The First Water-Soluble Hexarhenium Cluster Complexes with a Heterocyclic Ligand Environment: Synthesis, Luminescence, and Biological Properties

Abstract

The hexarhenium cluster complexes with benzotriazolate apical ligands [{Re6(μ3-Q)8}(BTA)6](4-) (Q = S, Se; BTA = benzotriazolate ion) were obtained by the reaction of [{Re6(μ3-Q)8}(OH)6](4-) with molten 1H-BTA (1H-benzotriazole). The clusters were crystallized as potassium salts and characterized by X-ray single-crystal diffraction, elemental analyses, and UV-vis and luminescence spectroscopy. In addition, their cellular uptake and toxicity were evaluated. It was found that both clusters exhibited luminescence with high lifetimes and quantum yield values; they were taken up by the cells illuminating them under UV irradiation and, at the same time, did not exhibit acute cytotoxic effects.

Supramolecular Frameworks Built up from Red‐Phosphor­escent trans‐Re6 Cluster Building Blocks: One Pot Synthesis, Crystal Structures, and DFT Investigations

“…Similar to other [{Re 6 Q i 8 }L a 6 ] complexes based on a {Re 6 Q 8 } 2+ cluster core (Q = S or Se) [10,24,77,78] the powdered samples 1 and 2 emit bright red phosphorescence upon UV photoexcitation (λ ex = 355 nm). Emission spectra are shown in Figure 7.…”

Prospects of molybdenum and rhenium octahedral cluster complexes as X-ray contrast agents

“…Recently we have shown that the anionic highly hydrophilic cluster complex [33]. Also, cluster complexes [{Re 6 (µ 3 -S) 8 }(BTA) 6 ] 4-and [{Re 6 (µ 3 -Se) 8 }(BTA) 6 ] 4-(BTAbenzotriazolate ion) with pseudo-amphiphilic ligand environment allows the cluster complexes to smoothly penetrate through the cell membrane [34]. In previous report [35] the authors have demonstrated the cellular uptake of [{Re 6 Se 8 }I 6 ] 3-, its subcellular distribution and the mechanisms that may be responsible for its cytotoxic effects.…”

The Cluster [Re6Se8I6]3− Induces Low Hemolysis of Human Erythrocytes in Vitro: Protective Effect of Albumin

“…Furthermore, the anionic hexa-iodo rhenium selenide cluster [Re 6 Se 8 I 6 ] 3− induces 100% early tumor cell death, whereas the same concentration leaves normal cells unaffected, allows for the localization of tumors and enables the observation of tumor regression through fluorescence measurement during treatment. It is therefore concluded that the octahedral rhenium cluster complexes have promising potential for therapeutic and diagnostic applications [1,2,3,4]. …”