A new Mo 6 cluster complex and its silica and polyurethane composites have been synthesized and characterized. These materials are highly luminescent with emission above 650 nm, produce singlet oxygen with high efficiency, are photostable, and can be excited up to 580 nm. These proper-[a] Institute of Inorganic Chemistry of the AS CR, v.v.i Husinec-Ř ež 1001, 25068 Ř ež,

The excited-state dynamics, luminescence, and redox properties of a series of hexanuclear molybdenum cluster complexes, (nBu4N)2[Mo6X14] and (nBu4N)2[Mo6X8(CF3COO)6] (X = Cl, Br, or I), were investigated. Substitution of the apical halogen ligands for the trifluoroacetate ligands increased the oxidation potentials and induced a blue shift in the absorption and luminescence bands as well as a considerable increase in the luminescence quantum yields for heavy inner ligands. Time-resolved transient absorption measurements showed that the intersystem crossing from the excited singlet states is ultrafast with time constants ranging between <120 fs and 1.68 ps and leads to hot triplet states. The following cooling occurred at a ps time scale and was assigned to electronic redistribution within the emissive triplet state sublevels. The formation of singlet oxygen, O2((1)Δg), suggested earlier on the basis of photooxidation experiments for some complexes, was revised by direct measurements of O2((1)Δg) phosphorescence. We showed the effects of the attached ligands on key physico-chemical and photophysical parameters of the title complexes. The synthesis and structural characterisation of a new cluster complex, (nBu4N)2[Mo6Br8(CF3COO)6], completed the series. Our results demonstrated that the complexes with heavy inner ligands (Br, I) and apical trifluoroacetate ligands were photochemically and electrochemically stable, highly luminescent, and good sensitisers of O2((1)Δg).

Newly synthesized octahedral molybdenum cluster compound (n-Bu4N)2[Mo6I8(OOC-1-adamantane)6] revealed uncharted features applicable for the development of X-ray inducible luminescent materials and sensitizers of singlet oxygen, O2((1)Δg). The compound exhibits a red-NIR luminescence in the solid state and in solution (e.g., quantum yield of 0.76 in tetrahydrofuran) upon excitation by UV-vis light. The luminescence originating from the excited triplet states is quenched by molecular oxygen to produce O2((1)Δg) with a high quantum yield. Irradiation of the compound by X-rays generated a radioluminescence with the same emission spectrum as that obtained by UV-vis excitation. It proves the formation of the same excited triplet states regardless of the excitation source. By virtue of the described behavior, the compound is suggested as an efficient sensitizer of O2((1)Δg) upon X-ray excitation. The luminescence and radioluminescence properties were maintained upon embedding the compound in polystyrene films. In addition, polystyrene induced an enhancement of the radioluminescence intensity via energy transfer from the scintillating polymeric matrix. Sulfonated polystyrene nanofibers were used for the preparation of nanoparticles which form stable dispersions in water, while keeping intact the luminescence properties of the embedded compound over a long time period. Due to their small size and high oxygen diffusivity, these nanoparticles are suitable carriers of sensitizers of O2((1)Δg). The presented results define a new class of nanoscintillators with promising properties for X-ray inducible photodynamic therapy.

Structure analysis of ground state (GS) and two light-induced (SI and SII) metastable linkage NO isomers of [Ru(py)4Cl(NO)](PF6)2.0.5H2O is presented. Illumination of the crystal by a laser with lambda = 473 nm at T = 80 K transfers around 92% of the NO ligands from Ru-N-O into the isomeric configuration Ru-O-N (SI). A subsequent irradiation with lambda = 980 nm generates about 48% of the side-on configuration Ru<(N)(O) (SII). Heating to temperatures above 200 K or irradiation with light in the red spectral range transfers both metastable isomers reversibly back to the GS. Photodifference maps clearly show the N-O configurations for both isomers and they could be used to find a proper starting model for subsequent refinements. Both metastable isomers have slightly but significantly different cell parameters with respect to GS. The main structural changes besides the Ru-O-N and RU<(N)(O) linkage are shortenings of the trans Ru-Cl bonds and the equatorial Ru-N bonds. The experimental results are compared with solid-state calculations based on density functional theory (DFT), which reproduce the observed structures with high accuracy concerning bond lengths and angles. The problem of how the different occupancies of SI and GS could affect refinement results was solved by a simulation procedure using the DFT data as starting values.

Phosphorescent hexamolybdenum cluster complexes with pyrene and anthracene carboxylates exhibit energy transfer from the grafted ligands to the {Mo6I8} core. The complex with the pyrene ligands exhibits the highest brightness of emission ever reported for a Mo6 cluster complex excited in the near‐UV region (ϵ355 = 2.3 105 M–1 cm–1, ΦL = 0.60). These antenna systems possess attractive features as UV/Red light convertors, optical oxygen sensors, or sensitizers of singlet oxygen.

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We report intensive visible light radioluminescence upon X-ray irradiation of archetypal tetranuclear copper(I) iodide complexes containing triphenylphosphine or pyridine ligands in the solid state. These properties, attractive for the design of X-ray responsive materials, can be attributed to the heavy {CuI} cubane-like core, the absence of oxygen quenching of the emissive triplet states, and the high photoluminescence quantum yields. Radioluminescence originates from the same emissive triplet states as those produced by ultraviolet excitation as confirmed by the observed radioluminescence thermochromism. The radioluminescence properties are also preserved after incorporation of these complexes into polystyrene films, making them appealing for the development of plastic scintillators.

Compounds were synthesized with the aim to develop efficient extraction agents for liquid-liquid extraction of polyvalent cations, i.e. lanthanides and actinides from high-level activity nuclear waste. Compounds of general formulation [(8-CMPO-(CH 2 -CH 2 O) 2 -1,2-C 2 B 9 H 10 )(1 ,2 -C 2 B 9 H 11 )-3,3 -Co(III)] − with different phosphorus and nitrogen substitution (CMPO= 2 R, 3 R P(O)-(CH 2 ) n C(O)N 1 R, 1 R = t-octyl, H, Ph, 2 R=Ph, n-octyl, 3 R=Ph, n = 1,2)-(4a to 4e), were prepared and characterized by combination of 11 B NMR, 1 H high field NMR, ESI-M.S., HPLC and other techniques. Molecular structure of the sodium complex of ligand 4a ( 1 R = t-octyl, 2 R = 3 R = Ph, n = 1) was determined by single crystal X-ray diffraction analysis. Effect of several modifications in the structure of 4a-4e on the extraction properties was outlined. The study resulted in the definition of ionic ligand with enhanced extraction efficiency for 4a,b (t-octyl and H on the amidic nitrogen atom) and a better solubility of 4a and 4d ( 1 R = t-octyl, 2 R = n-Oct, 3 R=Ph, n = 1) in less polar solvents. Low polar mixtures of hydrogenated tetrapropylene (TPH) hexyl methyl ketone (HMK) can be applied as an auxiliary solvent for 4a, selected for detailed studies, replacing thus the polar and less environmentally friendly nitro-, fluoro-and chloro-solvents used in the current dicarbollide liquid-liquid extraction process. Results of the fission products separation from the simulated PUREX feed using 4a are presented inclusive procedures for Eu 3+ stripping.