Crystal structures of dibromido{N-[(pyridin-2-yl-κN)methylidene]picolinohydrazide-κ2 N′,O}cadmium methanol monosolvate and diiodido{N-[(pyridin-2-yl-κN)methylidene]picolinohydrazide-κ2 N′,O}cadmium

Abstract

The title compounds, [CdBr2(C12H10N4O)]·CH3OH, (I), and [CdI2(C12H10N4O)], (II), are cadmium bromide and cadmium iodide complexes of the ligand (E)-N′-(pyridin-2-ylmethylene)picolinohydrazide. Complex (I) crystallizes as the methanol monosolvate. In both compounds, the Cd2+ cation is ligated by one O atom and two N atoms of the tridentate ligand, and by two bromide anions forming a Br2N2O pentacoordination sphere for (I), and by two iodide anions forming an I2N2O pentacoordination sphere for (II), both with a distorted square-pyramidal geometry. In the crystal of complex (I), molecules are linked by pairs of N—H...O and O—H...Br hydrogen bonds, involving the solvent molecule, forming dimeric units, which are linked by C—H...Br hydrogen bonds forming layers parallel to (101). In the crystal of complex (II), molecules are linked by N—H...I hydrogen bonds, forming chains propagating along [010]. In complex (II), measured at room temperature, the two iodide anions are each disordered over two sites; the refined occupancy ratio is 0.75 (2):0.25 (2).