Carbonyl-Monoolefin-Derivate des Chroms,Molybdäns und Wolframs. I. Tetracarbonyl-Phosphin-Olefin-Komplexe

Carbonyl Monoolefin Derivatives of the Group VI Transition Metals. I. Tetracarbonyl Phosphine Olefin Complexes Monoolefin complexes cis-M(CO)₄(PR₃)(olefin) (M ? Cr, Mo, W; R ? Et, Bu, Prⁱ, Ph; olefin ? maleic anhydride, dimethyl maleate, dimethyl fumarate, bis(trimethylsilyl) fumarate, ethylene) are obtained from the ionic compounds Et₄N[R₃PM(CO)₄Cl] either via ethanol or acetonitrile derivatives M(CO)₄(PR₃)L, or directly in a two phase system. The olefins are displaced by Lewis-bases such as amines or phosphines under mild conditions.     

Übergangsmetallphosphido-Komplexe. XIV. P-funktionelle phosphidoverbrückte Heterozweikern-komplexe mit und ohne Metall- Metall-Bindung; PH2-verbrückte cp(CO)xFe-Derivate

Transition Metal Phosphido Complexes. XIV. P-Functional Phosphido-Bridged Heterobimetallic Complexes with and without a Metal-Metal Bond; PH₂-Bridged cp(CO)_xFe-Derivatives Cleaving both Si? P bonds in the complexes cp(CO)₂[μ-P(SiMe₃)₂]M′L_m 1 (M′L_m = Co(CO)₂(NO) b , Fe(CO)(NO)₂ c Mn(NO)₃ d , Cr(CO)₅ f , Mo(CO)₅ g , W(CO)₅ h , Mncp(CO)₂ i , MnMecp(CO)₂ j , Crcp(CO)(NO) k , Vcp(CO)₃ l ) using CH₃OH, H₂O or CH₃COOH, respectively, gives the PH₂-bridged bimetallic complexes cp(CO)₂Fe(μ-PH₂)M′L_m 2b – d and 2f – l . The complexes H₃PM′L_m 4e, 4f, 4j (M′L_m = Fe(CO)₄ e ) which can be obtained reacting the P-silylated derivatives (Me₃Si)₃PM′L_m with CH₃OH can be transformed into LiH₂PM′L_m 5e, 5f, 5j using n-BuLi. 5e, 5f, 5j react with cp(CO)₂ FeBr to give 2e, 2f, 2j . The photochemical decarbonylation of 2b - l leads only in the case of 2i and 2j to isolable complexes containing a metal-metal bond cp(CO)Fe(μ-CO, μ-PH₂) M′L_m?1 6 (M′L_m?1 = Mncp(CO) i , MnMecp(CO) j ). 6i and 6j as well as 6k (M′L_m?1 = Crcp(NO) k ) are also available cleaving both Si? P bonds in cp(CO)Fe[μ-CO, μ-P(SiMe₃)₂]M′L_m?1 8i – k using CH₃OH. In other complexes 6 the PH₂-bridge causes a labilisation of the metal-metal bond. This can be used in some cases to add ligands under mild conditions. I.R., N.M.R. and mass spectral data are reported.     

Phosphinsubstituierte Chelatliganden. XVIII. Penta- und Tetracarbonylmetall-Komplexe des Chroms,Molybdäns und Wolframs mit sekundären und tertiären Phosphinothioformamid-Liganden

Phosphine Substituted Chelate Ligands. XVIII. Penta- and Tetracarbonylmetal Complexes of Chromium, Molybdenum, and Tungsten with Secondary and Tertiary Phosphinothioformamide Ligands Mono- and bidentately coordinated phosphinothioformamide complexes are obtained by photochemical substitution of the metal hexacarbonyls M(CO)₆ (M ? Cr ( a ), Mo ( b ), W ( c )). The M(CO)₅ · THF adducts react with secondary thioamides under exclusion of light to give the P-coordinate pentacarbonyl complexes [(CO)₅MPPh₂C(S)NHR¹] (R¹ ? Ph ( 1a – c ), Me ( 2a )). The photoreaction of M(CO)₅ · THF with secondary and tertiary thioamides at low temperatures leads to the formation of the P, S-chelate complexes . The corresponding N-silylated complexes 6a – c (R¹ ? Me₃Si, R² ? Ph) are obtained by direct photosubstitution of M(CO)₆ in cyclohexane solution. The labile bis(thioformamide) complexes [(CO)₄M(PPh₂C(S)NHMe)₂] ( 7a – c , cis-trans isomers) are synthesized in low yields according to the same procedure. The attempted alkylation of the chelate complexes 3a – c remains unsuccessful, whereas the secondary thioformamides react with n-BuLi/CH₂Br₂ to give the methylene bis(thioformirnidoesters) [Ph₂PC(NR¹)S]₂CH₂ (R¹ ? Ph (8), Me ( 9 )) in quantitative yields.     

Wolframkomplexe von Diphosphanylacetylenen

Tungsten Complexes of Diphosphanylacetylenes Diphosphanylacetylenes, R₂P? C?C? PR₂ [R?N(C₂H₅)₂ ( 1 ), N[(CH₂)₂]₂O ( 2 ), OCH₃ ( 3 )] and W(CO)₅ · tetrahydrofurane form the mononuclear complexes R₂P? C?C? PR₂ · W(CO)₅ [R?N(C₂H₅)₂ ( 1a ), N[(CH₂)₂]₂O ( 2a )], the dinuclear complexes (CO)₅W? PR₂? C?C? PR₂? W(CO)₅ [R?N(C₂H₅)₂ ( 1b ), N[(CH₂)₂]₂O ( 2b ), OCH₃ ( 3b )], and the trinuclear complex (CO)₅W? PR₂? C?C? PR₂? W(CO)₄? PR₂? C?C? PR₂? W(CO)₅ [R?N(C₂H₅)₂ ( 4 )]. The new compounds are characterized by their NMR, mass, and IR spectra. The results of an X-ray structural analysis of 4 are reported.     

Übergangsmetallphosphidokomplexe. XIII. P-funktionelle phosphidoverbrückte Heterozweikernkomplexe mit und ohne Metall-Metall-Bindung; P(SiMe3)2-verbrückte cp(CO)xFe-Derivate

Transition Metal Phosphido Complexes. XIII. P-functional Phosphido-Bridged Heterobimetallic Complexes with and without a Metal-Metal Bond; P(SiMe₃)₂-Bridged cp(CO)_xFe Derivatives cp(CO)₂FeP(SiMe₃)₂ 1 reacts with the carbonyl nitrosyl complexes Co(CO)₃(NO), Fe(CO)₂(NO)₂,Mn(CO)(NO)₃ substituting a CO ligand and with the THF complexes M′(CO)₅THF(M′ = Cr, Mo, W), Mncp(CO)₂THF MnMecp(CO)₂ which can be obtained in solution substituting the THF ligand to give the phosphido-bridged bimetallic complexes cp(CO)₂Fe[μ-P(SiMe₃)₂]M′L_m 2 (M′L_m = Co(CO)₂(NO) b , Fe(CO)(NO)₂ c , Mn(NO)₃ d , Cr(CO)₅ f , Mo(CO)₅ g , W(CO)₅ h , Mncp(CO)₂ i , MnMecp(CO)₂ j ). Solutions of Li(Me₃Si)₂PM′L_m 4e–l (M′L_m = Fe(CO)₄ e , Crcp(CO)(NO) k , Vcp(CO)₃ l ) are available by a selective cleavage reaction of a Si? P bond in the complexes (Me₃Si)₃PM′L_m 3e–l using n-BuLi. Reactions of cp(CO)₂FeBr with 4e–l give the bimetallic complexes 2e–l . The open-chain complexes 2c, 2f, 2h–k undergo a photochemical decarbonylation reaction to form the phosphido-bridged bimetallic complexes cp(CO)Fe[μ-CO, μ-P(SiMe₃)₂]M′L_m?1(Fe-M′) 5 (M′L_m?1 = Fe(NO)₂ c , Cr(CO)₄ f , W(CO)₄ h , Mncp(CO) i , MnMecp(CO) j , Crcp(NO) k ) containing a metal-metal bond. Equilibria between various isomers can partially be observed in solutions of the complexes 5. I.R., N.M.R., and mass spectral data are reported.     

Metallkomplexe mit anionischen Liganden von Elementen der 4. Hauptgruppe. VII. Über das Substitutionsverhalten von Carbonylnitrosyl-und Nitrosyltrifluorphosphin-Übergangsmetallkomplexen gegenüber Trichlorstannid-Ionen

Metal Complexes with Anionic Ligands of Elements of the Main Group IV. VII(¹) Substitution Reactions of Carbonylnitrosyl and Nitrosyltrifluorophosphine Transition Metal Complexes with Trichlorostannid L-substitution by [SnCl₃]^? occurs if the nitrosyl complexes Co(NO)L₃ and Fe(NO)₂L₂ (L = CO or PF₃) are reacted with [N(C₂H₅)₄][SnCl₃] thermically in tetrahydrofuran as well as photochemically induced in methylenechloride. The complexes Co(NO)L₃ yield the mono-substitution products [N(C₂H₅)₄][Co(NO)L₂SnCl₃], with the iron compounds Fe(NO)₂L₂ only the disubstituted derivative [N(C₂H₅)₄]₂[Fe(NO)₂(SnCl₃)₂] can be isolated. On the other hand CO substitution at (π-C₅H₅)Mo(NO)(CO)₂ by UV irradiation did not suceed both with [SnCl₃]^? and with PF₃. From the IR-spectroscopic data a leastly with PCl₃ comparable π-acceptor ability is derived for the trichlorostannido ligand.     

A study of the photochemistry and thermal chemistry of Ru3(CO)9(PR3)3{R = Ph,OMe} with two-electron donor ligands

The photochemistry of the tris-substituted clusters Ru₃(CO)₉(PR₃)₃ (R=Ph or OMe) with no added ligands, with CO, C₂H₄, alkynes and H₂ is compared and contrasted with results obtained for analogous thermal reactions. Photolysis of a CH₂Cl₂ solution of Ru₃(CO)₉(PPh₃)₃ leads to the metallated complex HRu₃(CO)₈(PPh₃)₂(PPh₂C₆H₄). In CCl₄, Ru(CO)₃(PR₃)Cl₂ is formed on photolysis of Ru₃(CO)₉(PR₃)₃. Photolysis of CO saturated solutions of Ru₃(CO)₉(PR₃)₃ leads to Ru(CO)₄(PR₃). C₂H₄ saturated solutions of Ru₃(CO)₉(PR₃)₃ generate the novel Ru(CO)₃(PR₃)(²-C₂H₄) complexes upon photolysis. With C₂H₂, photolysis of solutions of Ru₃(CO)₉(PR₃)₃ leads to the novel complexes Ru(CO)₃(PR₃)(²-C₂H₂). Substituted alkyne complexes have been prepared. Thermolysis of Ru₃(CO)₉(PR₃)₃ with HCCPh leads to the novel acetylide clusters HRu₃(CO)₆(PR₃)₃(₃-²-C₂Ph). With PhC CPh, only Ru₃(CO)₉{P(OMe)₃}₃ reacts, yielding the novel alkyne cluster Ru₃(CO)₆{P(OMe)₃}₃(₃-²-C₂Ph₂). With H₂, photolysis of CH₂Cl₂ solutions of Ru₃(CO)₉(PR₃)₃ leads to H₂Ru(CO)₂(PR₃)₂. Irradiating a 4:1 CH₂Cl₂ to EtOAc solution of Ru₃(CO)₉(PR₃)₃ under an atmosphere of H₂ leads to the novel dihydrido species H₂Ru₃(CO)₇(PR₃)₃. Thermolysis of H₂ saturated solutions of Ru₃(CO)₉(PR₃)₃ leads to H₄Ru₄(CO)₈(PR₃)₄.     

Schwefeldioxid als Ligand und Synthon. IX. Reaktionen von Cobaltcarbonylen mit Schwefeldioxid – Synthese und Charakterisierung von Alkoxysulfinyl-Cobaltcarbonyl-Komplexen

Sulfur Dioxide as Ligand and Synthon. IX. Reactions of Cobalt Carbonyls with Sulfur Dioxide – Synthesis and Characterization of Alkoxysulfinyl-Cobalt Carbonyl Complexes Reactions of phosphine substituted Co₂(CO)₈, (Ph₂P–(CH₂)_n–PPh₂: n = 1, dppm; n = 2, dppe; n = 3, dppp; n = 4, dppb), alkylcobalt carbonyls and alkoxycobalt carbonyls with sulfur dioxide have been investigated. The SO₂ containing cobalt complexes are characterized by means of I.R., ¹H-NMR, and mass spectra. Further on synthesis and properties of new alkoxysulfinylphosphine-cobalttricarbonyl complexes of the type ROS(O)Co(CO)₃PR₃¹ (R = Ph₃Si, Me; R¹ = Et, i-Pr, Ph) are described.     

Synthesis, spectroscopic and structural characterisation of molybdenum, tungsten and manganese carbonyl complexes of tetrathio- and tetraseleno-ether ligands

A range of complexes of the binucleating tetrathio- and tetraseleno-ether ligands, 1,2,4,5-C₆H₂(CH₂EMe)₄ (E = S, L³ or Se, L⁴) or C(CH₂EMe)₄ (E = S, L⁵ or Se, L⁶) and of bidentate analogues 1,2-C₆H₂(CH₂EMe)₂ (E = S, L¹ or Se = L²) with molybdenum and tungsten carbonyls and manganese carbonyl chloride have been prepared, and characterised by IR and multinuclear NMR (¹H, ¹³C{¹H}, ⁷⁷Se, ⁵⁵Mn, ⁹⁵Mo) spectroscopy and mass spectrometry. Crystal structures are reported for [Mo(CO)₄(L²)], [Mo(CO)₄(L³)], [Mo(CO)₄(μ-L³)Mo(CO)₄], [Mo(CO)₄(L⁴)], [Mn(CO)₃Cl(μ-L³)Mn(CO)₃Cl], [Mo(CO)₄(μ-L⁵)Mo(CO)₄], [Mn(CO)₃Cl(L⁵)] and two forms (containing meso and DL diastereoisomers) of [W(CO)₄(L⁵)].     

Nitrogen donor ligands bearing N–H groups: Effect on catalytic and cytotoxic activity of molybdenum η3-allyldicarbonyl complexes

Reactions of [Mo(η³-C₃H₅)Br(CO)₂(NCMe)₂] with the bidentate nitrogen ligands 2-(2′-pyridyl)imidazole (L1), 2-(2′-pyridyl)benzimidazole (L2), N,N′-bis(2′-pyridinecarboxamido)-1,2-ethane (L3), and 2,2′-bisimidazole (L4) led to the new complexes [Mo(η³-C₃H₅)Br(CO)₂(L)] (L = L1, 1; L2, 2; L4, 4) and [{Mo(η³-C₃H₅)Br(CO)₂}₂(μ-L3)] (3).The reaction of complexes 2 and 3 with Tl[CF₃SO₃] afforded [Mo(η³-C₃H₅)(CF₃SO₃)(CO)₂(L2)] (2T) and [{Mo(η³-C₃H₅)(CF₃SO₃)(CO)₂}₂(μ-L3)] (3T).Complexes 3 and 2T were structurally characterized by single crystal X-ray diffraction, showing the facial allyl/carbonyls arrangement and the formation of the axial isomer. In 2T, two molecules are assembled in a hydrogen bond dimer.The four complexes 1–4 were tested as precursors in the catalytic epoxidation of cyclooctene and styrene, in the presence of t-butylhydroperoxide (TBHP), with moderate conversions and turnover frequencies for complexes 1–3 and very low ones for 4. The increasing number of N–H groups in the complexes seems to be responsible for the loss of catalytic activity, compared with other related systems. The cytotoxic activities of all the complexes were evaluated against HeLa cells. The results showed that compounds 1, 2, 4, and 2T exhibited significant activity, complexes 2 and 2T being particularly promising.     

Molybdenum(0) and Tungsten(0) Complexes with P,S and P,Se Monooxidized Bis(phosphanyl)amine Ligands

Reactions of monooxidized thioyl and selenoyl bis(phosphanyl)amine ligands C₁₀H₇‐1‐N(P(E)Ph₂)(PPh₂) [E = S ( 1 ), Se ( 2 )] with Mo(CO)₄(pip)₂ and W(CO)₄(cod) afforded the complexes [M(CO)₄{ 1 ‐κ²P,S}] [M = Mo ( 3 ), W ( 4 )] and [M(CO)₄{ 2 ‐κ²P,Se}] [M = Mo ( 5 ), W ( 6 )]. Complexes 3 – 6 were characterized by multinuclear NMR (¹H, ¹³C, ³¹P, and ⁷⁷Se NMR) and IR spectroscopy. Crystal‐structure determinations were carried out on 3 , 5 , and 6 , which represent the first examples of structurally characterized complexes of such ligands with group‐6 metal carbonyls.     

Carbonylcobalt(I) complexes. The crystal and molecular structure of [Co(CO)(dppm)2]ClO4

New anionic carbonylcobalt(I) complexes [X₂Co(CO)₂(PPh₃)](PR₄) (X=Cl, PR₄ = PBzPh₃ (I); X = Br, PR₄ = PEtPh₃ (II)) have been prepared by reduction of the cobalt(II) halides with NaBH₄ in the presence of PPh₃ and the phosphonium salt PR₄X. Cleavage of halide bridges in dimeric or polymeric [XCo(PPh₃)₂]_n and [XCo(PPh₃)]_n gives the neutral dicarbonyl derivatives XCo(CO)₂PPh₃)₂. Treatment of ClCo(CO)₂(PPh₃)₂ with alkylating agents gives the known σ- and η- organocobalt(I) derivatives, and reactions with TIClO₄ in the presence of various amounts of different mono- and bi-dentate phosphines give the cationic tricarbonyl [Co(CO)₃(PPh₃)₂]⁺, dicarbonyl [Co(CO)₂(PMePh₂)₃]⁺ and monocarbonyl [Co(CO)L₄]⁺ complexes (L₄ = 4P(OMe)₃, 2 dppe and 2dppm). The dppm complex crystallizes in the monoclinic space group P2₁/c with a 17.895(6), b 10.751(2), c 24.687(4) Å, β 98.92(1)°, and D_calc 1.35 g cm⁻³ for Z = 4. A final R value of 0.077 ( R_w = 0.061), based on 2656 observed reflections, was obtained. The cobalt atom exhibits a distorted trigonal bipyramidal geometry. The perchlorate anion is severely disordered or freely rotating.     

Phosphido- und arsenido-verbrückte Zweikernkomplexe: Synthese und Struktur von (η5-C5H4R)2Zr{μ-P(SiMe3)2}2M(CO)4 (R = Me,M = Cr; R = H,M = Mo) sowie die Synthese von (η5-C5H5)2Zr{μ-As(SiMe3)2}2Cr(CO)4

Phosphido- and Arsenido-bridged Dinuclear Complexes. Synthesis and Molecular Structure of (η⁵-C₅H₄R)₂Zr{μ-P(SiMe₃)₂}₂M(CO)₄ (R = Me, M = Cr; R = H, M = Mo) and Synthesis of (η⁵-C₅H₅)₂Zr{μ-As(SiMe₃)₂}₂Cr(CO)₄ The reaction of (η⁵-C₅H₄R)₂Zr{E(SiMe₃)₂}₂ with M(CO)₄(NBD) (NBD = norbornadiene) yields the dinuclear phosphido- or arsenido-bridged complexes (η⁵-C₅H₄R)₂Zr{μ-E(SiMe₃)₂}₂M(CO)₄ (R = Me, E = P, M = Cr ( 1 ); R = H, E = P, M = Mo ( 2 ); R = H, E = As, M = Cr ( 3 )). No formation of dinuclear complexes was observed in the reaction of (η⁵-C₅H₄Me)₂Zr{P(SiMe₃)₂}₂ with Ni(PEt₃)₄, Ni(CO)₂(PPh₃)₂ or with NiCl₂(PPh₃)₂ in the presence of Mg. Complexes 1 – 3 were characterised spectroscopically (i. r., n. m. r., m. s.), and X-ray structure investigations were carried out on 1 and 2 . The central four-membered ZrP₂M ring is slightly puckered (dihedral angle between planes ZrP₂/CrP₂ 14.7°, ZrP₂/MoP₂ 14.2°). The Zr? P bond lengths are equivalent ( 1 : Zr? P1 2.654(4), Zr? P2 2.657(4) Å; 2 : Zr? P1 2.6711(9), Zr? P2 2.6585(7) Å), as are the M? P bond lengths (M = Cr ( 1 ): Cr? P1 2.513(4), Cr? P2 2.502(4) Å; M = Mo ( 2 ): Mo? P1 2.6263(7), Mo? P2 2.6311(10) Å). The long Zr ··· M distances of 3.414 Å (M = Cr ( 1 )) and 3.461 Å (M = Mo ( 2 )) indicate the absence of a metal-metal bond.     

Kinetische Untersuchungen über Substitutionsreaktionen an Metallkomplexen. 7. Mitteilung [1]. Kinetik und Mechanismus der Reaktion von Methoxyorganylcarbenpentacarbonyl-chrom-Verbindungen mit tertiären Phosphinen

The kinetics of the reactions of methoxyorganylcarbenechromium complexes Cr(CO)₅C(OCH₃)R′ (R′ = CH₃, C₆H₅) with tertiary phosphines PR₃ have been studied by means of spectrophotometric methods. The reaction products of general composition cis-Cr(CO)₄(PR₃)C(OCH₃)R′, Cr(CO)₅PR₃ and trans-Cr(CO)₄(PR₃)₂ are formed by cleavage of both the Cr-CO and the Cr-C(carbene) bonds. The two-term rate law indicates two parallel, dissociative and associative, mechanisms. The kinetic data will be discussed in connection with the concept of labilising and non-labilising ligands.     

The Simplest Amino‐borane H2B=NH2 Trapped on a Rhodium Dimer: Pre‐Catalysts for Amine–Borane Dehydropolymerization

The μ‐amino–borane complexes [Rh₂(L^R)₂(μ‐H)(μ‐H₂B=NHR′)][BAr^F₄] (L^R=R₂P(CH₂)₃PR₂; R=Ph, ⁱPr; R′=H, Me) form by addition of H₃B?NMeR′H₂ to [Rh(L^R)(η⁶‐C₆H₅F)][BAr^F₄]. DFT calculations demonstrate that the amino–borane interacts with the Rh centers through strong Rh‐H and Rh‐B interactions. Mechanistic investigations show that these dimers can form by a boronium‐mediated route, and are pre‐catalysts for amine‐borane dehydropolymerization, suggesting a possible role for bimetallic motifs in catalysis.     

Elektronenreiche übergangsmetallkomplexe : II. Nitril-phosphan-molybdändicarbonyle: Farbe und solvatochromie

Complexes of aromatic or α,β-unsaturated nitriles YCN of the type (YCN)₂(PR₃)₂Mo(CO)₂ and (YCN)(PR₃)₃Mo(CO)₂ are new chromophores. Their intense electronic absorption band in the visible spectrum is strongly influenced by substituents and solvent polarity. Acceptor properties of nitriles are discussed on the basis of CNDO-calculations. CT-character and solvato-chromism can be interpreted in terms of the back-bonding ability of the nitriles in electron-rich metal complexes.     

Silicon containing ferrocenyl phosphane ligands

New ferrocenyl phosphane ligands incorporating Si-P linkages, [(η-C₅H₄SiMe₂PR₂)₂Fe], where R=Ph and Me, and the corresponding metal complexes [Mo(CO)₄(L)] have been prepared and characterised. The molecular structures of [(η-C₅H₄SiMe₂PR₂)₂Fe], where R=Ph and Me have been determined by single crystal X-ray diffraction.     

Metallkomplexe mit biologisch wichtigen Liganden. LXXXII. Triphenylphosphan-Molybdän-, Wolfram-, Ruthenium- und Iridium-Komplexe mit N-acylierten α-Aminocarboxylaten

Metal Complexes of Biological Important Ligands. LXXXII. Triphenylphosphine Molybdenum, Tungsten, Ruthenium, and Iridium Complexes of N-Acyl-α-Aminocarboxylates The reactions of the hydrido complexes RuHCl(CO) · (PPh₃)₃, RuH₂(PPh₃)₄ and IrH₃(PPh₃)₃ with N-acyl-α-aminocarboxylates give the carboxylate complexes RuCl(O₂CCHRNHCOR′)(CO)(PPh₃)₂ ( 1–3 ), RuH(O₂CCHRNHCOR′)(PPh₃)₃ ( 4–6 ) and IrH₂(O₂CCH₂NHCOPh)(PPh₃)₃ ( 7 ). The structure of RuCl · (O₂CCHNHCOPh)(CO)(PPh₃)₂ ( 1 ) has been determined by x-ray diffraction. The triphenylphosphine complexes MBr · (O₂CCH₂NHCOR)(CO)₂(PPh₃)₂ (M = Mo, W) ( 8–12 ) and Mo(O₂CCHRNHCOR′)₂(CO)₂(PPh₃)₂ ( 13–17 ) are formed from MBr₂(CO)₂(PPh₃)₂ (M = Mo, W) with one or two equivalents of N-acyl-a-aminoacidates, respectively.     

Reactions of M2Cl4(PR3)4 (M  Mo and W) with carbon monoxide

The reactions of M₂Cl₄(PR₃)₄ derivatives (M  Mo, W and PR₃  PEt₃, PBu₃ⁿ) with CO at atmospheric pressure in toluene at 70°C to afford M(CO)₃(PR₃)₂Cl₂ and trans-M(CO)₄(PR₃)₂ are reported.     

Reactions of Cyclohexyl Isocyanide with η5‐Substituted Cyclo‐pentadienyl MoMo Triply Bonded Complexes. Crystal Structure of [Mo(CO)2(η5‐C5H4CO2CH3)]2(μ‐η2‐CNC6H11)

Reactions of one or two equiv. of cyclohexyl isocyanide in THF at room temperature with Mo?Mo triply bonded complexes [Mo(CO)₂(η⁵‐C₅H₄R)]₂ (R=COCH₃, CO₂CH₃) gave the isocyanide coordinated Mo? Mo singly bonded complexes with functionally substituted cyclopentadienyl ligands, [Mo(CO)₂(η⁵‐C₅H₄R)]₂(μ‐η²‐CNC₆H₁₁) ( 1a , R=COCH₃; 1b , R=CO₂CH₃) and [Mo(CO)₂(η⁵‐C₅H₄R)(CNC₆H₁₁)]₂ ( 2a , R=COCH₃; 2b , R=CO₂CH₃), respectively. Complexes 1a , 1b and 2a , 2b could be more conveniently prepared by thermal decarbonylation of Mo? Mo singly bonded complexes [Mo(CO)₃(η⁵‐C₅H₄R)]₂ (R=COCH₃, CO₂CH₃) in toluene at reflux, followed by treatment of the resulting Mo?Mo triply bonded complexes [Mo(CO)₂(η⁵‐C₅H₄R)]₂ (R=COCH₃, CO₂CH₃) in situ with cyclohexyl isocyanide. While 1a , 1b and 2a , 2b were characterized by elemental analysis and spectroscopy, 1b was further characterized by X‐ray crystallography.