Synthesis and X-ray crystal structure of the electron-deficient metal carbonyl cluster [Os3(CO)5(μ3-H)(μ-H)(μ-PtBu2)2(μ-Ph2PCH2PPh2)]

The reaction of [Os₃(CO)₁₀(μ-dppm)] (1) with ^tBu₂PH in refluxing diglyme results in the electron-deficient metal cluster complex [Os₃(CO)₅(μ₃-H)(μ-P^tBu₂)₂(μ-dppm)] (2) (dppm = Ph₂PCH₂PPh₂) in good yields. The molecular structure of 2 has been established by a single crystal X-ray structure analysis. In contrast to the known homologue [Ru₃(μ-CO)(CO)₄(μ₃-H)(μ-H)(μ-P^tBu₂)₂(μ-dppm)] (3), no bridging carbonyl ligand was found in 2. The electronically unsaturated cluster 2 does not react with carbon monoxide under elevated pressure, therefore 2 seems to be coordinatively saturated by reason of the high steric demands of the phosphido ligands.     

Functionalization of the cluster [FeCp(μ3–CO)]4

The 33-year-old cluster [FeCp(μ₃-CO)]₄ (1) has been functionalized by reaction with lithium diisopropylamide, followed by CO₂, to give the acid RCO₂H, 2 (R=Fe₄(μ₃–CO)₄Cp₃(C₅H₄–)), recently reported by Rauchfuss. The cluster 2 reacts with (CO)₂Cl₂ to give the new cluster RCOCl (3), which reacts with the disulfide {S(CH₂)₁₁NH₃⁺Cl^–}₂ to give the amido-cluster disulfide [Fe₄(μ₃–CO)₄Cp₃{η⁵′-C₅H₄C(O)NH(CH₂)₁₁S}]₂ (4), with NEt₃ to give the diethylamido cluster [Fe₄Cp₃(η⁵-C₅H₄CONEt₂)(μ₃-CO)₄] (5), and with N-hydroxysuccinimide to give the N-succinimidyl ester cluster 6. © 2000 Académie des sciences / Éditions scientifiques et médicales Elsevier SAScluster functionalization / tetrairon-cylopentadienyl-carbonyl cluster     

Dinuclear Ruthenium(II) Carbonyl Complexes Doubly Bridged by a Bromine Atom and a C5H3N-2-C(O)CH2-6-CH2 (Q) Group. Crystal Structures of Ru2(μ-Br)(μ-Q)Br(CO)4(PPh3)(MeOH) and Ru2(μ-Br)(μ-Q)Br(CO)3(PPh3)2

The oxidative addition reaction of 2,6-bis(bromomethyl)pyridine to Ru₃(CO)₁₂ gave scarcely soluble {Ru₂Br₂(-Q)(CO)₄} _n , 1, [Q=C₅H₃N-2-C(O)CH₂-6-CH₂] or a mixture of 1 and the mononuclear complex RuBr(Q)(CO)₃, 2, [Q=C₅H₃N-2-C(O)CH₂-6-CH₂Br] according to the reactant's mole ratio. Further reactions of 1 with some N- and P-donor ligands (L) afforded readily soluble dinuclear complexes, Ru₂(-Br)(-Q)Br(CO) _n (L) _m [n=4, m=1, L=PPh₃ 3a, or py 3b; n=3, m=2, L=PPh₃ 5a, or PPh₂(o-tolyl) 5b]. In this paper, the characterization of these products by the elemental analyses and the spectroscopic methods are described. The X-ray crystal structures of Ru₂(-Br) (-Q)Br(CO)₄(PPh₃)(MeOH), 4, which was obtained by crystallization of 3a from MeOH, and of 5a · (2CHCl ₃ ) are also described. Each of the metal atoms in 4 has a distorted octahedral coordination, while in 5a · (2CHCl ₃ ) one metal atom takes a distorted octahedral geometry and the other pseudooctahedral, which is completed by presenting a Ru ··· Br secondary bonding interaction.     

Synthesis and Reaction of [MnRe(CO)_6(μ-SH)(μ-SC(H)PPr_3~i)(PPh_3)]

In recent years the chemistry of mono- or hetero-binuclear complexes containing metal-S(C) bonding modes is a very active field of research. Many useful applications of this kind of complexes have been exploited, such as industrial catalytic hydrodesulfurization (HDS)1,2 and transition metals mediated organic synthesis3-5. In this paper we report that the reduction and subsequent protonation of hetero-binuclear complex [MnRe(CO)6(-S2CPPri3)] occur with cleavage of metal-metal bond and o…     

Synthesis and Structure of the Complex [Mo3(μ3-S)(μ2-S2)3(Et2NCS2)3 +Br-

Tri-₂-disulfido-₃-thiotris(diethyldithiocarbamato)-S,S'-triangle-trimolybdenum bromide [Mo₃(₃-S)(₂-S₂)₃(Et₂NCS₂)₃ ⁺Br^- was obtained and characterized.     

Four [Tp*W(μ3-S)3Cu3(μ3-Br)]-based clusters: synthesis, structural characterization and third-order NLO properties

Treatment of [Et(4)N][Tp*W(μ(3)-S)(3)(CuBr)(3)] (Tp* = hydridotris(3,5-dimethylpyrazol-1-yl)borate) (1) with an excess of α-methylpyridine (α-MePy) and NH(4)PF(6) in CH(2)Cl(2) afforded a cationic cluster [Tp*W(μ(3)-S)(3)Cu(3)(α-MePy)(3)(μ(3)-Br)](PF(6)) (2) while the reaction of 1 with an excess of 1,4-pyrazine (1,4-pyz) and NH(4)PF(6) in MeCN-CH(2)Cl(2) at 65 °C produced a polymeric cluster [Tp*W(μ(3)-S)(3)Cu(3)(1,4-pyz)((1,4-pyz)(0.5))(2)(μ(3)-Br)][Tp*W(μ(3)-S)(3)(CuBr)(3)] (3). Reactions of 1 with melamine (MA) in 1:1 or 1:2 gave rise to another polymeric cluster [{Tp*W(μ(3)-S)(3)Cu(3)Br(μ(3)-Br)}(2)(MA)(2)] (4) and a neutral cluster [Tp*W(μ(3)-S)(3)Cu(3)Br(μ(3)-Br)(MA)(2)] (5), respectively. Compounds 2-5 were characterized by elemental analysis, IR spectra, UV-vis spectra, (1)H NMR, electrospray ionization (ESI) mass spectra and X-ray crystallography. The cation of 2 has a cubane-like [Tp*W(μ(3)-S)(3)Cu(3)(μ(3)-Br)] structure with each α-MePy ligand coordinated at one Cu(i) center. For 3, each [Tp*W(μ(3)-S)(3)Cu(3)(μ(3)-Br)] core is interconnected by 1,4-pyz bridges to form a 1D cationic zigzag chain with the [Tp*W(μ(3)-S)(3)(CuBr)(3)](-) anions arranged along its two sides. For 4, each [Tp*W(μ(3)-S)(3)Cu(3)(μ(3)-Br)] core is interlinked by MA bridges to afford a 1D spiral chain. 5 adopts a cubane-like [Tp*W(μ(3)-S)(3)Cu(3)(μ(3)-Br)] structure in which one terminal Br and two MA ligands are coordinated at three Cu centers. The third-order nonlinear optical (NLO) properties of 1-5 in DMF were investigated by femtosecond degenerate four-wave mixing (DFWM) technique with a 80 fs pulse width at 800 nm. Compounds 1-5 exhibit good NLO responses, and 3 and 4 possess the largest second-order hyperpolarizability γ values among the known W/Cu/S clusters bearing the [Tp*WS(3)] unit.     

Formation of the imide [Ta(NMe2)3(μ-NSiMe3)]2 through an unprecedented α-SiMe3 abstraction by an amide ligand

Ta(NMe(2))(4)[N(SiMe(3))(2)] (1) undergoes the elimination of Me(3)Si-NMe(2) (2), converting the -N(SiMe(3))(2) ligand to the ═NSiMe(3) ligand, to give the imide "Ta(NMe(2))(3)(═NSiMe(3))" (3) observed as its dimer 4. CyN═C═NCy captures 3 to yield guanidinates Ta(NMe(2))(3-n)(═NSiMe(3))[CyNC(NMe(2))NCy](n) [n = 1 (5), 2 (6)]. The kinetic study of α-SiMe(3) abstraction in 1 gives ΔH(?) = 21.3(1.0) kcal/mol and ΔS(?) = -17(2) eu.     

Synthesis and Structure of Catena-[Bis(2-Methylimidazole)(μ-Phthalato)cobaltate(II)]

A new coordination compound [Co(Pht)(2-MeIm)₂] (I), where Pht^2–is the deprotonated radical of o-phthalic acid (H₂Pht) and 2-MeIm is 2-methylimidazole, was synthesized. Its structure was established using X-ray diffraction analysis. The crystal is orthorhombic: space group Pca2₁, a= 15.350(3), b= 7.957(2), c= 13.997(3) Å, (calcd.) = 1.505 g/cm³, and Z= 4. The tetrahedral coordination of the Co(II) atom includes two N atoms of two 2-methylimidazole molecules and two oxygen atoms of two carboxyl groups from different acid radicals. The Co–N distances are equal to 2.022(2) and 2.031(2) Å, while the Co–O distances are 1.972(2) and 2.000(2) Å. The carboxyl groups of the Pht^2–radical and the aromatic nucleus form angles of 47.2° and 35.9°, whereas the angle formed by the carboxyl groups themselves is 50.3°. Compound Iis a polymer, which is confirmed by the 1,6-bridging function of the o-phthalic acid radical. The Co···Co distance in a chain is equal to 7.367 Å. Separate chains are united in the crystal into a framework via N–H···O hydrogen bonds.     

A Chain Structure Based on Homodinuclear Scandium Units: [Sc(μ-OH)(2,5-pydc)(H2O)]n

The reaction of pyridine-2,5-dicarboxylic acid with Sc2O3 under hydrothermal con-dition yields a new complex [Sc(μ-OH)(2,5-pydc)(H2P)]n 1 which has a chain structure based on homodinuclear scandium units. Crystal data for 1: space group P1, a = 6.7192(13), b = 7.6131(13),c= 8.9313(14) A, α = 95.976(6), β = 101.663(6),γ,= 108.151(5)°, V = 418.26(13) A3, Z = 2, Dc =1.946 g/cm3,μ = 0.889 mm-1, F(000) = 248, C7H6NO6Sc, M, = 245.09, the final R = 0.0429 and wR = 0.1086.     

Chalcogenide Exchange Reaction of [RGa(μ3-Te)]4 with Elemental Sulfur and Selenium: A Density Functional Theory Study

Thermodynamic and mechanistic features of the chalcogen exchange reaction between [RGa( ₃-Te)]₄ and elemental sulfur or selenium have been studied employing density functional theory (DFT) calculations using the BL3YP basis set and Stuttgart pseudopotentials. For [MeGa( ₃-E)]₄ (E=S, Se, Te) the correlation between the calculated parameters and diffraction data for their isolable analogs is greater than 98%. Each step of the conversion of [MeGa( ₃-Te)]₄ to [MeGa( ₃-E)]₄ via [Me₄Ga₄( ₃-Te)_4–x ( ₃-E) _x ] (E=S, Se) is predicted to occur as a series of isolated reactions. The entropy change for each chalcogen exchange is small in magnitude and corresponds to the degree of cage distortion within the cubane molecules. Calculations performed on [MeGa( ₃-Te)]₄...S₈ and [MeGa( ₃-Te)]₄-S suggest that an increase in electrophilicity of the gallium next to a surface bound tellurium may result in nucleophilic cage opening for which intermediate structures are calculated.     

Metallation of the methyl group ino-nitrosotoluene: synthesis and the molecular structure of the binuclear complex [o-(NO)(CH2)C6H4)]2Pd2(μ-OOCCF3)2

The reaction of the tetranuclear cluster Pd₄(CO)₄(OOCCF₃)₄ witho-nitrosotoluene afforded the Pd¹¹-containing complex [o-(NO)(CH₂)C₆H₄]₂Pd₂(μ-OOCCF₃)₂. The elimination of CO₂ and the formation of organic products of transformation of tolylnitrene species (azotoluene, ditolylamine, and tolylisocyanate) were observed in the course of the reaction. The title complex was characterized by IR and¹H NMR spectroscopy. Its structure was established by X-ray diffraction analysis. It was suggested that the reaction proceeds through intermediate formation of nitrene complexes. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 147–150, January, 2000.     

Synthesis and Characterization of Nitrato-Triamine-Metal(II) Complexes. Conglomerate Crystallization Part 55. Crystal Structure of [Ni(dien)(O2NO)(ONO2)] (I), {[Cu(dien)-(μ-ONO2)]NO3}∞ (II), [Zn(dien)(O2NO)(ONO2)] (III), [Ni(Medpt)(O2NO)(ONO2)] (IV) and [Cu(Medpt)(ONO2)2] (V)

In absolute ethanol and in the presence of triethylorthoformate, reactions of metal(II) nitrates with linear tridentate amines afforded metal complexes of the formula M(NNN)(NO₃)₂, where M = Ni²⁺, Cu²⁺ and Zn²⁺, and NNN = dien and Medpt. The compounds fall into three categories in accordance with their stereochemistry and mode of binding of the nitrato ligands. Compounds I, [Ni(dien)(O₂NO)(ONO₂)] and III, [Zn(dien)(O₂NO)(ONO₂)] are isomorphous and isostructural. They crystallize in the monoclinic space group P2₁/n with nearly identical cell constants. The stereochemistry of these two compounds is such that the terdentate dien ligand forms a fac MN₃ moiety with the two oxygens of the bidentate nitrato ligand trans to the terminal NH₂. These ligands form the base of the octahedral arrangement in which the sixth position, trans to the secondary nitrogen of the dien, is an oxygen of the monodentate nitrato ligand. Compound IV, [Ni(Medpt)(O₂NO)(ONO₂)] falls into the same category as I and III despite the fact that the two rings in the Ni-Medpt moiety are six-membered rings, unlike those in compounds I and III which are five-membered rings. Nevertheless, the nickel-amine arrangement is fac. The bidentate nitrato-oxygens are trans to the terminal NH₂ of the amine ligand, and the oxygen of the monodentate nitrato ligand is trans to the tertiary amine-nitrogen. Such stereochemistry is prevalent for nickel and zinc compounds. Interestingly, compound IV crystallizes as a conglomerate (space group P2₁2₁2₁). Compound II, {[Cu(dien)(μ-ONO₂)]NO₃}_∞ belongs to the second category and has a polymeric structure. The repeating fragment in the polymeric chain is a Cu(dien)-O fragment with the monodentate nitrato ligand occupying an equatorial position of the base. A second oxygen of the equatorial nitrate becomes an axial ligand for an adjacent Cu-N₃O fragment. In this way the substance propagates into an infinite chain. The repeating unit has an effective square pyramidal, five-coordinate, configuration. Finally, the compound crystallizes as a racemate. The second nitrate necessary for charge compensation of this copper(II) compound is ionic and its function is to hold the infinite chains of the lattice. The third category represented by compound V, [Cu(Medpt)(ONO₂)₂] contains two molecules in the asymmetric unit of the racemic lattice (monoclinic, space group P2₁/a). The structure of Cu-Medpt is unlike that of IV in that both species present in the asymmetric unit have the amine ligand in a mer configuration which together with a monodentate oxygen of a nitrato ligand form a base plane of a square pyramid. The fifth ligand of both Cu²⁺ ions is a second monodentate nitrato ligand. The stereochemical differences between the two Cu²⁺ ions are insignificant for the Cu-Medpt fragment, which share the same conformation and configuration. The major difference between the two species is the torsional angles defined by the Cu-O-N-O angles. The difference arises from variation in the hydrogens of the primary amine moieties selected by nitrato-oxygens to form intramolecular hydrogen bonds. Finally, there is a little variation in the equatorial Cu-ONO₂ stereochemistry because of steric hindrance, imposed by the Medpt, preventing large torsional angles by these nitrato ligands. This is evident by comparing the two copper species shown in Finally, nitrate-to-Br ligand exchange was found to take place when KBr pellets are prepared for IR spectral measurements.     

Synthesis and Molecular Structure of Tris(pentamethylphenyl)aluminum, (C6Me5)3Al, and the Magnesium Cluster [Mg6(μ3-OH)2(μ3-Br)2(μ2-Br)8(OEt2)8]

The synthesis and molecular structures of tris(pentamethylphenyl)aluminum, (C₆Me₅)₃Al, (I), and the magnesium cluster [Mg₆( ₃-OH)₂( ₃-Br)₂( ₂-Br)₈(OEt₂)₈] (II), are reported. Both compounds were isolated from the same system. The aluminum atom in (I) resides in an almost idealized trigonal planar environment. The dihedral angles of the pentamethylphenyl rings relative to the AlC₃plane in (I) are 67.2, 62.4, and 61.2°. The neutral magnesium cluster, (II), is interesting in that contains six magnesium atoms each of which resides in octahedral environments.     

Synthesis and Structure of a Novel Mg6 Cluster Molecule Mg6(μ3-OH)2(μ3-Br)2(μ-Br)8(THF)8

A novel Mg₆ cluster molecule with the formula of Mg₆( ₃-OH)₂( ₃-Br)₂(-Br)₈(THF)₈ (1) has been isolated in 38% yield from a reaction of the Grignard reagent, 2-naphthyl-Mg-Br with BBr₃ in THF. The structure of 1, determined by a single-crystal X-ray diffraction analysis, contains two Mg₃ triangles linked together by two bridging bromide ligands. Within each Mg₃ triangle, one hydroxide and one bromide ligand function as triply bridging ligands capping both sides of the Mg₃ triangle. The coordination geometry around each Mg(II) ion is approximately octahedral. NMR studies revealed that compound 1 is highly fluxional in solution.     

Redox behavior of trinuclear M3(μ-H)(μ3-μ1:μ2:μ2-C2Fe)(Co)9 and tetranuclear RuM3 3(μ-H)(μ4-μ1:μ1:μ1:μ2-C2Fe)(Co)12 (M=Ru or Os; and Fc=ferrocenyl) clusters. Electronic interaction between the ferrocenylacetylide ligand and the metal core of the cluster

The redox properties of the clusters Ru₃(CO)₁₂(1), Ru₃(μ-H)(μ₃-μ¹:μ²:μ²-C₂Fe)(CO)₉ (2), OS₃(μ-H)(μ₃-μ¹:μ²:μ²-C₂Fe)(CO)₉ (3), Ru₄(μ-H)(μ₄-μ¹:μ¹:μ¹:μ²-C₂Fe)(CO)₁₂ (4), and RuOS₃(μ-H)(μ₄-μ¹:μ¹:μ¹:μ²-C₂Fe)(CO)₁₂ (5) in THF have been studied by cyclic voltammetry in the temperature range from ?60 to +20°C. It was demonstrated that reversible one-electron oxidation of the ferrocenyl fragment in clusters 2–5 occurs at more positive potentials (δE ⁰=0.15–0.26 V) than that of free ferrocene. This is indicative of the electron-withdrawing character of the cluster core with respect to the ferrocenylacetylide ligand. The electron-withdrawing effect of the metal core is more pronounced in tetranuclear clusters4 and 5 than in trinuclear clusters2 and3. Unlike complexes1–3, which undergo irreversible reduction, complexes4 and5 undergo reversible one-electron reduction to form the corresponding radical anions4 ^? and5 ^?.     

Novel polyselenidoarsenate and selenidoarsenate: solvothermal synthesis and characterization of [Co(phen)3][As2Se2(μ-Se3)(μ-Se5)] and [Co(phen)3]2[As8Se14

Novel cobalt polyselenidoarsenate [Co(phen)(3)][As(2)Se(2)(μ-Se(3))(μ-Se(5))] (1; phen = 1,10-phenanthroline) was methanolothermally synthesized by the reaction of CoCl(2), As(2)O(3), and Se templated by phen in a CH(3)OH solvent at 130 °C. The same reaction in a H(2)O solvent yielded cobalt selenidoarsenate [Co(phen)(3)](2)[As(8)Se(14)] (2). In 1, the AsSe(+) units are alternately joined by the μ-Se(3)(2-) and μ-Se(5)(2-) bridging ligands to form a novel helical polyselenidoarsenate chain [As(2)Se(2)(μ-Se(3))(μ-Se(5))(2-)](∞). In 2, eight pyramidal AsSe(3) units are connected via corner sharing into the new member of the selenidoarsenate aggregate [As(8)Se(14)](4-) with a condensation grade of 0.571, which represents the first discrete selenidoarsenate(III) with a condensation grade of above 0.50. The octahedral complex [Co(phen)(3)](2+) is formed in situ to act as a countercation in compounds 1 and 2. 1 and 2 exhibit steep absorption band gaps at 2.09 and 2.16 eV, respectively.     

Synthesis and Crystal Structure of [Cd(NBA)(μ_3-OH)(4,4′-bipy)_(1/2)]_n

A new cadmium polymer [Cd(NBA)(μ3-OH)(4,4′-bipy)1/2]n 1 (NBA = m-nitrobenzoic acid and 4,4′-bipy = 4,4-bipyridine) has been synthesized by hydrothermal reaction. Its structure was determined by single-crystal X-ray diffraction method, and characterized by elemental analysis and IR spectrum. The crystal is of monoclinic, space group C2/c, with a = 15.6912(9), b = 25.9394(15), c = 6.7332(4) ′, β = 114.7700(10)°, V = 2488.4(3) 3, C12H9CdN2O5, Mr = 373.61, Z = 8, Dc = 1.995 g/cm3, μ = 1.776 mm-1, F(000) = 1464, R = 0.0411 and wR = 0.1128 for 2130 observed reflections (I > 2σ(I)). X-ray diffraction studies reveal that the compound features a layered structure, in which 4,4′-bipy ligands bridge Z type of double chains [Cd(μ3-OH)]n and NBA ligands locate at the two sides of the layer. The π-π interactions between the benzene rings of NBA ligands of two adjacent layers lead to the 3D framework.     

Addition of HCl to a Cluster-Bound Vinylidene Ligand: Preparation and Structure of Ru5(μ3-SMe)(μ3-CMe)(μ-Cl)(μ-SMe)(μ-PPh2)2(CO)9·PhMe

Addition of aqueous HCl to Ru₅( ₃-C=CH₂)(-SMe)₂(-PPh₂)₂(CO)₁₀ afforded the structurally characterized carbyne complex Ru₅( ₃-SMe)( ₃-CMe)(-Cl)(-SMe)(-PPh₂)₂(CO)₉, formed by addition of H to the vinylidene ligand; a Cl atom bridges an Ru–Ru bond.     

S2CPR3 adducts as bridging ligands in tricobalt clusters. X-Ray structure of [Co3(CO)7(μ3-CH)(μ-S2CPCy3)]

[Co₃(CO)₉(μ₃-CX)] (X  H, Cl) react with S₂CPR₃ (R  cyclohexyl, Cy or isopropyl, ⁱPr) in CH₂ Cl₂ to give heptacarbonyltricobalt clusters [CO₃(CO)₇(μ₃-CX)(μ₂-S₂CPR₃)] in which the S₂CPR₃ act as four-electron ligands, bridging a CoCo cluster edge in a σ(S), σ(S′) fashion, as shown by an X-ray determination on a crystal of the derivative with X  H, R  Cy. The five-membered CoSCSCo ring is nearly perpendicular to the CO₃ triangle (i.e. axial), in contrast to the equatorial disposition usually found in related complexes with phosphorus ligands.     

The reaction of [PPN][(μ2-H)Os3(CO)10(μ2-CO)] with EPh3 (E=P or As) to form the intermediate [PPN][Os3(CO)9(ν2-CHO)(EPh3)]

The anion, [(₂-H)Os₃(CO)₁₀(₂-CO)]^–, reacts with the donor ligand EPh₃ (E=P or As) to produce, as an intermediate in the reaction to the substituted anion [(₂-H)Os₃(CO)₉(₂-CO)(EPh₃)]^–, a moderately stable formyl derivative which we tentatively formulate as [Os₃(CO)₉(²-CHO)(EPh₃)]^–.