Polymorphism in the Crystallization Behavior of Trinitrocobalt(III) Complexes with Tridentate Amine Ligands: Hydrogen-Bonding Analysis and Syntheses of Racemic and Conglomerate <i>mer</i>-Co(dpt)(NO₂)₃

Three trinitrocobalt(III) complexes with three different chelating amine ligands have been prepared and structurally characterized in order to record their crystallization modes. The meridional isomers of Co(Me-aepn)(NO2)3·H2O and Co(Me-dpt)(NO2)3 (Me-aepn = N,N-bis((2-aminoethyl)methyl)-1,3-propanediamine; Me-dpt = 3,3‘-diamino-N-methylpropanediamine) crystallize as simple racemates, but intermolecular hydrogen bonds between homochiral molecules are observed in their packing structures. Both racemic (Pcab) and conglomerate (P212121) forms of mer-Co(dpt)(NO2)3 (dpt = N-(3-aminoethyl)-1,3-propanediamine) have also been prepared by two different synthetic approaches, and their molecular structures are compared. The two are different in the torsional angles associated with the three NO2 groups and in the conformation of one of the two six-membered chelate rings.