Alcoholysis of hydridesilanes to give silyl ethers catalyzed by rhodacarboranes closo-3,3-(Ph3P)2-3-H-3,1,2-RhC2B9H11 and closo-3,3-(η2,η3-C7H7CH2)-3,1,2-RhC2B9H11

Rhodacarboranes closo-3,3-(Ph₃P)₂-3-H-3,1,2-RhC₂B₉H₁₁ and closo-(²,³-C₇H₇CH₂)-3,1,2-RhC₂B₉H₁₁ are catalysts for the alcoholysis of hydridesilanes. Closo-3,3-(²,³-C₇H₇CH₂)-3,1,2-RhC₂B₉H₁₁ displays greater activity than closo-3,3-(Ph₃P)₂-3-H-3,1,2-RhC₂B₉H₁₁ though both rhodacarboranes catalyze the alcoholysis of hydridesilanes more efficiently than (Ph₃P)₃RhCl.A. N. Nesmeyanov Institute of Organometallic Compounds, Russian Academy of Sciences, 117813 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 7, pp. 1657–1660, July, 1992.     

Photochemical arene exchange in the iron dicarbollide complex [(η-9-SMe2-7,8-C2B9H10)Fe(η-C6H6)]+

Visible light irradiation of the dicarbollide complex [(η-9-SMe₂-7,8-C₂B₉H₁₀)Fe(η-C₆H₆)]⁺ (2a) in the presence of the benzene derivatives in CH₂Cl₂/MeNO₂ resulted in cations [(η-9-SMe₂-7,8-C₂B₉H₁₀)Fe(η-C₆R₆)]⁺ (2b-g; arene is anisole (b), toluene (c), m-xylene (d), mesitylene (e), durene (f), and hexamethylbenzene (g)) due to the arene exchange. The structures of [2g]PF₆ and related tricarbollide complex [(η-1-Bu^tNH-1,7,9-C₃B₈H₁₀)Fe-(η-C₆H₆)]PF₆ (1) were confirmed by X-ray diffraction analysis. The nature of bonding in cations 1, 2a, and [CpFe(η-C₆H₆)]⁺ was analyzed by an energy decomposition analysis.     

Molecular structure of ansa-compound (η5-C5H4)CMe2(η5-C9H6)TiCl2

The structure of a new ansa compound, (⁵-C₅H₄)CMe₂(⁵-C₉H₆)TiCl₂ (1), was studied by X-ray analysis:a = 15.00(1),b =15.500(5),c = 13.032(4) Å, = 92.66°(4),V = 3025.1(1) ų, space groupP2₁/.,R = 0.038. The distorted tetrahedral coordination sphere of the Ti atom is formed by two Cl atoms and two -ligands. It was proposed that the angle () between theC-M direction and the line normal to M-Cp can be considered as one of the geometric parameters characteristic of the structure-properties correlation.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 305–308, February, 1995.     

Substitution and insertion reactions of (η5-C5H5)Cr(CO)3C2H5

The complex (η⁵-C₅H₅)Cr(CO)₃Cp42 H₅ has been made and its reactions with σ donor ligands L (L = (MeO)₃P and (EtO)₃P) and with SO₂ studied. The alkyl phosphites give compounds of the composition (η⁵-C₅H₅)Cr(CO)₂LC₂H₅, and sulfur dioxide gives the corresponding S-sulfinato (η⁵-C₅H₅)Cr(CO)₃SO₂C₂H₅.     

Insertion reactions of t-Bu(η5-C5H5)Fe(CO)2

The complex t-Bu(η⁵-C₅H₅)FE(CO)₂ has been treated with triphenylphosphine in refluxing THF to produce t-BuCO(η⁵-C₅H₅)Fe(CO)(PPh₃). The large steric bulk of the t-butyl group suggests that this reaction should be faster than the reaction involving the methyl group, and a kinetic investigation illustrates this to be the case. The same steric bulk predicts that the reaction with SO₂ should be slow, and indeed we have been unable to effect the related SO₂ insertion reaction. Attempts to prepare the corresponding t-Bu(η⁵-C₅H₅)W(CO)₃ led to formation of the related isobutyl complex.     

Synthesis and structure of (boratabenzene)rhodacarborane (η-7,8-C2B9H11)Rh(η-C5H5BMe)

The bromide complex [(η-C₅H₅BMe)RhBr₂]₂ (1) was synthesized by the reaction of the cyclooctadiene derivative (η-C₅H₅BMe)Rh(1,5-C₈H₁₂) with Br₂. The reaction of compound 1 with Tl[Tl(η-7,8-C₂B₉H₁₁)] gave (boratabenzene)rhodacarborane (η-7,8-C₂B₉H₁₁)Rh-(η-C₅H₅BMe) (2). The structure of compound 2 was determined by X-ray diffraction     

Synthesis and structures of the η5-C5H5Cl(CO)2W-η1,η5-(PPh2)C5H4(CO)2Fe-η1,η5-C5H4Mn(CO)3 and MeSi[C5H4(CO)2Fe-η1,η5-C5H4Mn(CO)2PPh3]3 complexes

The metallation of the η⁵-C₅H₅(CO)₂Fe-η¹,η⁵-C₅H₄Mn(CO)₃ complex with BuⁿLi (THF, ?78 °C) followed by the treatment of the lithium derivative with Ph₂PCl afforded the η⁵-Ph₂PC₅H₄(CO)₂Fe-η¹,η⁵-C₅H₄Mn(CO)₃ complex. The reaction of the latter with η⁵-C₅H₅(CO)₃WCl in the presence of Me₃NO produced the trinuclear complex η⁵-C₅H₅Cl(CO)₂W-η¹,η⁵-(Ph₂P)C₅H₄(CO)₂Fe-η¹,η⁵-C₅H₄Mn(CO)₃. The structure of the latter complex was established by IR, UV, and 1H and ³¹P NMR spectroscopy and X-ray diffraction. The reaction of MeSiCl₃ with three equivalents of LiC₅H₄(CO)₂Fe-η¹,η⁵-C₅H₄Mn(CO)₂PPh₃ gave the hexanuclear complex MeSi[C₅H₄(CO)₂Fe-η¹,η⁵-C₅H₄Mn(CO)₂PPh₃]₃.     

Synthesis of the iridacarborane halide complexes [(η-9-SMe2-7,8-C2B9H10)IrX2]2 (X = Cl,Br, or I)

The reaction of Na[9-SMe₂-7,8-C₂B₉H₁₀] with [(Cod)IrCl]₂ (Cod is cycloocta-1,5-diene) gave rise to the iridium complex (-9-SMe₂-7,8-C₂B₉H₁₀)Ir(Cod). Treatment of the latter with anhydrous acids HX (X = Cl, Br, or I) afforded the corresponding iridacarborane halide complexes [(-9-SMe₂-7,8-C₂B₉H₁₀)IrX₂]₂ analogous to the cyclopentadienyl complexes [(C₅Me₅)IrX₂]₂.     

The mechanism of fluxionality of (1,2,7-η3-2-Me-benzyl)(η5-C5H5)Mo(CO)2

It is shown that (1,2,7-η³-2-Me-benzyl)(η⁵-C₅H₅)Mo(CO)₂ exits in solution as one isomer which is fluxional, probably via (7-η¹-2-Me-benzyl)((η⁵-C₅H₅)Mo(CO)₂, with ΔG^≠₃₇₀ = 23.6 ± 1.0 kcal mol⁻¹. In contrast, (1,2,7-η³-3-Me-benzyl)(η⁵-C₅H₅)Mo(CO)₂ exits as two isomers at −20°C, which undergo interconversion at room temperature with ΔG^≠ 15.7 kcal mol⁻¹. This dynamic process is an allyl rotation. It is probable that there is also a low energy [1,5]-sigmatropic shift.     

The reactions of [Fe2(η-Cp)2(CNAr)4] complexes with halogens and tin(II) halides

Summary [Fe₂(-Cp)₂(CNAr)₄] (2) (540-01, C₆H₄Me-2, C₆H₄Et-2, C₆H₃Me₂-2,4, C₆H₃Me₂-2,6, C₆H₃(Me)Et-2,6, C₆H₃Et₂-2,6 or C₆H₃ i-Pr₂-2,6) react with I₂ to give [Fe(-Cp)(CNAr)₂I], but with Br₂[Fe(-Cp) (CNAr)₃]⁺ salts are the only products; IBr gives a mixture of the two. With SnX₂ (X = F, Cl, Br or I) in refluxing n-butanol, (2) gives isolable [{Fe(-Cp)(CNAr)₂}₂SnX₂] only when the CNAr ligands have two ortho substituents, otherwise decomposition occurred. When X = F, [Fe(-Cp) (CNAr)₂SnF₃] was also obtained from this reaction. Attempts to prepare [Fe(-Cp)(CNAr)₂X] (X = Cl or Br) by reaction of (2) with HX in the presence of air gave rather unstable products which with SnX₂ formed [Fe(-C₅H₅)-(CNAr)₂SnX₃]. Similar compounds, [Fe(-Cp) (CNAr)₂ SnX₂I], were obtained from [Fe(-Cp)-(CNAr)₂I] and SnX₂ (X = Cl or Br but not I). All of these complexes are much less stable than their Fe(-Cp)(CO)₂ counterparts; all decompose in solution to [Fe(-Cp)(CNAr)₃]⁺ which then break down to unidentified species. X-ray diffraction studies show that in [Fe(-Cp)(CNC₆H₃-i-Pr₂-2,6)₂I] and [{Fe(-Cp)(CNC₆H₃Me₂-2,6)₂}₂SnBr₂] there is pseudo-octahedral coordination about Fe. In the latter there is also distorted tetrahedral coordination about Sn so that its structure is very similar to that of [{Fe(-Cp)(CO)₂}₂SnCl₂]. Spectroscopic studies show that in all complexes rotation of the aryl rings of the CNAr ligands cannot be slowed in solution, and that there is free rotation about all 540-02 bonds.     

Ligand exchange reactions of the alkyluranium(III) complexes (η5-C5H5)3URLi

The Cp₃URLi compounds (Cp = η⁵-C₅H₅; R = Me, n-Bu, n-Pent) have been synthesized by reaction of CP₃U(THF) with 1 equivalent of RLi. Exchange of the R alkyl occurs on treatment with alkyllithium reagents or in hydrogenolysis in the presence of a terminal olefin. These reactions presumably involve the Cp₃U and Cp₂UR species which are in equilibrium with the Cp₃URLi complexes.     

Regiospecific substitution of carbonyl by phosphine ligands in hydrocarbyl-substituted carbonyl clusters. Synthesis and spectroscopic characterization of Fe3(CO)8(PPh3)(μ3-η2- ⊥ -EtC2Et) and (η5-C5H5)NiFe2(CO)5(PPh3)(η3-η2- ⊥-C2But)

The complexes Fe₃(CO)₈(PPh₃)(μ₃-η²- ⊥ -EtC₂Et) and (η⁵-C₅H₅)NiFe₂(CO)₅(PPh₃)(η₃-η²- ⊥-C₂Bu^t) have been obtained by treating Fe₃(CO)₉(C₂Et₂) or (Cp)NiFe₂(CO)₆(C₂Bu^t) with PPh₃ under mild conditions; the substituted clustes have been characterized spectroscopically. Structures are proposed in which the phosphine is on the unique metalatom σ-bonded to the alkyne or acetylide moiety. Replacement of CO by PPh₃ ligands rather than by addition, is observed for the formally unsaturated Fe₃(CO)₉(C₂Et₂). Reorientation of the acetylide was expected for (Cp)NiFe₂(CO)₆(C₂Bu^t) upon substitution, but was not observed.     

Boron cluster anions B10H10 2? and B10H11 ? in complexation reactions of copper(i). Positional isomers of the complex [Cu2(9Nphen)4B10H10]

The complexation reactions of Cu^I with the B₁₀H₁₀ ^2? anion and its protonated form, the B₁₀H₁₁ ^? anion, were studied in the presence of phenanthridine (9Nphen). Depending on the reaction conditions, positional isomers of the monomeric copper(i) complex [Cu₂(9Nphen)₄B₁₀H₁₀] were selectively isolated. The closo-decaborate anion in the complexes is coordinated to the Cu(i) atoms through the apical edges 1?C2, 7(8)?C10 or 1?C2, 1?C4 via the formation of multicenter CuHB bonds. The crystal structures and IR spectra of the complexes were studied. The compound [Cu₂(9Nphen)₄B₁₀H₁₀] is the first monomeric complex isolated in the form of the 1?C2, 7(8)?C10 isomer. It extends the series of positional isomers, which we have described earlier.     

Synthesis and reactions of dicarbonyl (η2-indene)-η5-indenyl complexes of manganese and rhenium

Photochemical reactions of M(CO)₃(⁵-C₉H₇), where M=Mn (1) or Re (2), with indene have produced ²-indene complexes M(CO)₂(²-C₉H₈)(⁵-C₉H₇), where M=Mn (3) or Re (4). Deprotonation of complex3 witht-BuOK in THF at –60 °C gives the anion [Mn(CO)₂(¹-C₉H₇)(⁵-C₉H₇)^– (5), in which there occurs a rapid interchange of the Mn(CO)₂(⁵-C₉H₇) group between positions 1 and 3 in the ¹-indenyl ligand. The reaction of complex4 with Ph₃CPF₆ in CH₂Cl₂ at 0 °C leads to the complex [Re(CO)₂(³-C₉H₇)(⁵-C₉H₇)PF₆, whereas the similar reaction of complex3 gives only decomposition products even at –20 °C.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1280–1285, July, 1993.     

(Arene)ruthenium complexes with the monoanionic carborane ligand [9-SMe2-7,8-C2B9H10]–

The ruthenium arene complexes [(-arene)Ru(-9-SMe₂-7,8-C₂B₉H₁₀)]⁺ (arene = C₆H₆ (3a); arene = 1,3,5-C₆H₃Me₃ (3b)) with the monoanionic carborane ligand were synthesized by the reactions of the [9-SMe₂-7,8-C₂B₉H₁₀]^– anion with [(-arene)RuCl₂]₂. The structure of the compound [3a]BPh₄ was established by single-crystal X-ray diffraction analysis.     

Synthesis of ferricinium bis[π-(3)-1,2-dicarbollyl]cobaltate(iii), [FeIII(η5-Cp)2]+{CoIII[π-(3)-1,2-B9C2H11]2}−

Ferricinium bis[-(3)-1,2-dicarbollyl]cobaltate(III), [Fe^III(⁵--Cp)₂]⁺{Co^III[-(3)-1,2-B₉C₂H₁₁]₂}^–, has been prepared by the reaction of Fe^III(⁵--Cp)₂]⁺ with the anion {Co^III[-(3)-1,2-B₉C₂H₁₁]₂}^–. It is a light-green amorphous precipitate that is stable as a dry solid up to 227 °C and unstable in solutions of acetonitrile and acetone.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No, 10, pp. 1810–1811, October, 1994.This work was supported by the Russian Foundation for Basic Research (Project No 93-03-5987).     

The formation of metal clusters by the facile condensation of electron-deficient metal centres; X-ray crystal structures of (η-C5H5)2Rh4(CO)4Cl2(CF3C2CF3) and (η-C5H5)4Rh4Pt(CO)2(CF3C2CF3)2

When solutions of (η-C₅H₅)₂Rh₂(CO)(CF₃C₂CF₃) and [Rh(CO)₂Cl]₂ in hexane are mixed and left at room temperature, black crystals of the condensation product (η-C₅H₅)₂Rh₄(CO)₄Cl₂(CF₃C₂CF₃) are deposited. X-ray structure determination shows that one rhodium atom of the [Rh(CO)₂Cl]₂ dimer has added to the RhRh bond of (η-C₅H₅)₂Rh₂(CO)(CF₃C₂CF₃) to form a triangular Rh₃ cluster. This is capped on one side by a semi-face bridging carbonyl and on the other by a μ₃η² bound alkyne. Variable temperature NMR data reveal that two isomers of the complex co-exist in solution and that they rapidly interconvert at room temperature. In similar reactions between (η-C₅H₅)₂Rh₂(CO)(CF₃C₂CF₃) and Pt(COD)₂ in hexane at room temperature, there is loss of cyclooctadine and the formation of two cluster products. One is formulated as (η-C₅H₅)₂Rh₂Pt(COD)(CF₃C₂CF₃) and the other as (η-C₅H₅)₄Rh₄Pt(CO)₂(CF₃C₂CF₃)₂. Determination of the X-ray crystal structure of the latter establishes that the Pt is a common apex for two linked Rh₂Pt triangles. Within each Rh₂Pt unit, a semi-bridging carbonyl spans one Rh-Rh edge, and the hexaluorobut-2-yne occupies a μ₃η² face bridging position.     

Comparison of the Bonding of Benzene and C60 to a Metal Cluster: Ru3(CO)9(μ3-η2,η 2,η2-C6H6) and Ru3(CO)9(μ3-η2,η2,η2-C60)

The electron distributions and bonding in Ru₃(CO)₉( ³- ², ², ²-C₆H₆) and Ru₃(CO)₉( ³- ², ², ²-C₆₀) are examined via electronic structure calculations in order to compare the nature of ligation of benzene and buckminsterfullerene to the common Ru₃(CO)₉ inorganic cluster. A fragment orbital approach, which is aided by the relatively high symmetry that these molecules possess, reveals important features of the electronic structures of these two systems. Reported crystal structures show that both benzene and C₆₀ are geometrically distorted when bound to the metal cluster fragment, and our ab initio calculations indicate that the energies of these distortions are similar. The experimental Ru–C_fullerene bond lengths are shorter than the corresponding Ru–C_benzene distances and the Ru–Ru bond lengths are longer in the fullerene-bound cluster than for the benzene-ligated cluster. Also, the carbonyl stretching frequencies are slightly higher for Ru₃(CO)₉( ³- ², ², ²-C₆₀) than for Ru₃(CO)₉( ³- ², ², ²-C₆H₆). As a whole, these observations suggest that electron density is being pulled away from the metal centers and CO ligands to form stronger Ru–C_fullerene than Ru–C_benzene bonds. Fenske-Hall molecular orbital calculations show that an important interaction is donation of electron density in the metal–metal bonds to empty orbitals of C₆₀ and C₆H₆. Bonds to the metal cluster that result from this interaction are the second highest occupied orbitals of both systems. A larger amount of density is donated to C₆₀ than to C₆H₆, thus accounting for the longer metal–metal bonds in the fullerene-bound cluster. The principal metal–arene bonding modes are the same in both systems, but the more band-like electronic structure of the fullerene (i.e., the greater number density of donor and acceptor orbitals in a given energy region) as compared to C₆H₆ permits a greater degree of electron flow and stronger bonding between the Ru₃(CO)₉ and C₆₀ fragments. Of significance to the reduction chemistry of M₃(CO)₉( ³- ², ², ²-C₆₀) molecules, the HOMO is largely localized on the metal–carbonyl fragment and the LUMO is largely localized on the C₆₀ portion of the molecule. The localized C₆₀ character of the LUMO is consistent with the similarity of the first two reductions of this class of molecules to the first two reductions of free C₆₀. The set of orbitals above the LUMO shows partial delocalization (in an antibonding sense) to the metal fragment, thus accounting for the relative ease of the third reduction of this class of molecules compared to the third reduction of free C₆₀.     

Electron transfer in organometallic clusters: XIV. Crystal and electronic structures of the tricobalt carbon cluster (η5-C5H5)Fe[η5-C5H4-CCo3(CO)9] and the biscarbyne cluster (η5-C5H5)Fe[η5-C5H4CCo3(η5-C5H5)3CH]

The crystal and molecular structures of (η⁵-C₅H₅)Fe[η⁵--C₅H₄CCo₃(CO)₉] (1), Pna2₁, α 17.354, b 11.463, c 11.207 Å Z = 4, R = 0.053, R_w = 0.056 for 939 reflections (I>3σ(I)) at 293 K, and (η⁵-C₅H₅Fe[η⁵--C₅H₄CCo₃(η⁵C₅H₅)₃CH] (2), P2₁/n, a 13.807(9), b 11.254(4), c 13.991(9) Å, β 99.98(5)°, Z = 4, R = 0.033 and R_w = 0.033 for 3051 observed reflections (I>3σ(I)) at 180 K, have been determined by X-ray methods.The results provide a detailed characterisation of related tricobalt-carbon complexes directly bound to ferrocene residues. In 1 the ferrocenyl moiety tops the pyramidal CCo₃ cluster core, while in 2 the CCo₃C core is bipyramidal with a ferrocenyl substituent on one capping carbon atom and a hydrogen atom at the other. In both cases the ferrocenyl group is tilted towards one cobalt atom of the cluster core, a distortion believed to be the consequence of the non-degeneracy of the carbyne p(π) orbitals resulting from a cooperative π-interaction between the clusters and the ferrocenyl substituents.