Heterometallische Clusterkomplexe der Typen Re2(μ-PR2)(CO)8(HgY) und ReMo(μ-PR2)(η5-C5H5)(CO)6(HgY) (R = Ph,Cy; Y = Cl,W(η5-C5H5)(CO)3)

Heterometallic Cluster Complexes of the Types Re₂(μ-PR₂)(CO)₈(HgY) and ReMo(μ-PR₂)(η⁵-C₅H₅)(CO)₆(HgY) (R = Ph, Cy; Y = Cl, W(η⁵-C₅H₅)(CO)₃) Dinuclear complexes Re₂(μ-H)(μ-PR₂)(CO)₈ and ReMo(μ-H)(μ-PR₂)(η⁵-C₅H₅)(CO)₆ (R = phenyl, cyclohexyl) were deprotonated and reacted as anions with HgCl₂ to compounds of the both types Re₂(μ-PR₂)(CO)₈HgCl) and ReMo(μ-PR₂)(η⁵-C₅H₅)(CO)₆(HgCl). The heterometallic three-membered cluster complexes correspond to an isolobal exchange of a proton against a cationic HgCl⁺ group. For one of the products ReMo(μ-PCy₂)(η⁵-C₅H₅)(CO)₆(HgCl) has been shown its conversion with NaW(η⁵-C₅H₅)(CO)₃ to ReMo(μ-PCy₂)(η⁵-C₅H₅)(HgW(η⁵-C₅H₅)(CO)₃) under substitution of the chloro ligand, par example. The newly prepared compounds were characterized by means of IR, UV/VIS and ³¹P NMR data. A complete determination of the molecular structure by single crystal analyses was done in the case of Re₂(μ-PCy₂)(CO)₈(HgCl) and of ReMo(μ-PCy₂)(η⁵-C₅H₅)(CO)₆(HgCl) which both are dimer because of the presence of an asymmetric dichloro bridge, and of ReMo(μ-PCy₂)(η⁵-C₅H₅)(CO)₆(HgW(η⁵-C₅H₅)(CO)₃). The structural study illustrates through comparison the influence of various metal types on an interaction between centric and edge-bridged frontier orbitals in three-membered metal rings.     

Darstellung carboxylatsubstituierter Rhenium-Gold-Metallatetrahedrane Re2(AuPPh3)2(μ-PCy2)(CO)7(η1-OC(R)O) (R = H,Me, CF3, Ph, 3,4-(OMe)2C6H3)

Synthesis of Carboxylate Substituted Rhenium Gold Metallatetrahedranes Re₂(AuPPh₃)₂(μ-PCy₂)(CO)₇(η¹-OC(R)O) (R = H, Me, CF₃, Ph, 3,4-(OMe)₂C₆H₃) The reaction of the in situ prepared salt Li[Re₂(μ-H)(μ-PCy₂)(CO)₇(ax-C(Ph)O)] ( 2 ) with 1,5 equivalents of monocarboxylic acid RCOOH (R = H ( 4 a ), Me ( 4 b ), CF₃ ( 4 c ), Ph ( 4 d ), 3,4-(OMe)₂C₆H₃ ( 4 e ) in tetrahydrofruan (THF) solution at 60 °C gives within 4 h under release of benzaldehyde (PhCHO) the η¹-carboxylate substituted dirhenium salt Li[Re₂(μ-H)(μ-PCy₂)(CO)₇(η¹-OC(R)O)] (R = H ( 4 a ), Me ( 4 b ), CF₃ ( 4 c ), Ph ( 4 d ), 3,4-(OMe)₂C₆H₃ ( 4 e )) in almost quantitative yield. The lower the pK_a value of the respective carboxylic acid the faster the reaction proceeds. It was only in the case of CF₃COOH possible to prove the formation of the hydroxycarbene complex Re₂(μ-H)(μ-PCy₂)(CO)₇(=C(Ph)OH) ( 5 ) prior to elimination of PhCHO. The new compounds 4 a–4 e were only characterized by ³¹P NMR and ν(CO) IR spectroscopy as they are only stable in solution. They are converted with two equivalents of BF₄AuPPh₃ at 0 °C in a so-called cluster expansion reaction into the heterometallic metallatetrahedrane complexes Re₂(AuPPh₃)₂(μ-PCy₂)(CO)₇(η¹-OC(R)O) (R = H ( 7 a ), Me ( 7 b ), CF₃ ( 7 c ), Ph ( 7 d ), 3,4-(OMe)₂C₆H₃ ( 7 e )) (yield 47–71% ). The expected precursor complexes of 7 a–7 e Li[Re₂(AuPPh₃)(μ-PCy₂)(CO)₇(η¹-OC(R)O] ( 8 ) were not detected by NMR and IR spectroscopy in the course of the reaction. Their existence was retrosynthetically proved by the reaction of 7 b with an excess of the chelating base TBD (1,5,7-Triazabicyclo[4.4.0]dec-5-en) forming [(TBD)_xAuPPh₃][Re₂(AuPPh₃)(μ-PCy₂)(CO)₇(η¹-OC(Me)O] ( 8 b ) in solution. The η¹-bound carboxylate ligand in 7 a–7 e can photochemically be converted into a μ-bound ligand in Re₂(AuPPh₃)₂(μ-PCy₂)(μ-OC(R)O)(CO)₆ (R = H ( 9 a ), Me ( 9 b ), CF₃ ( 9 c ), Ph ( 9 d ), 3.4-(MeO)₂C₆H₃ ( 9 e )) under release of one equivalent CO. All isolated cluster complexes were characterized and identified by the following analytical methods: elementary analysis, NMR (¹H, ³¹P) spectroscopy, ν(CO) IR spectroscopy and in the case of 7 d and 9 b by X-ray structure analysis.     

Zur Nucleophilie des sterisch anspruchsvollen Basenanions von Lithiumdiisopropylamid beim Protonenersatz gegen das isolobale AuPPh3-Kation in [(μ-H)(μ-PPh2) (CO)8Re2]

Nucleophilic Property of the Bulk Anion of the Base Lithium diisopropylamide at the Proton Exchange vs. the Isolobal AuPPh₃ Cation in [(μ-H) (μ-PPh₂) (CO)₈Re₂] The proton exchange in the starting material [(μ-H)(μ-PPh₂)(CO)₈Re₂] vs. the isolobal [AuPPh₃]⁺ cation when reacted with the steric expansive base LDA depending on reaction temperature leads to the three-membered metal ring substance [(μ-PPh₂)(CO)₈Re₂(AuPPh₃)] or the metallatetrahedron complex [(μ-C-(N i-Prop₂)O)(μ-PPh₂)(CO)₆Re₂(AuPPh₃)₂]. The tetrahedral cluster compound obtained through the nucleophilic property of LDA shows by means of cyclic voltammetry a reversible and a irreversible one-electron transfer redox step. The single crystal X-ray analysis of the compound with a tetrahedral Au₂Re₂ core gives following values of metal-metal bond lengths: Re? Re 312.2(2) pm, Au? Au 270.9(2) pm, and Au? Re 297.7(2) pm. The acyl diisopropylamido groups bridging the Re? Re bond is planar.     

Multiple C−H Bond Activations in Corannulene by a Dirhenium Complex

The reaction of Re₂(CO)₈(μ-C₆H₅)(μ-H), 1 with corannulene (C₂₀H₁₀) yielded the product Re₂(CO)₈(μ-H)(μ-η²-1,2-C₂₀H₉), 2 (65 % yield) containing a Re₂ metalated corannulene ligand formed by loss of benzene from 1 and the activation of one of the CH bonds of the nonplanar corannulene molecule by an oxidative-addition to 1 . The corannulenyl ligand has adopted a bridging η²-σ+π coordination to the Re₂(CO)₈ grouping. Compound 2 reacts with a second equivalent of 1 to yield three isomeric doubly metalated corannulene products: Re₂(CO)₈(μ-H)(μ-η²-1,2-μ-η²-10,11-C₂₀H₈)Re₂(CO)₈(μ-H), 3 (35 % yield), Re₂(CO)₈(μ-H)(μ-η²-2,1-μ-η²-10,11-C₂₀H₈)Re₂(CO)₈(μ-H), 4 (12 % yield), and Re₂(CO)₈(μ-H)(μ-η²-1,2-μ-η²-11,10-C₂₀H₈)Re₂(CO)₈(μ-H), 5 (12 % yield), by a second CH activation on a second rim double bond on the corannulene molecule. The isomers differ by the relative orientations of the coordinated Re₂(CO)₈(μ-H) groupings. All new products were characterized structurally by single crystal X-ray diffraction analysis.     

Synthesis and molecular structure of [Re2(μ:η-C24H18N4)(CO)6] containing the rtct-tetrakis(2-pyridyl)cyclobutandiyl ligand, derived from the reaction of [Re2(CO)8(MeCN)2] and 1,2-bis(2-pyridyl)ethene

The reaction of the labile compound [Re₂(CO)₈(CH₃CN)₂] with trans-1,2-bis(2-pyridyl)ethene (C₁₂H₁₀N₂) at room temperature in tetrahydrofuran affords the compounds [Re₂(μ:η³-C₁₂H₁₀N₂)(CO)₈] (1) and the oxidative addition product [Re₂(μ-H)(μ:η³-C₁₂H₉N₂)(CO)₇] (2). When the reaction is carried out at temperatures of refluxing tetrahydrofuran, besides compounds 1 and 2, the oxidative addition product [Re₂(μ-H)(μ:η⁴-C₁₂H₉N₂)(CO)₆] (3), the insertion product [Re₂(μ:η⁴-C₁₂H₁₀N₂)(CO)₈] (4) and [Re₂(μ:η⁶-C₂₄H₁₈N₄)(CO)₆] (5) are obtained. Compound 5 contains the organic ligand rtct-tetrakis(2-pyridyl)cyclobutandiyl which is derived from a [2 + 2] cycloaddition of 1,2-bis(2-pyridyl)ethene mediated by its coordination to the bimetallic framework. The molecular structures of 1, 2, 4 and 5 were confirmed by X-ray crystallographic studies.     

Heterometallatom-Koordinationsverbindungen Re2(μ-PPh2)2[mer-(CO)3]2-trans-[InX2(H2O)]2 und neue halogenhaltige drei- und vierkernige Rheniumcluster aus Reaktionen zwischen Re2[μ-PPh2)2(CO)8] und InX3 (X = Cl,Br, I)

Heterometallic Coordination Compounds Re₂(μ-PPh₂)₂[mer-(CO)₃]₂-trans-[InX₂(H₂O)]₂ and New Halogene Containing Three- and Four-Nuclear Rhenium Clusters from Reactions between Re₂(μ-PPh₂)₂(CO)₈ and InX₃ (X = Cl, Br, I) In sealed glass tubes equimolar amounts of Re₂(μ-PPh₂)₂(CO)₈ and InX₃ (X = Cl, Br, I) were reacted in the presence of xylene at 220°C to two types of products. The first type comprised the heterometallic coordination compounds Re₂(μ-PPh₂)₂(CO)₆[InX₂(H₂O)]₂ (X = Cl, Br, I) (yield 60%), and the second halogene containing rhenium complexes Re₃(μ₃-H)(μ₃-X)(μ-PPh₂)₃(CO)₆ (unsaturated three-membered metal ring with 46 VE) and Re₄(μ-H)(μ-X)(μ-PPh₂)₄(μ₄-PPh)(CO)₈ and additionally those substances as cis-IRe(CO)₄(PPh₂H), Re₂(μ-PPh₂)(μ-X)(CO)₈ (X = Cl, Br), Re₂(μ-I)₂[μ-(PPh₂)₂O](CO)₆ and Re₄(μ-Cl)₂(μ-PPh₂)₄(μ₄-PPh)(CO)₈ (four-membered metal ring with 66 VE with three Re? Re bonds) which have been observed in one or two of the three reaction systems. A proposal of the reaction course is discussed. The single X-ray analysis of Re₂(μ-PPh₂)₂[mer(CO)₃]₂-trans[InI₂(H₂O)]₂ · 2 Me₂CO shows for the two fold phosphido bridged dirhenium molecular fragment with 34 VE a Re? Re bond of 294.6(1) pm. From two possible transpositions of both In? Re bond vectors, the one found advantageously has sterical reasons. The average In? Re single bond length is 271.1(1) pm. The corresponding determination of the unsaturated three-membered ring compound Re₃(μ₃-H) (μ₃-Cl)(μ-PPh₂)₃(CO)₆ showed three Re? Re bond lenghts of comparable size, of which the mean value of 281.9(1) pm was significantly shortened by π electron delocalization effect compared to that of a saturated phosphido bridged three-membered rhenium ring compound. As it was recognized by further comparison, the structural data of the common molecular fragments in the three examined three-membered rhenium ring clusters (X = Cl, Br, I) are not dependent on the different kind of halogeno ligand atoms. Finally, the crystal structure determination of the substance Re₄(μ-H)(μ-Br)(μ-PPh₂)₄(μ₄-PPh)(CO)₈ shows the presence of square-pyramidal Re₄(μ₄-P) atomic arrangement, of which the planar basic plane has a sequence of up- and downwards orientated four diphenylphosphido bridging groups. The four measured Re? Re single bond lengths (mean value 302.7(3) pm change with the different kind of bridging atoms. The structural features observed are compared with those of a corresponding iodine derivative.     

Darstellung von μ-Hydrido-μ-diphenylphosphido-bis(tetracarbonylrhenium) · 1/2 Xylol und Molekülstruktur des Derivates Re2(CO)6(PPh3)2(μ-H)(μ-PPh2) (Ph = C6H5)

Preparation of μ-Hydrido-μ-diphenylphosphido-bis(tetracarbonylrhenium) · 1/2 Xylene and Molecular Structure of the Derivative Re₂(CO)₆(PPh₃)₂(μ-H)(μ-PPh₂) (Ph = C₆H₅) The reaction of dirhenium decacarbonyl with diphenylphosphine in xylene solution gave at 190–200°C in a glas tube crystals of Re₂(CO)₈(μ-H)(μ-PPh₂) · 1/2 C₈H₁₀. The obtained adduct was reacted in the same solvent with an excess of triphenylphosphine to the derivative Re₂(CO)₆(PPh₃)₂(μ-H)(μ-PPh₂). Both diamagnetic dirhenium compounds with μ-H atom and μ-PPh₂ group were characterized by ¹H and ³¹P spectroscopic measurements. The molecular structure of the derivative was acertained by a single crystal X-ray analysis. Its result showed a three-membered Re₂(μ-P) ring as central molecular fragment. At these Re central atoms were attached two PPh₃ ligands in an unprefered cis-arrangement due to sterical reasons. A thermodynamic transinfluence of the (μ-P)? Re bond favoured the found positions of the PPh₃ ligands.     

Synthesis of μ-hydrido-μ-phosphido heterotrimetal alkylidyne clusters: X-ray crystal structure of [Co2W(μ-H)(μ3-CMe)(μ-PPh2)(CO)6(η-C5H5]

Treatment of the μ-alkylidyne clusters [Fe₂W(μ₃-CC₆H₄Me-4)(μ-CO)- (CO)₈(η-C₅H₅)] and [Co₂W(μ₃-CMe)(CO)₈(η-C₅H₅)] with PPh₂H affords a series of new μ-phosphido-μ-hydrido alkylidyne complexes which undergo protonation with HBF₄·Et₂O to give cationic derivatives. The X-ray structure of [Co₂W(μ-H)(μ₃-CMe)(μ-PPh₂)(CO)₆(η-C₅H₅)] has been determined.     

Übergangsmetall-substituierte Acylphosphane und Phosphaalkene. 17 [1] Synthese und Struktur der μ-Isophosphaalkin-Komplexe [(η5-C5H5)2(CO)2Fe2(μ-CO)(μ-CPC6H2R3-2,4,6)] (R = Me,iPr, tBu)

Transition Metal Substituted Acylphosphanes and Phosphaalkenes. 17. Synthesis and Structure of the μ-Isophosphaalkyne Complexes [(η⁵-C₅H₅)₂(CO)₂Fe₂(μ-CO)(μ-C?PC₆H₂R₃)] (R = Me, iPr, tBu) . Condensation of (η⁵-C₅H₅)₂(CO)₂Fe₂(μ-CO)(μ-CSMe)}⁺SO₃CF₃^? ( 6 ) with 2,4,6-R₃C₆H₂PH(SiMe₃) ( 7 ) ( a : R = Me, b : R = iPr, c : R = tBu) affords the complexes (η⁵-C₅H₅)₂(CO)₂Fe₂(μ-CO)(η-C?PC₆H₂R₃-2,4,6) ( 9 a–c ) with edge-bridging isophosphaalkyne ligands as confirmed by the x-ray structure analysis of 9 a .     

Molybdenum alkyl- and aryl-thiolates

The reaction between [(η⁵-C₅H₅)MoH(CO)₃] and disulphides gives dimeric or trimeric complexes depending upon the conditions. The syntheses of the novel trinuclear molybdenum carbonyl complex [{Mo(η⁵-C₅H₅)(SR)(μ-CO)(CO)}₃] (R = Me), and dinuclear compounds [Mo₂(η⁵-C₅H₅)(μ-SR)₃(CO)₄] (R = Me) and [Mo₂(η⁵-C₅H₅)₂(SR)₂(CO)₂(μ-SR)(μ-Br)] (R = Me or Ph) are reported.     

Triosmium-antimony clusters containing the μ,η-phenylene ligand: Unusually long osmium-osmium bonds

The reaction of the osmium-antimony cluster Os₃(μ-H)(μ-SbPh₂)(μ₃,η²-C₆H₄)(CO)₉ with AsPh₃ at room temperature afforded the o-phenylene cluster Os₃(μ-H)(SbPh₂)(μ₂,η²-C₆H₄)(CO)₉(AsPh₃) by nucleophilic addition via a metal-metal bond cleavage, and the substitution product Os₃(μ-H)(SbPh₂)(μ₃,η²-C₆H₄)(CO)₈(AsPh₃). It reacted with ^tBuNC to afford the adduct Os₃(μ-H)(SbPh₂)(μ₂,η²-C₆H₄)(CO)₉(CN^tBu) quantitatively. This adduct isomerised slowly on standing via migration of the isonitrile, while photolysis led to decarbonylation to Os₃(μ-H)(SbPh₂)(μ₂,η²-C₆H₄)(CO)₈(CN^tBu). All the products have been characterised completely, including by X-ray crystallography, and their structures exhibit very long Os-Os bonds.     

Conversion of allene into μ-dimethylcarbene at a diruthenium centre

Treatment of [Ru₂(CO)(μ-CO) {μ-C(O)C₂Ph₂} (η-C ₅H₅)₂] with allene in toluene at 100°C displaces diphenylacetylene and produces [Ru(CO)(η-C₅H₅)-{η³-C₃H₄Ru(CO)₂(η-C₅H₅)}]; upon protonation a 1-methylvinyl cation [Ru₂(CO)₂(μ-CO){μ-C(Me)CH₂}(η-C₅H₅)₂]⁺ is formed which undergoes nucleophillic attack by hydride to yield the μ-dimethylcarbene complex [Ru₂(CO)₂-(μ-CO)(μ-CMe₂)(η-C₅H₅)₂].     

Preparation and Characterization of an Unusual Di-Cobalt Complex; X-Ray Crystal Structure of Co(CO)2(μ-CO)(μ:η2,η4-C4Ph4)Co(CO)2(PPh3)

Reaction of [MoCo(CO)₅(PPh₃)₂(η⁵-C₅H₅)] (1) with diphenylacetylene in tetrahydrofuran at 50 °C yielded two heterobimetallic compounds, [MoCo(CO)₄.(PPh₃){μ-PhC ? CPh}(η⁵-C₅H₅)] (4) and [MoCo(CO)₅{μ-PhC ? CPh} (η⁵-C₅H₅)] (5). However, an unexpected product, Co(CO)₂(μ-CO)(μ:η₂,η⁴-C₄Ph₄)Co(CO)₂(PPh₃) (6), was observed while attempting to grow the crystals for structural determination of 4. The X-ray crystal structure of 6 was determined: triclinic, $ {\rm P}\bar 1 $, a = 11.654(2) Å, b = 12.864(2) Å, c = 13.854(2) Å, α = 89.67(2)°, β = 86.00(2)°, γ= 83.33(2)°, V = 2057.9(6) ų Z=2. In 6, two cobalt fragments are at apical and basal positions of the pseudo-pentagonal pyramidal structure, respectively. The electron count for the apical cobalt fragments is 20, which is rather unusual. It is believed that 6 was formed after the fragmentation and recombination of the fragmented species of 4.     

The reactions of AgY salts with [Fe2(η-C5H5)2(CO)4-n(CNMe)n] complexes (Y−  NO3−, BF4− or PF6−; n  0, 1 or 2). The crystal structure of [Fe(η-C5H5)2(CNMe)]BF4

The oxidative cleavage of [Fe₂(η-C₅H₅)₂(CO)_4-n(CNMe)_n] (n=0−2) by 2AgX gives mononuclear products. It is shown to be a two-electron process in most solvents but a one-electron process in acetonitrile. The two-electron oxidations proceed by way of adducts such as [Fe₂(η-C₅H₅)₂(CO)(CNMe)(μ-CO){;μ-CN(Me)AgPPh₃};]BF₄ which are isolable when n = 2, detectable when n = 1 and postulatetd when n = 0. The one-electron process gives no adducts, and 1AgX cleaves all of the substrate to [Fe(η-C₅H₅)(CO)(L)(NCMe)]⁺ and [Fe(η-C₅H₅)(CO)(L)]^. (L  CO or CNME). The latter may combine or react with added CHBr₃ to give [Fe(η-C₅H₅)(CO)(L)Br]. The structure of [Fe(η-C₅H₅)(CO)₂-(CNMe)]BF₄ has been determined by X-ray diffraction.     

Reactivity of the 30-electron dimolybdenum anion [Mo2(η-C5H5)2(μ-PCy2)(μ-CO)2] towards β,γ-unsaturated organic halides: Alkenyl, allenyl and alkoxycarbyne derivatives

The 30-electron dimolybdenum anion [Mo₂Cp₂(μ-PCy₂)(μ-CO)₂]⁻ reacts at room temperature with allyl chloride to give the unsaturated σ:π-bonded alkenyl derivative trans-[Mo₂Cp₂(μ-η¹:η²-CMeCH₂)(μ-PCy₂)(CO)₂], this requiring a 2,1-hydrogen shift in the allyl moiety probably induced by the unsaturated nature of the dimetal center. In a similar way, the dimolybdenum anion reacts with trans-1-chloro-2-butene (crotyl chloride) to give a mixture of the alkenyl complexes trans-[Mo₂Cp₂(μ-η¹:η²-CEtCH₂)(μ-PCy₂)(CO)₂] and trans-[Mo₂Cp₂(μ-η¹:η²-CMeCHMe)(μ-PCy₂)(CO)₂] in a 3:2 ratio, which could not be separated by column chromatography. All these alkenyl species exhibit a dynamic behavior in solution (fast on the NMR timescale even at low temperatures) involving alternative π-bonding of the alkenyl ligand to each metal center. In contrast, the title anion reacts with propargyl chloride (ClCH₂-CCH) without further rearrangement of the propargyl moiety, to afford the allenyl derivative trans-[Mo₂Cp₂{μ-η²:η³-CH₂CCH)}(μ-PCy₂)(CO)₂] as the major species. Acryloyl chloride (ClC(O)-CHCH₂) also reacts with the title anion to give a mixture of two products, the carbyne complex [Mo₂Cp₂{μ-COC(O)CHCH₂}(μ-PCy₂)(μ-CO)] and the vinyl trans-[Mo₂Cp₂(μ-η¹:η²-CHCH₂)(μ-PCy₂)(CO)₂], in a 1:1 ratio. This reaction is a unique case in which a single electrophile can attack both nucleophilic positions in the dimolybdenum anion, these being located at the O(carbonyl) and metal sites, respectively. The formation of the vinyl derivative requires the decarbonylation of a metal-bound acryloyl group, which proved to be an irreversible reaction, since the addition of CO to the above alkenyl complex gave instead the tricarbonyl vinyl derivative cis-[Mo₂Cp₂(μ-η¹:η²-CHCH₂)(μ-PCy₂)(CO)₃]. The structure of this electron-precise complex was confirmed through a single-crystal X-ray diffraction analysis (Mo−Mo = 3.0858(7) Å).     

Unusual tetra- and penta-ruthenium complexes from linking of ethylidyne and vinylidene ligands

The complexes [Ru₂(CO)₂(μ-CO)(μ-CMe)(η-C₅H₅)₂]^? and [Ru₂CO₂(μ-CO)(μ-CCH₂)(η-C₅H₅)₂] react together to give [{Ru₂CO)₃(η-C₅H₅)₂}₂(μ-CMeCHCH)]⁺ and [{Ru₃(CO)₃(η-C₅H₅)₃}(μ-CCH₂CHC){Ru₂(CO)₃(η-C₅H₅)₂}], each characterised by X-ray diffraction. The former results from ethylidyne-vinylidene linking followed by an alkylidyne to vinyl rearrangement.     

The Thermolysis of [Ru3(CO)12] in Cyclohexene: Synthesis and Charaterisation of the New Clusters [Ru3H2(CO)9(μ3-η1:η2:η1-C6H8)] and [Ru5(CO)12(μ4-η2-C6H8)(η4-C6H8)]

Thermolysis of [Ru₃(CO)₁₂] in cyclohexene for 24 h affords the complexes [Ru(CO)₃(η⁴-C₆H₈)] (1), [Ru₃H₂(CO)₉(μ₂-η¹:η²:η¹-C₆H₈)] (2), [Ru₄(CO)₁₂(μ₄-C₆H₈)] (3) [Ru₄(CO)₉(μ₄-C₆H₈)(η⁶-C₆H₆)] (4a and 4b, two isomers) and [Ru₅(CO)₁₂(μ₄-η²-C₆H₈)(η⁴-C₆H₈)] (5), where 1, 3, 4a and 4b have been previously characterised as products of the thermolysis of [Ru₃(CO)₁₂] with cyclohexa-1,3-diene. The molecular structures of the new clusters 2 and 5 were determined by single-crystal X-ray crystallography, showing that two conformational polymorphs of 5 exist in the solid state, differing in the orientation of the cyclohexa-1,3-diene ligand on a ruthenium vertex.     

Exploratory organometal-sulfur chemistry; syntheses and unusual properties of rhenium CH2SR,CHSRR′, and CHSR]+ complexes

The methylidene complex [(η-C₅H₅)Re(NO)(PPh₃)(CH₂)]⁺PF₆^?(I) yields kinetically labile sulfonium salts when treated with CH₃SCH₃, CH₃SCH₂C₆H₅, and (η-C₅H₅)Re(NO)(PPh₃)(CH₂SCH₃) (V);the binuclear adduct formed in the latter case, [(η-C₅H₅)Re(NO)(PPh₃)CH₂]₂S⁺CH₃ (VI), is substantially more stable than the others and undergoes hydride transfer disproportionation to [(η-C₅H₅)Re(NO)(PPh₃)(CHSCH₃)]⁺PF₆^?(VII) and (η-C₅H₅)Re(NO)(PPh₃)(CH₃) (VIII) when heated.     

Oxalate-bridged dirhenium(I) hexacarbonyl complexes: synthesis, reactions, and crystal structures

The complex [{Re(CO)₅}₂(μ,η¹:η¹-C₂O₄)] 1 undergoes thermal decarbonylation to give [Re₂(CO)₆(C₂O₄)]_n, which reacts with triphenylphosphine and trans-1,2-bis(diphenylphosphino)ethylene (dppene) to give anti-[Re₂(PPh₃)₂(CO)₆(μ,η²:η²-C₂O₄)] 2 and [Re₂(μ-dppene)(CO)₆(μ,η²:η²-C₂O₄)] 4, respectively. Complex 2 is oxidized on prolonged exposure to air (1 week) to form anti-[Re₂(OPPh₃)₂(CO)₆(μ,η²:η²-C₂O₄)] 3. In the presence of excess dppene, the complex [Re₂(μ-dppene)₂(CO)₆(μ,η¹:η¹-C₂O₄)] 5 is also formed alongside 4. With the chelating diphosphine 1,3-bis(diphenylphosphino)propane (dppp), the complex [(η²-dppp)Re(CO)₃(μ,η¹:η¹-C₂O₄)Re(CO)₃(η²-dppp)] 6 is formed. The structures of 3 and 4 have been determined by X-ray crystallography. The dppene ligand in complex 4 adopts an unusual “syn” conformation wherein the two phosphorus lone pairs of electrons are eclipsed, thus forming an “A-frame” type of bridge.     

Zur Reaktivität von Disilylphosphidokomplexen des Eisens und Rutheniums gegenüber 2,4,6-t-Bu3C6H2AsCl2. Bildung und Struktur von Arsaphosphenylkomplexen,Diphosphaarsiranen, Phosphadiarsiranen und 1,2-Diphospha-3,4-diarsetanen

On the Reactivity of Disilylphosphido Complexes of Iron and Ruthenium towards 2,4,6-t-Bu₃C₆H₂AsCl₂. Generation and Structures of Arsaphosphenyl Complexes, Diphospha-ariranes, Phosphadiarsiranes, and 1,2-Diphospha-3,4-diarsetanes The reaction of (η⁵-C₅Me₅)(CO)₂Fe? P(SiMe₃)₂ ( 1a ) with 2,4,6-t-Bu₃C₆H₂AsCl₂ (= Aryl AsCl₂) ( 6 ) leads to the formation of the heterocycles [(η⁵-C₅Me₅)(CO)₂Fe? P]₂As-Aryl ( 7a ), (η⁵-C₅Me₅)(CO)₂Fe? P(As-Aryl)₂ ( 8a ), and [(η⁵-C₅Me₅)(CO)₂Fe? P-As-Aryl]₂( 9a ). The instable arsaphosphenyl complex [(η⁵-C₅Me₅)(CO)₂Fe? P?As-Aryl] can be intercepted as its Cr(CO)₅-adduct 13a . Analogously the ring compounds (η⁵-C₅Me₅)(CO)₂Ru? P]₂(As-Aryl)( 7b ) and (η⁵-C₅Me₅)(CO)₂Ru? P(As-Aryl)₂ ( 8b ) are obtained by treatment of (η⁵-C₅Me₅)(CO)₂Ru? P(SiMe₃)₂ ( 1b ) with 6 . Here again the primarily generated arsaphosphene has to be stabilized by coordination to Cr(CO)₅ which gave E-(η⁵-C₅Me₅)(CO)₂Ru? P[Cr(CO)₅ = As-Aryl ( E-13b ) and its Z-isomer ( Z-13b ). A comparable reaction sequence furnished the phosphaarsenyl complex (η⁵-C₅Me₅)(CO)(PPh)₃Fe? P[Cr(CO)₅] = As-Aryl ( 13c ). The molecular structures of 7a and 9a were elucidated by x-ray diffraction analysis. The most interesting feature of 7a is the AsP₂-triangle, in which the As? P(2) bond length (235,0(2) pm) is slightly elongated with respect to the As? P(1) distance (231,6(1) pm). This effect is presumably due to severe steric interactions at the cis-substituted As? P(2) bond. Molecule 9a displays the picture of a bended 1,2-diphospha-3,4-diarsetane (interplanar angle 137.6°) with its substituents in the all trans-orientation. The As? P and P? P separations are normal whereas the As? As bond (249,7(4) pm) is slightly widened with respect to the calculated value for a single bond (ca 244 pm).