n-stacked hydrogen-bonded dimers in 2-(2nitrophenylaminocarbonyl)-benzoic acid, and hydrogen-bonded sheets in orthorhombic and monoclinic polymorphs of 2-(4-nitrophenylaminocarbonyl)benzoic acid

Molecules of 2-(2-nitrophenylaminocarbonyl)benzoic acid, C14H10N2O5, are linked into centrosymmetric R-2(2) (8) dimers by a single O-H...O hydrogen bond [H...O=1.78 Angstrom, O...O=2.623 (2) Angstrom and O-H...O=178degrees] and these dimers are linked into sheets by a single aromatic pi-pi stacking interaction. The isomeric compound 2-(4-nitrophenylaminocarbonyl)benzoic acid crystallizes in two polymorphic forms. In the orthorhombic form (space group P2(1)2(1)2(1) with Z'=1, crystallized from ethanol), the molecules are linked into sheets of R-4(4)(22) rings by a combination of one N-H...O hydrogen bond [H...O=1.96Angstrom, N...O=2.833(3)Angstrom and N-H...O=171degrees] and one O-H...O hydrogen bond [H...O=1.78 Angstrom, O...O=2.614 (3)Angstrom and O-H...O=173degrees]. In the monoclinic form (space group P2(1)/n with Z'=2, crystallized from acetone), the molecules are linked by a combination of two N-H...O hydrogen bonds [H...O=2.09 and 2.16 Angstrom, N...O=2.873 (4) and 2.902 (3) Angstrom, and N-H...O=147 and 141degrees] and two O-H...O hydrogen bonds [H...O=1.84 and 1.83 Angstrom, O...O=2.664 (3) and 2.666 (3) Angstrom, and O-H...O=166 and 174degrees] into sheets of some complexity. These sheets are linked into a three-dimensional framework by a single C-H...O hydrogen bond [H...O=2.45 Angstrom, C...O=3.355 (4) Angstrom and C-H...O=160degrees].