











Supporting information
![]() | Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270101005819/gg1041sup1.cif |
![]() | Structure factor file (CIF format) https://doi.org/10.1107/S0108270101005819/gg1041Isup2.hkl |
![]() | Structure factor file (CIF format) https://doi.org/10.1107/S0108270101005819/gg1041IIsup3.hkl |
CCDC references: 169941; 169942
The title compound, (I), was prepared by Spa Contract Synthesis. Crystals of (I) were grown from an ethanol solution. Crystals of (II) were grown from an ethanol solution of equimolar amounts of (I) and 4-aminobenzoic acid (Aldrich). Theoretical pKa values were calculated using pKalc 3.2 from PALLAS 2.1 available from Compudrug; www.compudrug.com.
All aromatic H atoms were included in the refinement at calculated positions, as riding models with C—H set to 0.95 Å. All H atoms involved in the hydrogen-bonding associations were located in difference syntheses and both position and thermal parameters subsequently refined.
Data collection: DENZO (Otwinowski & Minor, 1997) and COLLECT (Hooft, 1998) for (I); DENZO (Otwinowski & Minor, 1997 and COLLECT (Hooft, 1998) for (II). For both compounds, cell refinement: DENZO and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON97 (Spek, 1997); software used to prepare material for publication: SHELXL97.
C9H8N4 | Dx = 1.411 Mg m−3 |
Mr = 172.19 | Melting point: 353-356 K K |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
a = 9.450 (2) Å | Cell parameters from 3577 reflections |
b = 13.689 (3) Å | θ = 2.9–47.8° |
c = 6.439 (1) Å | µ = 0.09 mm−1 |
β = 103.35 (3)° | T = 150 K |
V = 810.4 (3) Å3 | Prism, yellow |
Z = 4 | 0.27 × 0.12 × 0.12 mm |
F(000) = 360 |
Kappa-CCD diffractometer | 1841 independent reflections |
Radiation source: Enraf Nonius FR591 rotating anode | 1417 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.04 |
Detector resolution: 9.091 pixels mm-1 | θmax = 27.5°, θmin = 3.0° |
ϕ and ω scans | h = −11→12 |
Absorption correction: multi-scan (SORTAV; Blessing, 1995) | k = −17→17 |
Tmin = 0.976, Tmax = 0.989 | l = −8→8 |
6415 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)] = 0.047 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.132 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | w = 1/[σ2(Fo2) + (0.0846P)2 + 0.0128P] where P = (Fo2 + 2Fc2)/3 |
1841 reflections | (Δ/σ)max < 0.001 |
126 parameters | Δρmax = 0.25 e Å−3 |
0 restraints | Δρmin = −0.25 e Å−3 |
C9H8N4 | V = 810.4 (3) Å3 |
Mr = 172.19 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 9.450 (2) Å | µ = 0.09 mm−1 |
b = 13.689 (3) Å | T = 150 K |
c = 6.439 (1) Å | 0.27 × 0.12 × 0.12 mm |
β = 103.35 (3)° |
Kappa-CCD diffractometer | 1841 independent reflections |
Absorption correction: multi-scan (SORTAV; Blessing, 1995) | 1417 reflections with I > 2σ(I) |
Tmin = 0.976, Tmax = 0.989 | Rint = 0.04 |
6415 measured reflections |
R[F2 > 2σ(F2)] = 0.047 | 0 restraints |
wR(F2) = 0.132 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | Δρmax = 0.25 e Å−3 |
1841 reflections | Δρmin = −0.25 e Å−3 |
126 parameters |
Experimental. PLEASE NOTE cell_measurement_ fields are not relevant to area detector data, the entire data set is used to refine the cell, which is indexed from all observed reflections in a 10 degree phi range. |
Geometry. Mean plane data ex SHELXL97 ########################### Least-squares planes (x,y,z in crystal coordinates) and deviations from them (* indicates atom used to define plane) - 2.4652 (0.0045) x + 12.1614 (0.0072) y + 2.7539 (0.0034) z = 10.3692 (0.0063) * -0.0001 (0.0008) N1 * -0.0082 (0.0008) C2 * 0.0105 (0.0008) N3 * -0.0050 (0.0008) C4 * -0.0029 (0.0008) C5 * 0.0057 (0.0009) C6 - 0.0523 (0.0018) N21 Rms deviation of fitted atoms = 0.0064 - 0.4015 (0.0048) x + 13.6705 (0.0072) y + 0.2478 (0.0039) z = 11.9322 (0.0065) Angle to previous plane (with approximate e.s.d.) = 24.57 (0.05) * 0.0070 (0.0009) C7 * -0.0051 (0.0009) C8 * -0.0005 (0.0009) C9 * 0.0044 (0.0009) N10 * -0.0024 (0.0009) C11 * -0.0033 (0.0009) C12 Rms deviation of fitted atoms = 0.0043 |
x | y | z | Uiso*/Ueq | ||
N1 | −0.24503 (12) | 0.86156 (8) | −0.25879 (16) | 0.0263 (3) | |
C2 | −0.14313 (14) | 0.90228 (9) | −0.35034 (18) | 0.0229 (3) | |
N21 | −0.18924 (13) | 0.93476 (9) | −0.55106 (16) | 0.0287 (3) | |
H21 | −0.283 (2) | 0.9241 (11) | −0.627 (2) | 0.040 (4)* | |
H22 | −0.1250 (18) | 0.9663 (11) | −0.615 (2) | 0.045 (4)* | |
N3 | −0.00036 (11) | 0.91179 (7) | −0.25774 (15) | 0.0227 (3) | |
C4 | 0.04501 (14) | 0.87496 (8) | −0.06011 (19) | 0.0218 (3) | |
C5 | −0.05131 (14) | 0.83165 (9) | 0.04571 (19) | 0.0265 (3) | |
H5 | −0.0194 | 0.8060 | 0.1859 | 0.033* | |
C6 | −0.19526 (14) | 0.82755 (9) | −0.0619 (2) | 0.0272 (3) | |
H6 | −0.2628 | 0.7988 | 0.0085 | 0.034* | |
C7 | 0.20356 (15) | 0.87872 (9) | 0.03404 (19) | 0.0232 (3) | |
C8 | 0.26123 (16) | 0.87555 (10) | 0.2533 (2) | 0.0302 (3) | |
H8 | 0.1988 | 0.8711 | 0.3492 | 0.038* | |
C9 | 0.41009 (17) | 0.87887 (10) | 0.3299 (2) | 0.0353 (4) | |
H9 | 0.4472 | 0.8772 | 0.4801 | 0.044* | |
N10 | 0.50522 (13) | 0.88427 (9) | 0.20589 (19) | 0.0350 (3) | |
C11 | 0.44911 (16) | 0.88593 (10) | −0.0045 (2) | 0.0332 (4) | |
H10 | 0.5144 | 0.8892 | −0.0965 | 0.042* | |
C12 | 0.30230 (15) | 0.88321 (10) | −0.0957 (2) | 0.0286 (3) | |
H12 | 0.2686 | 0.8844 | −0.2466 | 0.036* |
U11 | U22 | U33 | U12 | U13 | U23 | |
N1 | 0.0204 (6) | 0.0303 (6) | 0.0285 (6) | 0.0002 (4) | 0.0061 (4) | 0.0022 (4) |
C2 | 0.0215 (7) | 0.0232 (6) | 0.0236 (6) | 0.0005 (5) | 0.0040 (5) | −0.0017 (5) |
N21 | 0.0210 (7) | 0.0398 (7) | 0.0230 (5) | −0.0022 (5) | 0.0002 (5) | 0.0041 (5) |
N3 | 0.0215 (6) | 0.0249 (6) | 0.0209 (5) | −0.0005 (4) | 0.0031 (4) | 0.0001 (4) |
C4 | 0.0229 (7) | 0.0210 (6) | 0.0212 (6) | 0.0010 (5) | 0.0041 (5) | −0.0018 (4) |
C5 | 0.0265 (8) | 0.0292 (7) | 0.0232 (6) | 0.0019 (5) | 0.0049 (5) | 0.0039 (5) |
C6 | 0.0250 (8) | 0.0288 (7) | 0.0294 (7) | 0.0005 (5) | 0.0093 (5) | 0.0042 (5) |
C7 | 0.0236 (7) | 0.0213 (6) | 0.0229 (6) | 0.0001 (5) | 0.0018 (5) | 0.0011 (5) |
C8 | 0.0281 (8) | 0.0376 (8) | 0.0236 (6) | −0.0019 (6) | 0.0034 (5) | 0.0002 (5) |
C9 | 0.0330 (9) | 0.0451 (9) | 0.0237 (7) | −0.0033 (6) | −0.0018 (6) | 0.0014 (6) |
N10 | 0.0238 (7) | 0.0460 (7) | 0.0312 (6) | −0.0010 (5) | −0.0019 (5) | 0.0056 (5) |
C11 | 0.0228 (8) | 0.0445 (8) | 0.0309 (7) | 0.0034 (6) | 0.0034 (6) | 0.0057 (6) |
C12 | 0.0255 (8) | 0.0364 (8) | 0.0226 (6) | 0.0021 (6) | 0.0029 (5) | 0.0042 (5) |
N1—C6 | 1.3303 (16) | C6—H6 | 0.95 |
N1—C2 | 1.3592 (16) | C7—C12 | 1.3899 (19) |
C2—N21 | 1.3408 (15) | C7—C8 | 1.3914 (17) |
C2—N3 | 1.3496 (17) | C8—C9 | 1.380 (2) |
N21—H21 | 0.919 (18) | C8—H8 | 0.95 |
N21—H22 | 0.917 (16) | C9—N10 | 1.3349 (18) |
N3—C4 | 1.3436 (16) | C9—H9 | 0.95 |
C4—C5 | 1.3895 (17) | N10—C11 | 1.3358 (18) |
C4—C7 | 1.482 (2) | C11—C12 | 1.377 (2) |
C5—C6 | 1.3779 (19) | C11—H10 | 0.95 |
C5—H5 | 0.95 | C12—H12 | 0.95 |
C6—N1—C2 | 115.26 (11) | C12—C7—C8 | 116.80 (13) |
N21—C2—N3 | 117.59 (11) | C12—C7—C4 | 120.76 (11) |
N21—C2—N1 | 116.67 (12) | C8—C7—C4 | 122.43 (12) |
N3—C2—N1 | 125.74 (11) | C9—C8—C7 | 119.33 (13) |
C2—N21—H21 | 121.4 (9) | C9—C8—H8 | 120.3 |
C2—N21—H22 | 119.3 (10) | C7—C8—H8 | 120.3 |
H21—N21—H22 | 119.3 (13) | N10—C9—C8 | 124.04 (12) |
C4—N3—C2 | 116.75 (11) | N10—C9—H9 | 118.0 |
N3—C4—C5 | 121.50 (12) | C8—C9—H9 | 118.0 |
N3—C4—C7 | 116.48 (11) | C9—N10—C11 | 116.27 (13) |
C5—C4—C7 | 121.96 (11) | N10—C11—C12 | 123.86 (13) |
C6—C5—C4 | 116.95 (11) | N10—C11—H10 | 118.1 |
C6—C5—H5 | 121.5 | C12—C11—H10 | 118.1 |
C4—C5—H5 | 121.5 | C11—C12—C7 | 119.68 (12) |
N1—C6—C5 | 123.77 (11) | C11—C12—H12 | 120.2 |
N1—C6—H6 | 118.1 | C7—C12—H12 | 120.2 |
C5—C6—H6 | 118.1 | ||
C6—N1—C2—N21 | 178.18 (11) | C5—C4—C7—C12 | 152.98 (12) |
C6—N1—C2—N3 | −1.11 (19) | N3—C4—C7—C8 | 157.49 (12) |
N21—C2—N3—C4 | −177.15 (11) | C5—C4—C7—C8 | −25.40 (17) |
N1—C2—N3—C4 | 2.13 (18) | C12—C7—C8—C9 | 1.23 (18) |
C2—N3—C4—C5 | −1.73 (17) | C4—C7—C8—C9 | 179.68 (11) |
C2—N3—C4—C7 | 175.40 (9) | C7—C8—C9—N10 | −0.6 (2) |
N3—C4—C5—C6 | 0.47 (17) | C8—C9—N10—C11 | −0.3 (2) |
C7—C4—C5—C6 | −176.50 (11) | C9—N10—C11—C12 | 0.5 (2) |
C2—N1—C6—C5 | −0.34 (19) | N10—C11—C12—C7 | 0.2 (2) |
C4—C5—C6—N1 | 0.63 (19) | C8—C7—C12—C11 | −1.06 (19) |
N3—C4—C7—C12 | −24.13 (16) | C4—C7—C12—C11 | −179.53 (11) |
D—H···A | D—H | H···A | D···A | D—H···A |
N21—H22···N3i | 0.917 (16) | 2.303 (17) | 3.1870 (17) | 161.7 (13) |
N21—H21···N10ii | 0.919 (18) | 2.114 (19) | 3.0295 (19) | 174.1 (14) |
Symmetry codes: (i) −x, −y+2, −z−1; (ii) x−1, y, z−1. |
C9H8N4·C7H7NO2 | Dx = 1.386 Mg m−3 |
Mr = 309.33 | Melting point: 356-358 K K |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
a = 7.881 (2) Å | Cell parameters from 10808 reflections |
b = 26.354 (5) Å | θ = 1.0–27.5° |
c = 7.297 (2) Å | µ = 0.10 mm−1 |
β = 102.04 (3)° | T = 150 K |
V = 1482.2 (5) Å3 | Prism, yellow |
Z = 4 | 0.55 × 0.20 × 0.20 mm |
F(000) = 648 |
Kappa-CCD diffractometer | 3303 independent reflections |
Radiation source: Enraf Nonius FR591 rotating anode | 2349 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.047 |
Detector resolution: 9.091 pixels mm-1 | θmax = 27.5°, θmin = 2.6° |
ϕ and ω scans | h = −9→10 |
Absorption correction: multi-scan (SORTAV; Blessing, 1995) | k = −34→27 |
Tmin = 0.949, Tmax = 0.981 | l = −9→9 |
10418 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)] = 0.048 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.123 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | w = 1/[σ2(Fo2) + (0.0708P)2] where P = (Fo2 + 2Fc2)/3 |
3303 reflections | (Δ/σ)max < 0.001 |
228 parameters | Δρmax = 0.28 e Å−3 |
0 restraints | Δρmin = −0.32 e Å−3 |
C9H8N4·C7H7NO2 | V = 1482.2 (5) Å3 |
Mr = 309.33 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 7.881 (2) Å | µ = 0.10 mm−1 |
b = 26.354 (5) Å | T = 150 K |
c = 7.297 (2) Å | 0.55 × 0.20 × 0.20 mm |
β = 102.04 (3)° |
Kappa-CCD diffractometer | 3303 independent reflections |
Absorption correction: multi-scan (SORTAV; Blessing, 1995) | 2349 reflections with I > 2σ(I) |
Tmin = 0.949, Tmax = 0.981 | Rint = 0.047 |
10418 measured reflections |
R[F2 > 2σ(F2)] = 0.048 | 0 restraints |
wR(F2) = 0.123 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | Δρmax = 0.28 e Å−3 |
3303 reflections | Δρmin = −0.32 e Å−3 |
228 parameters |
Experimental. PLEASE NOTE cell_measurement_ fields are not relevant to area detector data, the entire data set is used to refine the cell, which is indexed from all observed reflections in a 10 degree phi range. |
Geometry. Mean plane data ex SHELXL97 ########################### Least-squares planes (x,y,z in crystal coordinates) and deviations from them (* indicates atom used to define plane) - 1.5580 (0.0042) x + 17.9884 (0.0152) y + 5.3219 (0.0042) z = 7.6095 (0.0075) * 0.0123 (0.0010) N1A * -0.0092 (0.0010) C2A * -0.0042 (0.0009) N3A * 0.0141 (0.0010) C4A * -0.0101 (0.0010) C5A * -0.0028 (0.0010) C6A Rms deviation of fitted atoms = 0.0097 - 4.2315 (0.0043) x + 3.4876 (0.0165) y + 6.7635 (0.0038) z = 2.6173 (0.0067) Angle to previous plane (with approximate e.s.d.) = 38.49 (0.06) * 0.0017 (0.0010) C7A * 0.0102 (0.0010) C8A * -0.0126 (0.0010) C9A * 0.0022 (0.0010) N10A * 0.0102 (0.0010) C11A * -0.0117 (0.0010) C12A Rms deviation of fitted atoms = 0.0092 |
x | y | z | Uiso*/Ueq | ||
N1A | −0.87542 (14) | 0.45140 (5) | −0.34988 (16) | 0.0244 (3) | |
C2A | −0.72994 (17) | 0.47322 (6) | −0.3851 (2) | 0.0228 (3) | |
N21A | −0.75169 (17) | 0.50959 (5) | −0.51658 (19) | 0.0330 (4) | |
H21A | −0.863 (2) | 0.5206 (7) | −0.568 (2) | 0.045 (5)* | |
H22A | −0.655 (2) | 0.5214 (7) | −0.555 (2) | 0.043 (5)* | |
N3A | −0.56584 (14) | 0.46184 (5) | −0.29763 (16) | 0.0231 (3) | |
C4A | −0.54805 (18) | 0.42559 (5) | −0.16648 (19) | 0.0214 (3) | |
C5A | −0.68880 (18) | 0.39977 (6) | −0.1250 (2) | 0.0260 (3) | |
H5A | −0.6748 | 0.3732 | −0.0350 | 0.032* | |
C6A | −0.85032 (18) | 0.41491 (6) | −0.2220 (2) | 0.0249 (3) | |
H6A | −0.9493 | 0.3982 | −0.1957 | 0.031* | |
C7A | −0.36937 (17) | 0.41571 (6) | −0.05824 (19) | 0.0212 (3) | |
C8A | −0.31596 (18) | 0.36718 (6) | 0.0015 (2) | 0.0250 (3) | |
H8A | −0.3926 | 0.3392 | −0.0289 | 0.031* | |
C9A | −0.15072 (19) | 0.36007 (6) | 0.1051 (2) | 0.0270 (4) | |
H9A | −0.1143 | 0.3265 | 0.1411 | 0.034* | |
N10A | −0.03918 (15) | 0.39798 (5) | 0.15756 (17) | 0.0259 (3) | |
C11A | −0.09118 (19) | 0.44479 (6) | 0.1021 (2) | 0.0275 (4) | |
H11A | −0.0135 | 0.4722 | 0.1398 | 0.034* | |
C12A | −0.25215 (18) | 0.45521 (6) | −0.0073 (2) | 0.0251 (3) | |
H12A | −0.2826 | 0.4889 | −0.0472 | 0.031* | |
C1B | 0.48115 (18) | 0.32246 (5) | 0.51343 (19) | 0.0221 (3) | |
C11B | 0.30006 (18) | 0.33616 (6) | 0.4293 (2) | 0.0234 (3) | |
O10B | 0.17457 (12) | 0.31097 (4) | 0.45158 (15) | 0.0319 (3) | |
O11B | 0.28353 (13) | 0.37776 (4) | 0.32739 (15) | 0.0320 (3) | |
H11B | 0.157 (3) | 0.3855 (8) | 0.272 (3) | 0.072 (7)* | |
C2B | 0.51641 (18) | 0.27978 (6) | 0.6282 (2) | 0.0247 (3) | |
H2B | 0.4231 | 0.2597 | 0.6514 | 0.031* | |
C3B | 0.68411 (18) | 0.26637 (6) | 0.7082 (2) | 0.0258 (3) | |
H3B | 0.7050 | 0.2375 | 0.7878 | 0.032* | |
C4B | 0.82499 (18) | 0.29487 (6) | 0.67384 (19) | 0.0234 (3) | |
N41B | 0.99257 (18) | 0.28304 (6) | 0.7566 (2) | 0.0324 (3) | |
H41B | 1.016 (2) | 0.2544 (9) | 0.811 (3) | 0.056 (6)* | |
H42B | 1.076 (2) | 0.2932 (7) | 0.697 (3) | 0.046 (5)* | |
C5B | 0.78847 (17) | 0.33739 (6) | 0.55653 (19) | 0.0234 (3) | |
H5B | 0.8814 | 0.3571 | 0.5301 | 0.029* | |
C6B | 0.62055 (18) | 0.35102 (6) | 0.47934 (19) | 0.0223 (3) | |
H6B | 0.5990 | 0.3803 | 0.4018 | 0.028* |
U11 | U22 | U33 | U12 | U13 | U23 | |
N1A | 0.0184 (6) | 0.0286 (8) | 0.0258 (7) | −0.0015 (5) | 0.0036 (5) | 0.0004 (5) |
C2A | 0.0188 (7) | 0.0242 (8) | 0.0241 (7) | 0.0015 (6) | 0.0019 (6) | 0.0003 (6) |
N21A | 0.0187 (7) | 0.0397 (9) | 0.0393 (8) | 0.0029 (6) | 0.0031 (6) | 0.0176 (7) |
N3A | 0.0187 (6) | 0.0238 (7) | 0.0255 (7) | 0.0011 (5) | 0.0018 (5) | 0.0018 (5) |
C4A | 0.0217 (7) | 0.0207 (8) | 0.0213 (7) | 0.0013 (6) | 0.0030 (6) | −0.0015 (6) |
C5A | 0.0260 (8) | 0.0242 (8) | 0.0269 (8) | −0.0004 (6) | 0.0036 (6) | 0.0032 (6) |
C6A | 0.0220 (7) | 0.0279 (9) | 0.0251 (7) | −0.0027 (6) | 0.0059 (6) | −0.0009 (6) |
C7A | 0.0203 (7) | 0.0245 (8) | 0.0191 (7) | 0.0028 (6) | 0.0047 (6) | 0.0003 (6) |
C8A | 0.0245 (8) | 0.0222 (8) | 0.0270 (8) | 0.0004 (6) | 0.0023 (6) | 0.0010 (6) |
C9A | 0.0275 (8) | 0.0248 (9) | 0.0279 (8) | 0.0054 (6) | 0.0041 (6) | 0.0050 (6) |
N10A | 0.0221 (6) | 0.0295 (8) | 0.0248 (6) | 0.0037 (5) | 0.0018 (5) | 0.0028 (5) |
C11A | 0.0234 (8) | 0.0263 (9) | 0.0309 (8) | −0.0013 (6) | 0.0017 (6) | −0.0013 (7) |
C12A | 0.0224 (8) | 0.0221 (8) | 0.0298 (8) | 0.0024 (6) | 0.0031 (6) | 0.0014 (6) |
C1B | 0.0225 (7) | 0.0217 (8) | 0.0216 (7) | 0.0001 (6) | 0.0036 (6) | −0.0033 (6) |
C11B | 0.0229 (8) | 0.0244 (8) | 0.0230 (7) | 0.0008 (6) | 0.0047 (6) | −0.0028 (6) |
O10B | 0.0219 (6) | 0.0333 (7) | 0.0397 (6) | −0.0034 (5) | 0.0042 (5) | 0.0012 (5) |
O11B | 0.0216 (6) | 0.0334 (7) | 0.0382 (6) | 0.0034 (5) | −0.0001 (5) | 0.0119 (5) |
C2B | 0.0241 (8) | 0.0243 (9) | 0.0263 (8) | −0.0017 (6) | 0.0065 (6) | 0.0001 (6) |
C3B | 0.0295 (8) | 0.0225 (8) | 0.0247 (8) | 0.0042 (6) | 0.0043 (6) | 0.0037 (6) |
C4B | 0.0234 (8) | 0.0251 (8) | 0.0208 (7) | 0.0038 (6) | 0.0021 (6) | −0.0025 (6) |
N41B | 0.0238 (7) | 0.0352 (9) | 0.0362 (8) | 0.0068 (6) | 0.0014 (6) | 0.0073 (7) |
C5B | 0.0210 (8) | 0.0242 (8) | 0.0244 (7) | −0.0020 (6) | 0.0036 (6) | −0.0020 (6) |
C6B | 0.0241 (7) | 0.0208 (8) | 0.0213 (7) | 0.0012 (6) | 0.0030 (6) | 0.0002 (6) |
N1A—C6A | 1.3256 (19) | C11A—H11A | 0.95 |
N1A—C2A | 1.3543 (18) | C12A—H12A | 0.95 |
C2A—N21A | 1.3418 (19) | C1B—C2B | 1.395 (2) |
C2A—N3A | 1.3511 (18) | C1B—C6B | 1.396 (2) |
N21A—H21A | 0.928 (18) | C1B—C11B | 1.476 (2) |
N21A—H22A | 0.917 (17) | C11B—O10B | 1.2297 (17) |
N3A—C4A | 1.3386 (18) | C11B—O11B | 1.3160 (18) |
C4A—C5A | 1.388 (2) | O11B—H11B | 1.01 (2) |
C4A—C7A | 1.487 (2) | C2B—C3B | 1.375 (2) |
C5A—C6A | 1.380 (2) | C2B—H2B | 0.95 |
C5A—H5A | 0.95 | C3B—C4B | 1.406 (2) |
C6A—H6A | 0.95 | C3B—H3B | 0.95 |
C7A—C8A | 1.388 (2) | C4B—N41B | 1.3687 (19) |
C7A—C12A | 1.390 (2) | C4B—C5B | 1.403 (2) |
C8A—C9A | 1.376 (2) | N41B—H41B | 0.85 (2) |
C8A—H8A | 0.95 | N41B—H42B | 0.90 (2) |
C9A—N10A | 1.333 (2) | C5B—C6B | 1.3735 (19) |
C9A—H9A | 0.95 | C5B—H5B | 0.95 |
N10A—C11A | 1.336 (2) | C6B—H6B | 0.95 |
C11A—C12A | 1.378 (2) | ||
C6A—N1A—C2A | 115.69 (12) | C12A—C11A—H11A | 118.4 |
N21A—C2A—N3A | 117.59 (13) | C11A—C12A—C7A | 119.07 (14) |
N21A—C2A—N1A | 116.88 (13) | C11A—C12A—H12A | 120.5 |
N3A—C2A—N1A | 125.52 (13) | C7A—C12A—H12A | 120.5 |
C2A—N21A—H21A | 118.6 (11) | C2B—C1B—C6B | 118.42 (13) |
C2A—N21A—H22A | 118.2 (11) | C2B—C1B—C11B | 120.06 (13) |
H21A—N21A—H22A | 123.2 (16) | C6B—C1B—C11B | 121.51 (13) |
C4A—N3A—C2A | 116.31 (12) | O10B—C11B—O11B | 122.47 (13) |
N3A—C4A—C5A | 122.46 (13) | O10B—C11B—C1B | 123.21 (14) |
N3A—C4A—C7A | 116.82 (12) | O11B—C11B—C1B | 114.32 (12) |
C5A—C4A—C7A | 120.65 (13) | C11B—O11B—H11B | 111.4 (12) |
C6A—C5A—C4A | 116.10 (14) | C3B—C2B—C1B | 121.04 (14) |
C6A—C5A—H5A | 122.0 | C3B—C2B—H2B | 119.5 |
C4A—C5A—H5A | 122.0 | C1B—C2B—H2B | 119.5 |
N1A—C6A—C5A | 123.85 (14) | C2B—C3B—C4B | 120.79 (14) |
N1A—C6A—H6A | 118.1 | C2B—C3B—H3B | 119.6 |
C5A—C6A—H6A | 118.1 | C4B—C3B—H3B | 119.6 |
C8A—C7A—C12A | 117.71 (13) | N41B—C4B—C5B | 120.48 (14) |
C8A—C7A—C4A | 121.32 (13) | N41B—C4B—C3B | 121.67 (14) |
C12A—C7A—C4A | 120.92 (13) | C5B—C4B—C3B | 117.80 (13) |
C9A—C8A—C7A | 119.25 (14) | C4B—N41B—H41B | 119.9 (13) |
C9A—C8A—H8A | 120.4 | C4B—N41B—H42B | 116.8 (12) |
C7A—C8A—H8A | 120.4 | H41B—N41B—H42B | 112.4 (17) |
N10A—C9A—C8A | 123.20 (14) | C6B—C5B—C4B | 121.10 (13) |
N10A—C9A—H9A | 118.4 | C6B—C5B—H5B | 119.5 |
C8A—C9A—H9A | 118.4 | C4B—C5B—H5B | 119.5 |
C9A—N10A—C11A | 117.58 (13) | C5B—C6B—C1B | 120.84 (14) |
N10A—C11A—C12A | 123.13 (14) | C5B—C6B—H6B | 119.6 |
N10A—C11A—H11A | 118.4 | C1B—C6B—H6B | 119.6 |
C6A—N1A—C2A—N21A | 178.75 (14) | C9A—N10A—C11A—C12A | −0.8 (2) |
C6A—N1A—C2A—N3A | −2.1 (2) | N10A—C11A—C12A—C7A | 2.1 (2) |
N21A—C2A—N3A—C4A | 179.68 (14) | C8A—C7A—C12A—C11A | −1.2 (2) |
N1A—C2A—N3A—C4A | 0.5 (2) | C4A—C7A—C12A—C11A | 176.36 (13) |
C2A—N3A—C4A—C5A | 1.8 (2) | C2B—C1B—C11B—O10B | −1.6 (2) |
C2A—N3A—C4A—C7A | −175.06 (12) | C6B—C1B—C11B—O10B | 177.64 (13) |
N3A—C4A—C5A—C6A | −2.4 (2) | C2B—C1B—C11B—O11B | 178.57 (13) |
C7A—C4A—C5A—C6A | 174.39 (13) | C6B—C1B—C11B—O11B | −2.2 (2) |
C2A—N1A—C6A—C5A | 1.4 (2) | C6B—C1B—C2B—C3B | 0.9 (2) |
C4A—C5A—C6A—N1A | 0.7 (2) | C11B—C1B—C2B—C3B | −179.89 (13) |
N3A—C4A—C7A—C8A | −145.34 (14) | C1B—C2B—C3B—C4B | −1.1 (2) |
C5A—C4A—C7A—C8A | 37.7 (2) | C2B—C3B—C4B—N41B | 178.02 (14) |
N3A—C4A—C7A—C12A | 37.15 (19) | C2B—C3B—C4B—C5B | 0.4 (2) |
C5A—C4A—C7A—C12A | −139.81 (15) | N41B—C4B—C5B—C6B | −177.03 (13) |
C12A—C7A—C8A—C9A | −0.8 (2) | C3B—C4B—C5B—C6B | 0.6 (2) |
C4A—C7A—C8A—C9A | −178.43 (13) | C4B—C5B—C6B—C1B | −0.9 (2) |
C7A—C8A—C9A—N10A | 2.3 (2) | C2B—C1B—C6B—C5B | 0.1 (2) |
C8A—C9A—N10A—C11A | −1.5 (2) | C11B—C1B—C6B—C5B | −179.08 (13) |
D—H···A | D—H | H···A | D···A | D—H···A |
N21A—H21A···N1Ai | 0.928 (18) | 2.151 (18) | 3.0737 (19) | 172.8 (16) |
N21A—H22A···N3Aii | 0.917 (17) | 2.274 (17) | 3.1755 (18) | 167.5 (15) |
O11B—H11B···N10A | 1.01 (2) | 1.63 (2) | 2.6406 (17) | 173 (2) |
N41B—H41B···O10Biii | 0.85 (2) | 2.25 (2) | 3.0609 (19) | 159.0 (17) |
N41B—H42B···O10Biv | 0.90 (2) | 2.15 (2) | 2.981 (2) | 153.6 (16) |
Symmetry codes: (i) −x−2, −y+1, −z−1; (ii) −x−1, −y+1, −z−1; (iii) x+1, −y+1/2, z+1/2; (iv) x+1, y, z. |
Experimental details
(I) | (II) | |
Crystal data | ||
Chemical formula | C9H8N4 | C9H8N4·C7H7NO2 |
Mr | 172.19 | 309.33 |
Crystal system, space group | Monoclinic, P21/c | Monoclinic, P21/c |
Temperature (K) | 150 | 150 |
a, b, c (Å) | 9.450 (2), 13.689 (3), 6.439 (1) | 7.881 (2), 26.354 (5), 7.297 (2) |
β (°) | 103.35 (3) | 102.04 (3) |
V (Å3) | 810.4 (3) | 1482.2 (5) |
Z | 4 | 4 |
Radiation type | Mo Kα | Mo Kα |
µ (mm−1) | 0.09 | 0.10 |
Crystal size (mm) | 0.27 × 0.12 × 0.12 | 0.55 × 0.20 × 0.20 |
Data collection | ||
Diffractometer | Kappa-CCD diffractometer | Kappa-CCD diffractometer |
Absorption correction | Multi-scan (SORTAV; Blessing, 1995) | Multi-scan (SORTAV; Blessing, 1995) |
Tmin, Tmax | 0.976, 0.989 | 0.949, 0.981 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 6415, 1841, 1417 | 10418, 3303, 2349 |
Rint | 0.04 | 0.047 |
(sin θ/λ)max (Å−1) | 0.650 | 0.650 |
Refinement | ||
R[F2 > 2σ(F2)], wR(F2), S | 0.047, 0.132, 1.03 | 0.048, 0.123, 1.03 |
No. of reflections | 1841 | 3303 |
No. of parameters | 126 | 228 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.25, −0.25 | 0.28, −0.32 |
Computer programs: DENZO (Otwinowski & Minor, 1997) and COLLECT (Hooft, 1998), DENZO (Otwinowski & Minor, 1997 and COLLECT (Hooft, 1998), DENZO and COLLECT, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), PLATON97 (Spek, 1997), SHELXL97.
D—H···A | D—H | H···A | D···A | D—H···A |
N21—H22···N3i | 0.917 (16) | 2.303 (17) | 3.1870 (17) | 161.7 (13) |
N21—H21···N10ii | 0.919 (18) | 2.114 (19) | 3.0295 (19) | 174.1 (14) |
Symmetry codes: (i) −x, −y+2, −z−1; (ii) x−1, y, z−1. |
D—H···A | D—H | H···A | D···A | D—H···A |
N21A—H21A···N1Ai | 0.928 (18) | 2.151 (18) | 3.0737 (19) | 172.8 (16) |
N21A—H22A···N3Aii | 0.917 (17) | 2.274 (17) | 3.1755 (18) | 167.5 (15) |
O11B—H11B···N10A | 1.01 (2) | 1.63 (2) | 2.6406 (17) | 173 (2) |
N41B—H41B···O10Biii | 0.85 (2) | 2.25 (2) | 3.0609 (19) | 159.0 (17) |
N41B—H42B···O10Biv | 0.90 (2) | 2.15 (2) | 2.981 (2) | 153.6 (16) |
Symmetry codes: (i) −x−2, −y+1, −z−1; (ii) −x−1, −y+1, −z−1; (iii) x+1, −y+1/2, z+1/2; (iv) x+1, y, z. |
The design of multi-dimensional organic crystal lattices requires the use of molecules with several interactive substituents. Ideally, the association of these substituents can be predicted and their specific position used to construct the desired array (Desiraju, 1995). For a number of years the principal author has studied the association between carboxylic acids and either pyridines or 2-aminopyridine type molecules with the additional amine group used to lock the COOH and the heterocyclic ring in essentially the same plane (Fig. 1). If the secondary substituents on the carboxylic acid molecule do not have the hydrogen-bonding donor strength of the acid itself then association between the acid and the Lewis base can be expected (Lynch et al., 2000). However, competition between these two types of bases (in one molecule) has never been investigated by X-ray crystallography and the authors postulated as to which of the two groups a carboxylic acid would preferentially bind. Etter (1991) inversely showed that the same pyridine base, when placed in a mixed carboxylic acid solution, selectively co-crystallized the acid with the lower pKa value. Our purpose for this study was to investigate whether the same pKa difference would be important when two different bases were in competition for the same acid?
The principal author has always assumed that the 2-aminopyridine site is more stable for binding with COOH groups than pyridine itself, because the resultant synthon mimics acid dimer formation. Therefore, a simple molecule containing both a pyridine N and a 2-aminopyridine site has been produced to test whether a COOH group is preferentially attracted to either the stronger base or the more stable binding site. One of a series of simple molecules which contain both types of bases is 2-amino-4-(pyrid-4-yl)pyrimidine. This molecule subsequently exhibited a large difference in the pKa values of the two bases (pKa = 5.58 and 1.83 for the pyridine and the pyrimidine, respectively). The chosen acid was 4-aminobenzoic acid, which has proven to be a very useful crystallization aid for a number of functional multi-substituted molecules (Smith et al., 1997). The amine group, with the lesser inherent acid strength (pKa = 5.05), was not expected to directly compete with the COOH (pKa = 2.38) for binding to the stronger base yet additional hydrogen-bonding donors were required to satisfy the remaining hydrogen-bonding acceptors (after the COOH has bound). Here we report the single-crystal structures of 2-amino-4-(pyrid-4-yl)pyrimidine, (I), and its 1:1 adduct with 4-aminobenzoic acid, (II). \sch
The structure of (I) comprises nonplanar molecules (Fig. 2) that, similar to other analogous compounds, form R22(8) hydrogen-bonded dimers across one of the pyrimidine N/NH2 sites. The second amine H atom, instead of forming another dimer, interacts with the pyridyl N atom thus creating a linear hydrogen-bonded polymer chain (Fig. 3), the hydrogen-bonding geometry is listed in Table 1. In (I), the dihedral angle between the two rings is 24.57 (5)°. The structure of (II) (Fig. 4) comprises twisted 2-aminopyrimidine derivatives associating via continuous R22(8) hydrogen-bonded dimers with the inclusion of the acid molecules bound to the 4-pyridyl group (Fig. 5). The two 4-amino H atoms are also involved in the hydrogen-bonding network with three-centre associations to the carbonyl O atom and the hydrogen-bonding geometry is listed in Table 2. The dihedral angle between the two linked rings of the base in the structure of (II) is 38.49 (6)°.
4-Aminobenzoic acid is a relatively strong organic acid with a pKa value of 2.38, thus when adducted with 2-amino-4-(pyrid-4-yl)pyrimidine the carboxylic acid group could have bound to a complementary acidic pyrimidine N/NH2 site (pKa = 1.83), but instead was found to prefer the more basic pyridyl N atom (pKa = 5.58). The pKa difference between the COOH and the pyridyl group is < 3.75 (Johnson & Rumon, 1965) so no proton-transfer (and hence an organic salt) results. The pyrimidine N/NH2 sites then form dimers with themselves and leave the 4-amino H atoms to associate with the only other available hydrogen-bonding acceptor atom, the carbonyl O atom (although a few cases exist where the 4-amino N atoms have also been hydrogen-bond acceptors). The results of this study may have been affected by the fact that the carboxylic acid group has a higher pKa value than the pyrimidine N/NH2 site. However, to use an organic acid with a pKa < 1.83 would have led to a pKa difference between the COOH group and the pyridyl N atom being > 3.75, above which proton-transfer to the pyridyl group could have occurred (Johnson & Rumon, 1965), assuring binding to the pyridyl N atom. The acidity of the pyrimidine group was also affected by the direct substitution of an electron accepting group, thus attempts are underway to synthesize a molecule which contains these two heterocyclic bases but between which is an alkyl spacer (preferably hexa-cyclic such that the conformation can be controlled). In such a molecule the pKa value of the pyrimidine ring should be closer to the pKa value of 2-aminopyrimidine itself (pKa = 2.40). A lowering of the inherent acid strength of this group thus increases the potential for COOH binding to the pyrimidine as opposed to the pyridine.