Electronic, Chemical, Thermodynamics Properties Screening of [M(SDPH)(VDPH)(X)a(Y)b)]n (M = Cr, Mn, Fe, Co, Ni; X = NH3; Y: H2O; a=0 or 1; b=1 or 2; n=0 or 1) Metal Complexes with an Extended Tight Binding Quantum Chemical Method

The capability of the Schiff's base complex from the hydrazine group, which has azomethine (-NHN=CH-) as the main group, has been studied for its potential in the medical field, such as anticancer, antioxidant, and antibacterial. The synthesis method and its reaction condition for coordinating the first-row transition complex compound with base Schiff's ligands SDPH (Salicylaldehyde-2,4-Dinitrophenylhydrazine) and VDPH (Vanillin-Dinitrophenylhydrazine) were still challenging to be applied as not all reaction conditions can succeed in the synthesis experiment. To determine the potential of first-row transition metal ions coordinating with SDPH and VDPH ligands, this research studies computationally the Extended Tight Binding Quantum Chemical method, called GFN2-xTB. Variations of the octahedral complex molecular formula used in computational calculations are [M(L)(2)XaYb] and [M(L)(2)XaYb](+) with M = (Cr, Mn, Fe, Co, Ni); L = SDPH and VDPH; X = NH3 (a = 0 or 1); and Y = H2O (b = 1 or 2). In addition, these complex compounds, which have metal ions with electron configuration d(4)-d(7), were studied for their stability under high and low spin conditions. The data indicate the presence of stable complexes with more negative Delta G values were generally found in: (i) complexes with VDPH ligands, (ii) complexes containing the NH3 ligand, (iii) complexes with metal ions M+3, (iv) complexes having low spin magnetic properties. These results were also supported by the characteristics of global reactive descriptors, including a global electrophilicity index, electronegativity, chemical potential, chemical hardness, and chemical softness. It also included studies related to the HOMO-LUMO electronic energy to determine the reactivity and stability of the studied complex compounds.

Automated summary

This study investigates the potential and stability of Schiff's base complexes using computational methods. The results demonstrate that complexes with VDPH ligands, NH3 ligands, and M+3 metal ions tend to be more stable under specific conditions.