PENTAGONAL BIPYRAMIDAL COMPLEXES OF CO(II) WITH SINGLY-DEPROTONATED AND DOUBLY-DEPROTONATED 2'''-(2,6-PYRIDINDIYLDIETHYLIDENE)DIOXAMOHYDRAZIDE - THE CRYSTAL-STRUCTURE OF YRIDINDIYLDIETHYLIDENE)DIOXAMOHYDRAZIDECOBALT(II)] HEXAHYDRATE

This paper reports the first Co(II) complexes with a singly-and doubly -deprotonated H2L ligand (H2L = 2'''-(2,6-pyridindiyldiethylidene)diox amohydrazide belonging to the planar pentadentate class. The complexes were characterized by elemental analysis, thermal analysis, IR spectr oscopy, molar conductivity and magnetic susceptibility measurements. T he crystal structure of [Co(L)(H2O)(2)].6H(2)O complex has been determ ined. The pentagonal bipyramidal geometry present in the previously sy nthesized complex [Co(H2L)(H2O)(MeOH)](ClO4)2(,) wherein the ligand is present in a neutral form, has been preserved around Co(II).