Synthesis of mononuclear and oligomeric ruthenium(II) acetylides

The complexes trans-[Ru(PMe₃)₄(CCPh)₂] and trans-[Ru(PMe₃)₄(CCC₆H₄C₆H₄CCSnMe₃)₂] have been prepared from the reaction between trans-[Ru(PMe₃)₄Cl₂] and an excess of either Me₃SnCCPh or Me₃SnCCRCCSnMe₃ (R = p-C₆H₄C₆H₄), respectively. However, if only one equivalent of the latter reagent is used the rod-like polymeric species trans-[-Ru(PMe₃)₄CCRCC-]_n can be isolated.     

Synthesis of novel rigid rod iron metal containing polyyne polymers

Treatment of the dihaloiron-chelating phosphine complex, Fe(DEPE)₂Cl₂ (1) with 2.5 equivalents of Me₃SnCC₆H₅ (2) gives the monomeric complex, tras-Fe(DEPE)₂(CCC₆H₅)₂ (3, whereas the reaction of equimolar quantities of 1 and Me₃SnCCRCCSnMe₃ (R = p-C₆H₄ (4); p-C₃)₂C₆H₂ (5)) yields soluble and high molecular weight rigid rod polymeric species, trans-[-Fe(DEPE)₂(−CCRCC-)]_n (6,7).     

Molecular structures of acetylene derivatives of tin: Part III. Gas phase electron diffraction study of tetrakis(trifluoropropynyl)-tin,Sn(CC-CF3)4

A gas phase electron diffraction study of tetrakis(trifluoropropynyl)tin is reported. The model, based on T_d symmetry for the carbon—tin skeleton and C_3v symmetry for the CF₃ groups, refines to the following parameters (bond lengths, r_a, in nm; valence angles in degrees): Sn—C0.2070(7), CC 0.1215(6), C—C 0.1460(7), C—F 0.1343(2), CCF 111.3(0.2). The uncertainties (given in parentheses) represent three times the standard deviation values. The results obtained point to practically free rotation of the CF₃ groups. The presence of electronegative CF₃ causes shortening of the Sn-C bonds in Sn(CC—CF₃)₄ from Me₃SnCCH and Me₃ SnCCSnMe₃. The triple CC bond length is larger than in hexafluoro-2-butyne and nearly the same as in dimethylacetylene.     

Protonation of Cp(CO)(PPh3) RuCCPh: Formation of cationnic phenylacetylene and phenylvinylidene complexes and subsequent reaction with ethylene oxide to form the net [2 + 3] cycloadduct [Cp(CO)(PPH3)Ru=CCH(Ph)CH2CH2O]+

Protonation of the alkynyl complex Cp(CO)(PPh₃)RuCCPh (1) at low temperature affords quantitatively the vinylidened complex [Cp(CO)(PPh₃)RuCCH(Ph)]⁺ (3), which upon warming to room temperature forms an equilibrium with the η²-phenylacetylene complex [Cp(CO)(PPh₃)Ru(η²-HCCPh)]⁺ (4), with the latter predominating. Subsequent reaction with ethylene oxide yields the cyclic oxacarbene complex [Cp(CO)(PPH₃)Ru=CCH(Ph)CH₂CH₂O]⁺ (5), which can be regarded as the result of a net [3+2] cycloaddition reaction between 3 and ethylene oxide. Depronation of 5 affords teh corresponding neutral cyclic vinyl complex [Cp(CO)(PPH₃)RuC=C(Ph)CH₂CH₂O]⁺ (6), which can in turn be protonated to regenerate 5 in a diastereoselective manner. The structures of complexes 5 and 6 were determined by X-ray crystallography.     

Syntheses, crystal structures and DFT studies of [Me3EM(CO)5] (E = Sb, Bi; M = Cr, W), cis-[(Me3Sb)2Mo(CO)4], and [Bu3BiFe(CO)4]

Syntheses of [Me₃SbM(CO)₅] [M = Cr (1), W (2)], [Me₃BiM(CO)₅] [M = Cr (3), W (4)], cis-[(Me₃Sb)₂Mo(CO)₄] (5), [^tBu₃BiFe(CO)₄] (6), crystal structures of 1-6 and DFT studies of 1-4 are reported.     

The Diels—Alder reaction in organometallic chemistry VI. Diels—Alder reactions of α-pyrone with group IV element-substituted acetylenes

The Diels—Alder reactions of α-pyrone with Me₃SiCCSiMe₃, Me₃SiCCSiMe₂H, Me₂HSiCCSiMe₂H, Me₃GeCCGeMe₃, Me₃SiCCGeMe₃, Me₃SiCCSnMe₃ and EtCCEt were examined. All except the first two acetylenes gave the expected 1,2-disubstituted benzene product, in line with results obtained previously with Me₃SnCCSnMe₃. The first two acetylenes, Me₃SiCCSiMe₃ and Me₃SiCCSiMe₂H, also yielded benzene products containing substantial amounts of the 1,3-disubstituted benzenes, as well as minor amounts of the 1,4-isomers. This formation of unexpected isomers during these reactions was shown to result from acid-catalyzed rearrangement of the initially formed 1,2-disubstituted products, 1,2-(Me₃Si)₂C₆H₄ and 1-Me₃Si-2-Me₂HSiC₆H₄. The acidic impurities arose from pyrolysis of the bromobenzene solvent used or were introduced as contaminants of the α-pyrone. Such isomerizations were inhibited by addition of small amounts of triethylamine. The fact that no rearrangement took place with the other acetylenes is due to the scavenging of acidic impurities which might cause isomerization by the starting acetylene and the benzene product via metal—carbon bond cleavage processes.     

[(C5Me4R)TiAs3O6], Moleküle mit einem AB3X6-adamantan-gerüst

Thermolysis of As₂₍₄₎O₃₍₆₎ (1) with [(η⁵-C₅Me₄R)₂Ti(CO)₂] (2a: R = Me, 2b: R = Et) affords [(η⁵- C₅Me₄R)TiAs₃O₆] (3a, 3b), molecules with an TiAs₃O₆ adamantane skeleton. The struture of 3b has been elucidated by X-ray analyis.     

Synthese und Röntgenstrukturanalyse eines zweikernigen Bis(ansa-carben)-Komplexes

The cationic dicarbonyl(cyclopentadienyl)(methylcarbyne)manganese complex, [(η⁵-C₅H₅)(CO)₂MnCMe]BCl₄, reacts with dimethyl cyanamide, Me₂NCN, to give the binuclear bis(ansa-dimethylaminocarbene) complex 4 containing chelating η¹,η⁵-(dimethylamino)[(cyclopentadienyl) (organyl)methylamino]carbene ligands. The two ansa-carbene ligands are connected via a CH group. The structure of the complex is established by an X-ray analysis.     

Cationic arenechromium-nitrosyls and -hydrides

Complexes Cr(CO)₂L(C₆Me_6-nH_n), n = 0-3, L = CO and PPh₃, react with NOPF₆ in methanol/toluene to give [Cr(CO)L(NO)(C₆Me_6-nH_n)] PF₆, n = 0-3, L = CO; n = 0, L = PPh₃, and these react with nucleophiles (X^-) to give cyclohexadienyl derivatives Cr(CO)₂(NO)(C₆Me_6-nH_nX); the compounds Cr(CO)₂(PhCCPh)(C₆Me_6-nH_n) react with NOPF₆ to yield [Cr(H)(CO)₂(PhCCPh)(C₆Me_6-nH_n)] PF₆, n = 0 and 1.     

Synthesis and structural characterisation of rhodium hydride complexes bearing N-heterocyclic carbene ligands

Addition of excesses of N-heterocyclic carbenes (NHCs) IEt₂Me₂, IⁱPr₂Me₂ or ICy (IEt₂Me₂ = 1,3-diethyl-4,5-dimethylimidazol-2-ylidene; IⁱPr₂Me₂ = 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene; ICy = 1,3-dicyclohexylimidazol-2-ylidene) to [HRh(PPh₃)₄] (1) affords an isomeric mixture of [HRh(NHC)(PPh₃)₂] (NHC = IEt₂Me₂ (cis-/trans-2), IⁱPr₂Me₂ (cis-/trans-3), ICy (cis-/trans-4) and [HRh(NHC)₂(PPh₃)] (IEt₂Me₂(cis-/trans-5), IⁱPr₂Me₂ (cis-/trans-6), ICy (cis-/trans-7)). Thermolysis of 1 with the aryl substituted NHC, 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene (IMesH₂), affords the bridging hydrido phosphido dimer, [{(PPh₃)₂Rh}₂(μ-H)(μ-PPh₂)] (8), which is also the reaction product formed in the absence of carbene. When the rhodium precursor was changed from 1 to [HRh(CO)(PPh₃)₃] (9) and treated with either IMes (=1,3-dimesitylimidazol-2-ylidene) or ICy, the bis-NHC complexes trans-[HRh(CO)(IMes)₂] (10) and trans-[HRh(CO)(ICy)₂] (11) were formed. In contrast, the reaction of 9 with IⁱPr₂Me₂ gave [HRh(CO)(IⁱPr₂Me₂)₂] (cis-/trans-12) and the unusual unsymmetrical dimer, [(PPh₃)₂Rh(μ-CO)₂Rh(IⁱPr₂Me₂)₂] (13). The complexes trans-3, 8, 10 and 13 have been structurally characterised.     

Trimethylsilylsubstituierte Cyclopentadienylindium(I) Verbindungen; Synthese and Eigenschaften

Reaction of indium(I) chloride with trimethylsilylated cyclopentadienyllithium species yields the air- and moisture-sensitive cyclopentadienylindium complexes In[(Me₃Si)C₅H₄] (1), In[(Me₃Si)₂C₅H₃] (2) and In[(Me₃Si)₃C₅H₂] (3), which are volatile and easily soluble in nonpolar solvents. Compound 1 crystallizes as a chain polymer.     

Molecular structures of acetylene derivatives of tin: Part IV. Gas-phase electron-diffraction study of tetraethynyltin,Sn(CCH)4, and triethynyltin iodide,ISn(CCH)3

The geometrical parameters of tetraethynyltin and triethynyltin iodide have been determined by gas-phase electron diffraction. Triethynyltin iodide was present as an admixture in both the tetraethynyltin samples studied. Because the samples differed significantly in percentage of the iodide (17.4 ± 4.0 and 47.1 ± 3.5 mol %, in samples A and B, respectively), it was possible to determine the structures of both molecules to a sufficient degree of accuracy.The r_α, structures were solved by the least-squares treatment of the molecular intensities, using mean amplitudes and shrinkage corrections calculated from the force fields of a number of tin derivatives.The T_d-symmetry model of Sn(CCH)₄ was refined to give the following parameters: Sn-C, 2.068(5); CC, 1.228(8); CH, 1.079(51). The structural parameters for ISn(CCH)₃ (on the basis of the C_3v model with linear Sn-CC-H fragments) are as follows: Sn-I, 2.646(4); Sn-C, 2.062(17); CC, 1.226(6); ∠ISnC 108.0(2.8). (The thermal average bond distances, r_g, are given in Å, and the valence angle, rα, in degrees; the values in paren- theses are three times the standard deviations, 3σ.)The Sn-C bonds in Sn(CCH)₄, and ISn(CCH)₃ are shorter than the corresponding bonds in the monoethynyltin derivatives, Me₃SnCCH and Me₃SnCCSnMe₃. The SnI bond in ISn(CCH)₃ is noticeably shorter than those in stannane iodide and trimethylstannane iodide.     

Diyne coordination chemistry: Reactions of [RuClH(CO)(PPh3)3] with diphenylbutadiyne and bis(phenylethynyl)mercury

The reaction of the hydridometal complex [RuClH(CO)(PPh₃)₃] with 1,4-diphenyl-butadi-1,3-yne has been investigated and found to proceed with monoinsertion to give a coordinatively unsaturated σ-vinyl complex [Ru-{C(CCPh)CHPh} Cl(CO)(PPh₃)₂], which is also the major product of the reaction of [RuClH(CO) (PPh₃)₃] with [Hg(CCPh)₂].     

Synthesis and reactivity of [(η-[32](1,3)Cyclophane)Mn(CO)3][BF4]

The manganese cyclophane complex, [(η⁶-[3₂](1,3)cyclophane)Mn(CO)₃][BF₄] 2, was prepared by the reaction of [[3₂](1,3)cyclophane] 1 with Mn(CO)₅FBF₃. Reaction of 2 with NaBH₃CN yielded the cyclohexadienyl manganese complex [(η⁵-6H-[3₂](1,3)cyclophane)Mn(CO)₃] 3. Interestingly, treatment of 3 with Mn(CO)₅FBF₃ gave the bis-manganese complex (η⁶,η⁵-6H-[3₂](1,3)cyclophane)[Mn(CO)₃]₂[BF₄] 4. When NaBH₃CN was treated with 4, [(η⁵,η⁵-6H,6^′H-[3₂](1,3)cyclophane)Mn(CO)₃] 5 was isolated as yellow crystals. The structure of compounds 2 and 3 were determined by single-crystal X-ray crystallography.     

[{(C5Me4R)Ru}3Ru(η3-As3)(μ3,η3-As3)(μ3-As)3], arsenreiche Vierkerncluster

The interaction of [(η⁵-C₅Me₄R)Ru(CO)₂]₂ (1a: R = Me, 1b: R = Et) with yellor arsenic, As₄, affords besides the pentaarsaruthenocenes [(η⁵-As₅)Ru(η⁵-C₅Me₄R)] (2a, 2b) the tetranuclear clusters [{(η⁵-C₅Me₄R)Ru}₃Ru(η³-As₃)(μ₃,η³-As₃)(μ₃-As)₃] (3a, 3b). The structure of 2b and 3b has been elucidated by X-ray analysis.     

Mehrfachbindungen zwischen hauptgruppenelementen und übergangsmetallen: XVI. Doppelte oxidative addition von monosilan an das koordinativ ungesättigte organometall-fragment (η5-C5Me5)Mn(CO)2: Darstellung und molekülstruktur von μ-silylen-bis[dicarbonyl(hydrido)(η5-pentamethylcyclopentadienyl)mangan]

Upon treatment of the labile ether complex (η⁵-C₅Me₅)Mn(CO)₂(THF) (1) with monosilane the novel dinuclear complex of composition (μ-SiH₂)[(η⁵-C₅Me₅)Mn(CO)₂H]₂ (2) is formed in 15% isolated yield via double oxidative addition of the binary hydride precursor. According to a single-crystal X-ray diffraction study, the molecule exhibits a bent MnSiMn′ framework (≮Mn, Si, Mn′ 124.4(3)°), with the manganese—silicon bond lengths representing single bonds (243.4(3) pm). The resulting distance of 430.6 pm between the manganese atoms precludes any metal—metal bonding so that the complex fragments (η⁵-C₅Me₅)Mn(CO)₂H are exclusively connected to each other via the bridging silylene ligand. The hydrogen ligands attached to the manganese atoms could not be located by X-ray diffraction methods but were detected by NMR spectroscopy (δ(SiH) 4.59, δ(MnH) ?11.55; CDCl₃). Although thermolysis of 2 yields elemental hydrogen, the expected and hitherto unknown complex (μ-Si)[(η⁵-C₅Me₅)Mn(CO)₂]₂ is not observed.     

Ferrocene bridged and substituted tetramethylcyclopentadienyl (or indenyl) carbonyl complexes of iron, ruthenium, and molybdenum

Reactions of ferrocene bridged and substituted tetramethylcyclopentadiene ligands 1,1′-Fc(C₅Me₄H)₂ (1) (Fc = 1,1′-ferrocenediyl) and (C₅H₅FeC₅H₄)C₅Me₄H (5) with Ru₃(CO)₁₂, Fe(CO)₅, and Mo(CO)₃(CH₃CN)₃ in refluxing xylene gave the corresponding trinuclear and tetranuclear complexes Fc[(C₅Me₄)M(CO)]₂(μ-CO)]₂ [M = Ru (2), Fe (3)], Fc[(C₅Me₄)Mo(CO)₃]₂ (4) and [(C₅H₅ FeC₅H₄)C₅Me₄M(CO)]₂(μ-CO)₂ [M = Ru (6), Fe (7)], [(C₅H₅FeC₅H₄)C₅Me₄Mo(CO)₃]₂ (8). Reactions of (3-indenyl)ferrocene (9) with Ru₃(CO)₁₂ or Fe(CO)₅ in refluxing xylene or heptane, also gave the corresponding tetranuclear metal complexes [(C₅H₅FeC₅H₄)C₉H₆M(CO)]₂(μ-CO)₂ [M = Ru (10), Fe (11)]. The molecular structures of 2 and 3 were determined by X-ray diffraction analysis.     

Synthesis of homo- and heterodinuclear metal complexes with dimethylsilylene bridged unsymmetrical bis(cyclopentadienyl) ligand

The reaction of the dilithium salt Li₂[Me₂Si(C₅H₄)(C₅Me₄)] (2) of Me₂Si(C₅H₅)(C₅HMe₄) (1) with [MCl(C₈H₁₂)]₂ (M=Rh, Ir) and [RhCl(CO)₂]₂ afforded homodinuclear metal complexes [{Me₂Si(η⁵-C₅H₄)(η⁵-C₅Me₄)}{M(C₈H₁₂)}₂] (M=Rh: 3; M=Ir: 4) and [{Me₂Si(η⁵-C₅H₄)(η⁵-C₅Me₄)}Rh₂(CO)₂(μ-CO)] (5), respectively. The reaction of 2 with RhCl(CO)(PPh₃)₂ afforded a mononuclear metal complex [{Me₂Si(C₅HMe₄)(η⁵-C₅H₄)}Rh(CO)PPh₃] (6) leaving the C₅HMe₄ moiety intact. Taking advantage of the difference in reactivity of the two cyclopentadienyl moieties of 2, heterodinuclear complexes were prepared in one pot. Thus, the reaction of 2 with RhCl(CO)(PPh₃)₂, followed by the treatment with [MCl(C₈H₁₂)]₂ (M=Rh, Ir) afforded a homodinuclear metal complex [Rh(CO)PPh₃{(η⁵-C₅H₄)SiMe₂(η⁵-C₅Me₄)}Rh(C₈H₁₂)] (7) consisting of two rhodium centers with different ligands and a heterodinuclear metal complex [Rh(CO)(PPh₃){(η⁵-C₅H₄)SiMe₂(η⁵-C₅Me₄)}Ir(C₈H₁₂)] (8). The successive treatment of 2 with [IrCl(C₈H₁₂)]₂ and [RhCl(C₈H₁₂)]₂ provided heterodinuclear metal complex [Ir(C₈H₁₂){(η⁵-C₅H₄)SiMe₂(η⁵-C₅Me₄)}Rh(C₈H₁₂)] (9). The reaction of 2 with CoCl(PPh₃)₃ and then with PhCCPh gave a mononuclear cobaltacyclopentadiene complex [{Me₂Si(C₅Me₄H)(η⁵-C₅H₄)}Co(CPhCPhCPhCPh)(PPh₃)] (10). However, successive treatment of 2 with CoCl(PPh₃)₃, PhCCPh and [MCl(C₈H₁₂)]₂ in this order afforded heterodinuclear metal complexes [M(C₈H₁₂){(η⁵-C₅H₄)SiMe₂(η⁵-C₅Me₄)}Co(η⁴-C₄Ph₄)] (M=Rh: 11; M=Ir: 12) in which the cobalt center was connected to the C₅Me₄ moiety. Although the heating of 10 afforded a tetraphenylcyclobutadiene complex [{Me₂Si(C₅Me₄H)(η⁵-C₅H₄)}Co(η⁴-C₄Ph₄)] (13), in which the cobalt center was connected to the C₅H₄ moiety, simple heating of the reaction mixture of 2, CoCl(PPh₃)₃ and PhCCPh resulted in the formation of a tetraphenylcyclobutadiene complex [{Me₂Si(C₅H₅)(η⁵-C₅Me₄)}Co(η⁴-C₄Ph₄)] (14), in which the cobalt center was connected to the C₅Me₄ moiety. The mechanism of the cobalt transfer was suggested based on the electrophilicity of the formal trivalent cobaltacyclopentadiene moiety. In the presence of 1,5-cyclooctadiene, the reaction of 2 with CoCl(PPh₃)₃ provided a mononuclear cobalt cyclooctadiene complex [{Me₂Si(C₅Me₄H)(η⁵-C₅H₄)}Co(C₈H₁₂)] (15). The reaction of 15 with n-BuLi followed by the treatment with [MCl(C₈H₁₂)]₂ (M=Rh, Ir) afforded the heterodinuclear metal complexes of [Co(C₈H₁₂){(η⁵-C₅H₄)SiMe₂(η⁵-C₅Me₄)}M(C₈H₁₂)] (M=Rh: 16; M=Ir: 17). Treatment of 6 with Fe₂(CO)₉ at room temperature afforded a heterodinuclear metal complex [{Me₂Si(C₅HMe₄)(η⁵-C₅H₄)}{Rh(PPh₃)(μ-CO)₂Fe(CO)₃}] (18) in which the C₅HMe₄ moiety was kept intact. Treatment of dinuclear metal complex 5 with Fe₂(CO)₉ afforded a heterotrinuclear metal complex [{(η⁵-C₅H₄)SiMe₂(η⁵-C₅Me₄)}{Rh(CO)Rh(μ-CO)₂Fe(CO)₃}] (19) having a triangular metal framework. The crystal and molecular structures of 3, 11, 12, 18 and 19 have been determined by single-crystal X-ray diffraction analysis.     

A novel class of aryldiazene complexes: [(PPh3)2 (CO)IrCl(HNNC6H4R-p)(CCPh)] (BF4) (R = NO2, CN,COCH3)

In the reaction with phenylacetylene leading to [(PPh₃)₂(CO)IrCl (HNNC₆H₄R-p)(CCPh)] (BF₄) (R  NO₂, CN, COCH₃), the vacant coordination site in [(PPh₃)₂ (CO)IrCl(N₂C₆H₄ R-p)] (BF₄) plays a key role in the activation of the acetylenic CH bond. ca]To whom correspondence should be addressed.     

The reaction of π-cyclopentadienyldicarbonylcobalt with silyl-substituted acetylenes

The reaction of (π-C₅H₅)Co(CO)₂ with PhCCSiMe₂R (R = Me, SiMe₃) gave two isomeric cyclobutadiene complexes, cis- and trans-(π-C₅H₅)Co[Ph₂C₄(SiMe₂R)₂], in almost quantitative yields. However, the reaction with RMe₂SiCCSiMe₂R (R = Me, Ph) led to the formation of new dinuclear cobalt complexes. For example, with bis(trimethylsilyl)acetylene, (π-C₅H₅)₂Co(CO)[(Me₃Si)₂C₂] was obtained quantitatively. The latter was further converted to (π-C₅H₅)Co(Ph₄C₄) and (πC₅H₅)Co[cis-Ph₂C₄(Me₃Si)₂] by treatment with PhCCPh. The physical properties and spectroscopic characteristics of these new compounds are described.