Two crystal polymorphs of 3-(dimethylamino)benzoic anhydride

Two polymorphs of 3-(dimethylamino)benzoic anhydride have been determined by single crystal X-ray diffraction analysis. Polymorph (1) is triclinic (P1, a 7.112(3), b 9.289(4), c 13.364(5) Angstrom, alpha 96.39(2), beta 104.04(2), gamma 107.59(2)degrees, V 800.0(6) Angstrom (3) , Z 2) with the full molecule in the asymmetric unit, whereas polymorph (2) is monoclinic (C2/c, a 10.892(3), b 11.855(4), c 13.164 Angstrom, beta 112.14(3)degrees, V 1574.5(9) Angstrom (3), Z 4) with the central oxygen atom across a twofold axis. Differing conformations and C H hydrogen-bonding associations give rise to markedly different solid-state packing arrangements.