Crystal structures of three polymorphic forms of 4-hydroxy-3-methoxy-4′-nitro-trans-stilbene

Abstract

Abstract The structures of three polymorphic forms of 4-hydroxy-3-methoxy-4′-nitro-trans-stilbene (HMONS; C15H13NO4, M r = 271.27) are reported. Crystal growth experiments of HMONS from different solvents and varying conditions showed the existence of three crystalline phases, red crystals with symmetry of the orthorhombic space group Pbca, with a = 7.811(2) Å, b = 13.410(4) Å, c = 24.597(5) Å (1), yellow crystals belonging to the monoclinic space group C2/c with lattice parameters a = 18.788(2) Å, b = 6.6945(5) Å, c = 21.013(2) Å, β = 90.761(6)° (2), and yellowish-orange crystals with space group symmetry P21, and a = 6.9302(12) Å, b = 13.493(4) Å, c = 7.247(2) Å, β = 102.08(2)° (3). The latter exhibits a powder second harmonic generation (SHG) efficiency 70 times as large as that of urea.