organic compounds
2-Amino-4,6-dimethylpyrimidine–sorbic acid (1/1)
aSchool of Chemistry, Bharathidasan University, Tiruchirappalli 620 024, Tamilnadu, India
*Correspondence e-mail: tommtrichy@yahoo.co.in
In the crystal of the title compound, C6H9N3·C6H8O2, the 2-amino-4,6-dimethylpyrimidine and sorbic acid molecules are linked through N—H⋯O and O—H⋯N hydrogen bonds, which generate a cyclic bimolecular heterosynthon with an R22(8) graph-set motif. Further, two inversion-related pyrimidine molecules are base-paired via a pair of N—H⋯N hydrogen bonds, forming a cyclic bimolecular homosynthon with a graph-set of R22(8). A discrete hetero tetrameric supramolecular unit along the b axis is formed by the fusion of two heterosynthons and one homosynthon. An aromatic π–π interaction [centroid–centroid distance = 3.7945 (16) Å] is observed between these tetrameric units.
Related literature
For aminopyrimidine–carboxylic acid interactions, see: Hunt et al. (1980). For related structures, see: Thanigaimani et al. (2007); Ebenezer & Muthiah (2010, 2012). For hydrogen-bond motifs, see: Bernstein et al. (1995); Etter (1990).
Experimental
Crystal data
|
|
Data collection: APEX2 (Bruker, 2008); cell SAINT (Bruker, 2008); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009), Mercury (Macrae et al., 2008) and POV-RAY (Cason, 2004); software used to prepare material for publication: PLATON.
Supporting information
10.1107/S1600536813018175/is5286sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S1600536813018175/is5286Isup2.hkl
Hot aqueous solutions of 2-amino-4, 6-dimethylpyrimidine (31 mg, Aldrich) and sorbic acid (28 mg, Sisco) were mixed in a 1:1 molar ratio. The resulting solution was warmed over a water bath for half an hour and then kept at room temperature for crystallization. After a week, colorless prismatic crystals were obtained.
The hydrogen atoms for NH2 and OH groups were located in a difference Fourier map and refined freely. All other hydrogen atoms were positioned geometrically (C—H = 0.93–0.96 Å) and were refined using a riding model, with Uiso(H) = 1.2Ueq(C) for CH or 1.5Ueq(C) for CH3.
Data collection: APEX2 (Bruker, 2008); cell
SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009), Mercury (Macrae et al., 2008) and POV-RAY (Cason, 2004); software used to prepare material for publication: PLATON (Spek, 2009).C6H9N3·C6H8O2 | Z = 2 |
Mr = 235.29 | F(000) = 252 |
Triclinic, P1 | Dx = 1.194 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 7.8441 (6) Å | Cell parameters from 2280 reflections |
b = 9.9413 (8) Å | θ = 2.3–25.1° |
c = 10.2846 (13) Å | µ = 0.08 mm−1 |
α = 112.058 (7)° | T = 296 K |
β = 98.333 (8)° | Prism, colourless |
γ = 111.306 (5)° | 0.12 × 0.11 × 0.09 mm |
V = 654.69 (13) Å3 |
Bruker SMART APEXII CCD area-detector diffractometer | 2280 independent reflections |
Radiation source: fine-focus sealed tube | 1585 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.048 |
ϕ and ω scans | θmax = 25.1°, θmin = 2.3° |
Absorption correction: multi-scan (SADABS; Bruker, 2008) | h = −9→9 |
Tmin = 0.990, Tmax = 0.993 | k = −11→11 |
9667 measured reflections | l = −12→12 |
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)] = 0.069 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.210 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | w = 1/[σ2(Fo2) + (0.1185P)2 + 0.152P] where P = (Fo2 + 2Fc2)/3 |
2280 reflections | (Δ/σ)max < 0.001 |
169 parameters | Δρmax = 0.27 e Å−3 |
0 restraints | Δρmin = −0.28 e Å−3 |
C6H9N3·C6H8O2 | γ = 111.306 (5)° |
Mr = 235.29 | V = 654.69 (13) Å3 |
Triclinic, P1 | Z = 2 |
a = 7.8441 (6) Å | Mo Kα radiation |
b = 9.9413 (8) Å | µ = 0.08 mm−1 |
c = 10.2846 (13) Å | T = 296 K |
α = 112.058 (7)° | 0.12 × 0.11 × 0.09 mm |
β = 98.333 (8)° |
Bruker SMART APEXII CCD area-detector diffractometer | 2280 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 2008) | 1585 reflections with I > 2σ(I) |
Tmin = 0.990, Tmax = 0.993 | Rint = 0.048 |
9667 measured reflections |
R[F2 > 2σ(F2)] = 0.069 | 0 restraints |
wR(F2) = 0.210 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.03 | Δρmax = 0.27 e Å−3 |
2280 reflections | Δρmin = −0.28 e Å−3 |
169 parameters |
Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles |
Refinement. Refinement on F2 for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The observed criterion of F2 > σ(F2) is used only for calculating -R-factor-obs 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 | 0.2301 (3) | 0.2463 (2) | 0.49425 (19) | 0.0543 (7) | |
N2 | 0.0413 (4) | 0.3650 (3) | 0.5821 (3) | 0.0802 (10) | |
N3 | 0.1624 (3) | 0.4209 (2) | 0.40922 (19) | 0.0554 (7) | |
C2 | 0.1464 (3) | 0.3438 (3) | 0.4937 (2) | 0.0539 (7) | |
C4 | 0.2658 (3) | 0.3961 (3) | 0.3191 (2) | 0.0567 (8) | |
C5 | 0.3524 (4) | 0.2964 (3) | 0.3122 (3) | 0.0652 (9) | |
C6 | 0.3326 (3) | 0.2233 (3) | 0.4030 (2) | 0.0582 (8) | |
C7 | 0.2823 (4) | 0.4809 (4) | 0.2244 (3) | 0.0739 (10) | |
C8 | 0.4239 (5) | 0.1142 (4) | 0.4044 (3) | 0.0839 (11) | |
O1 | 0.0710 (4) | 0.2287 (3) | 0.7892 (2) | 0.1067 (10) | |
O2 | 0.2211 (3) | 0.1013 (2) | 0.6675 (2) | 0.0774 (8) | |
C9 | 0.1482 (4) | 0.1403 (3) | 0.7730 (3) | 0.0673 (9) | |
C10 | 0.1635 (4) | 0.0674 (3) | 0.8719 (3) | 0.0765 (10) | |
C11 | 0.2168 (3) | −0.0479 (3) | 0.8489 (3) | 0.0625 (8) | |
C12 | 0.2269 (4) | −0.1235 (3) | 0.9435 (3) | 0.0713 (9) | |
C13 | 0.2681 (4) | −0.2440 (4) | 0.9157 (3) | 0.0788 (11) | |
C14 | 0.2767 (5) | −0.3265 (4) | 1.0101 (4) | 0.0994 (14) | |
H2A | −0.017 (4) | 0.428 (3) | 0.589 (3) | 0.072 (7)* | |
H2B | 0.036 (4) | 0.321 (4) | 0.640 (4) | 0.095 (10)* | |
H5 | 0.42270 | 0.27890 | 0.24760 | 0.0780* | |
H7A | 0.17580 | 0.41340 | 0.13310 | 0.1110* | |
H7B | 0.40180 | 0.50070 | 0.20330 | 0.1110* | |
H7C | 0.27990 | 0.58280 | 0.27620 | 0.1110* | |
H8A | 0.49650 | 0.14980 | 0.50460 | 0.1250* | |
H8B | 0.50880 | 0.11920 | 0.34600 | 0.1250* | |
H8C | 0.32460 | 0.00410 | 0.36340 | 0.1250* | |
H2 | 0.212 (5) | 0.160 (4) | 0.610 (4) | 0.125 (12)* | |
H10 | 0.13270 | 0.10620 | 0.95800 | 0.0920* | |
H11 | 0.25130 | −0.08420 | 0.76420 | 0.0750* | |
H12 | 0.20160 | −0.08200 | 1.03180 | 0.0860* | |
H13 | 0.29520 | −0.28350 | 0.82780 | 0.0940* | |
H14A | 0.20900 | −0.30130 | 1.07910 | 0.1480* | |
H14B | 0.40940 | −0.28880 | 1.06350 | 0.1480* | |
H14C | 0.21730 | −0.44230 | 0.94810 | 0.1480* |
U11 | U22 | U33 | U12 | U13 | U23 | |
N1 | 0.0710 (12) | 0.0621 (12) | 0.0571 (10) | 0.0416 (10) | 0.0276 (9) | 0.0408 (9) |
N2 | 0.129 (2) | 0.1113 (19) | 0.0869 (15) | 0.0945 (18) | 0.0700 (15) | 0.0785 (15) |
N3 | 0.0718 (12) | 0.0614 (12) | 0.0544 (10) | 0.0374 (10) | 0.0231 (9) | 0.0399 (9) |
C2 | 0.0704 (14) | 0.0616 (13) | 0.0540 (11) | 0.0398 (12) | 0.0244 (10) | 0.0395 (10) |
C4 | 0.0640 (13) | 0.0602 (14) | 0.0558 (12) | 0.0265 (12) | 0.0198 (10) | 0.0382 (11) |
C5 | 0.0774 (16) | 0.0819 (17) | 0.0676 (14) | 0.0467 (14) | 0.0384 (12) | 0.0496 (13) |
C6 | 0.0665 (14) | 0.0676 (15) | 0.0602 (13) | 0.0393 (12) | 0.0246 (11) | 0.0387 (11) |
C7 | 0.0909 (18) | 0.0837 (18) | 0.0752 (16) | 0.0404 (15) | 0.0363 (14) | 0.0601 (15) |
C8 | 0.109 (2) | 0.106 (2) | 0.0947 (19) | 0.0792 (19) | 0.0544 (17) | 0.0657 (18) |
O1 | 0.191 (2) | 0.1244 (18) | 0.1037 (15) | 0.1172 (19) | 0.0929 (16) | 0.0885 (14) |
O2 | 0.1068 (14) | 0.1015 (14) | 0.0864 (12) | 0.0691 (12) | 0.0541 (11) | 0.0747 (11) |
C9 | 0.0954 (18) | 0.0668 (15) | 0.0625 (14) | 0.0436 (15) | 0.0318 (13) | 0.0433 (12) |
C10 | 0.119 (2) | 0.0733 (17) | 0.0605 (14) | 0.0492 (17) | 0.0374 (14) | 0.0455 (13) |
C11 | 0.0651 (14) | 0.0676 (15) | 0.0638 (13) | 0.0235 (12) | 0.0200 (11) | 0.0460 (12) |
C12 | 0.0867 (18) | 0.0665 (16) | 0.0652 (14) | 0.0271 (14) | 0.0169 (12) | 0.0453 (13) |
C13 | 0.0751 (17) | 0.092 (2) | 0.102 (2) | 0.0383 (16) | 0.0352 (15) | 0.0739 (18) |
C14 | 0.099 (2) | 0.093 (2) | 0.128 (3) | 0.0343 (18) | 0.0218 (19) | 0.087 (2) |
O1—C9 | 1.214 (5) | C7—H7A | 0.9600 |
O2—C9 | 1.296 (4) | C8—H8C | 0.9600 |
O2—H2 | 0.99 (4) | C8—H8A | 0.9600 |
N1—C2 | 1.355 (4) | C8—H8B | 0.9600 |
N1—C6 | 1.331 (3) | C9—C10 | 1.468 (4) |
N2—C2 | 1.323 (4) | C10—C11 | 1.311 (4) |
N3—C4 | 1.330 (3) | C11—C12 | 1.445 (4) |
N3—C2 | 1.349 (3) | C12—C13 | 1.293 (5) |
N2—H2A | 0.89 (3) | C13—C14 | 1.496 (5) |
N2—H2B | 0.86 (4) | C10—H10 | 0.9300 |
C4—C7 | 1.500 (4) | C11—H11 | 0.9300 |
C4—C5 | 1.378 (4) | C12—H12 | 0.9300 |
C5—C6 | 1.376 (4) | C13—H13 | 0.9300 |
C6—C8 | 1.504 (5) | C14—H14A | 0.9600 |
C5—H5 | 0.9300 | C14—H14B | 0.9600 |
C7—H7C | 0.9600 | C14—H14C | 0.9600 |
C7—H7B | 0.9600 | ||
O1···N2 | 2.946 (4) | H2···C8 | 2.88 (4) |
O2···N1 | 2.674 (3) | H2···C6 | 2.64 (4) |
O2···C8 | 3.351 (4) | H2A···N3iv | 2.19 (3) |
O1···H14Ai | 2.9100 | H2A···C4iv | 3.09 (3) |
O1···H2B | 2.10 (4) | H2B···C9 | 2.92 (4) |
O1···H14Cii | 2.7200 | H2B···O1 | 2.10 (4) |
O1···H8Ciii | 2.8400 | H2B···H2 | 2.43 (6) |
O2···H11 | 2.4600 | H5···H7B | 2.4700 |
N1···O2 | 2.674 (3) | H5···H8B | 2.4100 |
N2···N3iv | 3.076 (4) | H5···H13viii | 2.4400 |
N2···O1 | 2.946 (4) | H7B···H5 | 2.4700 |
N3···N2iv | 3.076 (4) | H7C···H8Aix | 2.4900 |
N1···H2 | 1.70 (4) | H8A···H7Cix | 2.4900 |
N2···H2 | 2.89 (4) | H8B···H5 | 2.4100 |
N3···H2Aiv | 2.19 (3) | H8B···H11viii | 2.4000 |
C2···C11iii | 3.521 (3) | H8C···O1iii | 2.8400 |
C7···C14v | 3.425 (5) | H10···H12 | 2.4600 |
C8···O2 | 3.351 (4) | H10···H12i | 2.5700 |
C11···C2iii | 3.521 (3) | H11···O2 | 2.4600 |
C14···C7vi | 3.425 (5) | H11···H13 | 2.4200 |
C2···H2 | 2.68 (4) | H11···H8Bviii | 2.4000 |
C4···H2Aiv | 3.09 (3) | H12···H10 | 2.4600 |
C6···H2 | 2.64 (4) | H12···H14A | 2.4200 |
C8···H2 | 2.88 (4) | H12···H10i | 2.5700 |
C9···H2B | 2.92 (4) | H13···H11 | 2.4200 |
C10···H14Bvii | 3.0700 | H13···H5viii | 2.4400 |
H2···N2 | 2.89 (4) | H14A···H12 | 2.4200 |
H2···C2 | 2.68 (4) | H14A···O1i | 2.9100 |
H2···N1 | 1.70 (4) | H14B···C10vii | 3.0700 |
H2···H2B | 2.43 (6) | H14C···O1x | 2.7200 |
C9—O2—H2 | 110 (2) | C6—C8—H8A | 109.00 |
C2—N1—C6 | 117.4 (2) | H8A—C8—H8C | 110.00 |
C2—N3—C4 | 116.8 (2) | H8B—C8—H8C | 109.00 |
C2—N2—H2B | 118 (2) | H8A—C8—H8B | 109.00 |
H2A—N2—H2B | 119 (3) | O1—C9—C10 | 121.9 (3) |
C2—N2—H2A | 123.3 (19) | O2—C9—C10 | 114.8 (3) |
N1—C2—N2 | 117.8 (2) | O1—C9—O2 | 123.3 (3) |
N2—C2—N3 | 117.5 (3) | C9—C10—C11 | 125.5 (3) |
N1—C2—N3 | 124.7 (2) | C10—C11—C12 | 125.8 (3) |
C5—C4—C7 | 121.6 (2) | C11—C12—C13 | 125.5 (3) |
N3—C4—C7 | 116.8 (2) | C12—C13—C14 | 126.8 (3) |
N3—C4—C5 | 121.7 (2) | C9—C10—H10 | 117.00 |
C4—C5—C6 | 118.6 (3) | C11—C10—H10 | 117.00 |
N1—C6—C8 | 116.8 (2) | C10—C11—H11 | 117.00 |
C5—C6—C8 | 122.3 (3) | C12—C11—H11 | 117.00 |
N1—C6—C5 | 120.9 (3) | C11—C12—H12 | 117.00 |
C6—C5—H5 | 121.00 | C13—C12—H12 | 117.00 |
C4—C5—H5 | 121.00 | C12—C13—H13 | 117.00 |
C4—C7—H7A | 109.00 | C14—C13—H13 | 117.00 |
C4—C7—H7C | 109.00 | C13—C14—H14A | 109.00 |
H7A—C7—H7B | 109.00 | C13—C14—H14B | 109.00 |
C4—C7—H7B | 109.00 | C13—C14—H14C | 109.00 |
H7B—C7—H7C | 109.00 | H14A—C14—H14B | 110.00 |
H7A—C7—H7C | 110.00 | H14A—C14—H14C | 110.00 |
C6—C8—H8B | 109.00 | H14B—C14—H14C | 109.00 |
C6—C8—H8C | 109.00 | ||
C6—N1—C2—N2 | 178.8 (2) | C7—C4—C5—C6 | 179.5 (3) |
C6—N1—C2—N3 | −1.1 (3) | C4—C5—C6—N1 | 0.9 (4) |
C2—N1—C6—C5 | 0.1 (3) | C4—C5—C6—C8 | −179.3 (3) |
C2—N1—C6—C8 | −179.7 (2) | O1—C9—C10—C11 | 168.8 (3) |
C4—N3—C2—N1 | 1.1 (3) | O2—C9—C10—C11 | −10.4 (5) |
C4—N3—C2—N2 | −178.9 (2) | C9—C10—C11—C12 | −178.1 (3) |
C2—N3—C4—C5 | 0.0 (3) | C10—C11—C12—C13 | 175.5 (3) |
C2—N3—C4—C7 | 179.6 (2) | C11—C12—C13—C14 | −179.0 (3) |
N3—C4—C5—C6 | −1.0 (4) |
Symmetry codes: (i) −x, −y, −z+2; (ii) x, y+1, z; (iii) −x, −y, −z+1; (iv) −x, −y+1, −z+1; (v) x, y+1, z−1; (vi) x, y−1, z+1; (vii) −x+1, −y, −z+2; (viii) −x+1, −y, −z+1; (ix) −x+1, −y+1, −z+1; (x) x, y−1, z. |
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H2···N1 | 0.99 (4) | 1.70 (4) | 2.674 (3) | 167 (4) |
N2—H2A···N3iv | 0.89 (3) | 2.19 (3) | 3.076 (4) | 176 (2) |
N2—H2B···O1 | 0.86 (4) | 2.10 (4) | 2.946 (4) | 171 (3) |
Symmetry code: (iv) −x, −y+1, −z+1. |
Experimental details
Crystal data | |
Chemical formula | C6H9N3·C6H8O2 |
Mr | 235.29 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 296 |
a, b, c (Å) | 7.8441 (6), 9.9413 (8), 10.2846 (13) |
α, β, γ (°) | 112.058 (7), 98.333 (8), 111.306 (5) |
V (Å3) | 654.69 (13) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.08 |
Crystal size (mm) | 0.12 × 0.11 × 0.09 |
Data collection | |
Diffractometer | Bruker SMART APEXII CCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Bruker, 2008) |
Tmin, Tmax | 0.990, 0.993 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 9667, 2280, 1585 |
Rint | 0.048 |
(sin θ/λ)max (Å−1) | 0.596 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.069, 0.210, 1.03 |
No. of reflections | 2280 |
No. of parameters | 169 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.27, −0.28 |
Computer programs: APEX2 (Bruker, 2008), SAINT (Bruker, 2008), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), PLATON (Spek, 2009), Mercury (Macrae et al., 2008) and POV-RAY (Cason, 2004), PLATON (Spek, 2009).
D—H···A | D—H | H···A | D···A | D—H···A |
O2—H2···N1 | 0.99 (4) | 1.70 (4) | 2.674 (3) | 167 (4) |
N2—H2A···N3i | 0.89 (3) | 2.19 (3) | 3.076 (4) | 176 (2) |
N2—H2B···O1 | 0.86 (4) | 2.10 (4) | 2.946 (4) | 171 (3) |
Symmetry code: (i) −x, −y+1, −z+1. |
Acknowledgements
SG thanks the UGC–SAP, India, for the award of an RFSMS. The authors thank the DST India (FIST programme) for the use of Bruker SMART APEXII diffractometer at the School of Chemistry, Bharathidasan University, Tiruchirappalli, Tamilnadu, India.
References
Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555–1573. CrossRef CAS Web of Science Google Scholar
Bruker (2008). APEX2, SAINT and SADABS. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Cason, C. J. (2004). POV-RAY. Persistence of Vision Raytracer Pty. Ltd, Victoria, Australia. Google Scholar
Ebenezer, S. & Muthiah, P. T. (2010). Acta Cryst. E66, o2634–o2635. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Ebenezer, S. & Muthiah, P. T. (2012). Cryst. Growth Des. 12, 3766–3785. Web of Science CSD CrossRef CAS Google Scholar
Etter, M. C. (1990). Acc. Chem. Res. 23, 120–126. CrossRef CAS Web of Science Google Scholar
Hunt, W. E., Schwalbe, C. H., Bird, K. & Mallinson, P. D. (1980). J. Biochem. 187, 533–536. CAS Google Scholar
Macrae, C. F., Bruno, I. J., Chisholm, J. A., Edgington, P. R., McCabe, P., Pidcock, E., Rodriguez-Monge, L., Taylor, R., van de Streek, J. & Wood, P. A. (2008). J. Appl. Cryst. 41, 466–470. Web of Science CrossRef CAS IUCr Journals Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Spek, A. L. (2009). Acta Cryst. D65, 148–155. Web of Science CrossRef CAS IUCr Journals Google Scholar
Thanigaimani, K., Muthiah, P. T. & Lynch, D. E. (2007). Acta Cryst. E63, o4450–o4451. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
The non-covalent interactions of aminopyrimidine with carboxylic acid derivatives are of immense significance, since they involve in many molecular recognition process of biological functions and protein-drug binding (Hunt et al.,1980). Sorbic acid is an antibacterial agent and widely used as a preservatives. Several salts and co-crystals involving 2-amino-4,6-dimethoxy/dimethyl pyrimidine and various carboxylates (Ebenezer & Muthiah, 2010) have already been reported from our laboratory.
The current investigation focuses on the supramolecular hydrogen-bonded patterns exhibited by the (1:1) co-crystal of 2-amino-4,6-dimethylpyrimidine with sorbic acid. The asymmetric unit of the titled co-crystal consists of one molecule of 2-amino-4,6-dimethylpyrimidine (AMPY) and a molecule of sorbic acid (SA) (Fig. 1). The SA molecule exists in the EE configuration. The extended conformation of SA can be inferred from the four torsion angles, C9—C10—C11—C12 = -178.1 (3)°, C10—C11—C12—C13 = 175.5 (3)°, C11—C12—C13—C14 = -179.0 (3)° and O1—C9—C10—C11 = 168.8 (3)°. The values are in close agreement with those in the literature (Thanigaimani et al., 2007).
The primary supramolecular synthon is assembled via N—H···O and O—H···N hydrogen bonds between the carboxylic group of SA and the amino pyrimidine moiety of AMPY to form a cyclic bimolecular heterosynthon with an R22(8) graph-set motif (Etter, 1990; Bernstein et al., 1995). Two centrosymmetric AMPY molecules are self-assembled to form complementary base pairing via a pair of N—H···N hydrogen bonds to form another R22(8) ring motif. The complementary base pairing involves 2-amino group and ring N3i atom of inversion related pyrimidine moiety of AMPY. The primary and secondary interactions lead to the generation of a discrete and stable linear hetero tetramer along the b axis (Ebenezer & Muthiah, 2012) which is a four-component supramolecule formed by the fusion of two centrosymmetric bimolecular heterosynthons [R22(8)] and a homosynthon [R22(8)] (Fig. 2). These discrete linear hetero tetrameric units are arranged in two dimensional space as sheets without any neighbouring interactions in the same plane.
The pyrimidine moiety of inversion related linear heterotetrameric units present in the parallel planes are stacked by an aromatic π–π interaction in a head to tail fashion (Fig. 3) with the interplanar distance of 3.580 Å, centroid to centroid distance of 3.7945 (16) Å [Cg–Cgi; symmetry code: (i) 1 - x,1 - y,1 - z] and the slip angle of 19.36°.