Octahedral metal cluster complexes have high potential for biomedical applications. In order to evaluate the benefits of these moieties for combined CT/X-ray luminescence computed tomography, this paper compares photoluminescence, radiodensity and X-ray induced luminescence properties of eight related octahedral molybdenum and tungsten cluster complexes [{MI}L] (where M is Mo or W and L is I, NO, OTs or OH/HO). This article demonstrates that despite the fact that molybdenum cluster complexes are better photoluminescence emitters, tungsten cluster complexes, in particular (BuN)[{WI}I], demonstrate significantly higher X-ray induced luminescence due to a combination of relatively good photoluminescence properties and high X-ray attenuation. Additionally, photo-degradation of [{MI}(NO)] was evaluated.

Octahedral molybdenum and tungsten clusters have potential biological applications in photodynamic therapy and bioimaging. However, poor solubility and hydrolysis stability of these compounds hinder their application. The first water-soluble photoluminescent octahedral tungsten cluster [{W I }(DMSO) ](NO ) was synthesised and demonstrated to be at least one order of magnitude more stable towards hydrolysis than its molybdenum analogue. Biological studies of the compound on larynx carcinoma cells suggest that it has a significant photoinduced toxicity, while the dark toxicity increases with the increase of the degree of hydrolysis. The increase of the dark toxicity is associated with the in situ generation of nanoparticles that clog up the cisternae of rough endoplasmic reticulum.

Finding methods that fight bacterial infection or contamination, while minimising our reliance on antibiotics is one of the most pressing needs of this century. Although the utilisation of UV-C light and strong oxidising agents, such as bleach, are still efficacious methods for eliminating bacterial surface contamination, both methods present severe health and/or environmental hazards. Materials with intrinsic photodynamic activity (i.e. a A c c e p t e d m a n u s c r i p t material's ability upon photoexcitation to convert molecular oxygen into reactive oxygen species such as singlet oxygen), which work with light within the visible photomagnetic spectrum could offer a significantly safer alternative. Here we present a new, bespoke molybdenum cluster (Bu4N)2[Mo6I8(n-C7F15COO)6], which is both efficient in the generation of singlet oxygen upon photoirradiation and compatible with the fluoropolymer (F23-L) known for its good oxygen permeability. Thus, (Bu4N)2[Mo6I8(n-C7F15COO)6]/F23-L mixtures have been solution-processed to give homogenous films of smooth and fibrous morphologies and which displayed high photoinduced antibacterial activity against four common pathogens under visible light irradiation. These materials thus have potential in applications ranging from antibacterial coatings to filtration membranes and air conditioners to prevent spread of bacterial infections.

An effective protocol for the solvent‐free fluorination of electron‐rich aromatic compounds with 1‐chloromethyl‐4‐fluoro‐1,4‐diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate) (F‐TEDA‐BF4) is described. The protocol allows the easy and efficient isolation of fluorinated products in high yields and purities with low E factors (kgwaste kgproduct–1) by vacuum‐sublimation without the use of any solvent. The solid‐state fluorination of naphthalen‐2‐ol was studied by differential thermal analysis, and scanning electron microscopy was used to obtain evidence for the solid‐state process. The crucial influence of alkali‐metal carbonates on the rate of the solvent‐free fluorination of hydroxynaphthalenes and estrone was demonstrated.

γ-Cyclodextrin (γ-CD) interacts in aqueous solution with octahedral halide clusters Na2[{M6X8}­Cl6] (M = Mo, W; X = Br, I) to form robust inclusion supramolecular complexes [{M6X8}­Cl6@2γ-CD]2–. Single-crystal X-ray diffraction analyses revealed two conformational organizations within the adduct depending on the nature of the inner halide X within the {M6X8} core. Using 35Cl NMR and UV–vis as complementary techniques, the kinetics of the hydrolysis process were shown to increase with the following order: {W6I8} < {W6Br8} ≈ {Mo6I8} < {Mo6Br8}. The complexation with γ-CD drastically enhances the hydrolytic stability of luminescent [{M6X8}­Cl6]2– cluster-based units, which was quantitatively proved by the same techniques. The resulting host–guest complexation provides a protective shell against contact with water and offers promising horizons for octahedral clusters in biology as revealed by the low dark cytotoxicity and cellular uptake.

The ever‐rising interest of researchers in octahedral halide cluster complexes is explained by their intrinsic superb luminescent properties. Nevertheless, to date chemistry of tungsten clusters, especially of iodide ones, has been poorly developed, and there is only a small number of known compounds. Two new compounds obtained in this work, (Bu4N)2[{W6I8}(NCS)6] (1) and (Bu4N)2[{W6I8}(N3)6] (2), expand the field of iodide tungsten clusters with inorganic ligands. The compounds are characterized by single crystal XRD, HR‐ESI‐MS and FTIR spectroscopy and elemental analysis. Both clusters demonstrate typical bright orange‐red emission sensitive to the concentration of oxygen in the environment. Using 1,5‐dihydroxynaphthalene as a trap for singlet oxygen, the observed rate constant of 1O2 generation is determined.

Preparation of 1D coordination polymers based on luminescent hexanuclear cluster complexes.

The family of chalcogenide molybdenum clusters is well presented in the literature by a series of compounds of nuclearity ranging from binuclear to multinuclear articulating octahedral fragments. Clusters actively studied in the last decades were shown to be promising as components of superconducting, magnetic, and catalytic systems. Here, we report the synthesis and detailed characterization of new and unusual representatives of chalcogenide clusters: square pyramidal complexes [{Mo5(μ3-Se)i4(μ4-Se)i(μ-pz)i4}(pzH)t5]1+/2+ (pzH = pyrazole, i = inner, t = terminal). Individually obtained oxidized (2+) and reduced (1+) forms have very close geometry (proven by single-crystal X-ray diffraction analysis) and are able to reversibly transform into each other, which was confirmed by cyclic voltammetry. Comprehensive characterization of the complexes, both in solid and in solution, confirms the different charge state of molybdenum in clusters (XPS), magnetic properties (EPR), and so on. DFT calculations complement the diverse study of new complexes, expanding the chemistry of molybdenum chalcogenide clusters.