2,5-Dimethyl-N-[1-(1H-pyrrol-2-yl)ethylidene]aniline

In the title compound, C14H16N2, the pyrrole and benzene rings form a dihedral angle of 72.37 (8)°. In the crystal, centrosymmetrically related molecules are assembled into dimers by by pairs of N—H⋯N hydrogen bonds, generating rings of R 2 2(10) graph-set motif. C—H⋯π interactions also occur.

In the title compound, C 14 H 16 N 2 , the pyrrole and benzene rings form a dihedral angle of 72.37 (8) . In the crystal, centrosymmetrically related molecules are assembled into dimers by by pairs of N-HÁ Á ÁN hydrogen bonds, generating rings of R 2 2 (10) graph-set motif. C-HÁ Á Á interactions also occur.   Table 1 Hydrogen-bond geometry (Å , ).

Related literature
Cg1 is the centroid of the C7-C12 ring.   (Wu et al., 2003). As the five-memberd ring substitute of pyridine six-memberd ring (Matsuo et al., 2001;He et al., 2009), pyrrole has been frequently introduced into the skeleton of the bis(imino)pyridine ligand to design new ligands and corresponding metal complexes as catalysts of olefin polymerizations (Britovsek et al., 2003;Dawson et al., 2000). As a part of our studies on mono(imino)pyrrole ligands (Su et al., 2009a,b), the crystal structure of the title compound is reported here.
The X-ray analysis of the title compound ( Fig. 1) shows that the molecule is non-planar, with a dihedral angle of 72.37 (8)° formed by the pyrrole and benzene rings. The imino N-C bond length (1.288 (2) Å) indicates a C═N double bond character. In the crystal (Fig. 2), a pair of classical N-H···N hydrogen bonds (Table 1) link centrosymmetrically related molecules into a dimer, generating a ring of R 2 2 (10) graph-set motif. The dimer is further enforced by C-H···π hydrogen interactions.

Experimental
The reagents 2-acetyl pyrrole (0.1528 g, 1.40 mmol) and 2,5-dimethylaniline (0.3393 g, 2.80 mmol) were placed in a 50ml flask. A few drops of acetic acid was then added in, and the mixture was subjected to radiation in a 800 W microwave oven for 3 min and 2 min on a medium-heat setting. The reaction was monitored by TLC, and the crude product was purified by silica gel column chromatography (eluant: petroleum ether/ethyl acetate, 5:1 v/v). Plate-like colourless single crystals used in X-ray diffraction studies were grown from an ethanolic solution by slow evaporation of the solvent at  ,7.60;N,13.20. Found: C,79.72;H,7.13;N,12.84.

Refinement
All H atoms were placed at calculated positions and refined as riding, with C-H = 0.93-0.96 Å, N-H = 0.86 Å, and with U iso (H) = 1.2 U eq (C, N) or 1.5 U eq (C) for methyl H atoms.

Figure 1
The molecular structure of the title compound. Displacement ellipsoids are drawn at the 50% probability level. H atoms are presented as small spheres of arbitrary radius.  The crystal packing of the title compound viewed down the a axis, with hydrogen bond is shown as dashed lines.  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 > σ(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.