Crystal structures and supramolecular studies of three organic picrate salts

C. S. Chidan Kumar1*, Huey Cho

Abstract

Three crystalline picrate salts with benzimidamidium (I), 2-isopropyl-6-methylpyrimidin-1,3-diium-4-olate (II) and N-(amino(pyrimidin-2-yl)methylene)hydroxyl ammonium (III) cations, respectively, were self-assembled and their three-dimensional structures were characterized by single-crystal X-ray diffraction. Salt I is crystallized in orthorhombic space group P212121 with a = 5.031(3) Å, b = 13.692(7) Å, c = 21.821(10) Å, V = 1503.1(13) Å3 and Z = 4. Salt II is crystallized in monoclinic space group P21/c with a = 7.9360 (8) Å, b = 18.852 (2) Å, c = 11.9140 (11) Å, β = 100.067 (2)°, V = 1755.0 (3) Å3 and Z = 2. Salt III is crystallized in non-centrosymmetric monoclinic space group P21 with a = 12.0404 (11) Å, b = 4.0308 (4) Å, c = 15.0078 (14) Å, β = 99.680 (2)°, V = 1503.1 (13) Å3 and Z = 2. Proton transfers are observed in all picrate salts, featuring short intermolecular N+–H···O- hydrogen bonds [d(N···O) ~ 2.7 Å]. Salt I displayed a three-dimensional structural network while salts II and III formed zerodimensional tetramer and two-dimensional plane, respectively, under the interactions of intermolecular hydrogen bonds.