Pentagonal bipyramidal complexes of Co(II) with singly- and doubly-deprotonated 2′,2′′′-(2,6-pyridindiyldiethylidene)dioxamohydrazide -: The crystal structure of [diaqua-2′,2′′′-(2,6-pyridindiyldiethylidene)dioxamohydrazidecobalt(II)] hexahydrate

This paper reports the first Co(II) complexes with a singly-and doubly-deprotonated H2L ligand (H2L = 2',2'''-(2,6-pyridindiyldiethylidene)dioxamohydrazide belonging to the planar pentadentate class. The complexes were characterized by elemental analysis, thermal analysis, IR spectroscopy, molar conductivity and magnetic susceptibility measurements. The crystal structure of [Co(L)(H2O)(2)].6H(2)O complex has been determined. The pentagonal bipyramidal geometry present in the previously synthesized complex [Co(H2L)(H2O)(MeOH)](ClO4)2(,) wherein the ligand is present in a neutral form, has been preserved around Co(II).