The formation and crystal and molecular structures of (η5-pentamethylcyclopentadienyl)(η5-cyclopentadienyl)dichloro-titanium, -zirconium and -hafnium

A reaction between (η⁵-C₅Me₅)TiCl₃ and C₅H₅Tl in benzene solution has afforded (η⁵-C₅Me₅)(η⁵-C₅H₅)TiCl₂ (I) in quantitative yield. (η⁵-C₅Me₅)(η⁵-C₅H₅)HfCl₂ (III) has been prepared in 83% yield from a reaction between (η⁵-C₅Me₅)HfCl₃ and C₅H₅Na·DME in refluxing toluene solution. The crystal and molecular structures of (η⁵-C₅Me₅)(η⁵-C₅H₅TiCl₂ (I), (η⁵-C₅Me₅)(η⁵-C₅H₅)ZrCl₂ (II) and (η⁵-C₅Me₅)(η⁵-C₅H₅HfCl₂ (III) have been determined from X-ray data measured by counter methods. The three compounds are isostructural, crystallizing in the orthorhombic space group Pnma. The cell constants are: (I): a 9.873(1), b 12.989(3), c 11.376(4) Å and D_calc 1.45 g cm^?3 for Z = 4; (II): a 9.930(3), b 13.231(9), c 11.628(3) Å and D_calc 1.58 g cm^?3 for Z = 4; (III): a 9.938(1), b 13.156(2), c 11.582(2) Å and D_calc 1.97 g cm^?3 for Z = 4. In each case the metal atom resides on a crystallographic mirror plane which bisects both cyclopentadienyl rings and the ClMCl bond angle. The MCl bond lengths are 2.3518(9) for I, 2.4421(9) for II and 2.415(1) Å for III. The metal—cyclopentadienyl and metal—pentamethylcyclopentadienyl bond distances average 2.38(5) and 2.42(2) Å for I, 2.50(4) and 2.53(2) Å for II, and 2.48(4) and 2.50(1) Å for III respectively.     

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.     

Indenyl and fluorenyl transition metal complexes : VII. Innersphere “ricochet” rearrangements on alkylation of η5-indenyl- and η5-fluorenyltricarbonylchromate anions

Alkylation of K[η⁵-C₉H₇Cr(CO)₃] (Xa) with CH₃I and C₆H₅CH₂Br leads to σ-alkyl derivatives of η⁵-C₉H₇Cr(CO)₃Alk type. These complexes undergo innersphere “ricochet” rearrangement, with the alkyl group being shifted to the endo position at C(1) and the chromium tricarbonyl group shifted to the benzene nucleus. The structure of the product of such a rearrangement in the case of η⁵-C₉H₇(CO)₃CrCH₂C₆H₅, i.e. (1-benzyl-3a,4-7,7a-η⁶-indene)chromium tricarbonyl (XVIII), is established by a low temperature X-ray study, indicating an endo position for the benzyl radical.On alkylation of equilibrium tautomeric mixtures of η⁵- and η⁶-fluorenylchromium tricarbonyl anions XIa ? XIb under similar conditions, the η⁵-anion (Xa) yields a σ-alkyl derivative, which is rearranged to (9-endo-alkyl-1-4,4a,9a-η⁶-fluorene)chromium tricarbonyl. Electrophilic attack of the η⁶-anion (XIb) takes place on the outer side at C(9) and leads to a corresponding 9-exo-alkyl derivative.     

The reaction between [η5-C5H5M(CO)3]2, η5-C5H5M(CO)3I (M  Mo,W) and isonitriles

The reaction between η⁵-C₅H₅M(CO)₃I (M  Mo, W) and isonitriles, RNC, (RNC  PhCH₂NC, t-BuNC and 2,6-dimethylphenylisocyanide (XyNC)) is catalysed by the dimer [η⁵-C₅H₅M(CO)₃]₂ (M = Mo, W) to yield η⁵-C₅H₅M(CO)_3?n(RNC)_nI (n = 1–3) and [η⁵-C₅H₅Mo(RNC)₄]I. The complexes (η⁵-C₅H₅)₂Mo₂(CO)₆?n(RNC)_n (n = 1, RNC = MeNC, PhCH₂NC, XyNC, t-BuNC; n = 2, RNC = t-BuNC) have been prepared in moderate yield from the direct reaction between [η⁵-C₅H₅Mo(CO)₃]₂ and RNC, and also catalyse the above reaction. A reaction pathway involving a fast non-chain radical mechanism and a slower chain radical mechanism is proposed to account for the catalysed reaction.     

The transition metal catalysed reaction between η5-C5H5Mo(CO)3I and isonitriles

The reaction betweeen (η⁵-C₅H₅Mo(CO)₃I and RNC is catalysed by [η⁵ -C₅H₅Mo(CO)₃]₂ and readily yields η⁵-C₅H₅Mo(CO)_3?n(RNC)_nI (n = 1–3). A free radical mechanism is consistent with experimental data.     

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.     

Photochemically induced reactions of decacarbonyldimanganese(0)

Photolysis at ca. 350 nm of Mn₂(CO)₁₀ in the presence of each of I₂, CH₃I, SnI₄, CuCl₂ - 2 H₂O, HgX₂ (X  Cl, Br or I), C₆H₅HgI, η⁵-C₅H₅Cr(NO)₂Cl, (η⁵-C₅H₅)₂Cr₂(NO)₄ and [Co₂(CNCH₃)₁₀](BF₄)₄, generally under N₂ or CO in several organic solvents (mainly cyclohexane and THF), was investigated. The observed photoreactions are best rationalized in terms of initial homolytic cleavage of the MnMn bond. In the presence of a halogen (X)-containing compound, the resultant Mn(CO)₅· radical abstracts X to yield Mn(CO)₅X. These reactions are characterized by high quantum efficiencies (generally, _φ-Mn2(CO)10?0.36). Following the abstraction, the remaining metal-containing species (usually a radical), SnCl₃·, CuCl, HgX·, C₆H₅Hg· or η⁵-C₅H₅Cr(NO)₂·, undergoes further abstraction of halogen by Mn(CO)₅·, coupling with the Mn(CO)₅· or ligand substitution. Isolated metal-containing products include SnI₂, Cu, Mn(CO)₅HgX, Hg, [Mn(CO)₅]₂Hg and η⁵-C₅H₅Cr(CO)₂NO. Photolysis of Mn₂(CO)₁₀ in the presence of each of the metal-metal bonded compounds, (η⁵-C₅H₅)₂Cr₂(NO)₄ and [Co₂(CNCH₃)₁₀](BF₄)₄, does not give the respective heterodinuclear combinations, (η⁵-C₅H₅)(NO)₂CrMn(CO)₅ and [(CH₃NC)₅CoMn(CO)₅]²⁺, as detectable or isolable species; instead, η⁵-C₅H₅Cr(CO)₂NO, Mn(CO)₄NO, Mn₂(CO)₉CNCH₃, and [Mn(CO)(CNCH₃)₅]₊ are among the isolated products. The photoreaction between Mn₂(CO)₁₀ and CH₃I provides a convenient synthesis of Mn(CO)₅I.     

Synthesis of the compounds [Re(CR)(CO)2(η5-C9H7)][BF4] (R = C6H4Me-4 or C6H3Me2-2,6) and the preparation of complexes with FeRe bonds

The salts [Re(CR)CO)₂(η⁵-C₉H₇)][BF₄] [R = C₆H₄Me-4 or C₆H₃Me-2,6; η⁵- C₉H₇ = indenyl] have been prepared and used to synthesize the dimetal compounds [FeRe(μ-CR)(μ-NO)(CO)₄(η⁵-C₉H₇)]. The iron-rhenium species containing a bridging p- tolylmethylidyne ligands react with [Fe₂(CO)₉] or with [Ru(CO)₄(η-C₂H₄)], respectively, to yield the trimetal compounds ([FeMRe(μ₃-CC₆H₄Me-4)(μ-CO)(μ-NO)(CO)₆(η ₅-C₉H₇)] (M = Fe or Ru).     

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 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.     

Crystal and molecular structure of(η-C5H5)W[C3(CME3)2Me](PME3)Cl2, a species with a tetrahedral WC3, core formed from a tungstenacyclobutadiene complex via attack on tungsten by a phosphorus-donor ligand

Mercury(II) chloride in refluxing methanol or acetone cleaves the molybdenum—tin bond of π-methylcyclopentadienylmolybdenum tricarbonyl triphenylstannyl [(η⁵-C₅H₄CH₃)(CO)₃MoSnPh₃] to give (η⁵-C₅H₄CH₃)(CO)₃MoHgCl. The same product was also obtained by reaction of [(η⁵-C₅H₄CH₃)(CO)₃Mo]₂Hg with HgCl₂ in acetone at room temperature. Similar reactions have given bimetallic complexes of the type (η⁵-C₅H₄CH₃)(CO)₃MoHgX (X = Br, I, SCN). The new complexes are air-stable crystalline solids. The structure of the compound (η⁵-C₅H₄CH₃)(CO)₃MoHgCl has been determined. It crystallizes in space group P2₁/c with Z = 4, a 6.613(2), b 13.647(4), c 13.257(4) Å, β 101.85(3)°, D_c 2.81 g/cm³, F(000) = 896, μ(Mo-K_α) 143.56 cm^?1. Final R = 0.055 for 1696 observed reflexions.     

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.     

Synthesis of cationic indenyliron complexes: [η5-C9H7Fe(CO)2L]+ (L = phosphine,phosphite, CO)

Synthetic routes to the cationic complexes [η⁵-C₉H₇Fe(CO)[₂L]⁺, (L = CO, phosphine, phosphite, nitrile, pyridine) have been investigated. The most versatile method is oxidation of the dimer [η⁵-C₉h₇Fe(CO)₂]₂ with ferricinium ion. in the presence of the appropriate ligand. [η⁵-C₉H₇Fe(CO)₃]⁺ is best prepared by oxidation of the dimer with Ph₃CBF₄. This tricarbonyl cation readily loses one CO group on reactiom with phosphines and P(OCH₃). The acentonitrile ligand [η⁵-C₉H₇Fe(CO)₂CH₃CN]⁺ can also be replaced bny phosphines. Finally, reactions of η⁵-C₉H₇Fe(CO)₂X, (X = Br, I) with phosphines also yield cationic products isolatedas PF₆⁻ salts.     

Darstellung und Charakterisierung von kationischen η2-1-Buten- und Acetonitrilkomplexen

Preparation and Characterization of Cationic η²-1-Butene and Acetonitrile Complexes The reaction of the species η⁵-C₅H₅M(CO)_n-σ-C₄H₇ (M = Fe, Mo, W; n = 2, 3) with (C₆H₅)₃CBF₄ yielded – instead of the expected cationic butadiene complexes of the type [η⁵-CpM(CO)_n?1-η⁴-C₄H₆][BF₄], which would have been formed in case of hydride cleavage – compounds of the type [η⁵-CpM(CO)_n η²-C₄H₈][BF₄], which were formed by protonation of the σ-C₄H₇ ligands. The reaction proceeded quantitatively. The BF₄^? anion can be substituted by other anions, such as ClO₄^?, B(C₆H₅)₄^?, PF₄^?, and [Cr(SCN)₄(NH₃)₂]^? in the complexes obtained. The mechanism of the reaction leading to the η²-bonded 1-butene complexes was determined by isotope experiments. In trying to recrystallize the butene complexes from acetonitrile the cationic complexes [η⁵-C₅H₅ Fe(CO)₂CH₃CN]BF₄ and [η⁵-C₅H₅ M(CO)₃CH₃CN]BF₄ were observed; the X-ray structure analysis of the former is reported.     

Molybdenum complexes containing substituted cyclopenta[l]phenanthrenyl ligand

The synthesis of new cyclopenta[l]phenanthrenyl complexes [(η⁵-C₁₇H₁₀Me)(η³-C₃H₅)Mo(CO)₂] and [(η⁵-C₁₇H₉(COOMe)N(CH₂)₄)(η³-C₃H₅)Mo(CO)₂] is described. Although these compounds are structural analogues their reactivity is different. Protonation of [(η⁵-C₁₇H₁₀Me)(η³-C₃H₅)Mo(CO)₂] gives a stable ionic compound [(η⁵-C₁₇H₁₀Me)Mo(CO)₂(NCMe)₂][BF₄] while its analogue containing both tertiary amino and carboxylic ester groups [(η⁵-C₁₇H₉(COOMe)N(CH₂)₄)(η³-C₃H₅)Mo(CO)₂] decomposes under the same conditions. [(η⁵-C₁₇H₁₀Me)Mo(CO)₂(NCMe)₂][BF₄] reacts with cyclopentadiene to give a stable η⁴-complex [(η⁴-C₅H₆)(η⁵-C₁₇H₁₀Me)Mo(CO)₂][BF₄] that was successfully oxidized to the Mo(IV) dicationic compound [(η⁵-C₅H₅)(η⁵-C₁₇H₁₀Me)Mo(CO)₂][Br][BF₄].     

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.     

Mehrfachbindungen zwischen hauptgruppenelementen und übergangsmetallen: XXXII. Insertions- und metathesereaktionen von metallorganischen eisen-selen-komplexen

The compound (μ-Se)[η⁵-C₅H₅)Fe(CO)₂]₂ (1) has labile metalselenium bonds and therefore undergoes insertion and metathesis reactions. Thus, reaction with elemental selenium gives the novel FeSeSeFe chain-type complex (μ,η¹:η¹-Se₂)[(η⁵-C₅H₅)Fe(CO)₂]₂ (2). Both compounds 1 and 2 react with the homodinuclear chromium complex [(η⁵-C₅H₅)Cr(CO)₃]₂ with formation of the heterodinuclear derivatives of composition (η⁵-C₅H₅)₂CrFe(CO)₅. (3; single-crystal X-ray structure: d(CrFe) 290.1(1) pm) and (μ-Se₂)[(η⁵-C₅H₅)₂CrFe(CO)₄] (4). The latter compound exhibits a diselenido bridge ligand in η¹:η²-coordination (single-crystal X-ray structure: d(CrSe) 249.5(2) and 255.5(2) pm, d(FeSe) 238.9(2), d(SeSe) 229.7(1) pm) and can also be obtained by treatment of the chromium complex 3 with elemental selenium.     

Complexes in polymers: FT-IR spectra and photochemistry of some monomeric organometallic carbonyl complexes in polystyrene,poly(methyl methacrylate), polystyrene—poly(methyl methacrylate) and polystyrene—polyacrylonitrile copolymers

A convenient method for embedding organometallic complexes in polymer films has been developed and the FT-IR spectra of these films have been investigated at room temperature. Infrared data in the n?(CO) stretching region are reported for M(CO)₆ (M = Cr, Mo, W), CpMn(CO)₃ (Cp = η⁵-C₅H₅), η-C₆H₆Cr(CO)₂L [L = CO, P(n-Bu)₃], (η₆-C₆H₅NH₂)Cr(CO)₃, [η⁶-o-C₆H₄(NH₂)MeCr(CO)₃], CpFe(CO)LR [L = CO, PPh₃; R = Me, C(O)Me] embedded in poly(methyl methacrylate) (PMMA), polystyrene (PS), polystyrene-poly(methyl methacrylate) (PS-PMMA), and polystyrene–polyacrylonitrile (PS-AN) plastic films. These matrices appear to approximate the common solvents ethyl acetate, toluene, toluene–ethyl acetate, and toluene–acetonitrile, respectively, with respect to n?(CO) vibrational band behavior. Several of the films have been subjected to UV irradiation and the photoproducts formed have been identified by FT-IR spectroscopy. PS-AN effectively traps photogenerated coordinatively unsaturated species via coordination of its pendant nitrile groups.     

Reaktionen der Cycloheptatrienylkomplexe [η7-C7H7W(CO)3]BF4 und η7-C7H7Mo(CO)2 Br mit Neutralliganden und die elektrochemische Reduktion des Wolframkomplexes

Reactions of the Cycloheptatrienyl Complexes [η⁷-C₇H₇W(CO)₃]BF₄ and η⁷-C₇H₇Mo(CO)₂Br with Neutral Ligands and the Electrochemical Reduction of the Wolfram Complex Compounds of the type [η⁷-C₇H₇M(CO)₂L][BF₄] (L = P(C₆H₅)₃, As(C₆H₅)₃, Sb(C₆H₅)₃ for M = W and L = N₂H₄ for M = Mo) were synthesized and characterisized. The iodide η⁷-C₇H₇W(CO)₂I reacts with the diphosphine ((C₆H₅)₂PCH₂)₂ to give the trihapto complex η³-C₇H₇ W(CO)₂I((C₆H₅)₂PCH₂)₂. In the case of η⁷-C₇H₇Mo(CO)₂ Br reaction with hydrazine leads to the substitution product [η⁷-C₇H₇ Mo(CO)₂N₂H₄]^⊕, which can be stabilized by large anions. The binuclear complex [C₇H₇W(CO)₃]₂ has been synthesized electrochemically.     

C2-Bridged sandwich and half-sandwich entities with Ti(IV) and Cr(0) centers

The intense purple colored bi- and trimetallic complexes {Ti}(CH₂SiMe₃)[CC(η⁶-C₆H₅)Cr(CO)₃] (3) ({Ti}=(η⁵-C₅H₅)₂Ti) and [Ti][CC(η⁶-C₆H₅)Cr(CO)₃]₂ (5) {[Ti]=(η⁵-C₅H₄SiMe₃)₂Ti}, in which next to a Ti(IV) center a Cr(0) atom is present, are accessible by the reaction of Li[CC(η⁶-C₆H₅)Cr(CO)₃] (2) with {Ti}(CH₂SiMe₃)Cl (1) or [Ti]Cl₂ (4) in a 1:1 or 2:1 molar ratio. The chemical and electrochemical properties of 3, 5, {Ti}(CH₂SiMe₃)(CCFc) [Fc=(η⁵-C₅H₅)Fe(η⁵-C₅H₄)] and [Ti][(CC)_nMc][(CC)_mM′c] [n, m=1, 2; n=m; n≠m; Mc=(η⁵-C₅H₅)Fe(η⁵-C₅H₄); M′c=(η⁵-C₅H₅)Ru(η⁵-C₅H₄); Mc=M′c; Mc≠M′c] will be comparatively discussed.