STUDY OF SOLVENT EFFECT ON THERMODYNAMICS AND ELECTRONIC PROPERTIES OF [MN(SDPH)2(H2O)2] COMPLEX COMPOUND WITH DFT METHOD

• Main Author: Eka Pratiwi, Winda
• Format: Theses
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/68896
• Institution: Institut Teknologi Bandung

The number of cancer patients, one of which is breast cancer, is included of the two highest after cardiovascular disease in the world, which reached 10 million people according to the World Health Organization (WHO) in 2020. The potential of complex compounds as anticancer drugs is still a study that continues to be developed. One of them is a complex compound with transition metal and Schiff base ligands which have been studied for their potential in bioactivity; for example, complex Mn(II) with Schiff base ligand aryl hydrazone (DPHN) has been successfully tested in vitro against cancer cell protein MCF-7. The Mn(II)-DPHN complex showed the potential to inhibit the development of cancer cells, supported by high cytotoxicity results. The common problem encountered in vitro studies of complex compounds as anticancer drugs are the solvation of complex compounds, generally insoluble in water and soluble in organic solvents. In this study, the interaction of the complex [Mn(SDPH)2(H2O)2] with several protic and aprotic solutions was studied using the DFT method of the DEF2-SVP basist set against the solvent. The solvents used include ethanol, methanol, DMSO, acetone, and water with complexes at high and low spin states. The parameters used in this study include the thermodynamic properties of both complex formation and complex solvation, electronic properties (Frontier Molecular Orbital), as well as intermolecular interactions in the complex [Mn(SDPH)2(H2O)2] and the solvent. In addition, the complex compound Mn(II) with the base Schiff of ligand which is salicylaldehyde-2,4-dinitrophenylhydrazine (SDPH), was also studied as an anticancer drug compound computationally through the molecular docking method. Based on the thermodynamic data (?Gf, ?Hf, and ?Sf) of the [Mn(SDPH)2(H2O)2] complex obtained, it shows that the low spin complex in ethanol and methanol solvents tends to be stable and can be formed spontaneously and the reaction is exothermic. The most negative ?Gf values indicate this, respectively -2974kJ.mol-1 and -2975 kJ.mol-1. Then, based on thermodynamic data (?Gsolv, ?Hsolv dan ?Ssolv), it shows that the solvation of the complex [Mn(SDPH)2(H2O)2] in ethanol and methanol solvents tends to dissolve easily and can occur more spontaneously compared to other solvents. The ?Gsolv values for the solvation of the complex in ethanol and methanol were is -133.071 kJ.mol-1 and -134.534. The solvation iv process is exothermic. In addition, the effect of solvent was also studied based on electronic properties which showed that the [Mn(SDPH)2(H2O)2] complex with low spin state in ethanol and methanol solvents had higher stability and was less reactive. This is obtained based on the analysis of the electronic properties parameters consisting of (i)HOMO-LUMO energy gap (?E),(ii) chemical potential(?), (iii)hardness index (?), (iv)electronegativity (?) ,(v) electrophilicity (?), and (vi) dipole moment. To support the electronic and thermodynamic data, intermolecular interactions in the [Mn(SDPH)2(H2O)2] complex with solvents were studied based on several theories, including QTAIM (Quantum Theory of Atoms in Molecule), NCI-RDG (Noncovalent Interaction-Reduce Density Gradient), IGMH (Independent Gradient Model on Hirshfeld Partition), IRI (Interaction Region Indicator), and NBO (Natural Bond Order). The results of this study indicate that the intermolecular interactions of the complex with ethanol and methanol solvents are stronger than other solvents. The types of interactions observed were strong intermolecular interactions in the form of hydrogen bonds and weak interactions in the form of dipole-dipole interactions, induced dipoles, and London dispersion forces. In addition, there is a repulsion of the steric effect on the benzene ring on the SDPH ligand, which increases the overall intermolecular interaction between the complex and the solvent. This can also affect the solubility of the complex in the solvent. Molecular docking studies using breast cancer cell of protein 17?-HSD with PDB code: 3HB5 showed that the low-spin [Mn(SDPH)2(H2O)2] complex can interact with 11 types of amino acids on the active site of cancer cell proteins with an energy affinity of -11.7 kcal.mol-1 and has a similar percentage of interaction with the active site of cancer cell of protein of 57.9%. Meanwhile, the interaction of cancer cell protein with SDPH ligand gave an energy affinity of -5.6 kcal.mol-1, and the similarity of the interaction with the active protein site was 26.3%. This indicates that the potential of the [Mn(SDPH)2(H2O)2] complex as an anticancer drug, especially in the cancer cell of protein 17?-HSD, is greater than the SDPH ligand as an anticancer drug.