From K[ReMoS(CN)] Solid Solution to Individual Cluster Complexes: Separation and Investigation of [ReMoS(CN)] and [ReMoS(CN)] Heterometallic Clusters.

A series of new cluster compounds with {ReMoS} and {ReMoS} cores has been obtained and investigated. The clusters with different Re/Mo ratios were isolated as individual compounds, which made it possible to study their spectroscopic and electrochemical properties. The geometry of the new clusters was studied using a combination of X-ray diffraction analysis, XAS and quantum chemical DFT calculations.

Evolution of the Electronic Structure of the -[ReSbipyCl] Octahedral Rhenium Cluster during Reduction.

Understanding the processes that occur during the redox transformations of complexes coordinated by redox-active apical ligands is important for the design of electrochemically active compounds with functional properties. In this work, a detailed analysis of the interaction energy and electronic structure was performed for cluster complexes -[ReSbipyCl] (n = 2-, 4-, 6-, 8-), which can be obtained by stepwise electrochemical reduction of a neutral cluster -[ReSbipyCl] in DMSO solution. It was shown that the formation of open-shell paramagnetic ions with S = 1, 2 and 1 is the most energetically favorable for n = 2-, 4- and 6-, respectively.

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

Octahedral cluster complexes of molybdenum and tungsten, [MXY] (M = Mo, W; X, Y = Cl, Br, I), are promising active components in various fields, including biomedicine and solar energy. Cluster complexes draw considerable attention due to their X-ray opacity, red/near-IR luminescence, and ability to convert triplet molecular oxygen to active singlet oxygen under UV and visible irradiation. Among the octahedral cluster complexes of molybdenum and tungsten, compounds with a {WBr} core are the least studied.

Unusual Square Pyramidal Chalcogenide Mo Cluster with Bridging Pyrazolate-Ligands.

The family of chalcogenide molybdenum clusters is well presented in the literature by a series of compounds of nuclearity ranging from binuclear to multinuclear articulating octahedral fragments. Clusters actively studied in the last decades were shown to be promising as components of superconducting, magnetic, and catalytic systems. Here, we report the synthesis and detailed characterization of new and unusual representatives of chalcogenide clusters: square pyramidal complexes [{Mo(μ-Se)(μ-Se)(μ-pz)}(pzH)] (pzH = pyrazole, i = inner, t = terminal).

Octahedral Rhenium Cluster Complexes with 1,2-Bis(4-pyridyl)ethylene and 1,3-Bis(4-pyridyl)propane as Apical Ligands.

A series of eight new octahedral rhenium cluster complexes with the general formula -[{ReQ}LX] (Q = S or Se; L = 1,2-Bis(4-pyridyl)ethylene (bpe) or 1,3-Bis(4-pyridyl)propane (bpp); X = Cl or Br) was synthesized and investigated. While bpe is a ligand with a conjugated aromatic system, bpp represents a molecule of opposite type and has independent aromatic systems of the two pyridine rings. It was shown that this difference in the electronic structure of the ligands has a fundamental effect on the electronic structure, electrochemical and luminescent properties of the corresponding cluster complexes.

Coordination Polymers Based on Rhenium Octahedral Chalcocyanide Cluster Anions and Ag Cations with Bipyridine Analogs.

A series of six coordination polymers based on octahedral cluster anions [ReQ(CN)] (Q = S or Se) and Ag cations coordinated by bipyridine analogs were synthesized under solvothermal conditions. Their structures have been characterized by single crystal X-ray diffraction. Compounds and described by the general formula [{Ag(phen)}ReQ(CN)] (Q = Se (), S (); phen = 1,10-phenanthroline) exhibit layered structures assembled into a supramolecular network by CH…π contacts.

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

Reactivity of new tetrahedral rhenium cluster complexes with pnictogenide inner ligands μ-As, μ-Sb, and μ-Bi has been investigated in reactions with aqueous HO. It has been found that the oxidation of clusters [{ReAsQ}(CN)] (Q = S or Se) led to the formation of stable clusters with μ-(AsO) ligands. Under the same conditions, the oxidation of [{ReAsS}(CN)] cluster led to substitution of μ-As ligands to μ-O.

Stabilization of Re/Re Metalloclusters by Cyanide Ligands in New Trinuclear Rhenium Cluster Complexes [{ReX}(CN)]/[{ReX}(CN)] (X = Br or I).

The interaction of rhenium(III) halides ReBr and ReI with aqueous solution of sodium cyanide resulted in the formation of the first trinuclear halide-cyanide rhenium cluster complexes [{ReX}(CN)]/[{ReX}(CN)] (X = Br or I) crystallized as salts of the compositions CsNa[{ReBr}(CN)]·5.25HO (), CsNa[{ReI}(CN)]·6HO (), Cs[{ReBr}(CN)]·2HO·0.5CsCl (), and Cs[{ReI}(CN)]·().

Cyanide Complexes Based on {MoI} and {WI} Cluster Cores.

Compounds based on new cyanide cluster anions [{MoI}(CN)], -[{MoI}(CN)(MeO)] and -[{WI}(CN)(MeO)] 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 {MoI} and {WI} cores do.

The {Re} Tetrahedral Cyanometalate Cluster Anion [{Re(μ-CCN)}(CN)] with Inner (μ-CCN) Ligands and Its Features in Coordination of Cu Cations.

A reaction between ReI and KCN at elevated temperature led to the formation of the new cyanometalate cluster anion [{Re(μ-CCN)}(CN)] (). The anion contains μ-CCN ligands, which are stabilized by the coordination to the triangular faces of the tetrahedral {Re} metallocluster in a μ mode. The compound crystallized as a potassium salt, and its crystal structure was determined by single-crystal X-ray diffraction analysis.

Soluble Molecular Rhenium Cluster Complexes Exhibiting Multistage Terminal Ligands Reduction.

Substitution of terminal halide ligands of octahedral rhenium cluster complexes [ReQX] in a melt of 4,4'-bipyridine (bpy) led to us obtaining four new compounds with the general formula -[ReQ(bpy)X] (Q = S or Se; X = Cl or Br) in high yield. In contrast to most of the known molecular rhenium cluster complexes with heteroaromatic terminal ligands, compounds - are soluble in organic solvents. This made it possible to carry out a detailed characterization of the new compounds both in solids and in solutions.

Tailoring Heterometallic Cluster Functional Building Blocks: Synthesis, Separation, Structural and DFT Studies of [Re Mo Se (CN) ].

Influence of the metal core composition and geometry on the structure, spectroscopic properties and redox potentials was investigated for the first time for heterometallic (Re/Mo) octahedral clusters. The discrete anionic clusters [Re Mo Se (CN) ] (x=2, 3; n=4, 5) were obtained as individual salts. Their isomeric composition and bond-length distribution were inspected using a combination of single-crystal X-ray structure analysis, NMR, EXAFS, and DFT calculations.

Luminescent twelve-nuclear rhenium clusters.

The first luminescent twelve-nuclear rhenium cluster complexes were obtained. Three new clusters, namely, [ReCS(μ-Cl)Cl], [ReCS(μ-Br)Cl] and [ReCS(μ-Br)Br], were synthesized using the non-isovalent substitution of μ-O ligands within the {ReCS(μ-O)} cluster core by halide anions. The geometry of the new clusters was investigated by X-ray structural analysis, and the electronic structures were evaluated by the use of DFT calculations.

From oxide to a new type of molecular tungsten compound: formation of bitetrahedral cluster complexes [{W(μ-O)(μ-CCN)}(CN)] and [{W(μ-O)(μ-As)}(CN)].

Tungsten trioxide has been found to be a convenient precursor for the synthesis of metal cluster compounds with new types of cluster cores. The reaction between WO3 and KCN led to the formation of the cluster complex [{W6(μ4-O)2(μ3-CCN)4}(CN)16]10-. Unexpectedly, it includes the fully deprotonated form of acetonitrile, the CCN3- anion, as a μ3-bridging ligand coordinated to the trigonal faces of the bitetrahedral W6 metallocluster.

Mixed-metal clusters with a {ReMoSe} core: from a polymeric solid to soluble species with multiple redox transitions.

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.

Multifunctional Metal-Organic Frameworks Based on Redox-Active Rhenium Octahedral Clusters.

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.

Facile Substitution of Bridging SO Ligands in Re Bioctahedral Cluster Complexes.

Selective substitution of μ-SO groups by either O or Se ions occurs upon heating the bioctahedral rhenium cluster complex K[ReCS(μ-SO)(CN)] in air atmosphere or in the presence of a Se source, respectively, manifesting the remarkable lability of SO ligands bound to a transition-metal cluster. A series of compounds based on the new mixed-ligand anions, [ReCS(μ-O)(CN)], [ReCS(μ-Se)(CN)], and [ReCS(μ-O)(OH)], were isolated and their solid-state structures were elucidated by single-crystal X-ray diffraction analysis. Along with the previously reported μ-sulfide clusters, the new species constitute a series of rhenium anionic complexes with the common formula [ReCS(μ-Q)L] (Q = O, S, Se, L = CN; Q = O, S, L = OH), within which the total charge and number of cluster valence electrons (CVEs) are constant.

Heterometallic clusters with a new {Re3Mo3S8} core: direct synthesis, properties and DFT calculations.

We report the direct facile high-temperature synthesis and investigation of heterometallic rhenium-molybdenum cluster K6[Re3Mo3S8(CN)4(CN)2/2] (1) with a new {Re3Mo3S8} core. Dissolution of polymeric compound 1 resulted in subsequent oxidation and formation of stable 23e paramagnetic anionic cluster complex [Re3Mo3S8(CN)6](6-).

Selective two-step oxidation of μ2-S ligands in trigonal prismatic unit {Re3(μ6-C)(μ2-S)3Re3} of the bioctahedral cluster anion [Re12CS17(CN)6]6–.

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.