Transition metal complexes with thiosemicarbazide-based ligands, Part IX. Cobalt(II) and nickel(II) complexes with 2-furaldehyde S-methylisothiosemicarbazone; crystal and molecular structure of aqua-bis(2-furaldehyde S-methylisothiosemicarbazone)cobalt(II)-diperchlorate

Abstract

The reaction of a warm ethanolic solution of CoII perchlorate or rodanide and NiII acetate with 2-furaldehyde S-methylisothiosemicarbazone (HL), yielded the complexes [Co(HL)2(H2O)](ClO4)2 (1), [Co(HL)3] [Co(NCS)4] (2) and NiL2, respectively. Both CoII complexes are high-spin, whereas the NiII complex is in lowspin state (diamagnetic). An x-ray analysis of (1) showed it to have a trans-trigonal bipyramidal configuration in which one coordination site in the equatorial plane is occupied by one H2O molecule. HL, a bidentate ligand, is coordinated via N(1) and N(4). The tris(ligand) cation in complex (2) has an octahedral configuration. Complex NiL2 has a square-planar configuration. The deep purple plate-like crystals of (1) are monoclinic with space group C2/c, having cell parameters:a=11.369(3), b=13.029(4), c=17.438(5) Å; β=103.39(2)o. The structure was solved by the heavy-atom method and refined by least-squares method to an R value of 0.060 for 1761 observed reflections. © 1989 Chapman and Hall Ltd.