Iodide clusters of molybdenum and tungsten as promising agents for photodynamic inactivation and therapy

Octahedral iodide clusters of molybdenum and tungsten [M₆I₈L₆] are considered as promising components of new classes of luminescent materials. When excited with the light at a wavelength of ≤450 nm, the clusters form long-lived triplet states emitting red phosphorescence. This phosphorescence is deactivated in the presence of molecular oxygen to form singlet oxygen in a high yield. Due to the capability of photogenerating singlet oxygen, the [M₆I₈L₆] clusters and related materials exhibit photoinduced cytotoxicity and bactericidal action. Universal methods developed to date make it possible to prepare cluster compounds with specified compositions and properties depending on ligand L. This review considers the prospects for developing drugs for antimicrobial photodynamic inactivation and photodynamic cancer therapy based on the [M₆I₈L₆] clusters.