Acta Cryst. (2008). E64, o2124 [ doi:10.1107/S1600536808031097 ]
The title cocrystal, 0.796C19H16N4·0.204C18H14N4, is a disordered mixture of two potentially bidentate Schiff base ligands. The difference in the two components of the cocrystal is the replacement of the methyl group in the linkage between the imine N atoms in the major component of the Schiff base ligand by an H atom. The imino (C=N) functional groups are coplanar with the benzene rings (only the major component) and extend in opposite directions (both components). Intermolecular ![[pi]](/logos/entities/pi_rmgif.gif)
- interactions with a centroid-to-centroid distance of 3.7371 (8) Å are observed in the crystal packing.
The synthetic method has been described previously (Fun, Kargar & Kia, 2008). Single crystals suitable for X-ray diffraction were obtained by evaporation of an ethanol solution at room temperature.
H atoms were positioned geometrically and refined using a riding model with C—H = 0.93–0.98 Å. The Uiso values were constrained to be 1.5Ueq of the carrier atom for the methyl H atoms and 1.2Ueq for the remaining H atoms. A rotating-group model was used for the methyl groups. Incorrect bond lengths of the methylene bridge, plus the presence of large peaks in the difference Fourier map near to the methylene bridge, led us to suspect positional disorder of this segment of the title compound. The refined ratio of the site-occupany factors for the disorder parts is 0.796 (2)/0.204 (2).
Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT (Bruker, 2005); data reduction: SAINT (Bruker, 2005); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2003).
![[Figure 1]](./ez2140fig1thm.gif)
| Fig. 1. The molecular structure of the title cocrystal, with atom labels and 50% probability ellipsoids for non-H atoms. Open bonds indicate the minor component. |
![[Figure 2]](./ez2140fig2thm.gif)
| Fig. 2. The crystal packing of the major component of (I), viewed down the b-axis. |
| 0.796C19H16N4·0.204C18H14N4 | Z = 2 |
| Mr = 297.68 | F(000) = 313 |
| Triclinic, P1 | Dx = 1.251 Mg m−3 |
| Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
| a = 9.2370 (2) Å | Cell parameters from 6569 reflections |
| b = 9.7769 (2) Å | θ = 3.2–30.8° |
| c = 9.8169 (2) Å | µ = 0.08 mm−1 |
| α = 81.846 (1)° | T = 100 K |
| β = 75.098 (1)° | Block, colourless |
| γ = 67.421 (1)° | 0.39 × 0.38 × 0.27 mm |
| V = 790.15 (3) Å3 |
| Bruker SMART APEXII CCD area-detector diffractometer | 4628 independent reflections |
| Radiation source: fine-focus sealed tube | 3746 reflections with I > 2σ(I) |
| graphite | Rint = 0.020 |
| φ and ω scans | θmax = 30.1°, θmin = 2.2° |
| Absorption correction: multi-scan (SADABS; Bruker, 2005) | h = −13→13 |
| Tmin = 0.890, Tmax = 0.979 | k = −13→13 |
| 17295 measured reflections | l = −13→13 |
| 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)] = 0.059 | Hydrogen site location: inferred from neighbouring sites |
| wR(F2) = 0.182 | H-atom parameters constrained |
| S = 1.05 | w = 1/[σ2(Fo2) + (0.0996P)2 + 0.2311P] where P = (Fo2 + 2Fc2)/3 |
| 4628 reflections | (Δ/σ)max < 0.001 |
| 230 parameters | Δρmax = 0.57 e Å−3 |
| 0 restraints | Δρmin = −0.48 e Å−3 |
| 0.796C19H16N4·0.204C18H14N4 | γ = 67.421 (1)° |
| Mr = 297.68 | V = 790.15 (3) Å3 |
| Triclinic, P1 | Z = 2 |
| a = 9.2370 (2) Å | Mo Kα radiation |
| b = 9.7769 (2) Å | µ = 0.08 mm−1 |
| c = 9.8169 (2) Å | T = 100 K |
| α = 81.846 (1)° | 0.39 × 0.38 × 0.27 mm |
| β = 75.098 (1)° |
| Bruker SMART APEXII CCD area-detector diffractometer | 4628 independent reflections |
| Absorption correction: multi-scan (SADABS; Bruker, 2005) | 3746 reflections with I > 2σ(I) |
| Tmin = 0.890, Tmax = 0.979 | Rint = 0.020 |
| 17295 measured reflections | θmax = 30.1° |
| R[F2 > 2σ(F2)] = 0.059 | H-atom parameters constrained |
| wR(F2) = 0.182 | Δρmax = 0.57 e Å−3 |
| S = 1.05 | Δρmin = −0.48 e Å−3 |
| 4628 reflections | Absolute structure: ? |
| 230 parameters | Flack parameter: ? |
| 0 restraints | Rogers parameter: ? |
Experimental. The low-temperature data was collected with the Oxford Cyrosystem Cobra low-temperature attachment. |
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 | Occ. (<1) | |
| N1A | 0.44472 (19) | 0.58449 (16) | 0.76563 (18) | 0.0277 (3) | 0.796 (2) |
| N2A | 0.31537 (17) | 0.28586 (16) | 0.96983 (15) | 0.0294 (3) | 0.796 (2) |
| C8A | 0.41965 (19) | 0.44248 (17) | 0.78683 (17) | 0.0276 (3) | 0.796 (2) |
| H8AA | 0.5235 | 0.3602 | 0.7675 | 0.033* | 0.796 (2) |
| C9A | 0.3328 (2) | 0.42957 (19) | 0.93985 (17) | 0.0311 (4) | 0.796 (2) |
| H9AA | 0.3933 | 0.4409 | 1.0021 | 0.037* | 0.796 (2) |
| H9AB | 0.2275 | 0.5079 | 0.9569 | 0.037* | 0.796 (2) |
| C19A | 0.3162 (2) | 0.44326 (18) | 0.68371 (15) | 0.0302 (4) | 0.796 (2) |
| H19A | 0.3770 | 0.4426 | 0.5883 | 0.045* | 0.796 (2) |
| H19B | 0.2204 | 0.5308 | 0.6954 | 0.045* | 0.796 (2) |
| H19C | 0.2873 | 0.3569 | 0.7039 | 0.045* | 0.796 (2) |
| N1B | 0.4751 (7) | 0.5817 (7) | 0.8069 (6) | 0.0236 (13)* | 0.204 (2) |
| N2B | 0.2894 (7) | 0.2948 (6) | 0.8959 (6) | 0.0294 (3) | 0.204 (2) |
| C8B | 0.4619 (7) | 0.4375 (6) | 0.8536 (6) | 0.0225 (11)* | 0.204 (2) |
| H8BA | 0.4726 | 0.4144 | 0.9508 | 0.027* | 0.204 (2) |
| H8BB | 0.5478 | 0.3612 | 0.7959 | 0.027* | 0.204 (2) |
| C9B | 0.2974 (6) | 0.4397 (6) | 0.8414 (6) | 0.0203 (10) | 0.204 (2) |
| H9BA | 0.2106 | 0.5179 | 0.8962 | 0.024* | 0.204 (2) |
| H9BB | 0.2881 | 0.4571 | 0.7437 | 0.024* | 0.204 (2) |
| N3 | 0.77232 (14) | 1.20704 (14) | 0.53274 (13) | 0.0356 (3) | |
| N4 | 0.04293 (17) | −0.36229 (15) | 1.22228 (16) | 0.0481 (4) | |
| C1 | 0.77783 (15) | 0.70764 (15) | 0.59144 (14) | 0.0310 (3) | |
| H1A | 0.8552 | 0.6156 | 0.5652 | 0.037* | |
| C2 | 0.81727 (15) | 0.83368 (15) | 0.55783 (13) | 0.0301 (3) | |
| H2A | 0.9207 | 0.8263 | 0.5101 | 0.036* | |
| C3 | 0.70001 (14) | 0.97147 (14) | 0.59648 (12) | 0.0250 (2) | |
| C4 | 0.54475 (14) | 0.98285 (14) | 0.66949 (13) | 0.0281 (3) | |
| H4A | 0.4671 | 1.0749 | 0.6957 | 0.034* | |
| C5 | 0.50763 (14) | 0.85626 (14) | 0.70243 (13) | 0.0274 (3) | |
| H5A | 0.4043 | 0.8635 | 0.7507 | 0.033* | |
| C6 | 0.62345 (14) | 0.71778 (14) | 0.66410 (12) | 0.0248 (2) | |
| C7 | 0.58542 (16) | 0.58172 (14) | 0.69901 (14) | 0.0302 (3) | |
| H7A | 0.6682 | 0.4882 | 0.6713 | 0.036* | 0.796 (2) |
| H7B | 0.6427 | 0.4971 | 0.6419 | 0.036* | 0.204 (2) |
| C10 | 0.18277 (17) | 0.28390 (16) | 1.04041 (17) | 0.0379 (3) | |
| H10A | 0.0979 | 0.3754 | 1.0711 | 0.045* | 0.796 (2) |
| H10B | 0.1389 | 0.3631 | 1.1042 | 0.045* | 0.204 (2) |
| C11 | 0.15451 (14) | 0.14439 (14) | 1.07915 (13) | 0.0269 (3) | |
| C12 | 0.00891 (15) | 0.14545 (14) | 1.16669 (14) | 0.0309 (3) | |
| H12A | −0.0691 | 0.2345 | 1.2005 | 0.037* | |
| C13 | −0.02034 (15) | 0.01501 (14) | 1.20368 (13) | 0.0285 (3) | |
| H13A | −0.1174 | 0.0161 | 1.2625 | 0.034* | |
| C14 | 0.09638 (15) | −0.11766 (14) | 1.15229 (13) | 0.0269 (3) | |
| C15 | 0.24291 (15) | −0.12015 (15) | 1.06462 (14) | 0.0316 (3) | |
| H15A | 0.3205 | −0.2092 | 1.0303 | 0.038* | |
| C16 | 0.27163 (14) | 0.01010 (14) | 1.02930 (13) | 0.0283 (3) | |
| H16A | 0.3695 | 0.0086 | 0.9720 | 0.034* | |
| C17 | 0.73983 (15) | 1.10277 (15) | 0.56153 (13) | 0.0281 (3) | |
| C18 | 0.06622 (17) | −0.25355 (16) | 1.19090 (15) | 0.0348 (3) |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| N1A | 0.0290 (7) | 0.0270 (7) | 0.0282 (7) | −0.0139 (5) | −0.0013 (6) | −0.0031 (5) |
| N2A | 0.0304 (6) | 0.0287 (6) | 0.0298 (7) | −0.0149 (5) | −0.0010 (5) | −0.0024 (5) |
| C8A | 0.0276 (7) | 0.0234 (7) | 0.0311 (8) | −0.0119 (6) | −0.0002 (6) | −0.0034 (6) |
| C9A | 0.0340 (8) | 0.0303 (8) | 0.0313 (8) | −0.0176 (6) | 0.0008 (6) | −0.0062 (6) |
| C19A | 0.0537 (10) | 0.0276 (7) | 0.0222 (7) | −0.0273 (7) | −0.0126 (6) | 0.0023 (5) |
| N2B | 0.0304 (6) | 0.0287 (6) | 0.0298 (7) | −0.0149 (5) | −0.0010 (5) | −0.0024 (5) |
| C9B | 0.024 (2) | 0.016 (2) | 0.021 (2) | −0.0076 (19) | −0.0053 (18) | 0.0005 (18) |
| N3 | 0.0337 (6) | 0.0363 (6) | 0.0387 (6) | −0.0187 (5) | 0.0002 (5) | −0.0055 (5) |
| N4 | 0.0457 (7) | 0.0340 (7) | 0.0585 (8) | −0.0165 (6) | 0.0000 (6) | 0.0008 (6) |
| C1 | 0.0258 (6) | 0.0283 (6) | 0.0341 (6) | −0.0090 (5) | 0.0027 (5) | −0.0060 (5) |
| C2 | 0.0239 (5) | 0.0335 (7) | 0.0312 (6) | −0.0127 (5) | 0.0020 (4) | −0.0046 (5) |
| C3 | 0.0253 (5) | 0.0294 (6) | 0.0229 (5) | −0.0134 (5) | −0.0033 (4) | −0.0031 (4) |
| C4 | 0.0235 (5) | 0.0265 (6) | 0.0325 (6) | −0.0096 (4) | −0.0006 (4) | −0.0051 (5) |
| C5 | 0.0225 (5) | 0.0294 (6) | 0.0298 (6) | −0.0116 (5) | −0.0006 (4) | −0.0036 (5) |
| C6 | 0.0252 (5) | 0.0268 (6) | 0.0219 (5) | −0.0112 (4) | −0.0011 (4) | −0.0029 (4) |
| C7 | 0.0304 (6) | 0.0258 (6) | 0.0308 (6) | −0.0108 (5) | 0.0010 (5) | −0.0025 (5) |
| C10 | 0.0293 (6) | 0.0273 (6) | 0.0558 (9) | −0.0129 (5) | 0.0018 (6) | −0.0112 (6) |
| C11 | 0.0248 (5) | 0.0261 (6) | 0.0312 (6) | −0.0105 (4) | −0.0043 (4) | −0.0055 (4) |
| C12 | 0.0260 (6) | 0.0257 (6) | 0.0360 (6) | −0.0066 (5) | 0.0000 (5) | −0.0066 (5) |
| C13 | 0.0236 (5) | 0.0305 (6) | 0.0283 (6) | −0.0094 (5) | −0.0015 (4) | −0.0008 (5) |
| C14 | 0.0269 (6) | 0.0263 (6) | 0.0263 (5) | −0.0094 (5) | −0.0046 (4) | −0.0005 (4) |
| C15 | 0.0271 (6) | 0.0265 (6) | 0.0358 (6) | −0.0072 (5) | 0.0004 (5) | −0.0057 (5) |
| C16 | 0.0232 (5) | 0.0299 (6) | 0.0303 (6) | −0.0100 (5) | −0.0006 (4) | −0.0054 (5) |
| C17 | 0.0256 (5) | 0.0330 (6) | 0.0269 (6) | −0.0134 (5) | −0.0013 (4) | −0.0054 (5) |
| C18 | 0.0326 (6) | 0.0304 (7) | 0.0372 (7) | −0.0113 (5) | −0.0012 (5) | −0.0005 (5) |
| N1A—C7 | 1.2878 (18) | C2—C3 | 1.3947 (18) |
| N1A—C8A | 1.4714 (19) | C2—H2A | 0.9300 |
| N2A—C10 | 1.2484 (18) | C3—C4 | 1.3979 (16) |
| N2A—C9A | 1.455 (2) | C3—C17 | 1.4400 (16) |
| C8A—C9A | 1.523 (2) | C4—C5 | 1.3818 (16) |
| C8A—C19A | 1.558 (2) | C4—H4A | 0.9300 |
| C8A—H8AA | 0.9800 | C5—C6 | 1.3944 (17) |
| C9A—H9AA | 0.9700 | C5—H5A | 0.9300 |
| C9A—H9AB | 0.9700 | C6—C7 | 1.4758 (16) |
| C19A—H19A | 0.9600 | C7—H7A | 0.9600 |
| C19A—H19B | 0.9600 | C7—H7B | 0.9600 |
| C19A—H19C | 0.9600 | C10—C11 | 1.4658 (17) |
| N1B—C7 | 1.267 (6) | C10—H10A | 0.9600 |
| N1B—C8B | 1.460 (8) | C10—H10B | 0.9600 |
| N2B—C9B | 1.464 (7) | C11—C12 | 1.3945 (17) |
| N2B—C10 | 1.521 (6) | C11—C16 | 1.3975 (17) |
| C8B—C9B | 1.546 (8) | C12—C13 | 1.3834 (17) |
| C8B—H8BA | 0.9700 | C12—H12A | 0.9300 |
| C8B—H8BB | 0.9700 | C13—C14 | 1.3897 (17) |
| C9B—H9BA | 0.9700 | C13—H13A | 0.9300 |
| C9B—H9BB | 0.9700 | C14—C15 | 1.3982 (17) |
| N3—C17 | 1.1484 (17) | C14—C18 | 1.4400 (18) |
| N4—C18 | 1.1489 (19) | C15—C16 | 1.3781 (17) |
| C1—C2 | 1.3883 (17) | C15—H15A | 0.9300 |
| C1—C6 | 1.3930 (16) | C16—H16A | 0.9300 |
| C1—H1A | 0.9300 | ||
| C7—N1A—C8A | 116.77 (13) | C1—C6—C5 | 119.43 (11) |
| C10—N2A—C9A | 117.17 (13) | C1—C6—C7 | 119.38 (11) |
| N1A—C8A—C9A | 107.68 (13) | C5—C6—C7 | 121.19 (10) |
| N1A—C8A—C19A | 108.24 (13) | N1B—C7—N1A | 24.5 (2) |
| C9A—C8A—C19A | 111.02 (13) | N1B—C7—C6 | 117.3 (3) |
| N1A—C8A—H8AA | 110.0 | N1A—C7—C6 | 122.07 (12) |
| C9A—C8A—H8AA | 110.0 | N1B—C7—H7A | 117.8 |
| C19A—C8A—H8AA | 110.0 | N1A—C7—H7A | 119.0 |
| N2A—C9A—C8A | 110.09 (13) | C6—C7—H7A | 119.0 |
| N2A—C9A—H9AA | 109.6 | N1B—C7—H7B | 121.9 |
| C8A—C9A—H9AA | 109.6 | N1A—C7—H7B | 111.9 |
| N2A—C9A—H9AB | 109.6 | C6—C7—H7B | 120.8 |
| C8A—C9A—H9AB | 109.6 | H7A—C7—H7B | 23.9 |
| H9AA—C9A—H9AB | 108.2 | N2A—C10—C11 | 121.33 (13) |
| C7—N1B—C8B | 115.5 (5) | N2A—C10—N2B | 31.9 (2) |
| C9B—N2B—C10 | 118.6 (4) | C11—C10—N2B | 116.6 (2) |
| N1B—C8B—C9B | 110.0 (5) | N2A—C10—H10A | 119.5 |
| N1B—C8B—H8BA | 109.7 | C11—C10—H10A | 119.2 |
| C9B—C8B—H8BA | 109.7 | N2B—C10—H10A | 114.8 |
| N1B—C8B—H8BB | 109.7 | N2A—C10—H10B | 107.4 |
| C9B—C8B—H8BB | 109.7 | C11—C10—H10B | 121.7 |
| H8BA—C8B—H8BB | 108.2 | N2B—C10—H10B | 121.8 |
| N2B—C9B—C8B | 107.0 (4) | H10A—C10—H10B | 32.0 |
| N2B—C9B—H9BA | 110.3 | C12—C11—C16 | 119.49 (11) |
| C8B—C9B—H9BA | 110.3 | C12—C11—C10 | 119.68 (11) |
| N2B—C9B—H9BB | 110.3 | C16—C11—C10 | 120.83 (11) |
| C8B—C9B—H9BB | 110.3 | C13—C12—C11 | 120.51 (11) |
| H9BA—C9B—H9BB | 108.6 | C13—C12—H12A | 119.7 |
| C2—C1—C6 | 120.64 (11) | C11—C12—H12A | 119.7 |
| C2—C1—H1A | 119.7 | C12—C13—C14 | 119.49 (11) |
| C6—C1—H1A | 119.7 | C12—C13—H13A | 120.3 |
| C1—C2—C3 | 119.28 (11) | C14—C13—H13A | 120.3 |
| C1—C2—H2A | 120.4 | C13—C14—C15 | 120.52 (12) |
| C3—C2—H2A | 120.4 | C13—C14—C18 | 119.56 (11) |
| C2—C3—C4 | 120.53 (11) | C15—C14—C18 | 119.92 (11) |
| C2—C3—C17 | 119.61 (10) | C16—C15—C14 | 119.61 (11) |
| C4—C3—C17 | 119.86 (11) | C16—C15—H15A | 120.2 |
| C5—C4—C3 | 119.44 (11) | C14—C15—H15A | 120.2 |
| C5—C4—H4A | 120.3 | C15—C16—C11 | 120.37 (11) |
| C3—C4—H4A | 120.3 | C15—C16—H16A | 119.8 |
| C4—C5—C6 | 120.68 (11) | C11—C16—H16A | 119.8 |
| C4—C5—H5A | 119.7 | N3—C17—C3 | 179.50 (14) |
| C6—C5—H5A | 119.7 | N4—C18—C14 | 179.53 (16) |
| C7—N1A—C8A—C9A | 134.28 (16) | C1—C6—C7—N1B | 152.5 (3) |
| C7—N1A—C8A—C19A | −105.62 (18) | C5—C6—C7—N1B | −27.5 (4) |
| C10—N2A—C9A—C8A | −136.91 (16) | C1—C6—C7—N1A | −179.80 (14) |
| N1A—C8A—C9A—N2A | −175.76 (13) | C5—C6—C7—N1A | 0.2 (2) |
| C19A—C8A—C9A—N2A | 65.92 (17) | C9A—N2A—C10—C11 | −178.46 (13) |
| C7—N1B—C8B—C9B | −116.7 (5) | C9A—N2A—C10—N2B | 90.8 (4) |
| C10—N2B—C9B—C8B | 105.6 (5) | C9B—N2B—C10—N2A | −83.9 (6) |
| N1B—C8B—C9B—N2B | −177.4 (5) | C9B—N2B—C10—C11 | 168.8 (4) |
| C6—C1—C2—C3 | −0.6 (2) | N2A—C10—C11—C12 | 175.33 (15) |
| C1—C2—C3—C4 | 0.61 (19) | N2B—C10—C11—C12 | −148.5 (3) |
| C1—C2—C3—C17 | −179.77 (11) | N2A—C10—C11—C16 | −4.8 (2) |
| C2—C3—C4—C5 | −0.45 (19) | N2B—C10—C11—C16 | 31.4 (3) |
| C17—C3—C4—C5 | 179.94 (11) | C16—C11—C12—C13 | −0.31 (19) |
| C3—C4—C5—C6 | 0.25 (19) | C10—C11—C12—C13 | 179.60 (12) |
| C2—C1—C6—C5 | 0.38 (19) | C11—C12—C13—C14 | −0.35 (19) |
| C2—C1—C6—C7 | −179.66 (11) | C12—C13—C14—C15 | 0.44 (19) |
| C4—C5—C6—C1 | −0.22 (19) | C12—C13—C14—C18 | 179.89 (12) |
| C4—C5—C6—C7 | 179.83 (11) | C13—C14—C15—C16 | 0.1 (2) |
| C8B—N1B—C7—N1A | 83.2 (8) | C18—C14—C15—C16 | −179.31 (12) |
| C8B—N1B—C7—C6 | −168.7 (4) | C14—C15—C16—C11 | −0.8 (2) |
| C8A—N1A—C7—N1B | −97.6 (8) | C12—C11—C16—C15 | 0.90 (19) |
| C8A—N1A—C7—C6 | 176.59 (13) | C10—C11—C16—C15 | −179.01 (12) |
H-KF and RK thank the Malaysian Government and Universiti Sains Malaysia for the Science Fund grant No. 305/PFIZIK/613312. RK thanks Universiti Sains Malaysia for a postdoctoral research fellowship. HK thanks PNU for financial support.
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Schiff bases are among the most prevalent mixed-donor ligands in the field of coordination chemistry. They play an important role in the development of catalysts and enzymatic reactions, magnetic materials and supramolecular architectures. Structures of Schiff bases derived from substituted benzaldehydes and closely related to the title compound have been reported recently (Li et al., 2005; Bomfim et al., 2005; Glidewell et al., 2005, 2006; Sun et al., 2004; Fun, Kargar & Kia, 2008; Fun, Kia & Kargar, 2008).
The title cocrystal consists of two bidentate Schiff base ligands. The bond lengths and angles in the two molecules (I, Fig. 1) are within normal ranges (Allen et al., 1987). In the major component, the imino (C=N) functional groups are coplanar with the benzene rings. The difference in the two components of the co-crystal, which are disordered over two sites, is the replacement of the methyl group in the major component by a hydrogen atom in the linkage between the imino N atoms. The ratio of the refined site occupancy factors of the major and minor components is 0.796 (2)/0.204 (2). The short distance between the centroids of the six-membered rings indicates the existence of π-π interactions (Fig. 2), with a Cg1···Cg1 distance of 3.7371 (8) Å (symmetry code: -x, -y, 2 - z; Cg1 is the centroid of the C11–C16 benzene ring).