Pyrrolidinium-2-carboxyl-ate-4-nitro-phenol (1/2).

In the title compound, C5H9NO2·2C6H5NO3, the pyrrolidine ring of the pyrrolidinium-2-carboxyl-ate zwitterion adopts a twisted conformation on the -CH2-CH2- bond adjacent to the N atom. The mean plane of this pyrrolidine ring forms dihedral angles of 25.3 (3) and 32.1 (3)° with the two nitro-phenol rings. An intra-molecular N-H⋯O hydrogen bond occurs in the pyrrolidinium-2-carboxyl-ate mol-ecule. In the crystal, mol-ecules are linked via O-H⋯O and N-H⋯O hydrogen bonds, enclosing R (3) 2(8) ring motifs, forming chains running parallel to the a axis. These chains are further cross-linked by O-H⋯O and C-H⋯O hydrogen bonds, forming undulating two-dimensional networks lying parallel to (001).

Morpholine-4-nitro-phenol (1/2).

In the title adduct, 2C6H5NO3·C4H9NO, the morpholine ring adopts a chair conformation. The dihedral angle between the two nitro-phenol rings is 69.47 (9)°. The nitro groups attached to the benzene rings make dihedral angles of 3.37 (16) and 3.14 (13)° in the two mol-ecules of nitro-phenol. The crystal structure is stabilized by N-H⋯O, O-H⋯N and O-H⋯O hydrogen bonds and further consolidated by C-H⋯O inter-actions, resulting in a three-dimensional network.