Über das Lithiumchloromolybdat Li[Mo6Cl13]

On the Lithium Chloromolybdate Li[Mo₆Cl₁₃] Li[Mo₆Cl₁₃] was obtained as single phase product from a solid state reaction of MoCl₅, Mo powder, and LiCl at 800 °C. The structure as refined by single crystal X‐ray diffraction, contains one‐dimensional [Mo₆Cl Cl Cl ]^– chains, formed by Cl^a–a bridges. Lithium ions are located in tunnels along the chain‐direction, each of them being surrounded by a distorted tetrahedral arrangement of outer chlorine ligands (Cl^a) belonging to four different clusters.     

Elektronenstruktur von strukturell offenen Derivaten des [Mo6X14]2−-Clusters: [Mo5Cl13]2− und [Mo4I11]2−

Electronic Structure of Structural Open Derivatives of the [Mo₆X₁₄]^2?-Cluster: [Mo₅Cl₁₃]^2? and [Mo₄I₁₁]^2? The electronic structure of structural open derivatives of the [Mo₆X₁₄]^2?-cluster [Mo₅Cl₁₃]^2? and [Mo₄I₁₁]^2? has been studied by the EHMO method. In [Mo₅Cl₁₃]^2? 9 occupied MO's with dominant Mo4d character are responsible for the formation of the 8 metal-metal bonds. In [Mo₄I₁₁]^2? the stronger covalent character of the Mo? I bonds affects the localization and the energy of molecular orbitals and also the charge distribution. The metal-metal bonds are formed by 8 MO's containing considerable participation of halogen AO's contrary to the chloride cluster. There is no bonding between the Mo atoms at the wing tips of the Mo₄ butterfly and the reason for decreasing the dihedral angle between the Mo₃ planes in [Mo₄I₁₁]^2? compared with the octahedral angle is apparently the stabilization of the whole system (Mo? Mo and Mo? I bonds). The unpaired electron occupies in both clusters a slightly antibonding (with regard to the Mo? Mo bonds) orbital.     

Synthese und Struktur von Mo2NCl8 und Mo3N2Cl11

Synthesis and Crystal Structure of Mo_2<>NCl₈ and Mo₃N₂Cl₁₁ The reaction of MoCl₅ with Cl₃VNCl at 140 °C in a sealed glass ampoule yields air sensitive black crystals of the mixed valent molybdenum(V, VI) nitride chloride, Mo₂NCl₈. It crystallizes in the monoclinic space group P2/c with a = 996.1(1), b = 629.4(1), c = 1780.8(3) pm, β = 101.82(2)°, and Z = 4. The crystal structure consists of dinuclear C₂‐symmetrical units [Cl₂(N≡)Mo(μ₂‐Cl)₃Mo(≡N)Cl₂]^— and [Cl₄Mo(μ₂‐Cl)MoCl₄]⁺, connected in an alternating sequence by asymmetric nitrido bridges Mo≡N‐Mo to form chains. The reaction of Cl₃VNCl with MoCl₃ at 140 °C affords Mo₃N₂Cl₁₁, but for the prolonged reaction period, MoNCl₃ is observed in addition. Mo₃N₂Cl₁₁ can also be obtained from MoNCl₃ and MoCl₅ (2:1) at 140 °C. It forms orthorhombic, black crystals with the space group Pca2₁ and a = 1256.1(1), b = 1001.9(1), c = 1330.10(5) pm, and Z = 4. The structure contains the same dinuclear units [Cl₂(N≡)Mo(μ₂‐Cl)₃Mo(≡N)Cl₂]^— as in Mo₂NCl₈, which in this case are connected with MoCl₄⁺ moieties by asymmetric nitrido bridges Mo≡N‐Mo forming chains. In Mo₂NCl₈ the Mo‐N distances in the nearly linear nitrido bridges are 167.6(2), and 214.8(2) pm, whereas in case of Mo₃N₂Cl₁₁ two sets of Mo‐N distances of 166, 8(4) and 214, 0(4) pm as well as 166, 9(4) and 211, 9(4) pm are observed.     

Darstellung von trans-[Mo6Cl8]Cl4Br22−ausgehend von kristallisierten [Mo6Cl8]Cl4(H2O)2 und die Kristallstruktur von [(C6H5)4As]2[Mo6Cl8]Cl4Br2

Preparation of trans-[Mo₆Cl₈]Cl₄Br₂^2? Starting from Crystalline [Mo₆Cl₈]Cl₄(H₂O)₂ and Crystal Structure of [(C₆H₅)₄As]₂[Mo₆Cl₈]Cl₄Br₂ The synthesis of the title compound is successful if the crystallized [(Mo₆Cl₈)Cl₄(H₂O)₂] containing the H₂O molecules in trans-position reacts with HBr + [(C₆H₅)₄As]Br in ethanol in a heterogeneous reaction. The X-ray structure investigation confirms the existence of discrete trans-Br-substituted cluster anions of composition [(Mo₆Cl₈)Cl₄Br₂]^2? in the crystal. The reaction in homogeneous solutions proceeds to Br-enriched compounds. [(C₆H₅)₄As]₂[(Mo₆Cl₈)Cl₄Br₂] crystallizes in the triclinic space group P¯1 with a = 11.071(2), b = 11.418(2), c = 12.813(2) Å, α = 116.10(2), β = 95.27(2) and γ = 94.41(2)° (?133°C). The crystal structure at ?133°C was determined from single crystal X-ray diffraction data (R₁ = 0.026). The [(Mo₆Cl₈)Cl₄Br₂]^2?-anions are not completely ordered but distributed statistically among the three positions which are possible within the limits of the ordered [Mo₆Cl₈]-cores (ratio 11:5:4). The frameworks of the anions consist of Mo₆ cluster units with (slightly distorted) octahedral arrangement of the metal atoms (d(Mo? Mo): 2.600(1) up to 2.614(1) Å), which are coordinated by the halogeno ligands in a square-pyramidal manner. The details of the structure will be discussed and compared with similar [(Mo₆X₈)Y₄] cluster units (X, Y ? Cl, Br).     

Compounds with Cluster Cations together with Cluster Anions [(M6X12)(EtOH)6]2+ besides [(Mo6Cl8)Cl4X2]2– (M = Nb,Ta; X = Cl,Br) – Synthesis and Crystal Structures

Compounds consisting of both cluster cations and cluster anions of the composition [(M₆X₁₂)(EtOH)₆][(Mo₆Cl₈)Cl₄X₂] · n EtOH · m Et₂O (M = Nb, Ta; X = Cl, Br) have been prepared by the reaction of (M₆X₁₂)X₂ · 6 EtOH with (Mo₆Cl₈)Cl₄. IR data are given for three compounds. The structures of [(Nb₆Cl₁₂)(EtOH)₆][(Mo₆Cl₈)Cl₆] · 3 EtOH · 3 Et₂O 1 and [(Ta₆Cl₁₂)(EtOH)₆][(Mo₆Cl₈)Cl₆] · 6 EtOH 2 have been solved in the triclinic space group P1 (No. 2). Crystal data: 1 , a = 10.641(2) Å, b = 13.947(2) Å, c = 15.460(3) Å, α = 65.71(2)°, β = 73.61(2)°, γ = 85.11(2)°, V = 2005.1(8) ų and Z = 1; 2 , a = 11.218(2) Å, b = 12.723(3) Å, c = 14.134(3) Å, α = 108.06(2)°, β = 101.13(2)°, γ = 91.18(2)°, V = 1874.8(7) ų and Z = 1. Both structures are built of octahedral [(M₆Cl₁₂)(EtOH)₆]²⁺ cluster cations and [(Mo₆Cl₈)Cl₆]^2– cluster anions, forming distorted CsCl structure types. The Nb–Nb and Ta–Ta bond lengths of 2.904 Å and 2.872 Å (mean values), respectively, are rather short, indicating weak M–O bonds. All O atoms of coordinated EtOH molecules are involved in H bridges. The Mo–Mo distances of 2.603 Å and 2.609 Å (on average) are characteristic for the [(Mo₆Cl₈)Cl₆]^2– anion, but there is a clear correlation between the number of hydrogen bridges to the terminal Cl and the corresponding Mo–Cl distances.     

Thiochloroanionen von Molybdän(IV). Die Kristallstruktur von (NEt4)3[Mo3(μ3-S)(μ-S2)3Cl6]Cl · CH2Cl2 Kristallstruktur,EPR-Spektrum und magnetische Eigenschaften von (NEt4)2[Mo2(μ-S2)(μ-Cl)2Cl6]

Thiochloro Anions of Molybdenum (IV). Crystal Structure of (NEt₄)₃[Mo₃(μ₃-S)(μ-S₂)₃Cl₆]Cl μ CH₂Cl₂. Crystal Structure, Magnetic Properties, and EPR-Spectrum of (NEt₄)₂ [Mo₂(μ-S₂)(μ-Cl)₂Cl₆] From molybdenum pentachloride and tetraethylammonium hydrogensulfide in CH₂Cl₂ an insoluble product of composition (NEt₄)₂[Mo₂S₃Cl₉] was obtained along with a brown solution, from which (NEt₄)₂[Mo₂(S₂)Cl₈] was crystallized. The insoluble product and NEt₄Cl react in CH₂Cl₂ to yield, among others, (NEt₄)₃[Mo₃(S)(S₂)₃Cl₆]Cl · CH₂Cl₂. The latter crystallizes in the orthorhombic space group Pnma, a = 2495.8, b = 1501.2, c = 1295.6 pm, Z = 4. According to the crystal structure determination (3070 observed reflexions, R = 0.049) the [Mo₃(S)(S₂)₃Cl₆]^2? ion consists of an Mo₃ triangle with Mo? Mo bonds, each side of the triangle is bridged by disulfido groups and one sulfur atom is capped over the Mo₃ triangle; the single chloride ion is looseley associated to three S atoms. (NEt₄)₂[Mo₂(S₂)Cl₈] also crystallizes in the space group Pnma, a = 1425.6, b = 1129.9, c = 2004.7 pm, Z = 4; structure determination with 1703 observed reflexions, R = 0.061. In the [Mo₂(S₂)Cl₈]^2? ion the Mo atoms are bridged via one disulfido group and two chlorine atoms. There is a Mo? Mo bond, but according to the magnetic properties and the EPR spectrum each Mo atom still possesses one unpaired electron.     

Synthese und Struktur von Mo2NCl7

Synthesis and Structure of Mo₂NCl₇ The reaction of VN with MoCl₅ at 175 °C in a sealed glass ampoule yields the molybdenum(V) nitride chloride Mo₂NCl₇ in form of air sensitive black crystals with the triclinic space group P1¯ and a = 905.7(8); b = 975.4((6); c = 1283.4(8) pm, α = 103.13(4)°; β = 109.83(5)° und γ = 98.58(5)°. The crystal structure is built up from dinuclear units [Mo₂N₂Cl₇]^3— and [Mo₂Cl₇]³⁺, which are connected by asymmetric nitrido bridges to form endless chains. Within both dinuclear units the Mo atoms are bridged by three Cl atoms resulting in a Mo‐Mo distance of 349.2(3) pm in the unit [Mo₂N₂Cl₇]^3—. In case of [Mo₂Cl₇]³⁺, however, a shorter Mo‐Mo distance of 289.4(3) pm is observed, which can be interpreted by a single bond. Correspondingly a reduced magnetic moment of 0.95 B.M. per Mo atom is observed.     

Mo2O3Cl4(Pyridin)4 · CH2Cl2 Synthese,IR-Spektrum und Kristallstruktur

Mo₂O₃Cl₄(Pyridine)₄ · CH₂Cl₂. Synthesis, IR Spectrum, and Crystal Structure Reduction of MoO₂Cl₂(pyridine)₂ with triphenylphosphane in toluene and recrystallisation from CH₂Cl₂ yields brown crystal needles of the complex Mo₂O₃Cl₄(pyridine)₄ · CH₂Cl₂. The compound crystallizes monoclinic in the space group P2₁/c with four formula units per unit cell of the dimensions a = 1 234.6 pm; b = 1 593 pm, c = 1 522.3 pm and β = 105.66° A structural investigation by X-ray methods (3 276 independent observed reflexions, R = 0.033) reveals the molecule with two molybdenum atoms in a distorted octahedral coordination linked by an almost linear Mo? O? Mo bridge with bond distances of 167 and 168 pm, respectively. The chlorine atoms are located in trans-position to the oxygen atoms which have different trans effects: The Mo? Cl bond opposite the bridge (length 242 pm) is 8 pm shorter than the bond in trans position to the terminal oxo ligands. The pyridine nitrogen atoms are in trans position to each other and complete the coordination of the molybdenum atoms. The i.r. spectrum of the compound is reported.     

Die Reaktion von [Mo6Cl8]X4 mit N-Basen

Reaction of [Mo₆Cl₈]X₄ with N-Bases [Mo₆Cl₈]X₄ (X = Cl, Br, I) in ethanol solution by titration with Ag⁺ showed 4 labil X atoms. The displacement of X^? especially by F^? accelerates the titration decisively. Conductivity measurements in ethanol or acetone showed that [Mo₆Cl₈]X₄ at 25°C behave as weak 1:1-electrolytes. Solutions of [Mo₆Cl₈]X₄ in DMF heated up to 60°C and than lowered to 25°C showed that the compounds in this solvent behave as (potential) strong 2:1-valent electrolytes. From the following compounds the labil halides have been determined by titration with Ag⁺: [Mo₆Cl₈]X₄(Py)₂ (X = Cl, Br), [Mo₆Cl₈]X₄(bipy)₂ (X = Cl, Br, I), [Mo₆Cl₈]X₄(Phenpy)₂ (X = Cl, Br, I), (PyH)₂[Mo₆Cl₈]X₆ (X = Cl, Br); (bipyH)₂[Mo₆Cl₈]I₄Cl₂. Always 4 (respectively 6) labil halides have been observed; exception [Mo₆Cl₈]Cl₄(Py)₂ in acetone (2 labil Cl). Lattice constants and mole volumina for the adducts with pyridin and bipyridin have been determined. The adducts with bipyridin and phenylpyridin are isotypic. Conductivity measurements have been made in different solutions. The decomposition on the thermobalance showed that in [Mo₆Cl₈]Cl₄(Py)₂ the bond of pyridin is weak. The 2 pyridin molecules are evolved at the same time. However [Mo₆Cl₈]I₄(Bipy)₂ loses 1 bipyridin only. (PyH)₂[Mo₆Cl₈]X₆ formed during the first decomposition step the novel compounds (PyH) [Mo₆Cl₈]X₅ (X = Cl, Br). Both compounds are isotypic. They behave in ethanol solution as strong 1:1-valent electrolytes.     

Synthesis,Crystal Structure,and Bonding of (PCl4)2[Mo2Cl10], the First Compound in Mo–P–Cl System

An ampule reaction between Mo and PCl₅ at 200 °C yielded (PCl₄)₂[Mo₂Cl₁₀], the first ternary compound in Mo–P–Cl system. Single crystal X-ray diffraction gave a triclinic unit cell: a = 6.870(1), b = 8.892(2), c = 9.423(2) Å, α = 100.24(2), β = 95.55(2), γ = 96.12(2)° (V = 559.3(2) ų, Z = 1, sp. gr. P1, wR₂ = 0.0575 and R₁ = 0.0279. The ionic compound is built from edge sharing bioctahedra [Mo₂Cl₁₀]^2– and two tetrahedra PCl₄⁺. The averaged Mo–Cl_b distance, 2.503(1) Å, is longer than the Mo–Cl_t distance, 2.33(2) Å. The Mo … Mo distance, 3.77 Å, indicates the absence of a direct Mo–Mo interaction. Semiempirical and ab initio calculations showed the possibility for [Mo₂Cl₁₀]^2– to exist with long and short Mo to Mo distances, the letter corresponding to the Mo–Mo bond.     

Synthese und Kristallstruktur von (PPh4)2[Mo2(S2)2Cl8] · 2 CH3CN und seine topotaktische Umwandlung zu (PPh4)2[Mo2(S2)2Cl8]

Synthesis and Crystal Structure of (PPh₄)₂[Mo₂(S₂)₂Cl₈] · 2 CH₃CN and its Topotactic Transformation to (PPh₄)₂[Mo₂(S₂)₂Cl₈] MoS₂Cl₃ was prepared from molybdenum and S₂Cl₂ at 200 °C. Its reaction with PPh₄Cl in acetonitrile yielded (PPh₄)₂[Mo₂(S₂)₂Cl₈] · 2 CH₃CN. In vacuum or upon warming, it loses the acetronitrile without degradation of the crystals. According to the X-ray crystal structure determinations both compounds, with and without acetonitrile, are triclinic. They contain the same [Cl₄Mo(μ-S₂)₂MoCl₄]^2– ions, in which the Mo atoms are joined by two disulfido groups and an Mo–Mo bond. Details of the crystal packings and their topotactic transformation are given.     

Molybdänhalogenidcluster mit sechs terminalen Alkoholatliganden: (C18H36N2O6Na)2[Mo6Cl8(OCH3)6] · 6CH3OH und (C18H36N2O6Na2)2[Mo6Cl8(OC6H5)6]

Molybdenum(II) Halide Clusters with six Alcoholate Ligands: (C₁₈H₃₆N₂O₆Na)₂[Mo₆Cl₈(OCH₃)₆] · 6CH₃OH and (C₁₈H₃₆N₂O₆Na)₂[Mo₆Cl₈(OC₆H₅)₆] . The reaction of Na₂[Mo₆Cl₈(OCH₃)₆] and 2,2,2-crypt yields (C₁₈H₃₆N₂O₆Na)₂[Mo₆Cl₈(OCH₃)₆] · 6 CH₃OH ( 1 ), which is converted to (C₁₈H₃₆N₂O₆Na)₂[Mo₆Cl₈(OC₆H₅)₆] ( 2 ) by metathesis with phenol. According to single crystal structure determinations ( 1 : P3 1c, a=14.613(3) Å, c=21.036(8) Å; 2 : P3 1c, a=15.624(1) Å, c=19.671(2) Å) the compounds contain anionic clusters [Mo₆Cl₈ⁱ(OR^a)₆]^2? ( 1 : d(Mo—Mo) 2.608(1) Å to 2.611(1) Å, d(Mo—Cl) 2.489(1) Å to 2.503(1) Å, d(Mo—O) 2.046(4) Å; 2 : d(Mo—Mo) 2.602(3) Å to 2.608(3) Å, d(Mo—Cl) 2.471(5) Å to 2.4992(5) Å, d(Mo—O) 2.091(14) Å). Electronic interactions of the halide cluster and the phenolate ligands in [Mo₆Cl₈(OC₆H₅)₆]^2? is investigated by means of UV/VIS spectroscopy and EHMO calculations.     

Das Addukt von BiCl3 mit Mo6Cl12: [BiCl]-Hanteln in der Struktur von [BiCl][Mo6Cl14]

The Adduct of BiCl₃ and Mo₆Cl₁₂: [BiCl] Dumbbells in the Structure of [BiCl][Mo₆Cl₁₄] MoCl₃ reacts under decomposition to MoCl₂ and Cl₂ with BiCl₃ in a sealed evacuated glass ampoule at 550 °C to form light red crystals of [BiCl][Mo₆Cl₁₄]. The crystal structure determination (monoclinic, C 2/c, a = 1268.1(4) pm, b = 1304.6(3) pm, c = 2571.9(8) pm, β = 91.79(3)°, Z = 8) shows that the structure is built of [(Mo₆Cl₈)Cl₆] units containing nearly regular octahedral Mo₆ clusters. These units are arranged in the motiv of a cubic closest packing. The octahedral interstices contain [BiCl] dumbbells with a Bi–Cl bond length of 249 pm. The coordination sphere of the Bi atom is completed by six weaker Bi–Cl-contacts of 275 to 308 pm length to a distorted monocapped trigonal prism. Neglecting the secondary Bi–Cl bonds, the title compound can be formulated as [(BiCl)²⁺][(Mo₆Cl₁₄)^2–].     

Über die Reaktion von 2,2-Dimethylpropylidinphosphan mit Molybdänpentachlorid; die Kristallstruktur von [Mo2Cl6(α,α′-Dipyridyl)3]

Reaction of 2,2-Dimethylpropylidynephosphine with Molybdenum Pentachloride; Crystal Structure of [Mo₂Cl₆(α,α′-dipyridyl)₃] 2,2-Dimethylpropylidynephosphine and molybdenum pentachloride dissolved in POCl₃ react with oxydation of the phosphorus and reduction of the molybdenum atom to give the alkyne complex [Mo₂Cl₄(μ-Cl)₂(μ-H₉C₄? C?C? C₄H₉)(OPCl₃)₂]. Addition of α,α′-dipyridyl or of methyltriphenylphosphonium chloride in dichloromethane results in a displacement of the ligands POCl₃ and H₉C₄? C?C? C₄H₉ from this complex and in the formation of [Mo₂Cl₆(dipy)₃] or [(H₅C₆? )₃P? CH₃]₃[Mo₂Cl₉]. Besides the latter compound small amounts of [(H₅C₆? )₃P? CH₃]₂[MoCl₆] can be isolated from the reaction mixture. [Mo₂Cl₆(dipy)₃] which has already been prepared by other methods crystallizes in the monoclinic space group P2₁/c with {a = 1612; b = 148; c = 1296 pm; γ 109.3°; Z = 4} at 20°C. As shown by a crystal structure determination the complex is built up from [MoCl₂(dipy)₂]⁺ cations and [MoCl₄(dipy)]^? anions. The molybdenum atoms are both octahedrally surrounded. With average values of 238 and 243 pm the Mo? Cl bond distances in the cation, where a cis-arrangement of the chlorine atoms is observed, and in the anion differ significantly from each other. [Mo₂Cl₆(dipy)₃] which has already been prepared by other methods crystallizes in the monoclinic space group P2₁/c with {a = 1612; b = 148; c = 1296 pm; γ = 109.3°; Z = 4} at 20°C. As shown by a crystal structure determination the complex is built up from [MoCl₂(dipy)₂]⁺ cations and [MoCl₄(dipy)]^? anions. The molybdenum atoms are both octahedrally surrounded. With average values of 238 and 243 pm the Mo? Cl bond distances in the cation, where a cis-arrangement of the chlorine atoms is observed, and in the anion differ significantly from each other.     

Cs2Mo15S19: a novel ternary reduced molybdenum sulfide containing Mo6 and Mo9 clusters

The crystal structure of dicaesium pentadecamolybdenum nonadeca­sulfide, Cs₂Mo₁₅S₁₉, consists of a mixture of Mo₆S₈S₆ and Mo₉S₁₁S₆ cluster units in a 1:1 ratio. Both units are interconnected via inter‐unit Mo—S bonds. The Cs⁺ cations occupy large voids between the different cluster units. The Cs and two inner S atoms lie on sites with 3 symmetry (Wyckoff site 12c) and the Mo and S atoms of the median plane of the Mo₉S₁₁S₆ cluster unit on sites with 2 symmetry (Wyckoff site 18e).     

Synthesis and structure of a seven electron triangular cluster complex [Mo3S4Cl3(dppe)2(PEt3]

The triangular six-electron cluster complex [Mo₃S₄Cl₄(PEt₃) _x (thf)₅] produced by the excision reaction of Mo₃S₇Cl₄ with triethypholsphine is reduced by magnesium at – 20°C. Subsequent addition of dppe (=1,2-his(diphenylphosphino)ethane) to the reduced species affords a seven-electron triangular cluster complex [Mo₃S₄Cl₃(dppe)₂(PEt₃)]. The complex crystallizes in the space groupCm witha=17.170(6),b-19.878(6),c = 13.289(5) = 121.73(2)°,V = 3858(2) A³, andZ = 2. The structure shows an almost equilateral triangle of three molybdenum atoms capped by a Sulfur atom and bridged by three sulfur atoms. The Mo Mo distances, ranging from 2.804(1) to 2.809(1) A are elongated ca. 0.04 A as compared with lose of a six-electron cluster complex with drape ligands. Two molybdenum atoms have a chlorine and a dppe ligands, and the other molybdenum atom bas a chlorine and a triethylphosphine ligands. The UV-Vis spectrum has a characteristic broad hand centered at 1410 n m, which is not observed for six-electron clusters. The ESR spectrum indicates the presence of an unpaired electron consistent with the formulation of the compound as a seven-electron cluster.Dedicated to Professor fiaxi Lu on the occasion of his 80th birthday.     

Synthese und Kristallstruktur von (PPh4)2[Mo2Cl10]

Synthesis and Crystal Structure of (PPh₄)₂[Mo₂Cl₁₀] The title compound is obtained in the reaction of [MoCl₄(Ph? C?C? Ph)]₂ with tetraphenylphosphonium chloride in dichloro methane, forming brown crystals. It is characterized by the i.r. spectrum and a crystal structure analysis by the aid of X-ray diffraction data. The complex crystallizes triclinic in the space group P1 with one formula unit per unit cell. The cell dimensions are a = 1122 pm, b = 1137 pm, c = 1283 pm; α = 63.4°, β = 69.1°, γ = 86.5°. The crystal structure determination (2959 observed, independent reflexions, R = 4.5%) shows the constants of the unit cell to consist of on centrosymmetric anion, two cations and one disordered molecule of dichloro methane. The distance Mo? Mo in the anion is 380 pm, which excludes direct magnetic interaction between the molybdenum atoms.     

15N- und 19F-NMR-spektroskopischer Nachweis und Xa-Austauschreaktionen der Clusteranionen [(Mo6Cl)(15NCS) X]2−, Xa = F,Cl, Br,I; n = 1–6

¹⁵N and ¹⁹F NMR Spectra and X^a-Exchange Reactions of the Cluster Anions [(Mo₆Clⁱ₈)(¹⁵NCS)^a_nX^a_6?n]^2?, X^a = F, Cl, Br, I; n = 1–6 By intermolecular ligand exchange reaction of the new compound [(Mo₆Clⁱ₈)(¹⁵NCS)^a₆] ^2? with [(Mo₆Clⁱ₆)X^a₆]^2?, X^a = F, Cl, Br, I, in acetone, the outersphere mixed cluster ions [(Mo₆Clⁱ₈)(¹⁵NCS)^a₆X^a_6?n]^2?, n = 1–6, are formed and characterized by their distinct ¹⁵N nmr chemical shifts. The ambident SCN^? is exclusively N-bonded, indicated by ¹⁵N nmr and vibrational spectra. The mixed cluster ions containing X^a = F are identified in acetonitrile by ¹⁹F nmr measurement as well. The kinetic analysis reveals equilibration at room temperature within 10 hours to statistical distribution of all compounds, inclusive the ratios for the geometric isomers for each system at any time with n = 2,4 cis:trans = 4 : 1 and n = 3 fac:mer = 2 : 3, indicating the equivalence of all X^a positions with respect to exchange reactions. For [(Mo₆Clⁱ₈)X^a₆]^2? the reaction rates increase in the series X^a = Cl < Br < I < SCN < F. The ¹⁵N nmr chemical shifts are depending on the electronegativity and the number of the X^a ligands. Furthermore an antipodal influence working on ¹⁵N trans-positioned to X^a effects an additional highfield shift for X^a = F and an additional downfield shift for X^a = Cl, Br, I.     

Einige Reaktionen mit [Mo6Cl8]Cl4

Some Reactions with [Mo₆Cl₈]Cl₄ The reaction of [Mo₆Cl₈]Cl₄ with different chemical agents has been investigated: The methoxylation depends on the CH₃O^? concentration in CH₃OH. The reaction with HF leads to a partial fluorinated [Mo₆Cl₈] product. With NH₄F (NH₄)₂[Mo₆Cl₈]F₆ in formed, the hydrolysis of which leads to [Mo₆Cl₈]F₃(OH) · 2.5 H₂O. This compound can be decomposed thermically into [Mo₆Cl₈]O₂. [Mo₆Br₈]F₆^2? on hydrolysis leads to [Mo₆Br₈]F₃(OH) · 5 H₂O. With CsF Cs₂[Mo₆Cl₈]F₆ is formed, which by hydrolysis is transformed into [Mo₆Cl₈]F₃(OH) · 2.5 H₂O and possibly to [Mo₆Cl₈]F₄ · xH₂O(?). In reaction of [Mo₆Cl₈]Cl₄ with H₂SO₄ one gets [Mo₆Cl₈](SO₄)₂. Salts e. g. [(C₆H₅)₄As]₂[Mo₆Cl₈](OC₆F₅)₆ and adducts e. g. [Mo₆Cl₈](OC₆F₅)₄ · 2 HMPA are prepared. The compounds have been characterized by X-ray powder-diagramms and by IR-spectra.     

Dithiolylium‐Chlorooxomolybdate(V): Synthese und Kristallstruktur von (C3Cl3S2)[MoOCl4] und (C3Cl3S2)[Mo2O2Cl7]

Dithiolylium Chlorooxomolybdates(V): Synthesis and Crystal Structure of (C₃Cl₃S₂)[MoOCl₄] and (C₃Cl₃S₂)[Mo₂O₂Cl₇] The reaction of 3, 4, 5‐Trichlor‐1, 2‐dithiolylium chloride with MoOCl₃ in dichlormethane under solvothermal conditions at 65 °C simultaneously yields the green tetrachlorooxomolybdate(V) (C₃Cl₃S₂)[MoOCl₄] and the yellow‐brown heptachlorodioxodimolybdate(V) (C₃Cl₃S₂)[Mo₂O₂Cl₇]. The crystal structures of both compounds contain nearly planar (C₃Cl₃S₂)⁺ ions with a S—S bond length of 203 pm. The discrete [MoOCl₄]^— ion in the structure of (C₃Cl₃S₂)[MoOCl₄] has the shape of a square pyramid with the oxygen atom at the apex. The molybdenum atom is displaced by 58 pm from the basal plane towards the oxygen atom. The [Mo₂O₂Cl₇]^— ion in the structure of (C₃Cl₃S₂)[Mo₂O₂Cl₇] has the form of a face‐sharing double octahedron. It is formally composed of a [MoOCl₄]^— ion and a MoOCl₃ molecule connected by one symmetrical and two unsymmetrical chloro bridges. The molybdenum atoms placed in the centers of such connected octahedra are 357 pm apart, indicating no Mo—Mo bond.