Further studies of M3(μ3-O)(μ-X)3(μ-O2CCH3)3L3 (M=Mo,W) type clusters with nine core electrons

Four new compounds having nine cluster electrons and cores of the types Mo₃OCl₃, Mo₃OBr₃, and W₃OCl₃ are reported. Compound (1) prepared by reduction of [Bu₄N][Mo₃OCl₆(OAc)₃] in THF with metallic zinc, was shown by X-ray crystallography to be Mo₃OCl₄(OAc)₃ (THF)₂ (1). It forms crystals in space groupP2₁ with unit cell dimensionsa=9.472(2) Å,b=13.546(4) Å,c=9.652(2) Å, =101.70(2)°,V=1201(1) Å₃,Z=2. The [Mo₃(₃-O)(-Cl)₃]⁴⁺ core is surrounded by three -O₂CCH₃ anions, one Cl^–, and two THF and has Mo-Mo distances of 2.620(1) Å, 2.613(1) Å, and 2.530(1) Å, with the shortest bond between the two Mo atoms to which the THF molecules are coordinated. Compounds [Bu₄N]₂ [Mo₃OBr₆(O₂CCH₃)₃] · Me₂CO, (2) and [Mo₃OBr₃(O₂CCH₃)₃(PMe₃)₃]₃ · BF₄, (3) are the first two nine-electron Mo₃ species with a [Mo₃(₃-O) Br₃]⁴⁺ core. Both were obtained by zinc reduction of [Mo₃OBr₆(O₂CCH₃)₃]^– in the presence of (NBu₄) Br (2) or PMe₃ and NaBF₄ (3), and each was characterized crystallographically. Compound (2) crystallized in space group Cc with unit cell dimensionsa=25.037(5) Å,b=12.827(2) Å,c=21.484(4) Å, =122.96(1)⁰,V=5790(3) ų,Z=4. While the anion has no crystallographically required symmetry, its virtual symmetry is C_3v . The Mo-Mo distances are 2.619(2) Å, 2.610(3) Å, 2.644(2) Å, with a mean value of 2.624[14] Å. Compound (3) crystallized in space groupP2₁/c with unit cell dimensionsa=10.846(2) Å,b=25.033(5) Å,c=12.641(5) Å, =94.74(2)⁰,V=3420(2) ų,Z=4. The cation occupies a general position but has virtual C_3v symmetry, with Mo-Mo distances of 2.601(2) Å, 2.610(2) Å, 2.627(2) Å, with a mean value of 2.613[14] Å. Thus the anionic and cationic Mo₃ clusters in (2) and (3), respectively, have average Mo-Mo distances that are equal within experimental error. Compound (4), [NEt₄]₂ [W₃OCl₆(O₂CCH₃)₃] is the first 9-electron compound of this type containing tungsten. It was prepared by reduction of [Et₄N][W₃OCl₆(OAc)₃] in benzene with Na/Hg. It crystallized in space groupP2₁2₁2₁ with unit cell dimensionsa=11.076(2) Å,b=14.345(2) Å,c=21.026(3) Å,V=3574(1) ų,Z=4. The anion resides on a general position but has virtual C_3v symmetry, with W-W distances of 2.577(1) Å, 2.612(1) Å, 2.584(1) Å and a mean value of 2.591[15] Å.     

The quadruply bondedbis-carboxylatescis-Re2(μ-O2CCH3)2X4L2 (X = halide;L = neutral donor) as synthons in dirhenium chemistry

The reactions of the quadruply bonded dirhenium(III) carboxylatescis-Re₂(-O₂CR)₂X₄L₂ (X=CI or Br; L=a monodentate donor) with monodentate, bidentate, and tridentate phosphine donors result in several types of redox behavior, usually involving partial or complete reductive decarboxylation of the dirhenium unit. Examples of dirhenium(VI, II), dirhenium(IV, II), dirhenium(III, II), and dirhenium(II, II) complexes, in which Re-Re bond orders of 4, 3.5, 3, l, or zero are encountered, have been isolated and repre-sentative examples structurally characterized. The course of these reactions is dependent upon the nature of the phosphine. The scope of this remarkably rich chemistry is discussed.     

Syntheses and Crystal Structures of Two Trinuclear Iron(Ⅲ) Carboxylate Complexes: [Fe3(μ3-O)(μ-O2CEt)6(H2O)3]Cl.3H2O and [Fe3(μ3-O)(μ-O2CEt)6Py3]Cl(Py=pyridine)

Two new oxo-centered trinuclear iron complexes [Fe3(μ3-O)(μ-O2CEt)6(H2O)3]Cl.3H2O 1 and [Fe3(μ3-O)(μ-O2CEt)6Py3]Cl 2 were prepared in non-aqueous solvent and their crystal structures have been determined. Crystal 1 is monoclinic, space group P21/n, a=9.909(3), b=24.467(8), c=14.542(7)(), β=107.85(4)° V=3356(4)()3, Z=4, Mr=765.52, Dc=1.52 g/cm3, μ=14.28 cm-1, F(000)=1588 and R=0.059, Rw=0.071 for 3745 unique reflections with I>3σ(I). Crystal 2 belongs to the monoclinic system with space group C2/c, a=13.750(3), b=18.439(4), c=16.696(3)(), β=93.42(3)°, V=4226(3)()3, Z=4, Mr=894.73, Dc=1.41 g/cm3, μ=11.4 cm-1, F(000)=2322 and R=0.058, Rw=0.062 for 2272 unique reflections with I>3σ(I). The two structures contain the same trimetal framework in which three iron(Ⅲ) atoms form a nearly equilateral triangle with a μ3-oxygen atom in the centre.     

Study of allylic rearrangement in (μ-H)Os3(μ-O=CNRCH2CH=CH2)(CO)10 (R=H or CH3) clusters

The migration of the double bond in the allylcarboxamide ligands of (μ-H)Os₃(μ-O=CN RCH₂CH=CH₂) (CO)₁₀ (R=H (1) or CH₃ (2)), (μ-D)Os₃(μ-O=CNDCH₂CH=CH₂) (CO)₁₀, and (μ-H)Os₃(μ-O=CNHCD₂CH=CH₂)(CO)₁₀ clusters was studied by¹H,²H, and¹³C NMR spectroscopy. Neither μ-D nor ND groups in the deuterated complexes are directly involved in prototropic processes of allylic rearrangement. Initially, the deuterium atom of the CD₂ group migrates to the ψ-carbon atom of the allyl fragment to form the −CD=CH-CH₂D propenyl moiety, in which the deuterium and hydrogen atoms are gradually redistributed between the ψ-and β-carbon atoms. The triosmium cluster complexes containing the bridging carboxamide ligands O=CNRR' catalyze the allylic rearrangement ofN-allylacetamide. Based on the data obtained, the probable scheme of the allylic rearrangements in clusters1 and2 was proposed. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2182–2186, November, 1999.     

STRUCTURAL STUDIES OF THE COPPER(II) ACETATE COMPLEXES Cu(o2CCH3)2(pyridine)3 AND Cu6(μ-O2CCH3)4(μ4-O2CCH3)2(μ-OCMe3)6

Abstract

[Cu(O₂CCH₃)₂]₂, 1, reacts with pyridine to form violet-blue Cu(O₂CCH₃)₂(pyridine)₃, 2, in > 90% yield. 2 crystallizes from pyridine with a distorted square-pyramidal geometry around copper with the monodentate acetate ligands located diagonally in the basal positions. 1 reacts with Bi(OCMe₃)₃ in THF to form blue Cu₆(μ-O₂CCH₃)₄(μ₄-O₂CCH₃)₂(μ-OCMe₃)₆, 3. 3 crystallizes from THF/hexanes with a hexagon of copper atoms linked by six doubly-bridging tert-butoxide ligands, four doubly-bridging bidentate acetates, and two quadruply-bridging bidentate acetate ligands.     

Chemical Synthesis Studies on Pb Zr Alkoxides: A New Pb-Zr Structural Type,Pb3Zr7(μ4-O)4 (μ3-O)4(μ-O2CCH3) 8(μ-OiPr)6(Oi Pr)4

The compound [Pb₃Zr₇(₄-O)₄ (₃-O)₄(O₂CCH₃)₈ (OPrⁱ)₁₀] has been isolated from a reaction mixture containing known Pb-Zr and Pb-Ti complexes and characterised by ²⁰⁷Pb and ¹ H NMR and IR spectroscopy. The compound crystallises in the space group P with a = 13.778(4) Å, b = 21.916(5) Å, c = 27.768(10) Å; = 86.52(3)°, = 87.68(3)°, = 72.72(2)° V 7989(4) ų, Z = 4, R = 0.0973. A Pb-Zr alkoxide complex containing acetylacetone has also been synthesised using PbO as a reagent having the composition [Pb₂Zr₄(O)₂ (OⁱPr)₆(OⁿPr)₈ (acac)₂] allocated on the basis of MW, mass spectral and ¹H NMR data.     

Complexes [Ni2(μ-OH2)(μ-O2CCH(CH3)2)2L2–4((CH3)2CHCO2)2]: Synthesis,Structure, and Mass Spectrometric Studies

Russian Journal of Coordination Chemistry - Three new binuclear aqua-bridged nickel(II) 2-methylpropionate complexes [Ni2(μ-OH2)(μ-O2CCH(CH3)2)2L2–4((CH3)2CHCO2)2] (L is...     

Syntheses and characterization of the vanadium trimer (V3(μ3-O)O2)(μ2-O2P(CH2C6H5)2)6(4,4′-bipyridine) and the vanadium hexamer [(V3(μ3-O)O2)(μ2-O2P(CH2C6H5)2)6]2(μ2-N1,N2-di(pyridin-4-yl)oxalamide)

Reacting VO(acac)₂ with six equivalents of dibenzylphosphinic acid in the presence of 4,4′-bipyridine or μ₂-N¹,N²-di(pyridin-4-yl)oxalamide leads to trimeric (V₃(μ₃-O)O₂)(μ₂-O₂P(CH₂C₆H₅)₂)₆(4,4′-bipyridine) or the hexamer [(V₃(μ₃-O)O₂)(μ₂-O₂P(CH₂C₆H₅)₂)₆]₂(μ₂-N¹,N²-di(pyridin-4-yl)oxalamide). The complexes were characterized by spectroscopic (FTIR and ¹H NMR spectroscopies), TGA, and by single crystal X-ray diffraction measurements. The structures consist of a planar central core where three vanadium ions are arranged in the form of a quasi-isosceles triangle and contain an interstitial O which is multiply bonded to one V and weakly interacting at different bond distances to the remaining two V ions.     

An Asymmetric Edge-Sharing Bioctahedral Complex: (η2-DAniF)MoIII(μ-DAniF)2(μ-O,Cl)MoVCl2 (DAniF=N,N′-di-p-anisylformamidinate)

A novel asymmetric, edge-sharing bioctahedral complex with formamidinato ligands ( ²-DAniF)Mo(-DAniF)₂(-O,Cl)MoCl₂, 1, (DAniF=N,N-di-p-anisylformamidinate) has been isolated as a byproduct from the preparation of the dimolybdenum(II,III) compound Mo₂(DAniF)₃Cl₂. An X-ray crystallographic study shows that the structure consists of edge-sharing bioctahedra, with the shared edge defined by the vector joining the: -O and -Cl ligands. Compound 1 is best formulated as a mixed-valent Mo^IIIMo^V compound, the Mo(V) ion being that with the two terminal Cl^– ligands. The cyclic voltammogram of 1 shows a reversible reduction at –0.472 V and a reversible oxidation at 1.028 V vs. the Ag/AgCl reference electrode, while the absorption spectrum of 1 reveals an intense low energy absorption at 523 nm ( _max=12 500) which is attributed to an intervalence charge transfer transition. Crystallographic data for 1 are as follows: a=13.387(1) Å, b=15.500(2) Å, c=21.855(2) Å, =98.786(2)°, V=4481.8(8) ų, P2₁/c, R1 (wR2)=0.082 (0.177).     

SYNTHESIS AND CRYSTAL STRUCTURE OF COMPLEX [CrMo_3 (μ_3-O)_3(μ-O)(μ-O_2CCH_3)_5(O_2CCH_3)_3]Na2 · H_2O

<正> The title complex C CrMo3 (μ3-O )3 (μ-O) (μ-O2CCH3 )5 (O2CCH3)3]2Na2 · H2O (Mr=1814. 32) crystallizes in monoclinic, space group P21/ n with a=11.209(5), b=18. 05(1), c=14. 44(1) A , β= 98. 30(5)°. V=2890 (3) A3, Z=2, A = 2. 08 g/cm3, F(000) -1780, Final R = 0. 049, Rw = 0. 058 for 2622 independent reflectons with I>3σ(I). The complex anion contains two Mo3O4 cores which connect two chromium atoms through four μ3-O atoms and eight bridging CH3COO- groups. Each of the Cr atoms and the Mo atoms is coordinated by six oxygen atoms. The anions are linked by Na cations to form one-dimensional infinite chain structure.     

Syntheses, X-ray structural characterizations, and thermal stabilities of two nonclassical trinuclear vanadium(IV) complexes, (V3(μ3-O)O2)(μ2-O2P(CH2C6H5)2)6(H2O) and (V3(μ3-O)O2)(μ2-O2P(CH2C6H5)2)6(py), and polymeric complexes of stoichiometry (VO(O2PR2)2)∞, R2 = Ph2 and o-(CH2)2(C6H4)

The preparation and structural characterization of two trinuclear vanadium complexes, (V(3)(μ(3)-O)O(2))(μ(2)-O(2)P(CH(2)C(6)H(5))(2))(6)(H(2)O), 1, and (V(3)(μ(3)-O)O(2))(μ(2)-O(2)P(CH(2)C(6)H(5))(2))(6)(py), 2, are reported. In these nonclassical structures, the planar central core consists of the three vanadium atoms arranged in the form of an acute quasi-isosceles triangle with the central oxygen atom multiply bonded to the vanadium atom at the center of the vertex angle and weakly interacting with the two other vanadium atoms on the base sites, each of which contain one external multiply bonded oxygen atom. Reacting VO(acac)(2)in the presence of diphenylphosphinic acid affords (VO(O(2)PPh(2))(2))(∞), 3, while 2-hydroxyisophosphindoline-2-oxide at room temperature in CH(2)Cl(2) affords ((H(2)O)VO(O(2)Po-(CH(2))(2)C(6)H(4))(2))(∞), 4, and at 120 °C in EtOH yields (VO(O(2)P(o-(CH(2))(2)(C(6)H(4)))(∞), 5 on the basis of elemental analyses. The thermal and chemical stability of the complexes were assessed by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) measurements. The bond strengths of the vanadium atoms to the OH(2) ligand in 1 and to the NC(5)H(5) ligand in 2 were assessed at 10.7 and 42.0 kJ/mol respectively. Room temperature magnetic susceptibility measurements reveal magnetic moments for trinuclear 1 and 2 at 3.02(1) and 3.05(1) μ(B/mol), and also close to spin only values (1.73 μ(B)) values for 3, 4, and 5 at 1.77(2), 1.758(7), and 1.77(3) μ(B), respectively. Variable-temperature, solid-state magnetic susceptibility measurements were conducted on complex 2 in the temperature range of 2.0-298 K and at an applied field of 0.5 T. Magnetization measurements at 2 and 4 K confirmed a very weak magnetic interaction between the vanadyl centers.     

钛配合物Cp2TiL,Cp2Ti2Cl2(μ-O)和Cp4Ti4Cl4(μ-O)4的合成与晶体结构研究(Cp=η5-C5H5,L=2,6-吡啶二羧酸盐)

利用溶剂热的方法将Cp2TiCl2(Cp=η5-C5H5)与2,6-吡啶二羧酸钠(L)反应,不同的反应时间得到了2个具有不同晶体空间群的化合物Cp2TiL(1a和1b),而在常温或低温下,Cp2TiCl2或CpTiCl3同羧酸盐或亚胺反应却得到了双核或四核氧桥联的钛化合物。     

Syntheses,crystal structures,and electrochemical studies of Fe2(CO)6(μ-PPh2)(μ-L) (L = OH,OPPh2, PPh2)

Reaction of Fe₃(CO)₁₂ and Ph₂PH in the presence of Et₃N in THF at 0?°C immediately forms Fe₂(CO)₆(μ-PPh₂)(μ-OH) (1), Fe₂(CO)₆(μ-PPh₂)(μ-k²O,P-OPPh₂) (2), and Fe₂(CO)₆(μ-PPh₂)₂ (3) in yields of 25, 14, and 19%, respectively. Experiments confirm that Et₃N shortens the reaction time. The absence of O₂ hinders the formation of 2. The presence of H₂O can increase the yield of 1. Their structures have been determined by X-ray crystallography and the complexes have been completely characterized by EA, IR, and ¹H, ¹³C, ³¹P NMR. Electrochemical studies reveal that they exhibit catalytic H₂-producing activities.     

Preparation and structural characterization of the isomorphous compounds: [Bu4N][Mo3(μ3-O)(μ-X)3(μ-OAc)3 X 3]·(CH3)2CO,X=Cl,Br

The reaction of MoCl₃(H₂O)₃ with a mixture of acetic acid and acetic anhydride in the presence of [N(C₄H₉)₄][BF₄] followed by crystallization from acetone/hexane gives a 77% yield of dark purple [NBu₄][Mo₃OCl₆(OAc)₃]·Me₂CO (1). A similar reaction employing MoBr₃(H₂O)₃ gives purple [NBu₄][Mo₃OBr₆(OAc)₃]·Me₂CO (2) in 50% yield. Also produced in this reaction in low (10–20%) yields are [NBu₄]₂[Mo₄OBr₁₂] · 0.5Me₂CO and [NBu₄]₂[Mo₃OBr₆(OAc)₃] · Me₂CO which will be discussed elsewhere Compounds (1) and (2) are isomorphous, space groupP2₁/n,Z=4 with the following unit cell dimensions, where the values for (1) and (2) are given in that order for each one:a=13.406(4), 13.726(5) Å;b=15.701(4), 15.839(5) Å;c=19.250(5), 19.831(6) Å; =101.61(2), 102.92(3)°. Both (1) and (2) are eight-electron species in which the mean Mo-Mo distances are 2.578(1) Å and 2.597(1) Å, respectively.     

Coordination Compounds of Strontium: Syntheses,Characterizations, and Crystal Structures of [Sr(μ-ONc)2(HONc)4]2 and Sr5(μ4-O)(μ3-ONep)4(μ-ONep)4(HONep)(solv)4 (ONc = O2CCH2CMe3; Nep = CH2CMe3; solv = Tetrahydrofuran or 1-Methyl-Imidazole)

Abstract

We have synthesized and characterized two novel Sr compounds: [Sr(μ-ONc)₂(HONc)₄]₂ (1, ONc ? O₂CCH₂CMe₃), and Sr₅(μ_?O)(μ₃?ONep)₄(μ?ONep)₄(HONep)(solv)₄ [ONep ? OCH₂CMe₃, solv = tetrahydrofuran (THF), 2a; 1-methyl-imidazole (Melm), 2b], that demonstrate increased solubility in comparison to the commercially available Sr precursors. The two metal centers of 1 share four unidentate bridging μ-ONc ligands and complete their octahedral geometry through coordination of four monodentate terminal HONc ligands. The structural arrangement of the central core of 2a and 2b are identical, wherein four octahedral Sr atoms are arranged in a square geometry around a μ₄-O ligand. An additional seven-coordinated Sr atom sits directly atop the μ₄-O to form a square-pyramidal arrangement of the Sr atoms, but the apical Sr-O distance is too long to be considered a bond. In solution, compound 1 is disrupted forming a monomer but 2a and 2b retain their structures.     

CRYSTAL STRUCTURE OF Mo_3(μ_3-O) (μ-S_2)_ 3 [S_2P(OEt)_2]_3I

<正> Mr=1178.9, monoclinic, P21/n, a=16.570(2), b=12.370(1), c=20.007(2) A,β=99.97(1)°, V=4039.0A3, Z=4, Dx=1.938 Mgm-3, λ(MoKα)=0.7107A, μ(MoKα)=23.96 F(000)=2296, room temperature. Final R value=0.047 for 4387 unique observed reflections. It consists of neutral mono-oxo-capped trinuclear molybdenum cluster molecules with an average Mo-Mo bond length of 2.626(4)A and an average Mo-0 bond length of 2.036(2)8.     

三核钼簇合物(Me4N)[Mo3(μ3-O)(μ-Cl)3(μ-O2CH)3Cl3]的制备和晶体结构测定

标题簇合物系通过液相氧化低价钼(MoCl3)制得,晶体属正交晶系,空间群为D2h[16]-Pmnb,晶胞参数:α=11.403(1),b=12.345(2),c=14.292(2)A,V=2011.8(8)A[3].Z=4,Dc=2.396g.cm[-3].使用四圆衍射仪收集衍射数据,晶体结构用重原子法解出,经全矩阵最小二乘修正,R=0.050,Rw=0.056.簇阴离子结构属M1型三核钼簇构型,Mo-Mo键2.577A;Mo-O-μ3键1.982A.还讨论了桥原子、键级以及配体对Mo-Mo键的影响。     

THE SYNTHESIS AND STRUCTURE OF Mo_3(μ_3-O)(μ-S)_3(μ-O_2CC_6H_5)_2(dtp)_2(Py)

<正> The title compound was prepared by reaction of Mo3(μ3-O) (μ-S)3-(dtp)4 (H2O) with C6H5COONa and pyridine. C27 H35 Mo3NO9P2S7, Mr = 1091.76, monoclinic, space group P21/c, a = 15. 057(5), b = 13. 052(5), c = 21. 662(6)(?), β=105.97(2)°, V = 4093(2) (?)3, Z = 4, Dc= 1. 77gcm-3, F(000) = 2176, μ(MoKα)=13.50cm-1, final R =0. 068 for 2835 observations. The molecular configuration is new and of approximate C, symmetry, and there are two C6H5COO bridging groups in the structure. The three Mo atoms form an isosceles triangle with three sides of 2. 567(3), 2. 576(3), and 2. 649(3)(?), where the two Mo-Mo bonds bridged by C6H5COO group are much shorter than that without. Something about the reactivity of Mo clusters is discussed.     

Formation of mixed-metal alkoxides mediated by the reactivity of coordinated pinacol: Synthesis and molecular structures of Ce2Ti2(μ3-O)2(μ,η2-OCMe2CMe2O)4(OPri)4(PriOH)2 and of Ce2Nb2(μ3-O)2(μ,η2-OCMe2CMe2O)4(OPri)6

The addition of pinacol to mixtures of titanium and cerium isopropoxides as well as the use of insoluble titanium and cerium pinacolate synthons was investigated as a route to M-Ce (M=Ti, Nb) species. Pinacol was able to promote the formation of mixed-metal species and the first Ce-Ti and Ce-Nb species namely Ce_2Ti(pin)₂(OPrⁱ)₈ and [M₂Ce₂(μ₃-O)₂(μ,η²pin)₄(OPrⁱ)₆H_x] [M=Ti, x=2; M=Nb, x=0; pin=OCMe₂-COMe₂] were isolated and characterized by FT-IR and ¹H NMR. The latter were also characterized by X-Ray diffraction. Their structures are based on a rhombus compressed along the M⋯M direction with 6-coordinated metals. The pinacolate moieties act as bridging-chelating ligands. The metal–oxygen bond lengths vary according to M–O(pin)<M-μ₃–O<Mμ–O(pin)<Ce–OPrⁱ<Ce–μ₃O.     

Synthesis and Crystal Structure of an Azido-Bridged Cadmium(II) Dimer [L2Cd2(μ-N3)2(N3)2] (L=1,4,7-Triazacyclononane)

A new dinuclear Cd(II) complex, [L₂Cd₂(μ-N₃)₂(N₃)₂], containing two end-on bridging azide ligands, two monodentate N₃ ligands and 1,4,7-triazacyclononane as the capping ligand, has been synthesized and its structure determined by X-ray crystallography. The complex crystallizes in the monoclinic space group P2₁/c with a=8.467(3), b=14.359(5), c=10.115(4)Å, β=95.026(6)° and z=4. The cadmium(II) centre is six-coordinate with distorted octahedral geometry, bonded to three N atoms of the 1,4,7-triazacyclononane, two nitrogen atoms of μ-azide bridges and one nitrogen atom of a monodentate azide ligand. Neighboring Cd(II) atoms are linked by the double end-on azide bridges.