Novel complexes of manganese with phenylvinylidene as a ligand

Three novel stable complexes of manganese were prepared by interaction of [(η⁵-C₅H₅)Mn(CO)₂ (THF)] with phenylacetylene. X-ray structure analysis of two of the complexes established the presence of a phenylvinylidene ligand. In [(η⁵-C₅H₅Mn(CO)₂(CCHPh)] this ligand forms an unusual double MnC bond and in [(η⁵-C₅H₅)Mn₂(CO)₄(CCHPh)] it acts as a bridge strengthening the MnMn bond.     

Preparation of new (η5-C5H4CH3)Mn(NO)(PPh3) and (η7-C7H7)Mo(CO)-(PPh3) complexes

The complex (η⁵-C₅H₄CH₃)Mn(NO)(PPh₃)I has been prepared by the reaction of NaI with [(η⁵-C₅H₄CH₃)Mn(NO)(CO)(PPh₃)]⁺ and also by the reaction of [(η⁵-C₅H₄CH₃)Mn(NO)(CO)₂]⁺ with NaI followed by PPh₃. This iodide compound reacts with NaCN to yield (η⁵-C₅H₄CH₃)Mn(NO)(PPh₃)CN which is ethylated by [(C₂H₅)₃O]BF₄ to yield [(η⁵-C₅H₄CH₃)Mn(NO)(PPh₃)(CNC₂H₅)]⁺. Both [(η⁵-C₅H₄CH₃)Mn(NO)(CO)₂]⁺ and [(η⁵-C₅H₄CH₃)Mn(NO)(PPh₃)(CO)]⁺ react with NaCN to yield [(η⁵-C₅H₄CH₃)Mn(NO)(CN)₂]^?. This anion reacts with Ph₃SnCl to yield cis-(η⁵-C₅H₄CH₃)Mn(NO)(CN)₂SnPh₃ and with [(C₂-H₅)₃O]BF₄ to yield [(η⁵-C₅H₄CH₃)Mn(NO)(CNC₂H₅)₂]⁺. The reaction of (η⁵-C₅-H₄CH₃)Mn(NO)(PPh₃)I with AgBF₄ in acetonitrile yields [(η⁵-C₅H₄CH₃)Mn-(NO)(PPh₃)(NCCH₃)]⁺. The complex (η⁵-C₅H₄CH₃)Mn(NO)(CO)I, produced in the reaction of [(η⁵-C₅H₄CH₃)Mn(NO)(CO)₂]⁺ with NaI, is not stable and decomposes to the dimeric complex (η⁵-C₅H₄CH₃)₂Mn₂(NO)₃I for which a reasonable structure is proposed. Similar dimers can be prepared from the other halide salts. The reaction of (η⁷-C₇H₇)Mo(CO)(PPh₃)I with NaCN yields (η⁷-C₇-H₇)Mo(CO)(PPh₃)CN which is ethylated by [(C₂H₅)₃O]BF₄ to yield [(η⁷-C₇H₇)-Mo(CO)(PPh₃)(CNC₂H₅)]⁺. The interaction of this molybdenum halide complex with AgBF₄ in acetonitrile and pyridine yields [(η⁷-C₇H₇)Mo(CO)(PPh₃)-(NCCH₃)]⁺ and [(η⁷-C₇H₇)Mo(CO)(PPh₃)(NC₅H₅)]⁺, respectively. Both (η⁵-C₅-H₄CH₃)Mn(NO)(PPh₃)I and (η⁷-C₇H₇)Mo(CO)(PPh₃)I are oxidized by NOPF₆ to the respective 17-electron cations in acetonitrile at ?78°C but revert to the neutral halide complex at room temperature. This result is supported by electrochemical data.     

Mehrfachbindungen zwischen hauptgruppenelementen und übergangsmetallen: XVII. Selen- und tellur-brücken in organometallkomplexen: AUFBAU,protonierung und methylierung

Selenium acts as a bridging ligand between two iron atoms in the novel complex (μ-Se)(η⁵-C₅H₅)Fe(CO)₂]₂ (1), obtained in 60% yield from Na⁺[(η⁵-C₅H₅)Fe(CO)₂] and Se₂Cl₂. 1 displays nucleophilic reactivity towards protic acids (e.g., HBF₄·OEt₂) and methyl triflate, CF₃SO₃CH₃, thus giving the protonated and methylated ionic species [(μ-SeR)(η⁵-C₅H₅)Fe(CO)₂₂]⁺ (R = H: 2a, BF₄ salt; R = CH₃: 2b, PF₆ salt) in quantitative yields. Rapid deprotonation of 2a occurs in the presence of bases such as diethylamine. Analogous protonation and methylation reactions have been observed with the tellurium complex (μ-Te)[(η⁵-C₅H₅)Cr(CO)₃]₂ (3); the ionic compounds [(μ-TeH)(η⁵-C₅H₅)Cr(CO)₃₂]BF₄ (4a) and [(μ-TeCH₃) (η⁵-C₅H₅)Cr(CO)₃₂]PF₆(4a), respectively, are obtained. In contrast, the electron-deficient tellurium ligand of the manganese complex (μ₃-Te)[(η⁵-C₅H₅)Mn(CO)₂]₃ (5) is neither attacked by Brønsted acids nor by electrophilic methylating agents (e.g., CF₃SO₃CH₃) but is rather methylated by methyllithium to give the anionic species [(μ₃-TeCH₃)η⁵-C₅H₅)Mn(CO)₂₃]^? that can be isolated pure as the PPN⁺ salt 6.     

Metallotropic rearrangement of η5-fluoroenyltricarbonyl-manganese in acid media

Using IR and PMR spectroscopy, it has been shown that on addition of trifluoroacetic acid to (η⁵-C₁₃H₉)Mn(CO)₃ in CH₂Cl₂ solution protonation of position 9 of the fluorenyl ligand takes place with simultaneous migration of the metal atom onto the six-membered ring of the fluorenyl ligand, forming of [(η⁶-C₁₃H₁₀)Mn(CO)₃]⁺.     

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.     

The mechanism of substitution of cymantrene derivatives by phosphines and phosphites

The kinetics of the thermal substitution of (η⁵-C₅H₄C(O)CH₃)Mn(CO)₂SC₄H₈, (η¹:η⁵-C₅H₄C(O)CH₂SCH₃)Mn(CO)₂ and (η¹:η⁵-C₅H₄C(O)CH₂CH₂SCH₃)Mn(CO)₂ by phosphines and phosphites have been measured in toluene and xylene. A proposed dissociative mechanism involving cleavage of the manganese–sulfur bonds as the rate-determining step is supported by the activation parameters obtained.     

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.     

Komplexchemie reaktiver organischer Verbindungen. XLV. Metallorganische Methandiazo – Komplexe: Protonierung und Cycloaddition

Complex Chemistry of Reactive Organic Compounds. XLV. Organometallic Methanediazo Complexes: Protonation and Cycloaddition The reactions of the methanediazo tungsten complex (η⁵-C₅H₅)W(CO)₂(N₂CH₃) ( 1 ) with protic acids are strongly governed by solvent effects: while trifluoromethylsulfonic acid induces clean protonation with formation of the ionic derivative [(η⁵-C₅H₅)W(CO)₂(HN₂CH₃)]+CF₃SO₃? ( 3 ) when diethylether is used as a solvent, compound 4 is formed in the presence of acetonitril which latter solvent has good coordination capabilities itself. Compound 4 originates from a novel type of cycloaddition reaction in which the protonated species of composition [(η⁵-C₅H₅)W(CO)(CH₃CN)(HN₂-CH₃)]+CF₃SO₃? is involved. Complete elimination of the nitrogeneous ligand ensemble with concomitant formation of the halogen complex (η⁵-C₅H₅)W(CO)₂Br₃ ( 5 ) occurs upon treatment of 1 with hydrogen bromide.     

Synthesis and characterization of complexes η5,η5-(CO)3Mn(C5H4-C5H4)(CO)2Fe-η1,η5-C5H4Mn(CO)3 and μ-(C≡C)[C5H4(CO)2Fe-η1,η5-C5H4Mn(CO)3]2

The complex η⁵,η⁵-(CO)₃Mn(C₅H₄-C₅H₄)(CO)₂Fe-η¹,η⁵-C₅H₄Mn(CO)₃ was synthesized by the reaction of η⁵-Cp(CO)₂Fe-η¹,η⁵-C₅H₄Mn(CO)₃ with BuⁿLi (THF, ?78 °C) and then with anhydrous CuCl₂. The complex μ-(C≡C)[C₅H₄(CO)₂Fe-η¹,η⁵-C₅H₄Mn(CO)₃]₂ was prepared by the reaction of η⁵-IC₅H₄(CO)₂Fe-η¹,η⁵-C₅H₄Mn(CO)₃ with Me₃SnC≡CSnMe₃ (2:1) in the presence of Pd(MeCN)₂Cl₂.     

Reactions of (η5-C5H5)Fe(CO)2(η1-C5H5) with phosphorus donor ligands

The course of the reaction of (η⁵-C₅H₅)Fe(CO)₂(η¹-C₅H₅) with phosphorus donor ligands depends strongly on the nature of the ligand; products derived from an Arbuzov-like rearrangement or from reduction have been found as well as the expected simple substitution product. The dynamic PMR behavior of (η⁵-C₅H₅)Fe(CO) (P(OPh)₃) (η¹-C₅H₅) has been examined.     

Studies in negative ion mass spectrometry. VIII—Electron capture by some monomeric and dimeric η5—cylcopentadienyl transition metal carbonyls

The negative ion mass spectra of a series of monomeric and dimeric η⁵-cyclopentadienyl transition metal carbonyls have been examined. The base peak in the case of the monomeric compounds (η⁵-C₅H₅)V(CO)₄, (η⁵-C₅H₅)Mn(CO)₃ and (η⁵-CH₃C₅H₄)Mn(CO)₃ arises from a reductive decarbonylation of the parent molecule—the resulting radical anion [M–CO]^? is formally isoelectronic with the molecular cations [M]^? observed in the positive ion mass spectra of these compounds and subsequently undergoes successive decarbonylations to the ‘aromatic’ cyclopentadienyl anions. For the compound (η⁵-C₅H₅)Co(CO)₂, however, a molecular anion was observed as the base peak which has been formulated as [(η³-C₅H₅)Co(CO)₂]^? in the light of considerations based on the rare gas rule. As expected, the dimeric molecules [(η⁵-C₅H₅)M(CO)₃]₂ (where M = Cr or Mo) and [(η⁵-C₅H₅)Fe(CO)₂]₂ (and its methyl analogue) undergo reductive cleavage of their metal-metal bonds to give the anions [(η⁵-C₅H₅)M(CO)₃]^? and [(η⁵-C₅H₅)Fe(CO)₂]^? as the base peaks in their negative ion mass spectra. The dimeric nickel compound [(η⁵-C₅H₅)Ni(CO)]₂, however, reductively decarbonylates to the [M-CO]^? radical anion as its predominant fragmentation in the gas phase. Very low abundances of [(η⁵-C₅H₅)Fe(CO)₂] and [(η⁵-CH₃C₅H₄)Fe(CO)₂] were also observed.     

The hapticity of cyclooctatetraene in its first row mononuclear transition metal carbonyl complexes: Several examples of octahapto coordination

The two cyclooctatetraene metal carbonyls that have been synthesized are the tetrahapto derivative (η⁴-C₈H₈)Fe(CO)₃ and the hexahapto derivative (η⁶-C₈H₈)Cr(CO)₃ using the reactions of cyclooctatetraene with Fe(CO)₅ and with fac-(CH₃CN)₃Cr(CO)₃, respectively. Related C₈H₈M(CO)_n (M = Ti, V, Cr, Mn, Fe, Co, Ni; n = 4, 3, 2, 1) species have now been investigated by density functional theory in order to explore the scope of cyclooctatetraene metal carbonyl chemistry. In this connection, the existence of octahapto (η⁸-C₈H₈)M(CO)_n species is predicted as long as the central metal M does not exceed the 18-electron configuration by receiving eight electrons from the η⁸-C₈H₈ ring. Thus the lowest energy structures (η⁸-C₈H₈)Ti(CO)_n (n = 3, 2, 1), (η⁸-C₈H₈)M(CO)_n (M = V, Cr; n = 2, 1), and (η⁸-C₈H₈)Mn(CO) all have octahapto η⁸-C₈H₈ rings. An exception is (η⁶-C₈H₈)Fe(CO), with a hexahapto η⁶-C₈H₈ ring and thus only a 16-electron configuration for the iron atom. Hexahapto (η⁶-C₈H₈)M(CO)_n structures are predicted for the known (η⁶-C₈H₈)Cr(CO)₃ as well as the unknown (η⁶-C₈H₈)Ti(CO)₄, (η⁶-C₈H₈)V(CO)₃, (η⁶-C₈H₈)Mn(CO)₂, and (η⁶-C₈H₈)Fe(CO)₂ with 18, 18, 17, 17, and 18 electron configurations, respectively, for the central metal atoms. There are two types of tetrahapto C₈H₈M(CO)_n complexes. In the 1,2,3,4-tetrahapto (η⁴-C₈H₈)M(CO)_n complexes two adjacent CC double bonds, forming a 1,3-diene unit similar to butadiene, are bonded to the metal atom. In the 1,2,5,6-tetrahapto (η^2,2-C₈H₈)M(CO)₃ derivatives two non-adjacent CC double bonds of the C₈H₈ ring are bonded to the metal atom. The known (η⁴-C₈H₈)Fe(CO)₃ is a 1,2,3,4-tetrahapto complex. The unknown isomeric 1,2,5,6-tetrahapto complex (η^2,2-C₈H₈)Fe(CO)₃ is predicted to lie ∼15 kcal/mol above (η⁴-C₈H₈)Fe(CO)₃. The related 1,2,5,6-tetrahapto complexes (η^2,2-C₈H₈)Cr(CO)₄, (η^2,2-C₈H₈)Mn(CO)₄, [(η^2,2-C₈H₈)Mn(CO)₃]⁻, (η^2,2-C₈H₈)Co(CO)₂, and (η^2,2-C₈H₈)Ni(CO)₂ are all predicted to be low-energy structures.     

Metal dimers as catalysts: IX. The catalysed reaction between [η5-C5H5)Fe(CO)2I] and group 15 donor ligands

The reaction between [η⁵-C₅H₅)Fe(CO)₂I] (I) and 1 equivalent of L (group 15 donor ligand) in the presence of catalysts (e.g. Pd/CaCO₃, PdO, [η⁵-C₅H₅)Fe(CO)₂]₂ (II)) yields [η⁵-C₅H₅)Fe(CO)(L)I] (phosphines, diphosphines, phosphite), [η⁵-C₅H₅)Fe(CO)₂L]I (phosphines) and [η⁵-C₅H₅)Fe(CO)(LL)]I (diphosphines). [η⁵-C₅H₅)Fe(CO)₂L]I can be converted into [η⁵-C₅H₅)Fe(CO)(L)I] in the presence of II. The reaction between [η⁵-C₅H₅)Fe(CO)(PMePh₂)I] or [η⁵-C₅H₅)Fe(CO)₂(PMePh₂)]I and PMePh₂ is also catalysed by II and yields in both instances [η⁵-C₅H₅)Fe(CO)(PMePh₂)₂]I. In the series of catalysed reactions the displacement sequence was found to be PMePh₂ > I⁻ > CO.     

Mehrfachbindungen zwischen hauptgruppenelementen und übergangsmetallen: XVIII. Heterometallische selenido-komplexe

The selenium bridge present in the iron complex (μ-Se)[(η⁵-C₅H₅)Fe(CO)₂]₂ (1) exhibits nucleophilic character and is thus prone to addition reactions with electrophilic reagents. Treatment of 1 with the coordinatively unsaturated fragment (η⁵-C₅H₅)Mn(CO)₂ results in formation of the heteronuclear complex (η⁵- C₅H₅)₃Fe₂MnSe(CO)₆ (2) which contains a flattened pyramidal Fe₂MnSe core, with the selenium atom occupying the top of position of this framework. No FeMn and FeFe bonds are present in this molecule (single crystal X-ray diffraction study). Compound 2 is very light-sensitive in solution, thus giving the derivative (η⁵-C₅H₅)₃Fe₂MnSe(CO)₅(3). According to a crystal structure determination, this latter compound once again exhibits a pyramidal Fe₂MnSe core but with the iron atoms directly connected with each other via a single bond (266.7(1) pm).     

Carbon-13 NMR spectra of some group VIB and VIIB transition metal chalcocarbonyl complexes

The ¹³C NMR spectra of the five series of chalcocarbonyl complexes, (η⁶-C₆H₆)Cr(CO)₂(CX), (η⁶-C₆H₅CO₂Me)Cr(CO)₂(CX), (η⁵-C₅H₅)Mn(CO)₂(CX), (η⁵-C₅H₄Me)Mn(CO)₂(CX) and (η⁵-C₅H₅)Re(CO)₂(CX) (X = O, S, Se), and some of their derivatives including several ¹³C-enriched species have been investigated at ?30 to ?50°C. The chemical shift variations observed with changes in the CX ligand suggest that the π-acceptor/σ-donor capacity of these ligands increases in the order CO < CS < CSe. Changes in the nuclear charge and in the electronic density at the central metal atom affect δ(¹³CS) and δ(¹³CO) in the same manner. The increased downfield chemical shift for δ(¹³CX) in the chromium and manganese series on changing X from O to S and Se is in the direction expected from considerations of Pople's paramagnetic shielding expression.     

Derivate des borols: VIII. (η5-borol)cobalt-komplexe

A large variety of (η⁵-borole)cobalt complexes have been prepared starting with η-(CO)₂[Co(CO)(η⁵-C₄H₄BR)]₂(CoCo) (IIIa: R = Me, IIIb: R = Ph), including inter alia, the sandwich complexes CpCo(η⁵-C₄H₄BR) (VIIa, b), the triple-decked complexes η-(η⁵-C₄H₄BR)[Co(η⁵-C₄H₄BR)]₂ (VIIIa, b) and μ-(η⁵-C₄H₄BR)(FeCp)[Co(η⁵-C₄H₄BR)] (X, R = Ph), the dinuclear complex μ-(CO)₂[Fe(CO)Cp][Co(CO)(η⁵-C₄H₄BPh)](FeCo) (IX), and salts M[Co(η⁵-C₄H₄BR)₂](XVa, b: M = Na; XVIa, b: M = NMe₄; XVII: M = Cs, R = Ph). The anions [Co(η⁵-C₄H₄BR)₂]⁻ readily undergo stacking reactions to form multiple-decked complexes such as the triple-decker compounds μ-(η⁵-C₄H₄BR)[Mn(CO)₃][Co(η⁵-C₄H₄BR)] (XIIa, b), μ-(η⁵-C₄H₄BR)[Co(η⁵-C₄H₄BR)][Rh(η-1,5-COD)] (XVIII), [NMe₃Ph][μ-η⁵-C₄H₄BPh){Cr(CO)₃}{Co(η⁵-C₄H₄BPh)}] (XX), and the quadruple-decker complex Ru[μ-(η⁵-C₄H₄BR)Co(η⁵-C₄H₄BR)]₂ (XXI). The monofacially bound η⁵-borole ligands in VIIb and VIIIb shows regiospecific H/D exchange, at the α position of the boron, on treatment with CF₃CO₂D at room temperature. VIIb undergoes a Friedel-Crafts substitution to give the 2-acetyl derivative XXIV with MeCoCl/SnCl₄ in CH₂Cl₂ at room temperature.The structure of VIIIa, as determined by X-ray diffraction studies is that of a typical triple-decker compound with nearly coplanar rings. The three borole rings form a helix with torsional angles of 59.8 and 72.2°. All intra-ring bond distances of the central ligand are longer than those of the outer ligands. The metal-ligand interaction is somewhat stronger for the outer ligands than for the central ligand.     

Zur kenntnis der cyclopentadienyl-nitrosyl-carbonyl-isonitril-komplexe der VI. Und der cyclopentadienyl-dicarbonyl-isonitril-komplexe der VII. Nebengruppe

The nitrosylcarbonylisonitrile complexes η⁵-C₅H₅M(NO)(CO)CNR (R = Me for Cr, Mo, W; R = Et, SiMe₃, GeMe₃, SnMe₃ for Mo) are formed by treatment of the nitrosylcarbonylcyanometalates Na[η⁵-C₅H₅M(NO)(CO)CN] with [R₃O]BF₄ (R = Me, Et), Me₃SiCl, Me₃GeCl or Me₃SnCl. The isoelectronic dicarbonylisonitrile compounds η⁵-C₅H₅Mn(CO)₂CNR (R = SiMe₃, GeMe₃, SnMe₃, PPh₂, AsMe₂) and η⁵-C₅H₅Re(CO)₂CNAsMe₂ are obtained by analogous reactions of Na[η⁵-C₅H₅M(CO)₂CN] (M = Mn, Re) with Me₃ECl (E = Si, Ge, Sn), Ph₂PCl and Me₂AsBr.With phosgene the anionic complexes Na[η⁵-C₅H₅M(CO)₂CN] (M = Mn, Re) can be transformed into the new carbonyldiisocyanide-bridged dinuclear complexes η⁵-C₅H₅M(CO)₂CN-C(O)-NC(OC)₂M-η⁵-C₅H₅. Finally, the reactions of η⁵-C₅H₅M(NO)(CO)CNMe (M = Cr, Mo, W) with NOPF₆, leading to the cationic dinitrosylisonitrile complexes [η⁵-C₅H₅M(NO)₂CNMe]⁺, are described.     

Heterobimetallic Re–Pd,Re–Au and Re–Cu complexes derived from diphenylphosphino cyrhetrene: Synthesis and X-ray structure

Diphenylphosphinecyrhetrene ligand (η⁵-C₅H₄PPh₂)Re(CO)₃ (1) reacts with 1 equiv. of PdCl₂(NCPh)₂ to form, after workup, the square-planar trans-[(η⁵-C₅H₄PPh₂)Re(CO)₃]PdCl₂(NCMe) (2). Similarly, reaction of 1 with (tetrahydrothiophene)AuCl produces, in excellent yield, the bimetallic complex [(η⁵-C₅H₄PPh₂)Re(CO)₃]AuCl (3) with a linear P–Au–Cl moiety. From the reaction of 2 equiv. of 1 with CuBr(SMe₂) the planar-trigonal complex [(η⁵-C₅H₄PPh₂)Re(CO)₃]₂CuBr (4) was obtained. ³¹P NMR and X-ray crystallography demonstrate, for the three cases, that (η⁵-C₅H₄PPh₂)Re(CO)₃ acts as a monodentate ligand. The structural parameters of the bimetallic complexes are compared with related diphenylphosphinoferrocene metal complexes, described in the literature.     

Syntheses and crystal structures of group 6 metal complexes containing allyl and cyanotrihydroborate groups

Compounds M(η³-C₃H₅)(CO)₂(NCCH₃)₂(NCBH₃) and [N(CH₃)₄]₂[M(η³-C₃H₅)(CO)₂(NCBH₃)₃] (M = Mo, W) were prepared and structurally characterized. In the solid state, the allyl group orients its open face to the two carbonyl groups producing an endo form in the above compounds. In solution, an exo form coexists with an endo form in compound Mo(η³-C₃H₅)(CO)₂(NCCH₃)₂(NCBH₃). The cyanotrihydroborate ligand bonds to the metal through a nitrogen atom. Both of the IR and the 11B NMR spectroscopic data suggest the negative charge of the cyanotrihydroborate ligand on the complex is almost localized on the BH₃ and this negative charge only has small effect on the metal-nitrogen interaction.     

Photochemical and thermal reactions of η5-cyclopentadienyltetracarbonylvanadium and bis(pentafluorophenyl)acetylene

The photolysis of (η⁵-C₅H₅)V(CO)₄ in the presence of one or two equivalents of bis(pentafluorophenyl)acetylene yields (η⁵-C₅H₅)V(CO)₂(C₆F₅CCC₆F₅). One carbon monoxide ligand in this acetylene adduct can be photochemically displaced by triphenylphosphine to yield (η⁵-C₅H₅)V(CO)[P(C₆H₅)₃](C₆F₅CCC₆F₅). This complex is also obtained by the photolysis of (η⁵-C₅H₅)V(CO)₃P(C₆H₅)₃ in the presence of bis(pentafluorophenyl)acetylene. In vacuo, melt-phase thermolysis of (η⁵-C₅H₅)V(CO)₂(C₆F₅CCC₆F₅) and bis(pentafluorophenyl)acetylene produces (η⁵-C₅H₅)V(CO)(C₆F₅CCC₆F₅)₂. This diacetylenic complex as well as the perfluorinated organic compounds 2,3,5,6-tetrakis(pentafluorophenyl)-1,4-benzoquinone, 2,3,4,5-tetrakis(pentafluorophenyl)cyclopentadienone and 2,3,4,5,6,7-hexakis(pentafluorophenyl)cycloheptatrienone are also obtained from thermal reactions of (η⁵-C₅H₅)V(CO)₄ and bis(pentafluorophenyl)acetylene in solution. Photolysis of (η⁵-C₅H₅)V(CO)(C₆F₅CCC₆F₅)₂ in the presence of carbon monoxide produces (η⁵-C₅H₅)V(CO)₂(C₆F₅CCC₆F₅). The photochemical and thermal reactions of bis(pentafluorophenyl)acetylene and (η⁵-C₅H₅)V(CO)₄ are compared and contrasted with similar reactions of diphenylacetylene and (η⁵-C₅H₅)V(CO)₄.