1,10-Phenanthrolin-1-ium nitrate–aquabis(4-hydroxybenzoato-κ2O,O′)(nitrato-κ2O,O′)(1,10-phenanthroline-κ2N,N′)erbium(III)–1,10-phenanthroline–water (1/1/0.5/2)

Abstract

In the title compound, C12H9N2+·NO3−·[Er(C7H5O3)2(NO3)(C12H8N2)(H2O)]·0.5C12H8N2·2H2O, the water-molecule-coordinated ErIII ion is chelated by one 1,10-phenanthroline (phen) ligand, two 4-hydroxybenzoate anions and one nitrate anion in a monocapped square-antiprismatic coordination geometry. The uncoordinating phen molecule is approximately parallel to the 1,10-phenanthrolin-1-ium (Hphen) anion [dihedral angle = 3.3 (4)°]. The centroid–centroid distance of 3.801 (5) Å between pyridine rings suggests the existence of π–π stacking. The crystal structure contains an extensive network of classical O—H...O and N—H...O and weak C—H...O hydrogen bonds. C—H...π interactions between phen and 4-hydroxybenzoate is also present in the crystal structure. In the crystal, the uncoordinating phen is equally disordered over two sites about an inversion center.