Preparation and Study of the Crystal Structure of a Complex Compound Based on Cobalt, 1,5-Disulfonaphthalene, and Ethylenediamine

A complex compound based on a divalent cobalt ion as a complexing agent and two different ligands, 1,5-disulfonaphthalene (1,5-naphthalenedisulfonic acid, Na₂NDS) and ethylenediamine, has been synthesized for the first time. The structure of the metal complex was investigated by IR and Raman spectroscopy. It was proved that the compound has a stoichiometric composition [Co(NO₃)⋅(C₂H₄(NH₂)₂)₂] \(_{2}^{ + }\) ⋅(C₁₀H₆O₆S₂)^2–⋅4H₂O. The complex was subjected to thermal analysis to determine its stability. Its stability, determined by the existence of intramolecular hydrogen bonds, was confirmed. Molecular rearrangements occur in the structure at 142°C, and gradual decomposition of the compound begins; in the range of 305–311°C the material studied undergoes melting, and complete destruction occurs only at 500°C. The crystal structure of the obtained metal complex was studied by X-ray diffraction analysis. A Hirshfeld surface analysis revealed intermolecular interactions between hydrogen and oxygen atoms and between hydrogen and nitrogen atoms, i.e., hydrogen bonds, stabilizing the complex.