Publication
Crystal structures of an imidazo[1,5-a]pyridinium-based ligand and its (C13H12N3)2[CdI4] hybrid salt
Publisher:
International Union of Crystallography (IUCr)
Date:
19-07-2019
DOI:
10.1107/S2056989019009964
Abstract: The monocation product of the oxidative condensation–cyclization between two molecules of pyridine-2-carbaldehyde and one molecule of CH 3 NH 2 ·HCl in methanol, 2-methyl-3-(pyridin-2-yl)imidazo[1,5- a ]pyridinium, was isolated in the presence of metal ions as bis[2-methyl-3-(pyridin-2-yl)imidazo[1,5- a ]pyridin-2-ium] tetraiodocadmate, (C 13 H 12 N 3 ) 2 [CdI 4 ], (I), and the mixed chloride/nitrate salt, bis[2-methyl-3-(pyridin-2-yl)imidazo[1,5- a ]pyridin-2-ium] 1.5-chloride 0.5-nitrate trihydrate, 2C 13 H 12 N 3 + ·1.5Cl − ·0.5NO 3 − ·3H 2 O, (II). Hybrid salt (I) crystallizes in the space group P 2 1 / n with two [ L ] 2 [CdI 4 ] molecules in the asymmetric unit related by pseudosymmetry. In the crystal of (I), layers of organic cations and of tetrahalometallate anions are stacked parallel to the ab plane. Antiparallel L + cations disposed in a herring-bone pattern form π-bonded chains through aromatic stacking. In the inorganic layer, adjacent tetrahedral CdI 4 units have no connectivity but demonstrate close packing of iodide anions. In the crystal lattice of (II), the cations are arranged in stacks propagating along the a axis the one-dimensional hydrogen-bonded polymer built of chloride ions and water molecules runs parallel to a column of stacked cations.