Growth and X-ray structure of single crystals of 1,3,5-tris[(6,7-dimethyl-3-phenyl)quinoxaline-2-yl] benzene

Single crystals of 1,3,5-tris[(6,7-dimethyl-3-phenyl)quinoxaline-2-yl] benzene (Me-TPQ) have been grown from the vapour phase under high-vacuum conditions. Me-TPQ belongs to the class of star-shaped tris(phenylquinoxalines) which form usually amorphous glasses. Thermal analysis indicated however, that the title compound possesses a crystal phase. The structure of Me-TPQ crystals has been determined by single crystal X-ray diffraction measurements. Two unit cells have been detected, monoclinic and orthorhombic. We report, here, the crystal structure of the latter, which might be of interest for non-linear optics applications.