Electron paramagnetic resonance study of the reactions of tetrathiomolybdate with roussin salts and esters, and with some related iron nitrosyls

The tetrathiomolybdate ion [MoS₄]²⁻ reacts in DMF solution with Roussin esters Fe₂(SR)₂(NO)₄ (R = Me, Et, n-Pr, i-Pr, n-Bu,t-Bu, n-C₅H₁₁) to yield the paramagnetic iron nitrosyls [Fe(NO)₂(SR)₂]⁻ (1), [Fe(NO)₂(S₂MoS₂]⁻ (2) and [Fe(NO)(S₂MOS₂)₂]⁻ (3). The new complexes (2) and (3) have been characterized by EPR spectroscopy and the assignment to them of constitutions based respectively upon tetrahedral and square pyramidal iron is supported by EHMO calculations. Fe₂(SPh)₂(NO)₄ with [MoS₄]²⁻ yields only [Fe(NO)₂(SPh)₂]⁻, and preformed (3) reacts with PhS⁻ to give firstly EPR-silent species, and then [Fe(NO)₂(SPh)₂]⁻. The mononitrosyl (3) can also be formed by reaction of [MoS₄]²⁻ with [Fe₄S₃(NO)₇]⁻, Fe₄S₄(NO)₄, or Fe₂I₂(NO)₄.     

The reported ion Fe3S2(NO)5: A re-investigation

Salts reported to contain the iron-sulphur cluster nitrosyl anion Fe₃S₂(NO)₅⁻ are shown to be identical with those containing the well-known anion Fe₄S₃(NO)₇⁻.     

Synthesis, crystal structure and third-order non-linear optical property of heterobimetallic cluster compound [MoOICu3S3(2,2′-bipy)2]

Nest-shaped cluster [MoOICu₃S₃(2,2′-bipy)₂] (1) was synthesized by the treatment of (NH₄)₂MoS₄, CuI, (n-Bu)₄NI, and 2,2′-bipyridine (2,2′-bipy) through a solid-state reaction. It crystallizes in monoclinic space group P2₁/n, a=9.591(2) Å, b=14.820(3) Å, c=17.951(4) Å, β=91.98(2)°, V=2549.9(10) ų, and Z=4. The nest-shaped cluster was obtained for the first time with a neutral skeleton containing 2,2′-bipy ligand. The non-linear optical (NLO) property of [MoOICu₃S₃(2,2′-bipy)₂] in DMF solution was measured by using a Z-scan technique with 15 ns and 532 nm laser pulses. The cluster has large third-order NLO absorption and the third-order NLO refraction, its ₂ and n₂ values were calculated as 6.2×10⁻¹⁰ and −3.8×10⁻¹⁷ m² W⁻¹ in a 3.7×10⁻⁴ M DMF solution.     

Das perfluortriazinium-kation als oxidationsmittel in der metallorganischen synthese—ein neuer weg zur darstellung von [Cp2MCl2](M = Mo

The oxidation of Cp₂MCl₂ (M= Mo, W) with perfluortriazinium tetrafluoroborate, [(FCN)₃F]⁺[BF₄]⁻, in the presence of a flouride ion acceptor (BF₃ or PF₅) in SO₂ solution yielded the cationic metallocene complexes [Cp₂MCl ₂]²⁺[BF₄]⁻ or [C_p2MCl₂] ²⁺[BF₄]⁻[PF₆]⁻ (M = Mo, W), respectively. In these reactions, for the first time the perfluortriazinium cation has proved to be easy to handle and a useful oxidizer in organometallic chemistry. The oxidizer strength of three fluorotriazinium cations, [(XCN)₃F]⁺ (X = F, Cl, H), has been computed ab initio (HF/6 − 31 + G) and calibrated on literature data which were obtained by local density functional calculations. It was anchored to its F⁺ zero point by an experimental value for KrF⁺. ab]Die Oxidation von Cp²MCl₂ mit (M = MO, W) Perfluortriaziniumtetrafluoroborat, [(FCN)₃F]⁺[BF₄]⁻, in Anwesenheit eines Fluoridionenakzeptors (BF₃ oder PF₅) führte in SO₂-Lösung zur Bildung der kationischen Metallocen-Komplexe [Cp₂MCl₂₊]²⁺[BF₄]₂⁻ bzw. [Cp₂MCl₂]²⁺[BF₄]⁻ [PF₆]⁻ (M = Mo, W). In diesen Reaktionen konnte erstmals gezeigt werden, daß Perfluortriazinium-Kationen einfach zu handhabende und nützliche Oxidationsmittel im Bereich der metallorganischen Synthese darstellen. Das (Mdationsvermögen von drei Fluorotriazinium-Kationen, [(XCN)₃F]⁺(X = F, Cl, H), wurde ab initio berechnet (HF/6 − 31 + G) und mit Hilfe von Literaturdaten, die mittels local density functional-Berechnungen erhalten und am experimentellen Wert von KrF ⁺ bezüglich des F⁺ Nullpunktes verankert wurden, kalibriert.     

The synthesis of phosphine derivatives of [Fe4N(CO)12]: Crystal structures of [Fe4N(CO)9(NO)(PPh3)2], [HFe4N (CO)11)PPh3)] and [(PPh3)2N][Fe4N(CO)11(PMe2Ph)]

Phosphines react with butterfly tetranuelear nitrido-iron clusters, [Fe₄N(CO)₁₂]⁻ and [Fe₄N(CO)₁₁(NO)], to give mono- and di-substituted complexes. X-Ray analyses of the title compounds showed that the phosphine ligands are bound to the wing-tip atoms.     

Interaction of heterocyclic thioamides with tellurium(II) and tellurium(IV). Syntheses and crystal structures of bis[2-(2-thioxo-1,3- thiazolidin-3-yl)-4,5-dihydro-1,3- thiazolium]hexabromotellurate(IV) and tris(1- methylimidazole-2-(3H)-thione)tellurium(II) bromide

Reaction of 1,3-thiazolidine-2-thione with tellurium(IV) in hydrobromic acid medium gave the hexabromotellurate, [C₆H₉N₂S₃]₂²⁺[Te^IVBr₆]²⁻ (3). Reaction of 1-methylimidazoline-2-(3H)-thione (L″) with tellurium(IV), in hydrobromic acid medium, gave the mixed-ligand tellurium(II) complex [Te^IIL″₃Br]⁺Br⁻ (4). The structures of [C₆H₉N₂S₃]₂²⁺[Te^IVBr₆]²⁻ (3) and [Te^IIL″₃Br]⁺Br⁻ were determined by single crystal X-ray diffraction methods. In 3 the unit cell contains [TeBr₆]²⁻ anions and two [C₆H₉N₂S₃]⁺ cations. There is no direct bonding between the metal atom and the cations. In the anion only slight angular deviations from the perfect octahedral geometry are observed. The lone pair of electrons on tellurium(IV) is found to be stereochemically inert. In the cation the two five-membered heterocyclic rings adopt different conformations. In complex 4, in the solid state, the planar [Te^IIL″₃Br]⁺ cation and Br⁻ anion are held together by ionic interactions. In the cation, L″ is bonded to the central tellurium atom through the sulphur atom.     

Synthesis and crystal structure of a novel mixed valence tri-iron complex salt: [hexakis(thiazole)iron(II)][μ-oxo- bis(trichloroiron(III))]

The title compound, [Fe(tz)₆][Fe₂OCl₆] (1) (tz = thiazole) has been synthesized under argon by the reaction of anhydrous FeCl₃ with thiazole in ethanol. 1 crystallises in the cubic space group (no. 205) with a = 15.001(5) Å, V = 3375(2) ų, Z = 4, R = 0.061 and R_w = 0.073. 1 consists of a face-centered cubic array of [Fe(tz)₆]² cations, with the oxo-bridged [Fe₂OCl₆]²⁻ anion occupying the cell and edge centres.     

Dinuclear molybdenum complexes derived from diphenols: electrochemical interactions and reduced species

The new diphenolato complexes [{Mo(NO){HB(dmpz)₃}Cl}₂Q] where dmpz = 3,5-dimethylpyrazolyl and Q = OC₆H₄(C₆H₄O (n = 1 or 2), OC₆H₄CR=CRC₆H₄O (R = H or Et), and OC₆H₄CH=CHC₆H₄CH=CHC₆H₄O have been prepared and their electrochemical properties (cyclic and differential pulse voltammetry) compared with previously reported analogues where Q = OC₆H₄O, OC₆H₄EC₆H₄O (E = SO₂, CO and S), OC₆H₄ (CO)C₆H₄ C₆H₄(CO)C₆H₄O and 1,5- and 2,7-O₂C₁₀H₆. The electrochemical interaction between the redox centres in the new complexes is very weak, in contrast to that in the 1,4-benzenediolato and naphthalendiolato species. The EPR spectra of the reduced mixed-valence species [{Mo(NO){HB(dmpz)₃}Cl}₂Q]⁻ where Q = 1,3- and 1,4-OC₆H₄O and OC₆H₄SC₆H₄O shows that they are valence-trapped at room temperature, whereas those of the dianions [{Mo(NO){HB(dmpz)₃}Cl}₂Q]²⁻ where Q = 1,4-OC₆H₄O, OC₆H₄EC₆H₄O (E = CO or S) and OC₆H₄CH=CHC₆H₄CH=CHC₆H₄O shows that the unpaired spins on each molybdenum centre are strongly correlated (J, the spin exchange integral A_Mo, the metal-hyperfine coupling constant). The electrochemical properties and the comproportionation constants for the reaction [{Mo(NO){HB(dmpz)₃} Cl}₂Q] + [{Mo(NO){HB(dmpz)₃}Cl}O]₂]²⁻2[{Mo(NO) {HB(dmpz)₃}Cl}₂Q]⁻ where Q = diphenolato bridge, are compared with related compounds containing benzenediamido and dianilido bridges.     

Das Reaktionsverhalten von Cp2NbCl2 gegenüber WF6—Struktur von [Cp2NbCl2]4[WF6]2[WCl6]

The oxidation of Cp₂NbCl₂ with pure WF₆ in SO₂ solution yielded the cationic metallocene species [Cp₂NbCl₂]⁺[WF₆]⁻ essentially in quantitative yield. The same reaction carried out in the presence of either equimolar amounts or a two-fold excess of HCN led to the preparation of the new niobocenium salt [Cp₂NbCl₂]₄⁺[WF₆]²⁻ which was studied by single crystal X-ray diffraction. This compound represents the first example of a structurally characterized metallocene-WF₆⁻ complex, and crystallizes in the tetragonal system: space group, P4₁2₁2(No. 92), a = 11.083(8) Å, c = 48.285 (9) Å; Z = 8; R = 0.0759, R_W = 0.0841. ab]Die Oxidation von Cp₂NbCl₂ mit reinem WF₆ führt in SO₂-Lösung zur Synthese von [Cp₂NbCl₂ ]⁺[WF₆]⁻ in nahezu quantitativer Ausbeute. Die analoge Reaktion führt unter Anwesenheit der äquimolaren Menge oder eines zweifachen Überschusses an HCN zur Ausbildung des Niobocenium-Komplexsalzes [Cp₂NbCl₂]₄⁺ [WF₆]₂⁻[WCl₆]²⁻, von dem eine Röntgenstrukturanalyse angefertigt wurde. Diese Verbindung repräsentiert den ersten structurell charakterisierten Vertreter eines Metallocen-WF₆⁻-Komplexes und kristallisiert im tetragonalen System: Raumgruppe P4₁2₁2 (Nr. 92), a = 11.083(8) Å, c = 48.285(9) Å; Z = 8; R = 0.0759, R_W = 0.0841. kw]Niobium; X-ray diffraction; Oxidation; Metallocenes     

Synthetic [FeFe]-H2ase models bearing phosphino thioether chelating ligands

Through the oxidation-reduction combination procedure, the neutral tri-substituted {2Fe3S} complex 2 was synthesized by replacing the CO ligand in 1 with phosphine. This substitution leads to the Fe-Fe bonds in 1 and 2 with large Lewis basicity difference, i.e. △pK_a^MeCN~10.     

Disproportionation of homoleptic rhodium carbonyls

Both [Rh₄(CO)₁₂] and [Rh₆(CO)₁₆] disproportionate in pyridine to cis-[Rh(CO)₂(py)₂]⁺ and [Rh₅(CO)₁₃(py)₂]⁻. In the same solvent, cis-[Rh(CO)₂(py)₂]⁺ is reduced by CO/H₂O to [(py)₂H][Rh₅(CO)₁₃-(py)₂], which has been structurally characterized.     

Reactivity of tri- and tetra-nuclear ethylidyne cyclopentadienylcobalt clusters towards protonic acids

The bis(μ₃-ethylidyne) tricobalt cluster [(CpCo)₃(μ₃-CCH₃)₂] (1b) is protonated by trifluoroacetic acid to give the dicobalt edge-protonated cation [H(CpCo)₃(μ₃-CCH₃)₂]⁺ [lb + H]⁺. Protonation of the μ₃-ethylidyne tetracobalt cluster hydride [H(CpCo)₄(μ₃-CCH₃)] (3) takes place in two consecutive steps. At low temperature [H₂(CpCo)₄(μ₃-CCH₃)]⁺ [3 + H]⁺ is formed first, and is then slowly converted into [H₃(CpCo)₄(μ₃-CCH₃)]²⁺ [3 + 2H]²⁺ by an excess of acid. As judged by the ¹H NMR data and the crystal structure of [3 + X]⁺[(CF₃COO)₂X]⁻ (X = H or D) the endo hydrogens in [3 + H]⁺ and [3 + 2H]²⁺ occupy μ₃-(Co₃) face capping hydridic positions. The cations [1b + H]⁺ and [3 + H]⁺ show hydride fluxionality in solution, which in the case of [3 + H]⁺ can be frozen out on the NMR timescale at low temperature (ΔG ^≠ (203 K) = 40.8 kJ/mol). The structure of [3 + X]⁺ [(CF₃COO)₂X]⁻ (X = H or D) was determined by X-ray crystallography. One of the hydrides/deuterides is located on the crystallographic mirror plane, capping a tricobalt face of the cluster cation. The other endo hydrogen atom is believed to be disordered between the other two μ₃-(Co₃) sites, which are related by space group symmetry. Deuteronation of 3 shows a strong normal kinetic deuterium isotope effect. From the temperature independence of the ¹H NMR spectrum of [3 + 2D]²⁺ a non-fluxional solution structure can be inferred. In all the systems studied, hydridic (μ₂- or μ₃-) sites are thermodynamically preferred to possible isomeric agostic CoHC or Co₂HC sites for the endo hydrogens. Agostic interactions cannot, however, be ruled out in transient intermediates during the course of the protonations.     

Collisional quenching of electronically excited germanium atoms, Ge[4p(S0)], by small molecules investigated by time-resolved atomic resonance absorption spectroscopy

The collisional quenching of electronically excited germanium atoms, Ge[4p²(¹S₀)], 2.029 eV above the 4p²(³P₀) ground state, has been investigated by time-resolved atomic resonance absorption spectroscopy in the ultraviolet at λ = 274.04 nm [4d(¹P₁⁰) ← 4p²(¹S₀)]. In contrast to previous investigations using the ‘single-shot mode’ at high energy, Ge(¹S₀) has been generated by the repetitive pulsed irradiation of Ge(CH₃)₄ in the presence of excess helium gas and added gases in a slow flow system, kinetically equivalent to a static system. This technique was originally developed for the study of Ge[4p²(¹D₂)] which had eluded direct quantitative kinetic study until recently. Absolute second-order rate constants obtained using signal averaging techniques from data capture of total digitised atomic decay profiles are reported for the removal of Ge(¹S₀) with the following gases (k_R in cm³ molecule⁻¹ s⁻¹, 300 K): Xe, 7.1 ± 0.4 × 10⁻¹³; N₂, 4.7 ± 0.6 × 10⁻¹²; O₂, 3.6 ± 0.9 × 10⁻¹¹; NO, 1.5 ± 0.3 × 10⁻¹¹; CO, 3.4 ± 0.5 × 10⁻¹²; N₂O, 4.5 ± 0.5 × 10⁻¹²; CO₂, 1.1 ± 0.3 × 10⁻¹¹; CH₄, 1.7 ± 0.2 × 10⁻¹¹; CF₄, 4.8 ± 0.3 × 10⁻¹²; SF₆, 9.5 ± 1.0 × 10⁻¹³; C₂H₄, 3.3 ± 0.1 × 10⁻¹⁰; C₂H₂, 2.9 ± 0.2 × 10⁻¹⁰; Ge(CH₃)₄, 5.4 ± 0.2 × 10⁻¹¹. The results are compared with previous data for Ge(¹S₀) derived in the single-shot mode where there is general agreement though with some exceptions which are discussed. The present data are also compared with analogous quenching rate data for the collisional removal of the lower lying Ge[4p²(¹D₂)] state (0.883 eV), also characterized by signal averaging methods similar to that described here.     

Electron transfer in organometallic clusters : XI. Redox chemistry of M3(CO)12(M = Ru, Os) and PPh3 derivatives; mechanism of catalysed nucleophilic substitution

The generality of a two-electron reduction process involving an mechanism has been established for M₃(CO)₁₂ and M₃(CO)₁₂−n(PPh₃)_n (M = Ru, Os) clusters in all solvents. Detailed coulometric and spectral studies in CH₂Cl₂ provide strong evidence for the formation of an ‘opened’ M₃(CO)₁₂²⁻ species the triangulo radical anions M₃(CO)₁₂^−· having a half-life of < 10⁻⁶ s in CH₂Cl₂. However, the electrochemical response is sensitive to the presence of water and is concentration dependent. An electrochemical response for “opened” M₃(CO)₁₂²⁻ is only detected at low concentrations < 5 × 10⁻⁴ mol dm⁻³ and under drybox conditions. The electroactive species ground at higher concentrations and in the presence of water M₃(CO)₁₁²⁻ and M₆(CO)₁₈²⁻ were confirmed by a study of the electrochemistry of these anions in CH₂Cl₂; HM₃(CO)₁₁⁻ is not a product. The couple [M₆(CO)₁₈]^−/2− is chemically reversible under certain conditions but oxidation of HM₃(CO)₁₁⁻ is chemically irreversible. Different electrochemical behaviour for Ru₃(CO)₁₂ is found when [PPN][X] (X = OAc⁻, Cl⁻) salts are supporting electrolytes. In these solutions formation of the ultimate electroactive species [μ-C(O)XRu₃(CO)₁₀]⁻ at the electrode is stopped under CO or at low temperatures but Ru₃(CO)₁₂^−· is still trapped by reversible attack by X presumably as [η¹-C(O)XRu₃(CO)₁₁]⁻. It is shown that electrode-initiated electron catalysed substitution of M₃(CO)₁₂ only takes place on the electrochemical timescale when M = Ru, but it is slow, inefficient and non-selective, whereas BPK-initiated nucleophilic substitution of Ru₃(CO)₁₂ is only specific and fast in ether solvents particulary THF. Metal---metal bond cleavage is the most important influence on the rate and specificity of catalytic substitution by electron or [PPN]-initiation. The redox chemistry of M₃(CO)₁₂ clusters (M = Fe, Ru, Os) is a consequence of the relative rates of metal---metal bond dissociation, metal-metal bond strength and ligand dissociation and in many aspects resembles their photochemistry.     

Anionic derivatives of pentafluoro-λ-sulfanyl (fluorosulfonyl) acetic acid esters

New ester salts [R₃NH]⁺[F₅SC(SO₂F)C(O)OR′]⁻ where RH, CH₃CH₂ and R′CH₃,(CH₃)₂CH have been prepared from corresponding esters and amines. The sodiumsalt Na[F₅SC(SO₂F)C(O)OCH(CH₃)₂] was used to prepare the following -substitutedderivatives: SF₅CX(SO₂F)C(O)OCH(CH₃)₂, XBr, Cl. The crystal structure of[(C₂H₅)₃NH]⁺[F₅SC(SO₂F)C(O)OCH₃]⁻ was determined and is monoclinic: P2₁/n;a=8.758(2) Å, b=9.645(2) Å and c=19.167(4) Å; β=97.92(3)°; V=1603.6 ų; Z=4.     

New aspects of the reaction of silver(I) cations with the ethylenediaminetetraacetate ion

The highly neutralized ethylenediaminetetraacetate (EDTA) titrant (95–99% as Y⁴⁻ anion) precipitates with Ag⁺ cations to form the Ag₄Y species, in aqueous medium, which is well characterized from conductometric titration, thermal analysis and potentiometric titration of the silver content of the solid. The precipitate dissolves in excess Y⁴⁻ to form a complex, AgY³⁻. Equilibrium studies at 25°C and ionic strength 0.50 M (NaNO₃) have shown from solubility and potentiometric measurements that the formation constant (95% confidence level) β₁ = (1.93 ± 0.07) × 10⁵ M⁻¹ and the solubility products are K_S0 = [Ag +]⁴[Y⁴⁻] = (9.0 ± 0.4) × 10⁻¹⁸ M⁵ and K_S1 = [Ag +]³[AgY³⁻] = (1.74 ± 0.08) × 10⁻¹² M⁴. The presence of Na⁺, rather than ionic strength, markedly affects the equilibrium; the data at ionic strength 0.10 M are: β₁ = (1.19 ± 0.03) × 10⁶ M⁻¹, K_S0 = (1.6 ± 0.4) × 10⁻¹⁹ M⁵ and K_S1 = (1.9 ± 0.5) × 10⁻¹³ M⁴; at ionic strength tending to zero; β₁ = (1.82 ± 0.05) × 10⁷ M⁻¹, K_S0 = (2.6 ± 0.8) × 10⁻²² M⁵ and K_S1 = (5 ± 1) × 10⁻¹⁵ M⁴. The intrinsic solubility is 2.03 mM silver (I) in 0.50 M NaNO₃. Well-defined potentiometric titration curves can be taken in the range 1–2 mM with the Ag indicator electrode. Thermal analysis revealed from differential scanning calorimetry a sharp exothermic peak at 142°C; thermal gravimetry/differential thermal gravimetry has shown mass loss due to silver formation and a brown residue, a water-soluble polymeric acid (decomposition range 135–157°C), tending to pure silver at 600°C, consistent with the original Ag₄Y salt.     

The reaction of tetrahydridododecacarbonyltetrarhenium(0) with pyridine and some nitrogen-containing bases

The reactions of H₄Re₄(CO)₁₂ with some nitrogen-containing bases L in chloroform at room temperature were investigated. For L = pyridine, γ-picoline and piperidine, two types of products, namely [H₄Re₃(CO)₉L]⁻[LH]⁺ and H₃Re₃(CO)₉L₃, were isolated. When L = -picoline, 4-CN-pyridine, imidazole or 2,4-dimethylimidazole, [H₄Re₃(CO)₉L]⁻[LH]⁺ is the only product with a yield close to 75%. The structure of H₃Re₃(CO)₉L₃ (L = pyridine) (1) and [H₄Re₃(CO)₉L]⁻[LH]⁺ (L = -picoline) (3) were determined by the X-ray diffraction method. For 1, the three rhenium atoms form an equilateral triangle with edge-bridging hydrides. Each rhenium is coordinated by three carbonyl groups and an axial pyridine. The three pyridines are not all on the same side of the triangular plane to reduce the steric repulsion which is obvious from bond angles and distances data. In 3, the three rhenium atoms form an isosceles with two hydride-bridged Re---Re single bonds and an Re---Re double bond bridged by two hydrides. Each rhenium is coordinated by three CO groups, and -picoline is coordinated to rhenium in the axial position.     

Reactions of Lewis bases with tetrakisdiphenylamide uranium(IV)

The coordinatively unsaturated uranium(IV) complex U[N(C₆H₅)₂]₄ has been prepared via the stoichiometric reaction of diphenylamine with [(Me₃Si)₂N]₂ H₂. U[N(C₆H₅)₂]₄ coordinates Lewis bases such as Et₂O, THF, pyridine or (EtO)₃PO, based on electronic absorption spectroscopy and ¹H NMR studies. Exchange between U[N(C₆H₅)₂]₄ and U[N(C₆H₅)₂]₄(L), where L is THF or pyridine, is rapid on the NMR time-scale between 307 and 323 K. Measurement of equilibrium constants for L = THF provides ΔH and ΔS values of −60 kJ mol⁻¹ and −1.8 × 10² J K⁻¹ mol⁻¹, respectively. U[N(C₆H₅)₂]₄ coordinates and binds (EtO)₃PO much more tightly (K_eq = & > 10⁴ M⁻¹) than THF or pyridine with the exchange rate between U[N(C₆H₅)₂]₄ and U[N(C₆H₅)₂]₄[OP(OEt)₃] being close to the NMR time-scale.     

Dimerization of Incomplete Cubane-Type Mo3S4(DTP)3 Units Linked by Bridging α, ω-Dicarboxylate

Since the trinuclear molybdenum cluster compound Mo₃S₄(DTP)₃(μ-DTP)(L) (DTP=diethyldithiophosphate, L=loosely-coordinated ligand) was reported^[1],a large number of monomeric trinuclear molybdenum derivatives have been synthesized from it by its diverse substitution reactions^[2]. This reaction provides a useful route to design cluster complexes with specific functions. By the reaction with α, ω-dicarboxylates, we successfully synthesized the first oligomer containing two incomplete cubane-type[Mo₃S₄] cores formulated as[Mo₃S₄(DTP)₃(DMF)]₂[η²-μ-OOC(CH₂)₃COO-μ-η²]) whose molecule structure is as follows:     

A localized molecular orbital study on the bonding of> Mo3S4]2Mo> and> Mo3S4]CuI> versus (C6H6)2Cr and C6H6Cr(CO)3

The energy-localized CNDO/2 molecular orbitais have been calculated for the clusters containing molybdenum, > {Mo₃S₄₂Mo}⁸⁺ and> Mo₃S₄]CuI> ⁴⁺, versus the prototype arene-metal sandwich (C₆H₆)₂Cr and half-sandwich complexes C₆H₆Cr(CO)₃. The bonding characteristics of these compounds are described from a localization bonding viewpoint. There are two typical M-arene and M-[Mo₃S₄] bondings. One is formed by electron donation from the three-center two-electron π-bonds in the arene or [Mo₃S₄]⁴⁺ ligands into the vacant hybrid orbitais of the “stranger” metal atom. In the other M-arene or M-[Mo₃S₄] bond there is very little donation by the lone electron pair occupying the d AOs of the “stranger” metal atom to the arene or [Mo₃S₄]⁴⁺ ligands. The analogy of the ligand [Mo₃S₄]⁴⁺ in the clusters studied with the ligand benzene is also briefly discussed.