Two Crystal Polymorphs of 3-(Dimethylamino)benzoic Anhydride

Abstract

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) Å, a 96.39(2), b 104.04(2), g 107.59(2)˚, V 800.0(6) Å 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 Å, b 112.14(3)˚, V 1574.5(9) Å 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.