The chemistry of metal carbonyl anions : III. Sodium-potassium alloy: An efficient reagent for the production of metal carbonyl anions

Reduction of several metal carbonyl dimers including Mn₂](CO)₁₀, [C₅H₅Fe(C0)₂]₂, Co₂(CO)₈, and [C₅H₅M(CO)₃]₂ (M = Cr, Mo and W) by sodium—potassium alloy (NaK) in tetrahydrofuran at room temperature provides a rapid and clean method for the production of the corresponding metal carbonyl anions in high yield. Isolation and characterization of [n-Bu₄N] [Fe(CO)₂C₅H₅] from the iron dimer reduction is described. Reductions of other carbonyls including M(CO)₆ (M = Cr, Mo and W) and Re₂(CO)₁₀ proceed more slowly than previously established methods and provide principally M₂(CO)₁₀^2? and Re(CO)₅₅^?. Methods for the preparation of Re(CO)₅^? are critically considered. The reaction of NaK with [C₅H₅NiCO]₂ is discussed in relation to previously reported results. Infrared solution spectra of a number of carbonyl anions in THF, obtained in a special infrared solution cell, are reported.     

Einführung eines terminalen Halogenoliganden in diorgano-verbrücke Dirhenium- und Molybdän-Rhenium-Komplexanionen in Gegenwart eines Amidinkations

Insertion of a Terminal Halogeno Ligand into Diorgano-bridged Dirhenium and Rhenium-Molybdenum Complex Anions in the Presence of an Amidin Cation and the Isomerization Processes The equimolar reaction of in situ generated anion Anions Re₂(μ-PCy₂)(CO)₈^? (Re? Re) in the presence of a steric expansive amidine cation DBUH⁺ with bromine and iodine in tetrahydrofuran solution gave the two isomers Re₂(PCy₂)(CO)₈X (Re? Re) and Re₂(μ-PCy₂)(μ-X)(CO)₈ (X = Br, I), of which the isomer with a terminal X ligand as major product was formed under maintenance of the Re? Re bond. The monotropic isomerization process of Re₂(μ-PCy₂)(CO)₈I runs thermically relative slowly, but more rapid in photochemical and electrochemical processes. The analogeous reaction of the heterometallic anion ReMo(η⁵-C₅H₅)(μ-PPh₂)(CO)₆^? with iodine delivers opposite to the former reaction mainly the bridged isomer ReMo(η⁵-C₅H₅)(μ-PPh₂μ-I)(CO)₆ besides ReMo(η⁵-C₅H₅)(μ-PPh₂)(CO)₆I. The obtained complexes were characterized by means of v(CO) and ³¹P NMR spectroscopic measurements. Single-crystal analyses led to the subsequent metal—metal bond lengths: Re? Re of 308.0(1) pm in Re₂(μ-PCy₂)(CO)₈Br and Re? Mo of 313.6(1) pm in ReMo(η⁵-C₅H₅)(μ-PPh₂)(CO)₆I.     

Übergangsmetall-substituierte vb elementsysteme : VIII. Darstellung und komplexchemisches verhalten von cyclopentadienyl(tricarbonyl)viametall-dimethylstibinen

Starting with the cyclopentadienyl(carbonyl)metal anions [π-C₅H₅(CO)₃M]^? (M = Cr, Mo, W) and (CH₃)₂SbBr, transition metal-substituted stibines of the form π-C₅H₅(CO)₃MSb(CH₃)₂ are obtained. The nucleophilic character of the VB element primarily determines the reactivity of these species, and shows itself in alkyl halide quarternization (a) or ligand exchange on activated metal carbonyl complexes (b). (a) yields the trialkylstibine-substituted metal cations [π-C₅H₅-(CO)₃MSb(CH₃)₂R]X (R = CH₃, CH₂CH=CH₂, CH₂C₆H₅; X = Br, J), (b) leads to the formation of the metal carbonyl derivatives LM(CO)₅, L₂M(CO)₄ (M = Cr, Mo, W), LNi(CO)₃ and LFe(CO)₄ [L = (CH₃)₂SbM(CO)₃-π-C₅H₅] which are the first (CH₃)₂Sb-bridged polynuclear complexes. Phosphorus ylides cause heterolytic cleavage of the antimonytransition metal bond. Transfer of the (CH₃)₂Sb-group to the ylidic carbanion occurs via substitution/transylidation. All new compounds have been fully characterized by means of ¹H NMR, IR and mass spectroscopy     

Säureinduzierte carbin-acylumwandlung

The reaction of dicarbonyl- and carbonyl(trimethylphosphine)(cyclopentadienyl)-carbyne complexes of molybdenum and tungsten η⁵-C₅H₅(CO)_2−n(PMe₃)_nMCR (n = 0, 1; M = Mo, W; R = CH₃, C₆H₅, C₆H₄CH₃, C₃H₅) with protic nucleophiles HX (X = Cl, CF₃COO, CCl₃COO) leads, through a combined protonation/carbon-carbon coupling reaction, to η²-acyl complexes η⁵-C₅H₅(CO)_1−nX₂(PMe₃)_n-M(η²-COCH₂R). The reaction conditions, the results of the spectroscopic measurements and the X-ray structure of η⁵-C₅H₅(CO)(Cl₂)W(η²-COCH₂CH₃) are reported.     

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.     

Isomere η2-Acyl- und σ-Alkyl(carbonyl)-Komplexe von Molybdän und Wolfram. Eine Studie zum Bildungs-mechanismus,zur Isomerisierungsgeschwindigkeit und zur Steuerung der Gleichgewichtslage

η²-Acyl and σ-Alkyl(carbonyl) Coordination in Molybdenum and Tungsten Complexes: Synthesis and Studies of the Isomerization Equilibria and Kinetics The anionic molybdenum and tungsten complexes [L_RM(CO)₃]^? (L_R^? = [(C₅H₅)Co{P(O)R₂}₃]^?, R = OCH₃, OC₂H₅, O-i-C₃H₇; M = Mo, W) have been alkylated with the iodides R′ I, R′ = CH₃, C₂H₅, i-C₃H₇, and CH₂C₆H₅. The reactivity pattern of the alkylation is in accord with a S_N2 mechanism. Depending on M, R′, reaction temperature, and time the η-alkyl (carbonyl) compounds [L_RM(CO)₃R′] and/or the isomeric η²-acyl compounds [L_RM(CO)₂(η²-COR′)] can be obtained. 8 new σ-alkyl(carbonyl) compounds and 15 new η²-acyl compounds have been isolated and characterized. The ¹H NMR and the IR spectra give conclusive evidence that the σ-alkyl(carbonyl) compounds [L_RM(CO)₃R′] are formed as the primary products of the alkylation and that they isomerize partly or completely to give the η²-acyl compounds [L_RM(CO)₂(η²-COR′)]. The position of the equilibrium σ-alkyl(carbonyl)/η²-acyl is controlled by the steric demands of the groups R′ and the ligands L_R^?. The molybdenum compounds isomerize much more readily than the tungsten compounds. The rate constants of the isomerization processes [L_RMo(CO)₃CH₃] → [L_RMo(CO)₂(η²-COCH₃)], R = OCH₃, OC₂H₅, and O-i-C₃H₇, measured at 305 K in acetone-d₆, are 6–8 x 10^?3 s^?1.     

A carbon-13 NMR study of some metal carbonyl compounds containing one-electron ligands

Carbon-13 NMR spectral data for complexes having the general formula CpM(CO)_nX (Cp = η⁵-C₅H₅; M = Mo or W, n = 3; M = Fe, n = 2; X = halogen, methyl or acetyl) and their phosphine and isocyanide substitution products are reported. For CpM(CO)₃X complexes two carbonyl resonances (1 : 2 ratio) are observed in all cases, consistent with the retention of the “piano-stool” geometries observed in the solid state. Substituted complexes CpM(CO)₂(L)X (M = Mo or W; L = PR₃ or cyclohexyl isocyanide) are unequivocally assigned cis or trans geometries on the basis of the number of observed carbonyl resonances and values of ²J(PC) for the phosphine substituted derivatives. Spectral data for [M(CO)₅X]^? (M = Cr, Mo or W; X = Cl, Br or I) and η⁷-C₇H₇Mo(CO)₂X and the halide derivatives above generally show an increase in the shielding for carbonyls adjacent to the halide ligand in the order Cl < Br < I. Carbonyl resonances are more shielded in isostructural complexes in the order Cr < Mo < W (triad effect).     

Synthesis of allyl-transition metal complexes by phase transfer catalyzed reactions of metal carbonyl halides: III. Considerations of the mechanisms

Mechanisms are proposed for the hydroxide ion-initiated reactions of metal carbonyl halides which lead to allyl-transition metal complexes under phase transfer conditions. Evidence is presented for intermediate anionic metallocarboxylic acids in reactions leading to η³-allyl products of molybdenum, iron, ruthenium and manganese, whereas η¹ complexes are shown to result from halide displacement reactions in which simple metal carbonyl anions are generated. In some cases phosphorus-containing ligands inhibit the hydroxide-promoted reactions of metal carbonyl halides with allyl bromide; a rationale involving decreased acidity of the carbonyl ligands is presented. Syntheses of η³-C₃H₅Mn(CO)₃P(OCH₃)₃ and η³-C₃H₅Mn(CO)₂[P(OCH₃)₃]₂ by phase transfer catalysis are also described.     

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.     

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.     

Complexes du titane et du zirconium contenant les ligands cyclopentadienyldiphenylphosphine et cyclopentadienylethyldiphenylphosphine: acces a des structures heterobimetalliques

Reactions of Ph₂P(CH₂)_n(C₅H₄)Li, (n = 0, 2), with MCl₄ or CpTiCl₃ (M = Ti, Zr; Cp = η⁵-C₅H₅) form Cl₂M[(η⁵-C₅H₄)(CH₂)_nPPh₂]₂ or Cl₂CpTi[(η⁵-C₅H₄)-(CH₂)₂PPh₂] in good yields. Chemical reduction with Al, or electrochemical reduction of these complexes, under CO, are described. The titanium(IV) and zirconium(IV) derivatives react with metal carbonyls (Mo(CO)₆, Cr(CO)₆, Fe(CO)₅, Mo(CO)₄(C₈H₁₂)) under formation of new heterobimetallic complexes. Reduction with Al of Cl₂CpTi[(η⁵-C₅H₄)(CH₂)₂PPh₂]Mo(CO)₅ under CO results in a new heterobimetallic species containing low valent titanium. Both complexes Cl₂M[(η⁵-C₅H₄)(CH₂)₂PPh₂]₂ (M = Ti, Zr) react with [Rh(μ-Cl)(CO)(C₂H₄)]₂ to yield {RhCl(CO)(Cl₂M[(η⁵-C₅H₄)(CH₂)₂PPh₂]₂)}x, which is assumed to be a dimer, in which the titanium or the zirconium compounds act as bridging diphosphine ligands between the rhodium atoms.     

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.     

Zur Kenntnis der Chemie der Metallcarbonyle und der Cyanokomplexe in flüssigem Ammoniak. XXXII. Über die Reaktionen von η5-C5H5Mo(CO)3CH3 und η5-C5H5Fe(CO)2CH3 mit flüssigem Ammoniak

The Chemistry of Metal Carbonyls and Cyano Complexes in Liquid Ammonia. XXXII. On the Reaction of η⁵-C₅H₅Mo(CO)₃CH₃ and η⁵-C₅H₅Fe(CO)₂CH₃ with Liquid Ammonia η⁵-C₅H₅Mo(CO)₃CH₃ reacts with liquid NH₃ to give η⁵-C₅H₅Mo(CO)₂(NH₃)H and acetamide: In contrast, η⁵-C₅H₅Fe(CO)₂CH₃ undergoes a carbonyl insertion to give the acetyl complex η⁵-C₅H₅Fe(CO)(NH₃)COCH₃: The NH₃ ligand in η⁵-C₅H₅Fe(CO)(NH₃)COCH₃ can be substituted by pyridine.     

Bildung siliciumorganischer Verbindungen. 80. Die Si-Metallierung von 1,3,5-Trisilacyclohexanen mit Übergangsmetallkomplexen

Formation of Organosilicon Compounds. 80. Si-Metalation of 1,3,5-Trisilacyclohexanes by Means of Trisition Metal Complexes Several Si-transition metal-substituted 1,3,5-trisilacyclohexanes are reported. l-Bromo-1,3,5-trisilacyclohexane reacts with the metal carbonyl anions W(CO)₅cp^?, Mo(CO)₃cp-, Cr(CO)₃cp^?, Mn(CO)₃^?, Fe(CO)₂cp^?, or Co(CO)_4minus;, resp., yielding monosubstituted derivatives as 6, e. g.(cp = π-cyclopentadienyl). 1,3-Dibromo-1,3,5-trisilacyclohexane forms disubstituted compounds aa 7, e. g., with 2 moles of the metal carbonyl anions Fe(CO)₂cp^?, Mn(CO)₅^? or Co(CO)₄^?. Starting from (H₂c? SiHBr)₃ compound 13 is accessible by reaction with KCo(CO)₄. In the soluted compounds the metal carbonyl groups occupy the equatorial positions in the chair form of the six membered ring. The reaction of 13 with Co₂(CO)₈ yields 17 , whereas 6 preferrably forms 18 . Starting from (H₂C? SiH₂)3 the reaction with Co₂(CO)₂ preferrably yields 19. The reported compounds are crystalline, air – and moisture – sensitive. The reported formulae are assured by analysis, IR, and NMR investigations.     

(η5-C5R5)2Fe2(CO)2(μ-CO)(μ-CH2) (R = H,CH3): A convenient one-pot synthesis using chloromethyl pivalate

The compounds (η⁵-C₅R₅)₂Fe₂(CO)₂(μ-CO)(μ-CH₂) (R = H, CH₃) have been prepared through the reaction of chloromethyl pivalate with the appropriate metal anions, η⁵-C₅H₅Fe(CO)₂K and η⁵-C₅Me₅Fe(CO)₂K.     

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].     

Adamantylcyclopentadienyldicarbonyliron(II) compounds

Synthesis of 1- and 2-adamantyl derivatives of η⁵-cyclopentadienyldicarbonyliron is reported. The 2-adamantyl is prepared from the metal carbonyl anion but the 1-adamantyl derivative is prepared by decarbonylation of the acyl derivative. 1-adCOFe(CO)₂(η⁵-C₅H₅) is in turn prepared from 1-AdCOCl and NaFe-(CO)₂(η⁵-C₅H₅). Phosphine-substituted acyl derivatives AdCOFe(CO)(PR₃)-(η⁵-C₅H₅) are also reported.     

Metallkomplexe mit anionischen Liganden von Elementen der 4. Hauptgruppe. IX. Zum komplexchemischen Verhalten von Trichlorstannid-und Trichlorgermid-Ionen gegenüber Komplexen von Übergangsmetallen in niedrigen Oxydationsstufen

Metal Complexes with Anionic Ligands of the Main Group IV Elements. IX. Reactions of Trichlorostannide and Trichlorogermide Ions with Complexes of Transition Metals in Low Oxidation States Carhonyl trichlorostannido- and carbonyl trichlorogermido-metalate complexes have been synthesized both by photochemical and thermical substitution reactions of [ECl₃]^? ions (E = Sn, Ge) with M(CO)₆, (M = Cr, Mo, W), Fe(CO)₅ Fe₃(CO)₁₂, Co₂(CO)₈, as well as with the metalcarbonyl derivatives (π-arene)M(CO)₃, (M = Cr, Mo), (h⁵-C₅,H₅,)V(CO)₄, Mn(CO)₅,Cl, Co(NO)(CO)₃, and Fe(NO)₂,(CO)₂. Mainly the bonding properties of the [ECl₃]^? ligands are discussed by means of i.r. spectroscopic investigations. The progress of the reactions and the necessary reaction conditions show that the nucleophilic properties oft both anions [ECl₃]^? are unexpectedly small. The slightly weaker hasicity of [SnCl₃]^? compared with [GeC1₃]^? arreared, when both anions were reacted with Co₂,(CO)₈, forming the substitution product. [Co₂,(CO)₇,SnCl₃]^? and the products of a “base reaction” Cl₃GcCo(CO)₄, and [Co(CO)₄]^?.     

Supported metals and metal oxides as promoters for the metal dimer and cluster catalysed co substitution reaction

Promotional effects due to PtO₂, PdO, Pd/C and Pd/CaCO₃ on the metal dimer or cluster (e.g. [(η⁵-C₅H₅)Fe(CO)₂]₂, Ru₃(CO)₁₂, Ir₄(CO)₁₂) catalysed reaction between metal carbonyls and isonitriles are shown to lead to enhanced reaction rates for the metal carbonyl substitution reaction.     

SYNTHESIS OF ORGANOTRANSITION METAL COMPLEXES CONTAINING p-METHOXYCARBONYLBENZOYLCYCLO-PENTADIENYL AND p-METHOXYCARBONYLPHENYL (HYDROXYMETHYL)CYCLOPENTADIENYL LIGANDS FROM SODIUM p-METHOXYCARBONYLBENZOYLCYCLO-PENTADIENIDE. X-RAY STRUCTURE OF η5-p-MeO2CC6H4COC5H4Mo(CO)3I

Abstract

A new functionally substituted cyclopentadienyl salt p-MeO₂CC₆H₄COC₅H₄Na (1) was prepared from cyclopentadienylsodium and dimethyl terephthalate in THF, and which might be utilized to synthesize a series of novel transition metal complexes containing difunctional group-substituted cyclopentadienyl ligands; 1 reacted with M(CO)₆(M = Mo, W) followed by treatment with PBr₃ or I₂ to give mononuclear organomolybdenum (or tungsten) halides η⁵-p-MeO₂CC₆H₄COC₅H₄M(CO)3X(2, M = Mo, X = Br; 3, M = W, X = Br; 4, M = Mo, X = I; 5, M = W, X = I), whereas reaction of 1 with W(CO)₆ and successive treatment with selenium powder and MeI or PhCH₂Cl afforded mononuclear organotungsten selenolate complexes η⁵-p-MeO₂CC₆H₄COC₅H₄W (CO)₃SeMe (6) and η⁵-p-MeO₂CC₆H₄COC₅H₄W(CO)₃SeCH₂Ph (7). In addition, 1 reacted with M(CO)₆(M = Mo, W) followed by treatment with FeCo₂(CO)₉(μ₃-S) to produce the corresponding polynuclear complexes η⁵-p-MeO₂CC₆H₄COC₅H₄MFeCo(CO)₈(μ₃?S) (8, M = Mo; 9, M = W), which could be converted with NaBH₄ into hydroxyl derivatives η⁵-p-MeO₂CC₆H₄CH(OH)C₅H₄MFeCo(CO)₈(μ₃?S) (10, M = Mo; 11, M = W). All the new transition metal complexes 2–11 have been fully characterized by elemental analysis, IR and ¹H NMR spectroscopy, as well as for 4 by an X-ray diffraction analysis.