Complexation of nickel (II) ion with B3 vitamin in aqueous dimethyl sulfoxide

The stability change of nickel(II) ion complexes including one and two nicotinamide (B3 vitamin) molecules in aqueous dimethyl sulfoxide (XDMSO = 0–0.85 m.f.) was studied at 298.2±0.1 K and 0.25 ionic strength value (NaClO4) using the potentiometric method. The first stage constant of complexation increased until organic solvent concentration was 0.5 m.f. and reduced at higher DMSO content. The difference between complex and central ions solvation is a dominating contribution into the Gibbs energy change of mononicotinamide complex formation reaction. When the second ligand molecule was bonded into the coordination compound, the nicotinamide contribution to ΔtrGr rose and became prevailing at XDMSO = 0.7–0.85. The ligand was found to replace a water molecule in the coordination sphere of the cation according to spectrophotometric study results.

Universal spectrochemical series of six-coordinate octahedral metal complexes for modifying the ligand field splitting

We studied a novel universal spectrochemical series of six-coordinated octahedral 3d transition metal complexes, which can be used for any combination of central metal atom and ligand molecules. A two dimensional spectrochemical series could be used to estimate the ligand field splitting energy of not only known compounds but also the unknown compounds. Therefore, it should be possible to control the physical properties, such as the electronic and magnetic properties and the optical phenomena of octahedral transition metal complexes by modifying the ligand field splitting.