Cytotoxic evaluations, spectral characterizations and DFT theoretical calculations of new dioxidovanadium(V) complexes

Two dioxidovanadium(V) complexes have been prepared with dinitrogen atoms donor (ophenylenediamine (OPD) and dithiooxamide (DTO)) ligands. The cytotoxicity studies of the prepared complexes against the L20B cell line displays that they have moderate activity 15 against the L20B cell line. Then, the complexes were characterized by different spectral techniques such as FT-IR, UV-Vis., mass, 1H-NMR spectroscopy, magnetic susceptibility, and molar conductivity. Finally, the spectral data were compared with the data obtained by 18 the DFT theoretical calculations. The obtained spectroscopic data confirmed that the two ligands are coordinated from the two amine groups and in cis-conformation with the two oxygen atoms. The experimental and theoretical calculations show that the two complexes 21 are mononuclear with proposed distorted octahedral structures. The complexes are very stable, the electronic energies are (-773.10 and -907.56 a.u.), the HOMO orbitals energies are (-0.386 and -0.504 a.u.), and the LUMO orbitals energies are (-0.213 and -0.421 a.u.) 24 for the complexes; respectively. The bond angles around the vanadium(V) atoms are in the range (69.44-91.36 A°), and the dihedral angles are in the range (111.22-161.94°). Calculations explained that the complexes are polarized (3.39-5.28) more than free ligands 27 (0.002-3.00). The electronic transition in the complex (2) (0.083) is less than for the complex (1) (0.173). After that, the findings showed that the two complexes have the feature of solubility in water rather than other anticancer compounds that lack such a property; even 30 though using different metal complexes like Platine complexes, etc. Thus, this feature will help researchers use such complexes in future studies.