyridine, both groups are present in the same molecule. Moreover, the increased acidity of NH in the –NHCO– group, in general, increases the hydrogen bonding donation ability of the NH proton. On the other hand, we used the sterically demanding pivaloyl group to hinder the efficient NH···O═C interaction of the —NHCO—tBu part of the title molecule. Thus the interacting acid is pushed to transfer the proton to the heterocyclic nitrogen and to form a salt with 2-pivaloylamino-6-aminopyridine. It is worth noting that the NH2 group attached to C6 of the pyridine ring causes an increase of electron density at the ring nitrogen. More systematic studies on co-crystallization of 2-acylaminopyridine with benzoic acids are in progress. For the steric effects in hydrogen bonded compounds, refer to our previous publications (Ośmiałowski et al., 2012a,b; 2010a,b).
As illustrated in Figure 1, the asymmetric unit of the title salt, (I), contains one protonated 2-pivaloylamino-6-aminopyridine cation and one benzoate anion, both located in general positions.
The geometric parameters of the 2-pivaloylamino-6-aminopyridine cation are in good agreement with those found for the related structures (Ośmiałowski et al., 2010a,b). In the benzoate anion the C—O distances, 1.268 (3) Å and 1.253 (3) Å, clearly indicate the delocalization of the negative charge within the carboxylate group.
In the crystal of the title salt, cations and anions are connected via four N—H···O hydrogen bonds (Table 1 and Figure 2). The protonated N1 atom and two nitrogen atoms (N6 and N7) interact with the carboxylate oxygen atoms (O13A and O13B; symmetry code (i): x, y + 1, z) and form hydrogen-bonded aggregates. Such structural motifs are further propagated into infinite chains running along b axis by N6—H6B···O13Bii [symmetry code (ii): -x + 1, y + 1/2, -z + 1/2] hydrogen bond. The crystal structure of (I) is further stabilized by an almost linear C4—H4···O8iii interaction (Table 1 and Figure 2) and by π···π stacking interactions; both of which connect the adjacent one-dimensional-chains to produce (100) supramolecular sheets. The thickness of each separate layer is equal to the a unit cell constant. No direction-specific interactions have been found between the supramolecular sheets.
The aforementioned π···π stacking interactions are observed between the pyridine rings of inversion-related cations, with a Cg···Cgiv distance of 3.867 (2) Å and interplanar distance of 3.455 (1) Å; Cg is the centroid of the N2/C2–C6 ring, symmetry code (iv): 1 - x, 1 - y, 1 - z.