This study deals with the nanoarchitectonic concept applied to the design of photoelectrodes built on two types of cluster core building blocks, namely, {Re6Si 8} and {Re6Sei 8}. The effect of the nature of the metal/ligand on photoinduced conductivity properties is thus investigated through an in‐depth photoelectrochemical study and it is rationalized by the establishment of an energy diagram using a set of complementary optical (ultraviolet–vis–near infrared), electrochemical and spectroscopic (X‐ray photoelectron spectroscopy) characterization techniques. The optical and electronic properties of {Re6Qi 8}‐based films (Q = S or Se) are drastically dependent on the composition. The sulfide‐based photoelectrodes exhibit ambipolar behavior with an n‐type domination whereas the selenide‐based photoelectrodes have a p‐type semiconducting behavior. Such electronic properties can be exalted by increasing the interactions between the cluster building blocks by heating. The design of mixed {Re6Qi 8}‐based photoelectrodes combining the two n‐{Re6Si 8} and p‐{Re6Sei 8} cluster core‐based building blocks is explored. The physical properties of the heterostructures can be tuned by controlling the {Re6Si 8}:{Re6Sei 8} ratio and the interaction between the clusters. The creation of such nanoarchitectonic p–n junctions allows the optimization of the photocurrents generated by increasing the separated charge state lifetime that turns out to be attractive for solar cell applications.

The redox-active rhenium octahedral cluster unit [ReSe(CN)] was combined with Gd ions and dicarboxylate linkers in novel types of metal-organic frameworks (MOFs) that display a set of functional properties. The hydrolytically stable complexes [{Gd(HO)}(L)ReSe(CN)]·nHO (1, L = furan-2,5-dicarboxylate, fdc; 2, L = thiophene-2,5-dicarboxylate, tdc) exhibit a 3D framework of trigonal symmetry where 1D chains of [{Gd(HO)}(L)] are connected by [ReSe(CN)] clusters. Frameworks contain spacious channels filled with HO. Solvent molecules can be easily removed under vacuum to produce permanently porous solids with high volumetric CO uptake and remarkable CO/N selectivity at room temperature. The frameworks demonstrate an ability for reversible redox transformations of the cluster fragment. The orange powders of compounds 1 and 2 react with Br, yielding dark-green powders of [{Gd(HO)}(L)ReSe(CN)]Br·nHO (3, L = fdc; 4, L = tdc). Compounds 3 and 4 are isostructural with 1 and 2 and also have permanently porous frameworks but display different optical, magnetic, and sorption properties. In particular, oxidation of the cluster fragment "switches off" its luminescence in the red region, and the incorporation of Br leads to a decrease of the solvent-accessible volume in the channels of 3 and 4. Finally, the green powders of 3 and 4 can be reduced back to the orange powders of 1 and 2 by reaction with hydrazine, thus displaying a rare ability for fully reversible chemical redox transitions. Compounds 1-4 are mentioned as a new class of redox-active cluster-based MOFs with potential usage as multifunctional materials for gas separation and chemical contamination sensors.

An oxidation of cluster anion [Re(12)CS(17)(CN)(6)](6-) by H(2)O(2) in water has been investigated. It was shown that selective two-step oxidation of bridging μ(2)-S-ligands in trigonal prismatic unit {Re(3)(μ(6)-C)(μ(2)-S)(3)Re(3)} takes place. The first stage runs rapidly, whereas the speed of the second stage depends on intensity of ultraviolet irradiation of the reaction mixture. Each stage of the reaction is accompanied by a change in the solution's color. In the first stage of the oxidation, the cluster anion [Re(12)CS(14)(SO(2))(3)(CN)(6)](6-) is produced, in which all bridging S-ligands are turned into bridging SO(2)-ligands. The second stage of the oxidation leads to formation of the anion [Re(12)CS(14)(SO(2))(2)(SO(3))(CN)(6)](6-), in which one of the SO(2)-ligands underwent further oxidation forming the bridging SO(3)-ligand. Seven compounds containing these anions were synthesized and characterized by a set of different methods, elemental analyses, IR and UV/vis spectroscopy, and quantum-chemical calculations. Structures of some compounds based on similar cluster anions, [Cu(NH(3))(5)](3)[Re(12)CS(14)(SO(2))(3)(CN)(6)]·9.5H(2)O, [Ni(NH(3))(6)](3)[Re(12)CS(14)(SO(2))(3)(CN)(6)]·4H(2)O, and [Cu(NH(3))(5)](2.6)[Re(12)CS(14)(SO(2))(3)(CN)(6)](0.6)[{Re(12)CS(14)(SO(2))(2)(SO(3))(CN)(5)(μ-CN)}{Cu(NH(3))(4)}](0.4)·5H(2)O, were investigated by X-ray analysis of single crystals.

Cluster compounds based on a new {ReMoSe} core were obtained and studied. The polymeric solid K[ReMoSe(CN)(CN)] (1) containing 24 cluster valence electrons (CVE) was isolated as a result of high-temperature reaction. Water-soluble salts K[ReMoSe(CN)]·11HO (2) and Cs[ReMoSe(CN)]·HO (3) were prepared from compound 1. Crystal structures of the diamagnetic compounds 2 and 3 contain a cluster anion [ReMoSe(CN)] with a 22-electronic core {ReMoSe}. Metathesis reaction followed by recrystallization from CHCN yielded paramagnetic salt (PhP)[ReMoSe(CN)]·2CHCN (4) containing the {ReMoSe} core with 21 CVE. Cyclic voltammetry of the solution of 4 displayed three quasi-reversible waves with E = -0.325, -0.818 and -1.410 V vs. Ag/AgCl electrode indicating the presence of [ReMoSe(CN)] transitions. Electronic structure calculations showed that both mer- and fac-isomers of [ReMoSe(CN)] clusters undergo great distortion when the number of CVE decreases.