Zwitterionic dioxidovanadium(v) complexes containing fluorinated triphenylphosphonium ligands: structure and biomacromolecule studies†

Research on metallodrugs with biological properties remains at the forefront, focusing on the development of compounds that interact non-covalently with deoxyribonucleic acid (DNA) and possess the ability to cleave the double helix strands of this biomacromolecule. In this context, vanadium(V) imine complexes featuring a fluorinated triphenylphosphonium group, (3-formyl-4-hydroxybenzyl)tris(4-fluorophenyl)phosphonium chloride ([AF]Cl), were studied for their targeting and accumulation in mitochondria, in addition to their interactions and ability to cleave DNA. The solid-state structures of complexes C1–C3 were elucidated using single-crystal X-ray diffraction and were characterized using vibrational techniques and elemental analysis, along with extensive characterization in solution. These studies revealed that the complexes contain cis-dioxidovanadium(V) species and are zwitterionic species. It was shown that C1–C3 can interact with and are capable of cleaving plasmid DNA through oxidative mechanisms without the need for photoinduction. When potential interactions with bovine serum albumin were analyzed, it was revealed that interactions in the order of 10⁴ M⁻¹ (Stern–Volmer quenching constant, K_SV) were observed. Additionally, in silico molecular docking studies showed that C1–C3 can preferentially interact with the minor grooves of DNA and with domain IB (site III) of bovine and human serum albumins.