Syntheses and Structural Characterization of Two Nitrilotriacetate Cobalt Complexes: [{CoK2(NTA)(Hmta)(H2O)3}NO3]nand [{Co(4,4′‐bpy)2(H2O)4}{Co2(NTA)2(4,4′‐bpy)(H2O)2}]

Two nitrilotriacetate cobalt complexes {[CoK2(NTA)(Hmta)(H2O)3]NO3}n(1) and [{Co(4,4′‐bpy)2(H2O)4}{Co2(NTA)2(4,4′‐bpy)(H2O)2}] (2) (NTA = nitrilotriacetate anion, Hmta = hexamethylenetetramine and 4,4′‐bpy = 4,4′‐bipyridine) were prepared and characterized by IR, elemental analysis and single crystal X‐ray diffraction study. The influence of the neutral ancillary ligands on the formation of the complexes with different structures in the Co‐NTA system was discussed. The coordination of NTA and Hmta to Co2+ions only resulted in the formation of mononuclear [Co(NTA)(Hmta)]−ions which are further connected by K+ions and water molecules to form a three‐dimensional network. The use of 4,4′‐bpy as ancillary ligand in 2led to the formation of separate mononuclear [Co(4,4′‐bpy)2(H2O)4]2+and dinuclear [Co2(NTA)2(4,4′‐bpy)(H2O)2]2−which are further connected by hydrogen bonds to form a supramolecular three‐dimensional network. In these cases it seems to suggest that the addition of neutral ancillary ligand into the Co‐NTA system leads to the formation of lower dimensional structures when the contribution of alkali ions to the structural dimensionality is neglected.