title: Anilinium monohydrogen DL-malate.
abstract: Crystals of the title salt, [(C(6)H(5)NH(3))](+).[(HOOC(CH(2))CH(OH)COO)](-) or C(6)H(8)N(+).C(4)H(5)O(5)(-), are built up from protonated anilinium residues and monodissociated DL-malate ions. The NH(3)(+) group of the anilinium cation is ordered at room temperature. Rotation of the NH(3)(+) group along the C(aromatic)-Nsp(3) bond (often observed at room temperature in other anilinium salts) is prevented by N-H.O hydrogen bonds between the NH(3)(+) group and the malate anions. The anions are connected by four O-H.O hydrogen bonds into two-dimensional sheets parallel to the (001) plane. The charged moieties, i.e. the anilinium cations and the sheets of hydrogen-bonded malate anions, form two-dimensional layers in which the phenyl rings of the anilinium residues lie perpendicular to the malate-ion sheets. The conformation of the monodissociated malate ion in the crystal is compared with that obtained from ab initio molecular-orbital calculations.
authors.affiliation: Departamento de Fisica, Instituto de Ciências Exatas e Biológicas, Universidade Federal de Ouro Preto, CEP 35.400-000, Ouro Preto, MG, Brazil.
authors.forename: Genivaldo Julio
authors.initials: GJ
authors.lastname: Perpétuo
authors.forename: Jan
authors.initials: J
authors.lastname: Janczak
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry*; D018360:Crystallography, X-Ray; D007477:Ions; D008293:Malates / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D011487:Protein Conformation; D012492:Salts / Q000737:chemistry*; D013696:Temperature
chemical_list: D000814:Aniline Compounds; D007477:Ions; D008293:Malates; D012492:Salts; C030298:malic acid; C023650:aniline