Cyanide Complexes Based on {Mo6I8}4+ and {W6I8}4+ Cluster Cores

Abstract

Compounds based on new cyanide cluster anions [{Mo6I8}(CN)6]2–, trans-[{Mo6I8}(CN)4(MeO)2]2– and trans-[{W6I8}(CN)2(MeO)4]2− were synthesized using mechanochemical or solvothermal synthesis. The crystal and electronic structures as well as spectroscopic properties of the anions were investigated. It was found that the new compounds exhibit red luminescence upon excitation by UV light in the solid state and solutions, as other cluster complexes based on {Mo6I8}4+ and {W6I8}4+ cores do. The compounds can be recrystallized from aqueous methanol solutions; besides this, it was shown using NMR and UV-Vis spectroscopy that anions did not undergo hydrolysis in the solutions for a long time. These facts indicate that hydrolytic stabilization of {Mo6I8} and {W6I8} cluster cores can be achieved by coordination of cyanide ligands.

Luminescent Supramolecular Ionic Frameworks based on Organic Fluorescent Polycations and Polyanionic Phosphorescent Metal Clusters

“…The tetraimidazolium salt [TPE‐Im 4 ]I 4 was obtained by the methylation of the corresponding imidazole [22] with iodomethane in a hot DMF solution (Figure S1). Mixing [TPE‐Im 4 ]I 4 at 25 °C with Cs 4 [Re 6 Se 8 (CN) 6 ] ⋅ 3H 2 O [21] or Cs 1.3 Na 0.7 [Mo 6 I 8 (CN) 6 ] ⋅ 2H 2 O [23] (further noted Cs 4 Re , or A 2 Mo , respectively) in a methanol or methanol/water mixture leads to a cationic metathesis and immediate precipitation of [TPE‐Im 4 ][Re 6 Se 8 (CN) 6 ] ( TPE‐Re ) or [TPE‐Im 4 ][Mo 6 I 8 (CN) 6 ] 2 ( TPE‐Mo ) respectively, as powders. These hybrids are insoluble in any common solvents.…”

“…The tetraimidazolium salt [TPE-Im 4 ]I 4 was obtained by the methylation of the corresponding imidazole [22] with iodomethane in a hot DMF solution (Figure S1). Mixing [TPE-Im 4 ]I 4 at 25 °C with Cs 4 [Re 6 Se 8 (CN) 6 ] • 3H 2 O [21] or Cs 1.3 Na 0.7 [Mo 6 I 8 (CN) 6 ] • 2H 2 O [23] (further noted Cs 4 Re, or A 2 Mo, respectively) in a methanol or methanol/water mixture leads to a cationic metathesis and immediate precipitation of According to the single-crystal X-ray diffraction analysis (SCXRD), [24] TPE-Re consists of compact layers in which the [TPE-Im 4 ] 4 + cations alternate with anionic cluster units forming zigzag chains (Figure 2a). Each [Re 6 Se 8 (CN) 6 ] 4À cluster is surrounded by 4 cations and vice versa, leading to a 1 : 1 stoichiometry.…”

Improved Synthesis of (TBA)2[W6Br14] Paving the Way to Further Study of Bromide Cluster Complexes

“…The latter feature was demonstrated in 1990 on a series of compounds [M 6 X 8 Y 6 ] n − (M = Mo, W; X, Y = Cl, Br, I) . The photophysical properties of halide cluster complexes strongly depend on the terminal ligands Y; for example, the use of perfluorinated acids as terminal ligands leads to a significant increase in the photoluminescence quantum yields. , In addition to changing the photophysical properties by replacing terminal ligands, cluster complexes can be imparted with the desired properties, such as water solubility − and hydrolytic stability. , On the other hand, the substitution of terminal halide ligands can increase the reactivity of the cluster due to the higher lability of the introduced ligands. Such highly reactive clusters can then be used for further transformations or binding to matrixes, resulting in functional materials. − A variety of properties and the possibility of chemical modification of cluster complexes are the main points to postulate their perspectives for application in medicine, for example, as X-ray contrast agents or agents for photodynamic therapy.…”

Selective Oxidation of Inner Pnictogenide Ligands in Mixed-Ligand Rhenium Cubane-Type Cluster Complexes

“…However, the inner ligands affect the electronic structure and physical properties of cluster compounds to a much greater extent than the apical ligands. As typical examples of such an influence, chalcogenide and halide clusters of molybdenum and tungsten with the {M 6 Q 8 } (Q = S, Se) or {M 6 X 8 } (X = Cl, Br, I) cluster cores, chalcohalide rhenium clusters with {Re 6 Q 8– n X n } cores, and 12-nuclear clusters with {Re 12 CS 14 (Q/X) 3 } cores should be mentioned. These compounds exhibit very different optical, chemical, and electrochemical properties, depending on the composition of the inner ligand environment.…”