Structurally Characterized BODIPY-Appended Oxidovanadium(IV) β-Diketonates for Mitochondria-Targeted Photocytotoxicity.

Mixed-ligand oxidovanadium(IV) β-diketonates having NNN-donor dipicolylamine-conjugated to boron-dipyrromethene (BODIPY in L) and diiodo-BODIPY (in L) moieties, namely, [VO(L)(acac)]Cl (), [VO(L)(acac)]Cl (), and [VO(L)(dbm)]Cl (), where acac and dbm are monoanionic O,O-donor acetylacetone and 1,3-diphenyl-1,3-propanedione, were prepared, characterized, and tested for their photoinduced anticancer activity in visible light. Complexes and were structurally characterized as their PF salts ( and ) by X-ray crystallography. They showed VNO six-coordinate geometry with dipicolylamine base as the facial ligand. The non-iodinated BODIPY complexes displayed absorption maxima at ∼501 nm, while it is ∼535 nm for the di-iodinated in 10% DMSO-PBS buffer medium (pH = 7.2). Complexes and being green emissive (λ, ∼512 nm; λ, 470 nm; Φ, ∼0.10) in 10% aqueous DMSO were used for cellular imaging studies. Complex localized primarily in the mitochondria of the cervical HeLa cells with a co-localization coefficient value of 0.7. The non-emissive diiodo-BODIPY complex showed generation of singlet oxygen (Φ ≈ 0.47) on light activation. Annexin-V assay showed singlet oxygen-mediated cellular apoptosis, making this complex a targeted PDT agent.