2,4-Diamino-6-methyl-1,3,5-triazine methanol solvate

The crystal structure of the title compound, C4H7N5·CH4O, is determined by an extensive network of hydrogen bonding. A sequence of centrosymmetric dimeric associations, formed by two different N—H(amino)⋯N(ring) hydrogen bonds, connects the triazine rings into a planar molecular tape. The methanol solvent molecules act as di-acceptors and mono-donors of hydrogen bonds and interlink, almost perpendicularly, the hydrogen-bonded tapes into a three-dimensional structure.

The crystal structure of the title compound, C 4 H 7 N 5 ÁCH 4 O, is determined by an extensive network of hydrogen bonding. A sequence of centrosymmetric dimeric associations, formed by two different N-H(amino)Á Á ÁN(ring) hydrogen bonds, connects the triazine rings into a planar molecular tape. The methanol solvent molecules act as di-acceptors and monodonors of hydrogen bonds and interlink, almost perpendicularly, the hydrogen-bonded tapes into a three-dimensional structure.
The bond lengths within the ring are exceptionally uniform in all the 2,4-diaminotriazine derivatives. For 38 compounds found in the CSD (Allen, 2002; search conditions: only organics, no disorder, no errors) the mean standard deviation of the C≐N bond lengths is as small as 0.007 Å. The same is true for the title compound, the mean value of the C≐N bond distances being 1.346 (14) Å. The triazine ring is planar (Fig. 1), with a maximum deviation from the least-squares plane of 0.013 (1)Å for N5. The amino groups are almost coplanar with the ring plane, the dihedral angles between the NH 2 groups and the ring plane are 6(3)° for N2H 2 and 2(2)° for N4H 2 . Only the methyl carbon atom C61 deviates significantly from the plane by 0.055 (3) Å.
The crystal structure is determined by an extensive network of hydrogen bonds. Each NH 2 group acts as a donor in hydrogen bond with the ring nitrogen atoms of neighboring molecules, related by two different centres of symmetry. The sequence of such hydrogen-bonded dimers creates an almost planar molecular tape of molecules along the [101] direction ( Fig. 2). The tapes are interlinked by hydrogen bonds with the methanol solvent molecules, which act as di-acceptors and mono-donors of hydrogen bonds (Fig. 3). As a result, a three-dimensional structure of almost perpendicular tapes is formed in the crystal.

Experimental
To a solution of lanthanum(III) nitrate complex of Schiff base ligand, product of [2 + 1] condensation of one molecule of 2,4-diamino-6-methyl-1,3,5-triazine with two molecules of 2,6-diacetylpyridine (0.1 mmol), in methanol (10 ml), 2,4diamino-6-methyl-1,3,5-triazine (0.1 mmol) dissolved in hot methanol (10 ml) was added in order to receive the [2 + 2] Schiff base macrocyclic complex. After standing at room temperature for several hours, transparent crystals of the title compound were obtained. The crystals were initially transparent but after few minutes in open air they became opaque and gradually lost their crystallinity. Therefore the crystal used for data collection was sealed in a glass capillary.

Refinement
The methyl hydrogen atoms were positioned geometrically (AFIX 137) and refined using a riding model, with U iso (H) = 1.3 U eq (C). All other hydrogen atoms were located in difference Fourier maps and freely refined. Fig. 1. Anisotropic displacement ellipsoid representation (at the 50% probability level) of the molecule of the title compound, together with the numbering scheme. The hydrogen atoms are drawn as spheres with arbitrary radii. The intermolecular hydrogen bond is depicted as a dashed line.  Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > 2sigma(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.