XPS experimental and DFT investigations on solid solutions of Mo1-xRexS2 (0 < x < 0.20).

The synthesis, characterization, experimental X-ray photoelectron spectra (XPS) and density-functional theory (DFT) investigations on solid solutions of Mo1-xRexS2 (x = 0.05, 0.10, 0.15 and 0.20) are reported herein. It is shown that even at a low concentration of dopant Re atoms, clustering occurs. At an Re concentration of 5% the formation of dimer-like impregnations is observed. An increase in the dopant concentration leads to an increase in the amount of clustered rhenium atoms and to the formation of rhombic clusters. The absence of magnetism within the studied Mo1-xRexS2 solid solutions allowed us to suggest a mechanism for the distribution of rhenium inside molybdenum disulphide through the initial formation of rhenium disulphide and its subsequent spreading.

Stabilization of Ni2+ dimers in hexacyano Mo6 cluster-based Prussian blue derivatives: experimental and theoretical investigations of magnetic properties.

Herein, two new octahedral molybdenum cyanide cluster compounds, namely [{Ni(NH3)6}4{Ni2(NH3)8}1][Mo6Br6Q2(CN)6]3·12H2O, Q = S (1) and Se (2), have been synthesized as single crystals by slow diffusion of a solution of nickel chloride into aqueous ammonia solutions of a K2Cs2[Mo6Br6Q2(CN)6] molybdenum cyanide cluster-based compound. Both 1 and 2 were structurally characterized by single-crystal X-ray diffraction. They are isostructural and crystallize in the cubic system (Im3[combining macron]m (no. 229); Z = 2, a = 18.147(1) Å, and V = 5976(1) Å3 and a = 18.188(2) Å and V = 6016(2) Å3 for 1 and 2, respectively). 1 and 2 are based on the association of [Mo6Bri6Qi2(CN)a6]4- (Q = S, Se) cluster anions with Ni2+ dimer-based cubic [Ni2(NH3)8]4+ and octahedral [Ni(NH3)6]2+ cations. The structure is based on 2-fold interpenetrated [{Ni(NH3)6}4{Ni2(NH3)8}1][Mo6Br6Q2(CN)6]3 frameworks related to each other by [½, ½, ½] translation. The unit cell is based on a body-centered cubic framework of cubic [Ni2(NH3)8]4+. The [Mo6Bri6Qi2(CN)a6]4- (Q = S, Se) cluster units are located in the middle of the edges and at the center of the faces of the cell. The [{Ni(NH3)6}]2+ cations are located at the center of the cubes of the a/2 edge. The dimers [Ni2(NH3)8]4+ are stabilized by hydrogen bonds between the cyanide ligands of the cluster unit and the hydrogen atoms of the ammonia molecules. Both compounds exhibit a weak antiferromagnetic coupling within the [Ni2(NH3)8]4+ dimer entities at low temperatures together with a paramagnetic behavior originating from the cations of the octahedral [{Ni(NH3)6}]2+ complexes.