Crystal structures of di-bromido-{ N-[(pyridin-2-yl-? N)methyl-idene]picolinohydrazide-? 2N', O}cadmium methanol monosolvate and di-iodido{ N-[(pyridin-2-yl-? N)methyl-idene]picolinohydrazide-? 2N', 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-yl-methyl-ene)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 penta-coordination sphere for (I), and by two iodide anions forming an I2N2O penta-coordination sphere for (II), both with a distorted square-pyramidal geometry. In the crystal of complex (I), mol-ecules are linked by pairs of N-H?O and O-H?Br hydrogen bonds, involving the solvent mol-ecule, forming dimeric units, which are linked by C-H?Br hydrogen bonds forming layers parallel to (101). In the crystal of complex (II), mol-ecules 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).