Interaction of polynuclear palladium (I) carbonyl carboxylates with gaseous NO: X-ray structure of eight-nuclear clusters Pd8(μ-CO)4(μ-OOCR)4[μ-N(O)O–]4

The reaction of palladium carbonyl carboxylates Pd₆(CO)₆(RCOO)₆ with gaseous nitrogen monoxide was investigated. These clusters were found to promote the NO disproportionation into N₂ and NO₂ under mild conditions. The reaction is accompanied with the oxidation of coordinated carbon monoxide. These processes result in unusual eight-nuclear palladium carboxylate clusters Pd₈(CO)₄(NO₂)₄(RCOO)₈.     

Synthesis of 62-electron square planar clusters with group 15 and 16 main group atoms: Structural characterization of Ru4(CO)11(μ4-PPh)(μ4-S) and Ru4(CO)10(μ4-PPh)(μ4-Se)(PEt3): Bonding preferences in cappingNido Ru4(CO)13(μ3-PPh)

Thecloso octahedral cluster Ru₄(CO)₁₁(μ₄-PPh)(μ₄-S)1 and selenium and tellurium analogues, the first examples of unsaturated ruthenium clusters with a planar metal core and different main group 15 and 16 atoms have been synthesized fromnido Ru₄(CO)₁₃(μ₃-PPh). An X-ray analysis of1 and Ru₄(CO)₁₀(μ₄-PPh)(μ₄-Se)(PEt₃)2a has confirmed thetrans disposition of phosphorus and group 16 main group fragments.     

Rh2(CO)4(μ-Cl)2和Rh4(μ-CO)3(CO)4的简正振动分析

金属簇合物具有独特的结构和成键方式。本文对铑簇合物的简正振动分析进行了研究。通过红外光谱用石蜡油糊涂KBr和聚乙烯窗口, 在Nicolet 200SXV FT-IR光谱上测定了Rh2(CO)4(μ-Cl)2的构型, 并使用分子振动全分析程序MVTA(Basic语言), 在PC机上进行计算。     

Synthesis and characterisation of hexanuclear ruthenium clusters containing a μ4-nitrene ligand. Crystal structures of [Ru6(CO)15(μ-CO)2(μ4NH)(μ-OMe)μ3-η2-N(H)C(O)OMe] and [Ru6(CO)16(μ-CO)2(μ4-NH)(μ-OMe)(μ-NCO)]

Two hexaruthenium carbonyl clusters [Ru₆(CO)₁₅(μ-CO)₂(μ₄-NH) (μ-OMe){μ₃-η²-N(H)C(O)OMe}] and [Ru₆(CO)₁₆(μ-CO)₂-(μ₄-NH)(μ-OMe)(μ-NCO)]2 have been isolated from the pyrolysis of H₂Ru₃(CO))₉NOCH₃, and single-crystal X-ray structure analysis shows that both 1 and 2 have a square planar arrangement of four ruthenium atoms capped by a μ₄-nitrene ligand, with two additional ruthenium atoms bridging two opposite RuRu edges of the square base to form a ‘boat’ form metal framework.     

An approach to heterometallic alkoxide-β-diketonate complexes with a M4O4 cubane-like core and new prospects of their application in preparation of solid catalysts. X-ray single crystal study of (Co,Ni)4(acac)4(μ3-OMe)4(MeOH)4, Co2Ni2(acac)4(μ3-OMe)4(OAc)2 and Mg4(acac)4(μ3-OMe)4(MeOH)4

The interaction of the individual M₄(acac)₄(μ₃-OMe)₄(MeOH)₄ complexes, M=Co, Ni in toluene/methanol media provided crystals of (Co,Ni)₄(acac)₄(μ₃-OMe)₄(MeOH)₄ (I) — the product of co-crystallization of isomorphous products. The oxidation of a MeOH solution of I in air in the presence of NaOAc and aminoalcohols as catalysts gave Co₂Ni₂(acac)₄(μ₃-OMe)₄(OAc)₂ (II), an individual heterometallic derivative. The interaction of Mg(OCH(CH₃)CH₂NMe₂)₂ with Cu(acac)₂ in toluene/methanol media produced Mg₄(acac)₄(μ₃-OMe)₄(MeOH)₄ (III) as the only isolatable product. The starting Co and Ni homometallic complexes as well as the heterometallic CoNi complex II were used to prepare the zeolite-supported oxide catalysts which exhibited extremely high activity towards methanol oxidation.     

Tetramers Cu4(μ4-O)(η-X)6(L4): Analysis of structural data

This review summarizes structural parameters for forty five Cu₄(μ₄-O)(η-X)₆(L₄) tetramers. There are four types of structurally equal core units, CuCl₃ON, CuCl₃OO, CuCl₃OCl and CuBr₃ON. There are also tetramers which contain structurally unequal core units: CuCl₃ON (x2) and CuCl₂BrON (x2); CuCl₃ON (x1), CuCl₂BrON (x2) and CuCl₃OCl (x1). There is a tendency for an elongated Cu?Cu separation as well as Cu–L bond distances with increase of the covalent radius of the coordinating atom(s). Tetrahedral distortion around oxygen atom (OCu₄) increases in the order: 1.67° (CuCl₃OCl) < 2.10° (CuCl₃ON) < 2.11° (CuCl₃OO′) < 2.27° (CuBr₃ON). The mean Cu–Cl–Cu bridge angle of 80.5° is about 4.0° more open than that of a Cu–Br–Cu (76.5°). The cluster Cu₁₆O₄Br₇Cl₁₇(4-Mepy)₁₆ (4-Mepy = 4-methylpyridine) contains four crystallographically independent tetramers: Cu₄OBrCl₅(4-Mepy)₄ (1), Cu₄OBrCl₅(4-Mepy)₄ (2) Cu₄OBr₂Cl₄(4-Mepy)₄ (3) and Cu₄OBr₃Cl₃(4-Mepy)₄ (4), which is a unique example of stereoisomerism. There are other examples which exist in two isomeric forms. Another contains two or even four crystallographically independent tetramers within the same crystal, differing mostly by degree of distortion and is an examples of distortion isomerism. Pairs of Cu₄OCl₆(n-Meim)₄ (n-Meim = n-methylimidazole) (n = 1 or 2) are examples of ligand isomerism.     

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.     

Diphosphine ligand chelation and bridging and regiospecific ortho metalation in the reaction of 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd) with Ir4(CO)12: X-ray diffraction structures of Ir4(CO)7(μ-CO)3(bpcd), Ir4(CO)5(μ-CO)3(bpcd)(μ-bpcd), and HIr4(CO)4(μ-CO)3(bpcd)[μ-PhP(C6H4)CC(PPh2)C(O)CH2C(O)]

Me₃NO activation of the tetrairidium cluster Ir₄(CO)₁₂ (1) in presence of the diphosphine ligand 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd) furnishes the bpcd-substituted clusters Ir₄(CO)₁₀(bpcd) (3) and Ir₄(CO)₈(bpcd)₂ (4) as the minor and major products, respectively. Cluster 3 has been isolated as the sole observable product from the reaction of [Ir₄(CO)₁₁Br][Et₄N] (2) with bpcd in presence of AgBF₄ at room temperature. Both 3 and 4 have been isolated and fully characterized in solution by spectroscopic methods. The solid-state structure of 3 reveals that the ancillary bpcd ligand is bound to a single iridium center, with chelating and bridging bpcd ligands found in the X-ray structure of cluster 4. Cluster 4 is unstable at room temperature and slowly loses CO to afford the hydride-bridged cluster HIr₄(CO)₄(μ-CO)₃(bpcd)[μ-PhP(C₆H₄)CC(PPh₂)C(O)CH₂C(O)] (5). Cluster 5 has been fully characterized in solution by IR and NMR spectroscopies, and the C–H bond activation attendant in the ortho metalation step is shown to occur regioselectively at one of the aryl groups associated with the bridging bpcd ligand. The redox properties of clusters 3–5 have been explored and the electrochemical behavior discussed with respect to extended Hückel MO calculations and related diphosphine-substituted cluster compounds prepared by our groups.     

Synthesis,Crystal Structure and Catalytic Activity of a Hexa-μ-chloro-tetrakis-(1-triphenylmethyltriazole)-μ4-oxo-tetracopper(Ⅱ)

A new Cu(Ⅱ) complex,[Cu_4Cl_6O(1-TrTz)_4]where 1-Tr Tz is 1-trityl-1H-[1,2,4]triazole,was synthesized by the reaction of 1-trityl-1H-[1,2,4]triazole with two hydrated cupric chlorides,and its structure was characterized by X-ray single-crystal diffraction.[Cu_4Cl_6O(1-TrTz)_4]is of monoclinic system,space group P21/c,a=12.5024(13),b=26.400(3),c=28.588(3)?,β=112.807(4)°,V=8698.1(16)?~3,Z=4,ρ_(calc)=1.411 g/cm~3,μ=1.265 mm~(–1),F(000)=3772,the final R=0.1293 and w R=0.3644 for 55774 observed reflections (I2s(I)),R(all data)=0.1972,w R(all data)=0.3989,completeness to theta of 25.242 is 99.9%and GOF=1.103.In the structure of[Cu_4Cl_6O(1-TrTz)_4],the central O atom is tetrahedral and is coordinated with four Cu atoms.The distance between copper and oxygen bond is 1.909(6)?.In addition,the catalytic property of this complex was investigated and it could effectively catalyze the Ullmann coupling reaction of various (hetero)aryl chlorides with azoles.     

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.     

Silver(I) ion induced formation of 2-D ternary lead(II)-silver(I)-4-tolythiolate [PbAg2(μ-Stol)2(μ4-Stol)2]n from 1-D binary lead(II)-4-tolythiolate [(μ-Cl)Pb2(Stol)(μ-Stol)2]n (tol = 4-tolyl)

Treatment of [Pb(Stol)₂]_n with an equiv of [Et₄N]Cl in DMF afforded a new 1-D polymeric complex, [(μ-Cl)Pb₂(Stol)(μ-Stol)₂]_n (1), with Pb–Cl–Pb links. Interaction of 1 with a suspension of [Ag(Stol)] in DMF resulted in formation of a 2-D polymeric complex, [PbAg₂(μ-Stol)₂(μ₄-Stol)₂]_n (2), with the planar four-membered Ag₂S₂ and PbAgS₂ rings bridged by μ-Stol and μ₄-Stol ligands. Both polymeric complexes were structurally characterized by single-crystal X-ray diffraction analysis.     

Bulk polymerization of rac-lactide initiated by guanidinate alkoxide complexes of rare earth metals. The molecular structure of the cluster [{(Me3Si)2NC(NPri)2}Nd]4(μ3-OPri)8Li7(μ2-Cl)3(μ3-Cl)2(μ4-Cl)2

The complexes {(Me₃Si)₂NC(NPrⁱ)₂}₂LnOBu^t (Ln = Y (1), Lu (2)) initiate the bulk polymerization of racemic lactide (LA) at 130 °C. At the monomer: initiator molar ratio ([LA]: 1) equal to 1000: 1, the quantitative conversion of the monomer is achieved within 6 h. The resulting polymers are characterized by a rather narrow monomodal molecular weight distribution (M _w/M _n = 1.46–1.82) and molecular weights up to 33400 g mol^?1. The molecular weights of the resulting polylactides measured by gel permeation chromatography are 3–11 times lower than the values calculated from the monomer: initiator ratio on the assumption of one growing polymer chain per catalytic center. The reaction of the in-situ prepared complex [(Me₃Si)₂NC(NPrⁱ)₂]NdCl₂ with 2 equiv. of PrⁱOLi produced the 11-nuclear cluster [{(Me₃Si)₂NC(NPrⁱ)₂}Nd]₄(μ³-OPrⁱ)₈Li₇(μ²-Cl)₃(μ³-Cl)₂(μ⁴-Cl)₂ (3), which was isolated in 62% yield. The structure of compound 3 was established by X-ray diffraction. Complex 3 initiates both the bulk and solution polymerization of rac-lactide. In the bulk polymerization at the molar ratio [LA]: [Nd] = 500: 1, the 89% conversion of the monomer was achieved within one hour. The polylactide thus synthesized has the molecular weight M _n = 19720 g mol^?1 and a rather narrow polydispersity M _w/M _n = 1.54.     

A study of zinc complexes of the metalloligand [Pt2(μ-S)2(PPh3)4] of the type [Pt2(μ-S)2(PPh3)4ZnL]+ (L = bidentate chelating ligand)

Reactions of [Pt₂(μ-S)₂(PPh₃)₄] with zinc acetate and an ancillary chelating ligand L (HL = 8-hydroxyquinoline, 8-tosylaminoquinoline or maltol) with added trimethylamine in methanol give new cationic platinum–zinc sulfide aggregates [Pt₂(μ-S)₂(PPh₃)₄ZnL]⁺, isolated as their BF₄^? salts. The complexes were characterized by NMR spectroscopy, ESI mass spectrometry, microelemental analysis, and an X-ray structure determination of the tosylamidoquinoline derivative [Pt₂(μ-S)₂(PPh₃)₄Zn(TAQ)]BF₄, which showed a distorted tetrahedral coordination geometry at zinc. Additional examples, containing picolinate, dithiocarbamate, or dithiophosphinate ligands were also synthesized and partly characterized in order to demonstrate a wider range of available derivatives.     

Synthesis, Characterization and Crystal Structure of [Co2Mo2(μ4-C2HPh)(μ-CO)4(CO)4(η5-C5H4C(O)Me)2]

The reaction of μ-alkyne-bridged dimolybdenum compound [Mo2(μ-C2HPh)(CO)4(η5-C5H4C(O)Me)2] 1 with Co2(CO)8 in refluxing toluene gave a new butterfly compound [Co2Mo2(μ4-C2HPh)(μ-CO)4(CO)4(η5-C5H4C(O)Me)2] 2 which was fully characterized by elemental analysis, IR, 1H NMR and X-ray single crystal diffraction techniques. 2 crystallized in monoclinic system, C30H20Co2Mo2O10, Mr=850.23, space group P21/a(#14), a=14.165(5), b=12.498(2), c=16.204(2)(A), β = 96.50(2)°, V = 2850(1)(A)3, Z = 4, Dc = 1.981 g cm-3, F(000)=1672, μ(MoKα)=20.41 cm-1, final R=0.030, Rw=0.039 for 4831 observable reflections with I>2σ(I). The structure contains a Co2Mo2 butterfly core, and each Mo-Co bond is spanned by an asymmetric semi-bridging carbonyl ligand.     

Synthesis and Crystal Structure of a Novel Polymeric Complex [WS4Cu4(Py)4(μ-CN)2]∞

The reaction of [Et4N]2WS4 with 4 equiv of CuCN in pyridine produced a new polymeric complex [WS4Cu4(Py)4(μ-CN)2]∞ 1, whose crystal structure has been characterized by single-crystal X-ray analysis. 1 (C22H2oCu4N6S4W, Mr=934.71) crystallizes in monoclinic, space group P21/n with a ='8.994(2), b=16.038(3), c=12.026(3) A, β= 90.85(1)°, V= 1734.6(6) A3, Z=2, Dc=1.789 g/cm3, F(000)=896,t(MoKa)=59.8 cm-1 and T=193 K. The structure was refined to R=0.064 and Rw=0.080 for 2209 observed reflections (I ＞ 3.0σ(I)). The X-ray analysis shows that the tetrahedral WS4 core is coordinated by four Cu atoms, forming a saddle-like WS4Cu4 unit. These repeating units are further interconnected by four Cu-μ-CN-Cu 2.726(2) and 2.723(2) A, respectively.     

Solid–Gas Hydrogenation of Hex-3-yne and 1,4-Cyclohexadiene in the Presence of Ru3(CO)9(μ-H)(μ-PPh2), Ru3(CO)10(μ-H)(μ-PPh2), Ru3(CO)7(μ-PPh2)2(C6H4), and Ru4(CO)11(μ4-PPh)(C6H4) Deposited on Pyrex Glass, Silica, and Alumina

The title complexes were tested in the hydrogenation of hex-3-yne and of 1,3- and 1,4-cyclohexadiene (CHD) under solid–gas conditions. The clusters were deposited on three “standard” supports, that is, pyrex glass, alumina, and silica. All the clusters, particularly (μ-H)Ru₃(CO)₁₀(PPh₂), show hydrogenation activity. However, they are not particularly selective toward the formation of monoenes; “disproportionation” of 1,3- and 1,4-CHD to hydrogenated products and benzene also occurs. The hydrogenation activity of the clusters is dependent on their nature, the type of substrate, and the characteristics of the supporting material; silica and pyrex glass are usually more active than alumina. Attempts at detecting the formation of organometallic intermediates or by-products (through IR spectroscopy) were made. HRTEM was used to check for eventual decomposition on some supports.     

Crystal Structure of Hexa(μ-bromo)-#x03BC;4-oxo-tetrakis-(1-ethyltetrazole)-tetracopper(II)

The structure of the [Cu₄(-Br)₆(₄-O)(ettz)₄] complex of the monoclinic crystal system was investigated by X-ray diffraction analysis: a = 45.016(12), b = 9.363(4), c = 15.698(5) , = 100.28(2)°, V _cell = 6510(4) ³, space group C2/c, Z = 8,_calc = 2.330 g/cm³, R1 = 0.0697 for 714 F_hkl 4 (F). The copper atoms form a tetrahedron with an oxygen atom in the middle and bromine atoms on the edges. The coordination polyhedron around the copper atom is a distorted trigonal bipyramid (CuOBr₃N unit). All tetrazole ligands are monodentate and coordinated by the N⁴ atoms.     

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.     

Synthesis and characterisation of novel selenium-containing clusters; crystal structures of [Ru4(μ4-Se)2(CO)8(μ-CO)3] and [Ru3(μ3-Se)2(CO)7(Ph2P(CH2)3PPh2)]

The compound [Ru₄(μ-Se)₂(CO)₈(μ3-CO)₃] (1), has been obtained in good yield by vacuum pyrolysis of [RU₃(CO)₁₂] with [Ph₂Se₂] at 185°C. Reaction of 1 with 1,3-bis(diphenylphosphino)propane at room temperature affords the novel cluster [RU₃(μ₃-Se)₂(CO)₇(Ph₂P(CH₂)₃PPh₂)] (2). The structures of 1 and 2 have been determined by an X-ray diffraction study.