Synthesis, molecular structures, and properties of heterometallic cobalt tetramethylcyclobutadiene complexes (C4Me4)Co(CO)2TePh, (C4Me4)Co(CO)2TePh[W(CO)5], and Me4C4Co(μ3-S)2Cr2Cp2(μ-SC4H9)

The reaction of Cb*Co(CO)₂I (1) (Cb* is tetramethylcyclobutadiene) with sodium phenyltelluride afforded the mononuclesar complex Cb*Co(CO)₂TePh (2). The reaction of the latter with W(CO)₅(THF) produced the Cb*Co(CO)₂TePh[W(CO)₅] compound (4). The reaction of 1 with the Cp₂Cr₂(SCMe₃)₂S complex gave the heterometallic cluster Cb*Co(μ₃-S)₂Cr₂Cp2 (μ-SCMe₃) (5). Complexes 2, 4, and 5 are diamagnetic. Their structures were determined by X-ray diffraction. Complex 2 contains the Co-Te bond (2.585(1) Å); complex 4, the Co-Te (2.558(8) Å) and W-Te (2.8467(6) Å) bonds. Complex 5 has the stable triangular sulfide-and tert-butylmercaptide-bridged core Cr₂Co (Cr-Cr and Cr-Co bond lengths are 2.626(2) and 2.673(2) Å, respectively) with Cp ligands at the chromium atoms and a Cb* ligand at the cobalt atom. Complex 5 was characterized by cyclic voltammetry. The thermolysis of complex 4 was studied.     

Electrochemical reductive acylation of (η6-arene)Cr(CO)3 complexes and (benzophenone)[Cr(CO)3]2

The electrochemical reductive acylation of (benzophenone)Cr(CO)₃ and (benzophenone) [Cr(CO)₃]₂ has been performed in DMF, by electrochemical reduction of complexed ketones in the presence of acetic and benzoic anhydride in excess. Three complexed benzhydryl esters ArCH(OCOR)PhCr(CO)₃, (Ar = Ph, R = Me: Ar = PhCr(CO)₃, R = Me; Ar = PhCr(CO)₃, R = Ph) were obtained in 46–57.5% yields after purification. Electrochemical reduction of (diphenylmethane)Cr(CO)₃ in the presence of acetic anhydride in excess leads to m-benzyl acetophenone.     

Reactions of dipropargyl manolate,terephthalate with Co2(CO)8, Mo2Cp2(CO)4 and RuCo2(CO)11 give the di or tetranuclear clusters. The crystal structure of [CH2(CO2CH2C2H-μ)2][Co2(CO)6]2 and [p-(HC2CH2OCO)C6H4(CO2CH2C2H-μ)][Co2(CO)6]

The reactions of dipropargyl manolate and terephthalate, respectively, with Co₂(CO)₈ in THF at room temperature gave four new compounds [R(CO₂CH₂C₂H-μ)₂][Co₂(CO)₆]₂ (R=CH₂, 1a; R=C₆H₄, 1b) and [(HC₂CH₂OCO)R(CO₂CH₂C₂H-μ)][Co₂(CO)₆] (R=CH₂, 2a; R=C₆H₄-1,4-, 2b), and compounds 2a and b reacted with RuCo₂(CO)₁₁ to form two new linked clusters [R(CO₂CH₂C₂H-μ)₂][Co₂(CO)₆][RuCo₂(CO)₉] (R=CH₂, 3a; R=C₆H₄-1,4-, 3b). The treatment of two dipropargyl esters, respectively, with RuCo₂(CO)₁₁ afforded another two new clusters [R(CO₂CH₂C₂H-μ)₂][RuCo₂(CO)₉]₂ (R=CH₂, 4a; R=C₆H₄-1,4-, 4b). The reactions of dipropargyl manolate, terephalate with Mo₂Cp₂(CO)₄ gave rise to the formation of dinuclear complexes [(HC₂CH₂OCO)R(CO₂CH₂C₂H-μ)][Mo₂Cp₂(CO)₄] (R=CH₂, 5a; R=C₆H₄-1,4-, 5b), compound 5a reacted with Co₂(CO)₈ to produce the cluster [CH₂(CO₂CH₂C₂H-μ)₂][Co₂(CO)₆][Mo₂Cp₂(CO)₄] 6a. All the new clusters have been characterized by C/H elemental analysis, IR and ¹H NMR spectroscopies. The structure of [CH₂(CO₂CH₂C₂H-μ)₂][Co₂(CO)₆]₂ 1a and [p-(HC₂CH₂OCO)C₆H₄(CO₂CH₂C₂H-μ)][Co₂(CO)₆] 2b have been determined by single crystal X-ray diffraction methods.     

Acetylene as a ligand on clusters: An accurate determination of the crystal and molecular structure of (Cp)2Ni2Fe(CO)3(μ3−C2H2) and of (CP)2Ni2Fe2(CO)6(μ4−C2H2)

Abstarct The Cp)₂Ni₂Fe(CO)₃(µ₃-C₂H₂) and Cp)₂Ni₂Fe(CO)₃(µ₃-C₂H₂) (B) complexes have been synthesized and spectroscopically characterized. An accurate X-ray study and a comparison with related structures shows that the substituents of the alkyne ligands exert considerable effects on the bonding parameters.Crystal data for complex A, monoclinic space group P2₁/n,a = 8.418(1),b = 15.779(2),c = 14,493(1) Å, = 91.64(1)°,Z = 4, 2753 observed reflections,R = 0.022; crystal data for complex B, monoclinic space group C2/c,a = 16.2189(7),b = 7.445(3),c = 25.745(5) Å, = 103.74(3),Z=8, 1853 observed reflections,R = 0.051.     

Phosphenium-übergangsmetallkomplexe: XX. Stabilisierung von mesitylphosphiniden durch ein Cp(CO)2W- und ein Cp(CO)2 Fe-Fragment

The reaction of the secondary metallo-phosphanes Cp(CO)₂(L)W-PH(Mes) (L  CO, PMe₃) (1a,b) with the iron complex [Cp(CO)₃Fe]BF₄ (2) or Cp(CO)2Fe-I (3), respectively, affords the ferrio(wolframio)phosphonium salts [Cp(CO)₂(L)W-P(Mes)-Fe(CO)₂Cp]X (X  I (4a), BF₄ (4b). Deprotonation of 4a, b with DBU results, in both cases, in the selective formation of a WP bond owing to additional CO- or Me₃P-elimination to give the phosphinidene complex Cp(CO)₂WP(Mes)-Fe(CO)₂Cp (6).     

Reactions of (η6-diphenylacetylene) chromiumtricarbonyl complexes with polynuclear carbonyls I. Synthesis of Cr(CO)3(η6-diphenylacetylene) complex and its reaction with Co2(CO)8. Crystal and molecular structure of Cr(CO)3(η6:η2-diphenylacetylene)Co2(CO)6

The reaction of Cr(CO)₃(NH₃)₃ with diphenylacetylene affords as a main product the complex with Cr(CO)₃ moiety bound to a phenyl ring of diphenylacetylene; Cr(CO)₃(η⁶-PhC₂Ph) (I). Complex I readily reacts with Co₂(CO)₈ yielding the mixed metal complex Cr(CO)₃(η⁶:η²-PhC₂Ph)Co₂(CO)₆ (II). The reaction proceeds with retention of the Cr(CO)₃ (η⁶-arene) structural unit, the Co₂(CO)₆ fragment being bound to the triple bond of diphenylacetylene in μ₂,η²-mode. The structure of II was determined by single crystal X-ray analysis. The complex crystallizes in space group P2₁/c with unit cell parameters a 8.666(3) Å, b 18.046(3) Å, c 15.155(6) Å. β 97.57(3)°, V 2349(2) ų, Z = 4, D_x = 1.70 g/cm³. The structure was solved by direct methods and refined by full-matrix least-squares technique to R and R_w values of 0.032 and 0.034, respectively, for 3655 observed reflections. The data obtained show that two structural units in II, Cr(CO)₃(η⁶-Ph-) and Co₂(CO)₆(μ₂,η²-CC), are distorted due to steric repulsion between these metal carbonyl moieties. The Cr(CO)₃ fragment is shifted from the centre of the phenyl ring and slightly tilted with respect to the phenyl ring plane. The Co₂C₂ tetrahedron in the Co₂(CO)₆(μ₂,η²-CC) moiety is distorted in such a way that two of the four Co_iC_j bonds are elongated.     

Photoelectron spectroscopy of (CO2)n(H2O) m − clusters

Photoelectron spectra of (CO₂)_nH₂O^? (2≤n≤8) and (CO₂)_n(H₂O) ₂ ^? (1≤n≤2) were measured at the photon energy of 3.49 eV. The spectra show unresolved broad features, which are approximated by Gaussians. The vertical detachment energies (VDEs) were determined as a function of the cluster size. For (CO₂)_nH₂O^?, the VDE-n plots exhibit a sharp discontinuity between n=3 and 4; the VDE value is ≈3.5 eV at n=3, while it drops down abruptly to 2.59 eV at n=4. This discontinuity in VDE is ascribed to "core switching" at n=4; a C₂O ₄ ^? dimer anion forms the core of (CO₂)_nH₂O^? for n≤3, while a monomer CO ₂ ^? is the core for n≥4. The (CO₂)₂(H₂O) ₂ ^? ion has a VDE of 2.33 eV, indicating the presence of a CO ₂ ^? monomer core in the binary clusters containing two H₂O molecules.     

Density functional calculations of the structures and bond energies of Cr(CO)6 and (η6-C6H6) Cr(CO)2(CX) (X=O,S) complexes

Summary Quantum chemical calculations based on density functional theory have been performed on Cr(CO)₆, (⁶-C₆H₆)Cr(CO)₃ and (⁶-C₆H₆)Cr(CO)₂(CS) at the local and nonlocal level of theory using different functionals. Good agreement is obtained with experiment for both optimized geometries and metal-ligand binding energies. In particular, a comparison of metal-arene bond energies calculated for the (⁶-C₆H₆)Cr(CO)₃ and (⁶-C₆H₆)Cr(CO)₂(CS) complexes correlates well with kinetic data demonstrating that substitution of one CO group by CS leads to an important labilizing effect of this bond, which may be primarily attributed to a larger -backbonding charge transfer to the CS ligand as compared with CO.     

Reactions of [Y(BDI)(I)2(THF)] [BDI = {HC(CMeNAr)2}−, Ar = 2,6-diisopropylphenyl] with Na[M(Cp)(CO)3] (M = Cr,W): X-ray crystal structures of [{Y(BDI)[Cr(Cp)(CO)3]2(THF)}2] and [W(Cp)(CO)3][Na(THF)2]

Reaction of [Y(BDI)(I)₂(THF)] (1) with two equivalents of Na[Cr(Cp)(CO)₃] affords the dimeric complex [{Y(BDI)[Cr(Cp)(CO)₃]₂(THF)}₂] (2). Complex 2 contains two yttrium-BDI units which are each linked by two isocarbonyl bridging [Cr(Cp)(CO)₃]^? anions; a terminal, isocarbonyl bound [Cr(Cp)(CO)₃]^? anion and THF molecule completes the coordination sphere at each yttrium. This results in formation of a centrosymmetric, 12-membered C₄O₄Cr₂Y₂ ring. Forcing conditions were required to produce carbonyl metallate derivatives such as 2, as exemplified by the isolation of crystals of [W(Cp)(CO)₃][Na(THF)₂] (3) from the analogous reaction between 1 and two equivalents of Na[W(Cp)(CO)₃]. Complex 3 loses coordinated THF very easily and all isolated samples exhibit spectra consistent with the known, un-solvated form of Na[W(Cp)(CO)₃]. The crystal structure of 3 shows dimeric sodium units bridged by two THF molecules and one isocarbonyl group. Each sodium centre is further coordinated by one THF molecule and two isocarbonyl ligands. There are two crystallographically distinct [W(Cp)(CO)₃]^? units; one exhibits two bridging isocarbonyl groups and the other exhibits three bridging isocarbonyl groups to different sodium dimer units. This results in a 2-dimensional polymeric sheet network in the solid state. Complex 2 was characterised by single crystal X-ray diffraction, NMR spectroscopy, FTIR spectroscopy and CHN microanalysis; complex 3 was characterised by single crystal X-ray diffraction only.     

Cp*MCpMoFe(CO)7(μ3-S), Cp*MoCpMFe(CO)7(μ3-S) (M = W,Mo) and Cp*WCp*MoFe(CO)7(μ3-S). Crystal structure of CpMoCp*WFe(CO)7(μ3-S)

CpMoFeCo(CO)₇(₃-S) reacts with Cp^*M(CO)₃Cl or CpM(CO)₃Cl (M=W, Mo) to gave the mixed-metal clusters Cp^*WCpMoFe(CO)₇(₃-S) (1), Cp^*MoCpMoFe(CO)₇(₃-S) (2), CpWCp^*MoFe(CO)₇(₃-S) (3), CpMoCp^*MoFe(CO)₇(₃-S) (4) and Cp^*WCp^*MoFe(CO)₇(₃-S) (5). The title clusters have been characterized by i.r., ¹H/¹³C-n.m.r. spectroscopy and their compositions have been confirmed by elemental analyses. The X-ray crystal structure analysis shows the two independent enantiomeric molecules of clusters (1) in one crystal structure unit.     

Carbonylmetall-verbindungen des bis(di-t-butylphosphino)schwefeldiimids: Bildung von zweikernkomplexen S{NPtBu2[MLn]}2 (MLn = Cr(CO)5), Mo(CO)5, W(CO)5, Fe(CO)4) und chelatkomplexen S(NPtBu2)2M(CO)4 (M = Cr,Mo, W). Kristall- und molekülstruktur von S(NPtBu2)2Cr(CO)4

The reaction of bis(di-t-butylphosphino) sulphur diimide, S(NP^tBu₂)₂ (1) ¹, with coordinatively unsaturated 16-electron complex fragments [M(CO)₅] leads to both binuclear 1 : 2 adducts S{NP^tBu₂[M(CO)₅]}₂ (M = Cr (2B), Mo (3B) and W (4B)) and mononuclear chelate complexes S(NP^tBu₂)₂M(CO)₄ (M = Cr (2C), Mo (3C) and W (4C)). A binuclear compound S{NP^tBu₂[Fe(CO)₄]}₂ (5B) is obtained from the reaction of 1 with Fe₂(CO)₉. The new complexes which all contain the intact sulphyr diimide 1 are characterized on the basis of their infrared, ¹H, ¹³C and ³¹P NMR spectra. An X-ray structure analysis of S(NP^tBu₂)₂Cr(CO)₄ (2C) reveals a distorted octahedral coordination sphere around the central chromium atom and an almost planar but twisted six-membered Cr(PN)₂S heterocycle with angles of 91.98(2)° at chromium (P(1)CrP(2)) and 124.6(1)° at sulphur (N(1)SN(2)).     

Phosphine-centred resolution of (η4-diene)Fe(CO)3 complexes: (η4-tropone)Fe(CO)2L and (η4-isoprene)Fe(CO)2L [L = (+)-(neomenthyl)PPh2]

(η⁴-Tropone)Fe(CO)₃ and (η⁴-isoprene)Fe(CO)₃ form separable diastereoisomers on substitution of CO by (+)-(neomenthyl)PPh₂. In the tropone complex, diastereoisomer interconversion occurs by a 1,3-metal shift. The absolute configuration of the isoprene complex has been determined crystallographically.     

对苯二甲酸二丙炔醇酯与C02(CO)8、M02Cp2(CO)4和RuC02(CO)11的反应

室温下,对苯二甲酸二丙炔醇酯分别与Co2(CO)8,Mo2Cp2(CO)4和RuCo2(CO)11反应,得到三个有机金属化合物[C6H4-p-(CO2CH2C2H-μ)2][Co2(CO)6]2(1)、[C6H4-p-(CO2CH2C2H)2][RuCo2(CO)9]2(2)和[(HC2CH2OCO)C6H4-p-(CO2CH2C2H-μ)][Mo2Cp2(CO)4](3).研究发现三种金属核对端炔氢的屏蔽作用依次为RuCo2(CO)9＞Co2(CO)6＞Mo2(CO)4Cp2.化合物1的晶体衍射发现,属三斜晶系,空间群PT,a=8.139(2)A,b=8.808(3)A,c=1 1.343(3)A,β=96.260(6)°,V=773.4(4)A3,Z=1,Dc=1.748g@cm-3,R=0.0513,wR=0.1266.     

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。     

A kinetic study on the iron(III)-promoted aquation of [Cr(C2O4)2(picolinato)]2− and [Cr(C2O4)2(2-pyridineacetato)]2− complexes

Two [Cr(C₂O₄)₂(AB)]^2– type complexes, obtained from the reaction of cis-[Cr(C₂O₄)₂(H₂O)₂]^– with the AB ligand, [AB = picolinic (pyac) or 2-pyridine-ethanoic acid (pyeac) anions], were converted into [Cr(C₂O₄)(pyac)(H₂O)₂]⁰ and [Cr(C₂O₄)(pyeac)(H₂O)₂]⁰ compounds, respectively via Fe^III-induced substitution of the oxalato ligand. The aquation products were separated chromatographically and their spectral characteristics and acid dissociation constants determined. The kinetics of the oxalato ligand substitution were studied with a 10–40 fold excess of Fe^III over [Cr^III] at [H⁺] = 0.2 M and at constant ionic strength 1.0 M (Na⁺, H⁺, Fe³⁺, ClO^– ₄). The reaction rate law is of the form: r = k _obs[Cr^III], where k _obs = kQ[Fe^III]/(1 + Q[Fe^III]). The first-order rate constants (k), preequilibria quotients (Q) and activation parameters derived from the k values have been determined. The reaction mechanism is discussed in terms of a Lewis acid catalyzed (induced) ligand substitution.     

First Examples of Electrophilic Addition to a Fe2Q Face of [Fe3(μ3-Q)(CO)9]2− (Q=Se, Te)—Synthesis and Characterisation of [MFe3(μ4-Q)(CO)9Cp*] and [IrFe2(μ3-Q)(CO)7Cp*] (M=Rh, Ir; Cp*=η5-C5(CH3)5)

The reaction of [Et₄N]₂[Fe₃(μ ₃-Q)(CO)₉] (Q=Se ([Et₄N]₂[1b]), Te ([Et₄N]₂[1c])) with [Cp*M(CH₃CN)₃][CF₃SO₃]₂ (M=Rh, Ir) leads to the addition of a Cp*M²⁺ unit to a Fe₂Q face of the initial cluster. In this way four new heteronuclear clusters [MFe₃(μ ₄-Q)(CO)₉Cp*] (M=Rh (2b, c); M=Ir (3b, c)) were obtained possessing a butterfly-shaped cluster core bridged by a μ ₄-Q unit. Furthermore, reaction with the Ir starting complex leads to the metal-substituted derivatives [IrFe₂(μ ₃-Q)(CO)₇Cp*] (4b, c) in lower yields, whose structures consist of a triangular metal core capped by a μ ₃-Q ligand. The products were comprehensively characterised by spectroscopic methods and the molecular structures of 2b, 3c, and 4c were established by single crystal X-ray diffraction measurements.     

Application of the Spherical Harmonic Model to the ν(CO) Vibrational Spectra of Some Fe(CO)4 and M(CO)5 (M=Cr, W) Transition Metal Cluster Carbonyl Species

When the Fe(CO)₄ and M(CO)₅ (M=Cr, W) groups are co-ordinated in C_3v and C_4v fashion, respectively, in transition metal carbonyl cluster species they contain two sets of non-symmetry related carbonyl groups. In the application of the spherical harmonic model (SHM) to the interpretation of the infrared spectra of these compounds it proves necessary first to treat these as for a normal, isolated, M(CO)₄ or M(CO)₅ group and then apply the SHM. This recognition gives insights into the general application of the SHM.