Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270101004784/gd1147sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270101004784/gd1147IIIsup2.hkl | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270101004784/gd1147Vsup3.hkl |
CCDC references: 166997; 166998
The title compounds were prepared from readily accessible N-(4-pyridyl)nitramine and its methylated derivative. 1,2-Dihydro-1-methyl-4-nitriminopyridine (3.06 g, 20 mmol) was dissolved in 20% sulfuric acid (10 ml). A saturated aqueous solution of sodium nitrite (2.80 g, 40 mmol) was slowly added dropwise at room temperature. The solution was stirred at 298–303 K until evolution of gases ceased, and then cooled. The crude product (3.95 g, 91%) was collected by filtration, washed with iced water and dried in vacuo (m.p. 431–437 K). Crystallization from methanol (45 ml) provided light-yellow prisms of (III) (2.18 g), suitable for X-ray diffraction studies. Pure (III) melted at 433–436 K with decomposition. From the mother liquor, another crop of the product was isolated; it was contaminated with some inorganic salts. Spectroscopic analysis: IR (KBr, cm-1): 3100–2350 (broad, intense band with several sub-maxima, hydrogen-bonded N—H group), 1385, 1336, 1316, 1296 and 1254 (N—O stretching vibrations in nitrate anion and NNO2 group); 1H NMR (DMSO-d6, δ, p.p.m.): 12.1 (s, N—H), 8.65 (d, 2H), 7.77 (d, 3J = 7.5 Hz, 2H, aromatic H), 4.15 (s, 3H, N-methyl group); 13C NMR (DMSO-d6, δ, p.p.m.): 153.1 (C4), 145.2 (C2, C6), 113.9 (C3, C5), 45.8 (N—CH3). N-(4-Pyridyl)nitramine (1.39 g, 0.01 mol) was dissolved in 70% aqueous methanesulfonic acid (5.0 ml) and left for 12 h at room temperature. 4-Nitraminopyridinium methanesulfonate was collected by filtration, washed with tetrahydrofuran and dried in vacuo. The product formed large, colourless prisms of (V) (m.p. 436–439 K) suitable for X-ray diffraction studies. From the liquor another crop of the salt was obtained after dilution with tetrahydrofuran and cooling (total yield 1.71 g, 73%). Spectroscopic analysis: IR (KBr, cm-1): 1451, 1338 (N—NO2 stretching vibrations), 761, 753 (N—NO2 deformations); 1H NMR (DMSO-d6, δ, p.p.m.): 10.6 (s, N—H), 8.69 (d, 2H), 7.82 (d 3J = 7.5 Hz, 2H, aromatic H), 2.49 (s, 3H, S-methyl group); 13C NMR (DMSO-d6, δ, p.p.m.): 152.8 (C4), 142.2 (C2, C6), 113.4 (C3, C5), 39.6 (S—CH3).
In compound (III), the H atom coordinates were refined, leading to C—H distances in the range 0.90 (3)–0.95 (2) Å and N—H distances of 0.94 (2) Å, and H—C—H angles in the range 97 (2)–115 (2)°. In compound (V), the H atoms were treated as riding, with C—H = 0.96 and N—H = 0.90 Å.
For both compounds, cell refinement: Kuma Diffraction Software (Kuma Diffraction, 1997); data reduction: Kuma Diffraction Software; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990a); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL/PC (Sheldrick, 1990b); software used to prepare material for publication: SHELXL97.
C6H8N3O2+·NO3− | F(000) = 448 |
Mr = 216.16 | Dx = 1.584 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
a = 7.108 (1) Å | Cell parameters from 35 reflections |
b = 17.598 (4) Å | θ = 12–14° |
c = 7.246 (1) Å | µ = 0.14 mm−1 |
β = 90.33 (3)° | T = 293 K |
V = 906.4 (3) Å3 | Prism, light yellow |
Z = 4 | 0.5 × 0.4 × 0.4 mm |
Kuma KM4 diffractometer | Rint = 0.014 |
Radiation source: fine-focus sealed tube | θmax = 30.1°, θmin = 2.9° |
Graphite monochromator | h = −10→10 |
ω scans | k = 0→24 |
2824 measured reflections | l = −10→0 |
2640 independent reflections | 2 standard reflections every 50 reflections |
1746 reflections with I > 2σ(I) | intensity decay: 1.1% |
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)] = 0.043 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.141 | All H-atom parameters refined |
S = 1.03 | |
2640 reflections | (Δ/σ)max < 0.001 |
168 parameters | Δρmax = 0.30 e Å−3 |
0 restraints | Δρmin = −0.18 e Å−3 |
C6H8N3O2+·NO3− | V = 906.4 (3) Å3 |
Mr = 216.16 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 7.108 (1) Å | µ = 0.14 mm−1 |
b = 17.598 (4) Å | T = 293 K |
c = 7.246 (1) Å | 0.5 × 0.4 × 0.4 mm |
β = 90.33 (3)° |
Kuma KM4 diffractometer | Rint = 0.014 |
2824 measured reflections | 2 standard reflections every 50 reflections |
2640 independent reflections | intensity decay: 1.1% |
1746 reflections with I > 2σ(I) |
R[F2 > 2σ(F2)] = 0.043 | 0 restraints |
wR(F2) = 0.141 | All H-atom parameters refined |
S = 1.03 | Δρmax = 0.30 e Å−3 |
2640 reflections | Δρmin = −0.18 e Å−3 |
168 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. |
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. |
x | y | z | Uiso*/Ueq | ||
N1 | 0.41533 (19) | 0.58830 (7) | 0.25002 (19) | 0.0417 (3) | |
C2 | 0.3782 (2) | 0.66302 (8) | 0.2501 (2) | 0.0430 (4) | |
C3 | 0.5025 (2) | 0.71522 (8) | 0.1821 (2) | 0.0415 (3) | |
C4 | 0.6729 (2) | 0.68986 (8) | 0.1098 (2) | 0.0366 (3) | |
C5 | 0.7077 (2) | 0.61148 (9) | 0.1089 (2) | 0.0439 (4) | |
C6 | 0.5790 (2) | 0.56292 (8) | 0.1795 (2) | 0.0453 (4) | |
N7 | 0.81323 (19) | 0.73406 (7) | 0.0355 (2) | 0.0443 (3) | |
N8 | 0.82239 (19) | 0.81143 (7) | 0.0425 (2) | 0.0434 (3) | |
O10 | 0.95126 (19) | 0.84000 (7) | −0.0420 (2) | 0.0577 (4) | |
O9 | 0.7056 (2) | 0.84584 (7) | 0.1291 (2) | 0.0704 (5) | |
C11 | 0.2770 (3) | 0.53398 (11) | 0.3242 (4) | 0.0587 (5) | |
N12 | 1.18647 (18) | 0.62500 (7) | −0.1671 (2) | 0.0434 (3) | |
O13 | 1.3313 (2) | 0.61432 (7) | −0.2549 (2) | 0.0708 (5) | |
O14 | 1.1052 (2) | 0.57168 (8) | −0.0930 (3) | 0.0787 (5) | |
O15 | 1.12243 (18) | 0.69110 (7) | −0.1524 (2) | 0.0592 (4) | |
H6 | 0.597 (3) | 0.5096 (12) | 0.185 (3) | 0.053 (5)* | |
H2 | 0.264 (3) | 0.6786 (11) | 0.303 (3) | 0.048 (5)* | |
H5 | 0.817 (3) | 0.5920 (12) | 0.061 (3) | 0.050 (5)* | |
H3 | 0.476 (3) | 0.7653 (11) | 0.189 (3) | 0.049 (5)* | |
H11A | 0.186 (5) | 0.5225 (19) | 0.241 (5) | 0.116 (11)* | |
H11B | 0.236 (4) | 0.5499 (18) | 0.438 (4) | 0.101 (10)* | |
H11C | 0.335 (4) | 0.4870 (19) | 0.324 (4) | 0.101 (9)* | |
H7 | 0.918 (3) | 0.7143 (14) | −0.026 (3) | 0.075 (7)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
N1 | 0.0441 (7) | 0.0308 (6) | 0.0504 (7) | 0.0002 (5) | 0.0050 (6) | −0.0020 (5) |
C2 | 0.0401 (7) | 0.0335 (7) | 0.0557 (9) | 0.0037 (6) | 0.0090 (7) | −0.0033 (6) |
C3 | 0.0405 (7) | 0.0287 (6) | 0.0554 (9) | 0.0045 (5) | 0.0058 (6) | −0.0027 (6) |
C4 | 0.0357 (7) | 0.0328 (6) | 0.0414 (7) | 0.0018 (5) | 0.0005 (5) | −0.0031 (5) |
C5 | 0.0395 (7) | 0.0354 (7) | 0.0568 (9) | 0.0080 (6) | 0.0046 (7) | −0.0069 (6) |
C6 | 0.0491 (9) | 0.0292 (6) | 0.0576 (10) | 0.0062 (6) | 0.0028 (7) | −0.0043 (6) |
N7 | 0.0414 (7) | 0.0335 (6) | 0.0582 (8) | 0.0021 (5) | 0.0121 (6) | −0.0029 (5) |
N8 | 0.0416 (7) | 0.0351 (6) | 0.0537 (8) | −0.0005 (5) | 0.0029 (6) | −0.0003 (5) |
O10 | 0.0548 (7) | 0.0471 (7) | 0.0714 (8) | −0.0068 (6) | 0.0152 (6) | 0.0083 (6) |
O9 | 0.0620 (8) | 0.0356 (6) | 0.1141 (13) | −0.0024 (6) | 0.0335 (8) | −0.0149 (7) |
C11 | 0.0632 (12) | 0.0376 (9) | 0.0754 (14) | −0.0089 (8) | 0.0174 (11) | 0.0025 (9) |
N12 | 0.0365 (6) | 0.0347 (6) | 0.0591 (8) | 0.0014 (5) | 0.0070 (6) | −0.0003 (6) |
O13 | 0.0555 (8) | 0.0398 (6) | 0.1174 (13) | 0.0049 (5) | 0.0418 (8) | 0.0006 (7) |
O14 | 0.0670 (9) | 0.0476 (7) | 0.1219 (14) | 0.0046 (6) | 0.0428 (9) | 0.0229 (8) |
O15 | 0.0518 (7) | 0.0361 (6) | 0.0901 (10) | 0.0057 (5) | 0.0224 (7) | −0.0043 (6) |
N1—C2 | 1.341 (2) | C6—H6 | 0.95 (2) |
N1—C6 | 1.350 (2) | N7—N8 | 1.364 (2) |
N1—C11 | 1.475 (2) | N7—H7 | 0.94 (2) |
C2—C3 | 1.369 (2) | N8—O9 | 1.206 (2) |
C2—H2 | 0.94 (2) | N8—O10 | 1.214 (2) |
C3—C4 | 1.396 (2) | C11—H11A | 0.90 (3) |
C3—H3 | 0.90 (2) | C11—H11B | 0.92 (3) |
C4—N7 | 1.377 (2) | C11—H11C | 0.93 (3) |
C4—C5 | 1.401 (2) | N12—O14 | 1.227 (2) |
C5—C6 | 1.354 (2) | N12—O13 | 1.227 (2) |
C5—H5 | 0.92 (2) | N12—O15 | 1.254 (2) |
C2—N1—C6 | 119.7 (1) | C5—C6—H6 | 123 (1) |
C2—N1—C11 | 120.2 (1) | N8—N7—C4 | 125.7 (1) |
C6—N1—C11 | 120.1 (1) | N8—N7—H7 | 111 (1) |
N1—C2—C3 | 122.0 (1) | C4—N7—H7 | 124 (2) |
N1—C2—H2 | 117 (1) | O9—N8—O10 | 125.3 (1) |
C3—C2—H2 | 121 (1) | O9—N8—N7 | 119.2 (1) |
C2—C3—C4 | 119.0 (1) | O10—N8—N7 | 115.5 (1) |
C2—C3—H3 | 120 (1) | N1—C11—H11A | 112 (2) |
C4—C3—H3 | 121 (1) | N1—C11—H11B | 110 (2) |
N7—C4—C3 | 126.8 (1) | H11A—C11—H11B | 116 (3) |
N7—C4—C5 | 115.2 (1) | N1—C11—H11C | 106 (2) |
C3—C4—C5 | 118.0 (1) | H11A—C11—H11C | 97 (2) |
C6—C5—C4 | 120.0 (1) | H11B—C11—H11C | 115 (3) |
C6—C5—H5 | 119 (1) | O14—N12—O13 | 120.5 (1) |
C4—C5—H5 | 121 (1) | O14—N12—O15 | 120.0 (1) |
N1—C6—C5 | 121.3 (1) | O13—N12—O15 | 119.5 (1) |
N1—C6—H6 | 115 (1) | ||
C6—N1—C2—C3 | −0.7 (3) | C2—N1—C6—C5 | 0.2 (3) |
C11—N1—C2—C3 | −179.8 (2) | C11—N1—C6—C5 | 179.3 (2) |
N1—C2—C3—C4 | 0.3 (3) | C4—C5—C6—N1 | 0.7 (3) |
C2—C3—C4—N7 | 179.7 (2) | C3—C4—N7—N8 | 9.8 (3) |
C2—C3—C4—C5 | 0.6 (2) | C5—C4—N7—N8 | −171.0 (2) |
N7—C4—C5—C6 | 179.7 (2) | C4—N7—N8—O9 | 4.5 (3) |
C3—C4—C5—C6 | −1.0 (2) | C4—N7—N8—O10 | −175.3 (2) |
D—H···A | D—H | H···A | D···A | D—H···A |
N7—H7···O15 | 0.94 (2) | 1.77 (2) | 2.700 (2) | 171 (2) |
C3—H3···O13i | 0.90 (2) | 2.39 (2) | 3.270 (2) | 165 (2) |
C2—H2···O15i | 0.94 (2) | 2.52 (2) | 3.226 (2) | 131 (2) |
C2—H2···O10i | 0.94 (2) | 2.51 (2) | 3.396 (2) | 156 (2) |
C5—H5···O14 | 0.92 (2) | 2.37 (2) | 3.265 (2) | 166 (2) |
C6—H6···O13ii | 0.95 (2) | 2.30 (2) | 3.229 (2) | 168 (2) |
C11—H11C···O9iii | 0.93 (3) | 2.52 (3) | 3.330 (2) | 146 (2) |
Symmetry codes: (i) x−1, −y+3/2, z+1/2; (ii) −x+2, −y+1, −z; (iii) −x+1, y−1/2, −z+1/2. |
C5H6N3O2+·CH3SO3− | F(000) = 976 |
Mr = 235.22 | Dx = 1.627 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
a = 11.824 (2) Å | Cell parameters from 27 reflections |
b = 8.138 (2) Å | θ = 10–14° |
c = 20.125 (4) Å | µ = 0.35 mm−1 |
β = 97.36 (3)° | T = 293 K |
V = 1920.5 (7) Å3 | Prism, colourless |
Z = 8 | 0.45 × 0.40 × 0.35 mm |
Kuma KM4 diffractometer | Rint = 0.017 |
Radiation source: fine-focus sealed tube | θmax = 25.1°, θmin = 1.9° |
Graphite monochromator | h = −13→14 |
ω scans | k = −9→0 |
3500 measured reflections | l = −23→0 |
3402 independent reflections | 2 standard reflections every 50 reflections |
3022 reflections with I > 2σ(I) | intensity decay: 2.0% |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.033 | H-atom parameters constrained |
wR(F2) = 0.099 | |
S = 1.08 | (Δ/σ)max = 0.001 |
3402 reflections | Δρmax = 0.32 e Å−3 |
272 parameters | Δρmin = −0.36 e Å−3 |
0 restraints | Extinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0140 (10) |
C5H6N3O2+·CH3SO3− | V = 1920.5 (7) Å3 |
Mr = 235.22 | Z = 8 |
Monoclinic, P21/n | Mo Kα radiation |
a = 11.824 (2) Å | µ = 0.35 mm−1 |
b = 8.138 (2) Å | T = 293 K |
c = 20.125 (4) Å | 0.45 × 0.40 × 0.35 mm |
β = 97.36 (3)° |
Kuma KM4 diffractometer | Rint = 0.017 |
3500 measured reflections | 2 standard reflections every 50 reflections |
3402 independent reflections | intensity decay: 2.0% |
3022 reflections with I > 2σ(I) |
R[F2 > 2σ(F2)] = 0.033 | 0 restraints |
wR(F2) = 0.099 | H-atom parameters constrained |
S = 1.08 | Δρmax = 0.32 e Å−3 |
3402 reflections | Δρmin = −0.36 e Å−3 |
272 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. |
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. |
x | y | z | Uiso*/Ueq | ||
S1A | 0.96655 (4) | 0.16340 (6) | 0.88431 (2) | 0.03100 (16) | |
O1A | 0.89121 (13) | 0.2008 (2) | 0.82329 (8) | 0.0456 (4) | |
O2A | 1.02645 (14) | 0.0106 (2) | 0.88084 (9) | 0.0493 (4) | |
O3A | 1.04239 (12) | 0.3017 (2) | 0.90336 (9) | 0.0469 (4) | |
C1A | 0.8786 (2) | 0.1461 (3) | 0.94767 (12) | 0.0481 (6) | |
H1AB | 0.8265 | 0.0563 | 0.9376 | 0.058* | |
H1AC | 0.9246 | 0.1264 | 0.9898 | 0.058* | |
H1AD | 0.8363 | 0.2462 | 0.9503 | 0.058* | |
S1B | 0.78304 (4) | 0.15907 (6) | 0.60078 (2) | 0.03083 (16) | |
O1B | 0.82024 (14) | 0.3109 (2) | 0.57272 (9) | 0.0544 (5) | |
O2B | 0.81240 (14) | 0.1544 (2) | 0.67325 (8) | 0.0494 (4) | |
O3B | 0.82175 (14) | 0.0152 (2) | 0.56889 (9) | 0.0548 (5) | |
C1B | 0.63379 (18) | 0.1612 (3) | 0.58461 (12) | 0.0425 (5) | |
H1BB | 0.6108 | 0.1642 | 0.5371 | 0.051* | |
H1BC | 0.6038 | 0.0640 | 0.6030 | 0.051* | |
H1BD | 0.6050 | 0.2566 | 0.6049 | 0.051* | |
N1A | 0.93370 (15) | 0.4883 (2) | 0.75694 (9) | 0.0380 (4) | |
H1AE | 0.9168 | 0.3830 | 0.7652 | 0.046* | |
C6A | 0.85229 (17) | 0.5873 (3) | 0.72760 (11) | 0.0364 (5) | |
H6AA | 0.7764 | 0.5459 | 0.7155 | 0.044* | |
C5A | 0.87597 (16) | 0.7470 (3) | 0.71478 (10) | 0.0339 (4) | |
H5AA | 0.8172 | 0.8181 | 0.6937 | 0.041* | |
C4A | 0.98599 (16) | 0.8073 (2) | 0.73226 (9) | 0.0284 (4) | |
C3A | 1.06987 (18) | 0.7009 (3) | 0.76228 (11) | 0.0384 (5) | |
H3AB | 1.1468 | 0.7383 | 0.7741 | 0.046* | |
C2A | 1.03998 (19) | 0.5433 (3) | 0.77403 (12) | 0.0430 (5) | |
H2AB | 1.0967 | 0.4695 | 0.7954 | 0.052* | |
N7A | 1.00054 (14) | 0.9713 (2) | 0.71823 (9) | 0.0339 (4) | |
H7AA | 0.9378 | 1.0283 | 0.7020 | 0.041* | |
N8A | 1.10057 (16) | 1.0538 (2) | 0.72647 (9) | 0.0406 (4) | |
O9A | 1.18902 (14) | 0.9780 (2) | 0.73772 (12) | 0.0655 (6) | |
O10A | 1.09294 (16) | 1.2027 (2) | 0.71938 (10) | 0.0577 (5) | |
N1B | 1.00488 (17) | 0.5026 (3) | 0.58539 (10) | 0.0466 (5) | |
H1BE | 0.9555 | 0.4189 | 0.5869 | 0.056* | |
C6B | 1.1168 (2) | 0.4755 (3) | 0.60025 (12) | 0.0464 (6) | |
H6BA | 1.1436 | 0.3670 | 0.6126 | 0.056* | |
C5B | 1.19288 (19) | 0.5990 (3) | 0.59804 (11) | 0.0384 (5) | |
H5BA | 1.2733 | 0.5786 | 0.6077 | 0.046* | |
C4B | 1.15278 (16) | 0.7576 (2) | 0.58145 (9) | 0.0288 (4) | |
C3B | 1.03578 (17) | 0.7822 (3) | 0.56593 (10) | 0.0366 (5) | |
H3BB | 1.0058 | 0.8891 | 0.5536 | 0.044* | |
C2B | 0.96588 (19) | 0.6515 (3) | 0.56859 (11) | 0.0440 (6) | |
H2BB | 0.8851 | 0.6673 | 0.5579 | 0.053* | |
N7B | 1.23622 (15) | 0.8752 (2) | 0.58183 (9) | 0.0353 (4) | |
H7BA | 1.3090 | 0.8404 | 0.5862 | 0.042* | |
N8B | 1.21785 (17) | 1.0401 (2) | 0.57608 (9) | 0.0403 (4) | |
O9B | 1.12074 (15) | 1.0926 (2) | 0.57340 (10) | 0.0551 (5) | |
O10B | 1.30284 (16) | 1.1236 (2) | 0.57564 (11) | 0.0619 (5) |
U11 | U22 | U33 | U12 | U13 | U23 | |
S1A | 0.0245 (3) | 0.0323 (3) | 0.0355 (3) | −0.00104 (19) | 0.00121 (19) | 0.0028 (2) |
O1A | 0.0370 (8) | 0.0547 (10) | 0.0421 (8) | −0.0062 (7) | −0.0066 (7) | 0.0128 (7) |
O2A | 0.0459 (9) | 0.0395 (9) | 0.0632 (11) | 0.0092 (7) | 0.0099 (8) | 0.0018 (8) |
O3A | 0.0300 (8) | 0.0443 (9) | 0.0649 (10) | −0.0080 (7) | 0.0003 (7) | −0.0052 (8) |
C1A | 0.0453 (13) | 0.0536 (14) | 0.0477 (13) | −0.0010 (11) | 0.0150 (11) | 0.0026 (11) |
S1B | 0.0255 (3) | 0.0341 (3) | 0.0327 (3) | 0.00245 (19) | 0.00313 (19) | 0.00479 (19) |
O1B | 0.0411 (9) | 0.0534 (10) | 0.0681 (11) | −0.0122 (8) | 0.0045 (8) | 0.0200 (9) |
O2B | 0.0462 (9) | 0.0675 (11) | 0.0333 (8) | 0.0159 (8) | 0.0003 (7) | 0.0051 (8) |
O3B | 0.0493 (10) | 0.0572 (11) | 0.0579 (11) | 0.0190 (8) | 0.0066 (8) | −0.0097 (8) |
C1B | 0.0282 (10) | 0.0483 (13) | 0.0504 (13) | 0.0000 (9) | 0.0032 (9) | 0.0029 (10) |
N1A | 0.0386 (10) | 0.0296 (9) | 0.0471 (10) | −0.0004 (8) | 0.0103 (8) | 0.0064 (8) |
C6A | 0.0285 (10) | 0.0390 (12) | 0.0427 (11) | −0.0021 (9) | 0.0081 (8) | 0.0025 (9) |
C5A | 0.0264 (10) | 0.0371 (11) | 0.0380 (11) | 0.0041 (8) | 0.0038 (8) | 0.0039 (9) |
C4A | 0.0309 (10) | 0.0300 (10) | 0.0248 (9) | 0.0027 (8) | 0.0058 (7) | 0.0009 (7) |
C3A | 0.0304 (10) | 0.0375 (12) | 0.0451 (12) | 0.0007 (9) | −0.0034 (9) | 0.0049 (9) |
C2A | 0.0386 (12) | 0.0403 (12) | 0.0483 (13) | 0.0082 (10) | −0.0005 (10) | 0.0104 (10) |
N7A | 0.0299 (9) | 0.0297 (9) | 0.0415 (9) | 0.0005 (7) | 0.0020 (7) | 0.0029 (7) |
N8A | 0.0387 (10) | 0.0360 (10) | 0.0478 (11) | −0.0066 (8) | 0.0079 (8) | −0.0017 (8) |
O9A | 0.0318 (9) | 0.0533 (11) | 0.1107 (16) | −0.0043 (8) | 0.0062 (9) | 0.0103 (11) |
O10A | 0.0635 (11) | 0.0316 (9) | 0.0801 (13) | −0.0104 (8) | 0.0173 (10) | −0.0011 (8) |
N1B | 0.0504 (12) | 0.0461 (11) | 0.0457 (11) | −0.0200 (10) | 0.0154 (9) | −0.0052 (9) |
C6B | 0.0572 (15) | 0.0306 (11) | 0.0521 (14) | −0.0043 (10) | 0.0103 (11) | 0.0024 (10) |
C5B | 0.0378 (11) | 0.0330 (11) | 0.0448 (12) | 0.0032 (9) | 0.0063 (9) | 0.0035 (9) |
C4B | 0.0310 (10) | 0.0293 (10) | 0.0264 (9) | −0.0006 (8) | 0.0050 (7) | −0.0002 (8) |
C3B | 0.0303 (10) | 0.0395 (12) | 0.0400 (11) | 0.0048 (9) | 0.0044 (8) | 0.0009 (9) |
C2B | 0.0309 (11) | 0.0589 (15) | 0.0434 (12) | −0.0069 (10) | 0.0093 (9) | −0.0067 (11) |
N7B | 0.0303 (9) | 0.0287 (9) | 0.0463 (10) | 0.0023 (7) | 0.0028 (7) | 0.0055 (7) |
N8B | 0.0490 (11) | 0.0304 (9) | 0.0406 (10) | −0.0002 (9) | 0.0026 (8) | 0.0019 (8) |
O9B | 0.0538 (10) | 0.0346 (9) | 0.0762 (12) | 0.0132 (8) | 0.0057 (9) | −0.0031 (8) |
O10B | 0.0598 (11) | 0.0400 (10) | 0.0838 (13) | −0.0183 (9) | 0.0009 (10) | 0.0074 (9) |
S1A—O2A | 1.437 (2) | C3A—C2A | 1.359 (3) |
S1A—O1A | 1.454 (2) | C3A—H3AB | 0.9600 |
S1A—O3A | 1.459 (2) | C2A—H2AB | 0.9601 |
S1A—C1A | 1.752 (2) | N7A—N8A | 1.352 (2) |
C1A—H1AB | 0.9600 | N7A—H7AA | 0.9000 |
C1A—H1AC | 0.9601 | N8A—O9A | 1.210 (3) |
C1A—H1AD | 0.9600 | N8A—O10A | 1.222 (3) |
S1B—O3B | 1.438 (2) | N1B—C2B | 1.325 (3) |
S1B—O1B | 1.450 (2) | N1B—C6B | 1.337 (3) |
S1B—O2B | 1.456 (2) | N1B—H1BE | 0.9000 |
S1B—C1B | 1.753 (2) | C6B—C5B | 1.354 (3) |
C1B—H1BB | 0.9600 | C6B—H6BA | 0.9600 |
C1B—H1BC | 0.9600 | C5B—C4B | 1.400 (3) |
C1B—H1BD | 0.9600 | C5B—H5BA | 0.9601 |
N1A—C6A | 1.334 (3) | C4B—N7B | 1.374 (3) |
N1A—C2A | 1.337 (3) | C4B—C3B | 1.393 (3) |
N1A—H1AE | 0.9000 | C3B—C2B | 1.352 (3) |
C6A—C5A | 1.361 (3) | C3B—H3BB | 0.9600 |
C6A—H6AA | 0.9600 | C2B—H2BB | 0.9600 |
C5A—C4A | 1.393 (3) | N7B—N8B | 1.361 (2) |
C5A—H5AA | 0.9600 | N7B—H7BA | 0.9000 |
C4A—N7A | 1.380 (3) | N8B—O10B | 1.214 (2) |
C4A—C3A | 1.394 (3) | N8B—O9B | 1.220 (2) |
O2A—S1A—O1A | 113.1 (1) | C2A—C3A—C4A | 118.4 (2) |
O2A—S1A—O3A | 112.9 (1) | C2A—C3A—H3AB | 121.0 |
O1A—S1A—O3A | 110.5 (1) | C4A—C3A—H3AB | 120.6 |
O2A—S1A—C1A | 108.0 (1) | N1A—C2A—C3A | 121.9 (2) |
O1A—S1A—C1A | 106.0 (1) | N1A—C2A—H2AB | 119.1 |
O3A—S1A—C1A | 105.8 (1) | C3A—C2A—H2AB | 119.1 |
S1A—C1A—H1AB | 109.4 | N8A—N7A—C4A | 125.9 (2) |
S1A—C1A—H1AC | 109.5 | N8A—N7A—H7AA | 117.1 |
H1AB—C1A—H1AC | 109.5 | C4A—N7A—H7AA | 117.0 |
S1A—C1A—H1AD | 109.5 | O9A—N8A—O10A | 125.2 (2) |
H1AB—C1A—H1AD | 109.5 | O9A—N8A—N7A | 119.4 (2) |
H1AC—C1A—H1AD | 109.5 | O10A—N8A—N7A | 115.3 (2) |
O3B—S1B—O1B | 113.0 (1) | C2B—N1B—C6B | 120.7 (2) |
O3B—S1B—O2B | 112.2 (1) | C2B—N1B—H1BE | 119.6 |
O1B—S1B—O2B | 111.5 (1) | C6B—N1B—H1BE | 119.7 |
O3B—S1B—C1B | 107.2 (1) | N1B—C6B—C5B | 120.9 (2) |
O1B—S1B—C1B | 105.5 (1) | N1B—C6B—H6BA | 119.6 |
O2B—S1B—C1B | 106.9 (1) | C5B—C6B—H6BA | 119.5 |
S1B—C1B—H1BB | 109.6 | C6B—C5B—C4B | 119.1 (2) |
S1B—C1B—H1BC | 109.4 | C6B—C5B—H5BA | 120.7 |
H1BB—C1B—H1BC | 109.5 | C4B—C5B—H5BA | 120.3 |
S1B—C1B—H1BD | 109.4 | N7B—C4B—C3B | 126.4 (2) |
H1BB—C1B—H1BD | 109.5 | N7B—C4B—C5B | 114.8 (2) |
H1BC—C1B—H1BD | 109.5 | C3B—C4B—C5B | 118.8 (2) |
C6A—N1A—C2A | 120.9 (2) | C2B—C3B—C4B | 118.2 (2) |
C6A—N1A—H1AE | 119.5 | C2B—C3B—H3BB | 121.1 |
C2A—N1A—H1AE | 119.6 | C4B—C3B—H3BB | 120.7 |
N1A—C6A—C5A | 120.4 (2) | N1B—C2B—C3B | 122.3 (2) |
N1A—C6A—H6AA | 119.8 | N1B—C2B—H2BB | 118.9 |
C5A—C6A—H6AA | 119.7 | C3B—C2B—H2BB | 118.8 |
C6A—C5A—C4A | 119.8 (2) | N8B—N7B—C4B | 125.4 (2) |
C6A—C5A—H5AA | 120.3 | N8B—N7B—H7BA | 117.3 |
C4A—C5A—H5AA | 119.9 | C4B—N7B—H7BA | 117.3 |
N7A—C4A—C5A | 115.2 (2) | O10B—N8B—O9B | 125.3 (2) |
N7A—C4A—C3A | 126.1 (2) | O10B—N8B—N7B | 115.4 (2) |
C5A—C4A—C3A | 118.7 (2) | O9B—N8B—N7B | 119.2 (2) |
C2A—N1A—C6A—C5A | −0.3 (3) | C2B—N1B—C6B—C5B | −0.5 (3) |
N1A—C6A—C5A—C4A | 0.2 (3) | N1B—C6B—C5B—C4B | 1.5 (3) |
C6A—C5A—C4A—N7A | −178.9 (2) | C6B—C5B—C4B—N7B | 178.8 (2) |
C6A—C5A—C4A—C3A | 0.5 (3) | C6B—C5B—C4B—C3B | −1.7 (3) |
N7A—C4A—C3A—C2A | 178.3 (2) | N7B—C4B—C3B—C2B | −179.6 (2) |
C5A—C4A—C3A—C2A | −0.9 (3) | C5B—C4B—C3B—C2B | 1.0 (3) |
C6A—N1A—C2A—C3A | −0.2 (3) | C6B—N1B—C2B—C3B | −0.3 (3) |
C4A—C3A—C2A—N1A | 0.8 (3) | C4B—C3B—C2B—N1B | 0.1 (3) |
C5A—C4A—N7A—N8A | −175.3 (2) | C3B—C4B—N7B—N8B | 9.6 (3) |
C3A—C4A—N7A—N8A | 5.4 (3) | C5B—C4B—N7B—N8B | −170.9 (2) |
C4A—N7A—N8A—O9A | 11.6 (3) | C4B—N7B—N8B—O10B | −178.0 (2) |
C4A—N7A—N8A—O10A | −170.9 (2) | C4B—N7B—N8B—O9B | 3.6 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
N7A—H7AA···O2Bi | 0.90 | 1.83 | 2.734 (2) | 176 |
N7B—H7BA···O3Aii | 0.90 | 1.77 | 2.665 (2) | 172 |
N1A—H1AE···O1A | 0.90 | 1.94 | 2.771 (2) | 154 |
N1B—H1BE···O1B | 0.90 | 1.82 | 2.668 (2) | 157 |
C3A—H3AB···O9A | 0.96 | 2.16 | 2.737 (3) | 117 |
C3B—H3BB···O9B | 0.96 | 2.15 | 2.716 (3) | 117 |
C5A—H5AA···O1Aiii | 0.96 | 2.62 | 3.176 (3) | 117 |
C6A—H6AA···O1Aiii | 0.96 | 2.39 | 3.072 (3) | 127 |
C3B—H3BB···O3Bi | 0.96 | 2.46 | 3.169 (3) | 131 |
C5B—H5BA···O2Aii | 0.96 | 2.41 | 3.369 (3) | 173 |
C6B—H6BA···O10Aiv | 0.96 | 2.66 | 3.306 (3) | 125 |
Symmetry codes: (i) x, y+1, z; (ii) −x+5/2, y+1/2, −z+3/2; (iii) −x+3/2, y+1/2, −z+3/2; (iv) x, y−1, z. |
Experimental details
(III) | (V) | |
Crystal data | ||
Chemical formula | C6H8N3O2+·NO3− | C5H6N3O2+·CH3SO3− |
Mr | 216.16 | 235.22 |
Crystal system, space group | Monoclinic, P21/c | Monoclinic, P21/n |
Temperature (K) | 293 | 293 |
a, b, c (Å) | 7.108 (1), 17.598 (4), 7.246 (1) | 11.824 (2), 8.138 (2), 20.125 (4) |
β (°) | 90.33 (3) | 97.36 (3) |
V (Å3) | 906.4 (3) | 1920.5 (7) |
Z | 4 | 8 |
Radiation type | Mo Kα | Mo Kα |
µ (mm−1) | 0.14 | 0.35 |
Crystal size (mm) | 0.5 × 0.4 × 0.4 | 0.45 × 0.40 × 0.35 |
Data collection | ||
Diffractometer | Kuma KM4 diffractometer | Kuma KM4 diffractometer |
Absorption correction | – | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 2824, 2640, 1746 | 3500, 3402, 3022 |
Rint | 0.014 | 0.017 |
(sin θ/λ)max (Å−1) | 0.705 | 0.597 |
Refinement | ||
R[F2 > 2σ(F2)], wR(F2), S | 0.043, 0.141, 1.03 | 0.033, 0.099, 1.08 |
No. of reflections | 2640 | 3402 |
No. of parameters | 168 | 272 |
H-atom treatment | All H-atom parameters refined | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.30, −0.18 | 0.32, −0.36 |
Computer programs: Kuma Diffraction Software (Kuma Diffraction, 1997), Kuma Diffraction Software, SHELXS97 (Sheldrick, 1990a), SHELXL97 (Sheldrick, 1997), SHELXTL/PC (Sheldrick, 1990b), SHELXL97.
C4—N7 | 1.377 (2) | N8—O9 | 1.206 (2) |
N7—N8 | 1.364 (2) | N8—O10 | 1.214 (2) |
C2—N1—C6 | 119.7 (1) | C6—C5—C4 | 120.0 (1) |
N1—C2—C3 | 122.0 (1) | N1—C6—C5 | 121.3 (1) |
C2—C3—C4 | 119.0 (1) | N8—N7—C4 | 125.7 (1) |
N7—C4—C3 | 126.8 (1) | O9—N8—O10 | 125.3 (1) |
N7—C4—C5 | 115.2 (1) | O9—N8—N7 | 119.2 (1) |
C3—C4—C5 | 118.0 (1) | O10—N8—N7 | 115.5 (1) |
C3—C4—N7—N8 | 9.8 (3) | C4—N7—N8—O9 | 4.5 (3) |
C5—C4—N7—N8 | −171.0 (2) | C4—N7—N8—O10 | −175.3 (2) |
D—H···A | D—H | H···A | D···A | D—H···A |
N7—H7···O15 | 0.94 (2) | 1.77 (2) | 2.700 (2) | 171 (2) |
C3—H3···O13i | 0.90 (2) | 2.39 (2) | 3.270 (2) | 165 (2) |
C2—H2···O15i | 0.94 (2) | 2.52 (2) | 3.226 (2) | 131 (2) |
C2—H2···O10i | 0.94 (2) | 2.51 (2) | 3.396 (2) | 156 (2) |
C5—H5···O14 | 0.92 (2) | 2.37 (2) | 3.265 (2) | 166 (2) |
C6—H6···O13ii | 0.95 (2) | 2.30 (2) | 3.229 (2) | 168 (2) |
C11—H11C···O9iii | 0.93 (3) | 2.52 (3) | 3.330 (2) | 146 (2) |
Symmetry codes: (i) x−1, −y+3/2, z+1/2; (ii) −x+2, −y+1, −z; (iii) −x+1, y−1/2, −z+1/2. |
C4A—N7A | 1.380 (3) | C4B—N7B | 1.374 (3) |
N7A—N8A | 1.352 (2) | N7B—N8B | 1.361 (2) |
N8A—O9A | 1.210 (3) | N8B—O10B | 1.214 (2) |
N8A—O10A | 1.222 (3) | N8B—O9B | 1.220 (2) |
C6A—N1A—C2A | 120.9 (2) | C2B—N1B—C6B | 120.7 (2) |
N1A—C6A—C5A | 120.4 (2) | N1B—C6B—C5B | 120.9 (2) |
C6A—C5A—C4A | 119.8 (2) | C6B—C5B—C4B | 119.1 (2) |
N7A—C4A—C5A | 115.2 (2) | N7B—C4B—C3B | 126.4 (2) |
N7A—C4A—C3A | 126.1 (2) | N7B—C4B—C5B | 114.8 (2) |
C5A—C4A—C3A | 118.7 (2) | C3B—C4B—C5B | 118.8 (2) |
C2A—C3A—C4A | 118.4 (2) | C2B—C3B—C4B | 118.2 (2) |
N1A—C2A—C3A | 121.9 (2) | N1B—C2B—C3B | 122.3 (2) |
N8A—N7A—C4A | 125.9 (2) | N8B—N7B—C4B | 125.4 (2) |
O9A—N8A—O10A | 125.2 (2) | O10B—N8B—O9B | 125.3 (2) |
O9A—N8A—N7A | 119.4 (2) | O10B—N8B—N7B | 115.4 (2) |
O10A—N8A—N7A | 115.3 (2) | O9B—N8B—N7B | 119.2 (2) |
C5A—C4A—N7A—N8A | −175.3 (2) | C3B—C4B—N7B—N8B | 9.6 (3) |
C3A—C4A—N7A—N8A | 5.4 (3) | C5B—C4B—N7B—N8B | −170.9 (2) |
C4A—N7A—N8A—O9A | 11.6 (3) | C4B—N7B—N8B—O10B | −178.0 (2) |
C4A—N7A—N8A—O10A | −170.9 (2) | C4B—N7B—N8B—O9B | 3.6 (3) |
D—H···A | D—H | H···A | D···A | D—H···A |
N7A—H7AA···O2Bi | 0.90 | 1.83 | 2.734 (2) | 176 |
N7B—H7BA···O3Aii | 0.90 | 1.77 | 2.665 (2) | 172 |
N1A—H1AE···O1A | 0.90 | 1.94 | 2.771 (2) | 154 |
N1B—H1BE···O1B | 0.90 | 1.82 | 2.668 (2) | 157 |
C3A—H3AB···O9A | 0.96 | 2.16 | 2.737 (3) | 117 |
C3B—H3BB···O9B | 0.96 | 2.15 | 2.716 (3) | 117 |
C5A—H5AA···O1Aiii | 0.96 | 2.62 | 3.176 (3) | 117 |
C6A—H6AA···O1Aiii | 0.96 | 2.39 | 3.072 (3) | 127 |
C3B—H3BB···O3Bi | 0.96 | 2.46 | 3.169 (3) | 131 |
C5B—H5BA···O2Aii | 0.96 | 2.41 | 3.369 (3) | 173 |
C6B—H6BA···O10Aiv | 0.96 | 2.66 | 3.306 (3) | 125 |
Symmetry codes: (i) x, y+1, z; (ii) −x+5/2, y+1/2, −z+3/2; (iii) −x+3/2, y+1/2, −z+3/2; (iv) x, y−1, z. |
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The reaction of primary nitramines with nitrous acid provides the same products as diazotation of the corresponding parent amines. When N-methylnitramine is treated with sodium nitrite in acidic solution, methanol and N,N-dimethylnitramine are formed. The latter is formed as a result of methylation of the substrate with diazomethane, the intermediate formed in the first step of the reaction. Because of the relative stability of aromatic diazonium salts they are the principal products, often formed quantitatively, of reactions of N-arylnitramines with nitrous acid (Wright 1969). We have assumed that this rule is applicable to the N-pyridylnitramines as well. Nitration of 4-aminopyridine with mixed acids provides the corresponding nitrimine, (I), in good yield (Deady & Korytsky, 1983). Methylation of (I) gives the nitrimine, (II), as the only product; the isomeric secondary nitramine has been obtained via another route (Daszkiewicz et al., 1997). The protonation of (II) must provide a cation, (III), containing a primary nitramino group bound to the positively charged aromatic ring. Its reaction with nitrous acid should give 1-methyl-4-pyridone as the main product. To our surprise, compound (II) is resistant to the action of nitrous acid and its rapid disproportionation gives 1-methyl-4-nitraminopyridine nitrate, (III), as the only product. Compound (II) cannot be rearranged like a typical nitramine under the influence of concentrated sulfuric acid, so the stability of its protonated form in (III) is not surprising. On the other hand, the primary nitramine is susceptible to rearrangement and forms 4-amino-3-nitropyridine in strongly acidic media. In spite of this, we were able to prepare from (I) the salt 4-nitraminopyridinium methanesulfonate, (V), and determine its structure, which is presented here with the structure of (III). The result confirms Deady & Korytsky's supposition that the rearrangement of pyridylnitramines requires double protonation of a substrate. \sch
The molecular structures of (III) and (V) are shown in Figs. 1 and 2. Compound (V) crystallizes with two independent molecules, A and B, in the asymmetric unit. The pyridine ring in (III) and (V) is not affected by the methyl substituent on N1, the positive charge or the character of the N-nitro group (primary, secondary or nitrimine). The C2—C3 and C5—C6 bonds are shorter (mean 1.356 Å) than the remaining C—C bonds (mean 1.396 Å) (Fig. 1). Another common feature is a decreased valence angle centred on C4, and slightly increased angles centred on C2 and C6. It is an inductive effect of the N-nitro group that is responsible for this apparent deformation. The Ar—N bonds are of the same length in all the molecules; the differences of ca 0.01 Å are incompatible with the expected differences between the formally single [(IV) (Meiyappan et al., 1999), (III) and (V) (present work)] and double bonds [(I) and (II) (Anulewicz et al., 1993; Krygowski et al., 1996)].
An interesting geometric parameter of all aromatic nitramines is the torsion angle along the Ar—N bond. This angle may be considered a gauge of the mesomeric interaction between the nitramine π-electron system and the aromatic sextet. The nitrimines (I) and (II) are planar or nearly planar, indicating conjugation between the ring and the substituent. It can be expected that protonation of the amide atom N9 can disconnect the conjugation, but this is not what has been observed: the molecules of (III) and (V) are nearly planar. The twist of the nitramino group about the C—N and N—N bonds does not exceed 10°. The deviations from coplanarity are accounted for with non-valence interactions.
In typical secondary nitramines in the benzene (Bujak et al., 1998; Ejsmont et al., 1998) and pyridine series (Zaleski et al., 1999a,b), the nitramino group is also almost planar. It is twisted with respect to the phenyl ring by ca 60° about the C—N bond [(VI) (Zaleski et al., 1999a)]. The length of the C—N bond is ca 0.025 Å longer, whereas the length of the N—N bond is almost the same as the corresponding bonds in the primary nitrimines, (I) and (II), and nitramines, (III) and (V). The twist of the nitramino group relative to the phenyl ring is steric in origin. It is impossible to accommodate the H3CNNO2 group and the phenyl ring on the same plane. Even when the methyl group is substituted by an H atom, coplanarity of the NHNO2 group and a phenyl ring leads to the deformation of the bond angles within the NNO2 group from 120°. The C4—N7—N8 and C3—C4—N7 angles are increased by ca 6°, whereas the C5—C4—N7 angle is decreased by ca 5°. Within the nitro group, there is an increase of ca 5° in the O9—N8—O10 angle and a decrease of the O10—N8—N7 angle, whereas the O9—N8—N7 angle remains close to 120°.
It should be mentioned that in the nitrimines, (I) and (II), a slightly different deformation of the NNO2 group is observed. The C4—N7—N8 angle remains close to 120°, whereas the C3—C4—N7 angle is more enlarged (by ca 10–11°). In the NO2 group as well, it is the O9—N8—N7 angle that is increased by ca 4°, whereas the O9—N8—O10 angle remains close to 120°. The reason for the observed differences is not clear. One possible explanation is an interaction between the lone electron pair on N7 and the NO2 group. Its relatively large size may lead to the increase of the valence angle centred on N8, rather than N7 as in the nitrimines (I) and (II).
The 1-methyl-4-nitraminopyridinium cations in (III) are connected to the NO3- anions by relatively strong N—H···O hydrogen bonds [H···O 1.77 (2) Å], forming pairs (Fig. 3). These pairs are interconnected with each other by much weaker C—H···O hydrogen bonds, forming layers close to the [101] plane. In the salt, (V), each 4-nitraminopyridinium cation is connected to two CH3SO3 anions by N—H···O hydrogen bonds [N···O 2.665 (2)–2.771 (2) Å], forming chains (Fig. 4). These hydrogen bonds are assisted by much weaker C—H···O ones [C···O 3.072 (3)–3.369 (3) Å], interconnecting the molecules into a three-dimensional structure. It should be mentioned that the hydrogen bonds binding one of the two independent cations are stronger than those in the other molecule: the H···O separations for the cation of molecule B are ca 0.06–0.12 Å shorter that those for the cation of molecule A.