Optical property trends in a family of {Mo₆I₈} aquahydroxo complexes

Abstract

Luminescence is one of the key properties of octahedral molybdenum cluster complexes and the basis for most areas of their possible practical applications. Nevertheless, the factors affecting optical properties of...

Nano TiO2 and Molybdenum/Tungsten Iodide Octahedral Clusters: Synergism in UV/Visible-Light Driven Degradation of Organic Pollutants

“…Interestingly, but on the spectra of both n 0.1 @TiO 2 one can see another straight line with E g of 1.8 eV, which can be attributed to the shoulder in the absorption spectra (Figure 4A). This value can be referred to hydrolyzed cluster complex on the surface of the particles (e.g., E g of [38]), thus confirming our earlier suggestion.…”

Evidence of the Ambipolar Behavior of Mo6 Cluster Iodides in All-Inorganic Solar Cells: A New Example of Nanoarchitectonic Concept

“…They all crystallize with the [{M 6 Br 8 }­Br 4 (H 2 O) 2 ] structure type (tetragonal, space group I 4/ m ) reported by Guggenberger and Sleight . More recently, the structural investigations of several aqua hydroxo complexes based on the {Mo 6 I 8 } 4+ cluster core have been reported, namely, [{Mo 6 I 8 }­(H 2 O) 4 (OH) 2 ]­(An) 2 · n H 2 O (An = NO 3 – , n = 3; An = OTs – , n = 2, OTs – - p -toluenesulfonate)] and [{Mo 6 I 8 }­(OH) 4 (H 2 O) 2 ]· n H 2 O ( n = 2, 12, and 14) . It turns out that after substitution of apical ligands by water molecules or hydroxo groups, the [{Mo 6 I 8 }­(OH) 4 (H 2 O) 2 ] cluster units crystallize along with the water molecules.…”

A Neutral Heteroleptic Molybdenum Cluster trans-[{Mo6I8}(py)2I4]

“…Interestingly, the reverse situation is observed in the solution in pyridine, and the complex obtained here exhibits an emission intensity comparable to that of the initial complex (Figure 4B). This behavior is explained by a decrease in inter-cluster interactions in the solution, thus, reducing the efficiency of non-radiative energy transfer [2,49]. Indeed, according to crystal data, the distances between apical and inner (I a -I i and I i -I i ) iodine ligands belonging to neighboring cluster units are 3.800-3.875 Å (Figures S5 and S6), which is lower than the sum of van der Waals radii (1.98 Å ), thus, indicating the formation of weak halogen (I-I) bonds [50].…”

“…Octahedral halide M 6 -clusters of the general formula [{M 6 X 8 }L 6 ] n (M = Mo, W, X = halogen, L-ligand of any nature) are unique compounds possessing a number of valuable practically oriented properties-this is the main point to consider when regarding compounds as promising components of different multifunctional materials. Among these properties are (i) bright luminescence in red/near infrared spectral regions (with microsecond lifetimes and high quantum yields) under the excitation of ultraviolet/visible light (up to 550 nm) or X-rays [1][2][3][4][5][6][7][8]; (ii) the efficient photosensitization of the reactive oxygen species generation process (mainly singlet oxygen, 1 O 2 ) [4,[8][9][10]; (iii) high radiopacity due to a high local concentration of heavy atoms in a cluster core [7,11]. Thus, different groups have demonstrated the utilization of cluster complexes individually or as active components of the materials in numerous areas, such as catalytic systems [12][13][14][15][16], liquid crystals [17,18], oxygen sensors [19][20][21][22], solar concentrators [16,23,24], an active layer of solar cells [25,26], bioimaging, photodynamic therapy (PDT) [27][28][29][30][31][32][33], as components of self-sterilizing materials [34]…”