Singlet Oxygen Production and Biological Activity of Hexanuclear Chalcocyanide Rhenium Cluster Complexes [{Re₆Q₈}(CN)₆]^4– (Q = S, Se, Te)

Abstract

Octahedral rhenium cluster complexes have recently emerged as relevant building blocks for the design of singlet oxygen photosensitizing materials toward biological applications such as blue-light photodynamic therapy. However, their singlet oxygen generation ability as well as biological properties have been studied only superficially. Herein we investigate in detail the singlet oxygen photogeneration, dark and photoinduced cytotoxicity, cellular uptake kinetics, cellular localization and in vitro photoinduced oxidative stress, and photodynamic cytotoxicity of the series of octahedral rhenium cluster complexes [{ReQ}(CN)], where Q = S, Se, Te. Our results demonstrate that the selenium-containing complex possesses optimal properties in terms of absorption and singlet oxygen productivity. These features coupled with the cellular internalization and low dark toxicity lead to the first photoinduced cytotoxic effect observed for a molecular [{MQ}L] complex, making it a promising object for further study in terms of blue-light PDT.

Hexasubstituted Iodide Tungsten Cluster Complexes with Azide and Isothiocyanate Ligands

“…Interestingly, among the tungsten complexes 1 shows the best activity, although the Q value for (Bu 4 N) 2 [{W 6 I 8 }I 6 ] is the greatest. These discrepancies can be explained by different efficiency of 1 O 2 quenching by cluster units (this process occurs without cluster degradation) …”

Host–Guest Binding Hierarchy within Redox‐ and Luminescence‐Responsive Supramolecular Self‐Assembly Based on Chalcogenide Clusters and γ‐Cyclodextrin

“…The increaseo fl uminescence parameters upon inclusion of the clusters to g-CDc an be attributed to the combination of two factors: exclusion of water molecules from the solvation shell of cluster molecules in the cyclodextrin cavity and reduction of collisionalq uenching by water molecules from the bulk. [27] As shown recently by analyzing the magnitude of D 2 O/ H 2 Oi sotopice ffects on the triplet state behavior of these clusters, [28] energy transfer from their excited states to H 2 Ov ibrational modes leads to extensive non-radiative deactivation. Indeed, due to hydrophobic characteri nsidet he cyclodextrin cavity and the fact that water molecules are expelled from the interior and substituted with the cluster body,c ontacts of excited cluster moleculesw ithwater molecules are reduced.…”

Ionic columnar clustomesogens: associations between anionic hexanuclear rhenium clusters and liquid crystalline triphenylene tethered imidazoliums

“…Complexes with 24 cluster valence electrons can be highly phosphorescent in the red-NIR area. [29][30][31][32][33][34][35] Because of their high potential in biology for ROS production, as nanoscintillators or contrast agents, [36][37][38] in optoelectronic [39][40][41] or lighting, 42 many efforts have been devoted these last years to counterpart their ceramic-like behaviour and integrate them in host matrices. [43][44][45][46][47][48][49][50][51][52][53][54] Hence, several strategies have been developed to solubilize the [M 6 Q i 8 X a 6 ] nanionic units in organic media, 55,56 or to integrate them directly in a polymeric or liquid crystalline organic host matrix 23,25,49,57,58 by replacing, via a metathesis reaction, their alkali counter cations by functional organic ones.…”