Coordinated 2-halo-1,3,2-dioxaphosphorinane ligands. II. Syntheses and 13C, 31P and 95Mo NMR and IR spectroscopic characterization of some Cr and Mo pentacarbonyl complexes of 2-substituted-4-methyl-1,3,2-dioxaphosphorinanes

A study of the reactions of M(CO)₅(P(OCH₂CH₂CH(Me)O)Cl) (M=Cr, Mo) with a variety of nucleophiles of the type HER (E=NH, O, S; R=H, alkyl, aryl) is reported. The ¹³C, ³¹P and ⁹⁵Mo NMR and IR spectral data for the M(CO)₅(P(OCH₂CH₂CH(Me)O)ER) complexes is presented and compared to that previously reported for some Mo(CO)₅(P(OCH₂CMe₂CH₂O)ER) complexes. This comparison provides insight into the manner in which variations in the metal and in the substitution on the 1,3,2-dioxaphosphorinane ring affect the electron density distribution within these complexes.The results from a study of the rates of chloride substitution by n-propylamine in the M(CO)_s(P(OCH₂CH₂CH(Me)O)Cl) complexes are also presented. These rates are compared with those previously reported for chloride substitution by n-propylamine in the Mo(CO)₅(P(OCH₂CMe₂CH₂O)Cl) and Mo(CO)₅(Ph₂PCl) complexes. These comparisons, in conjunction with the NMR and IR studies, suggest that both the position of the Me groups on the phosphorinane ring and the amount of electron density on the P have significant effects upon the rate of chloride substitution in these complexes.     

Preparation and multinuclear NMR and IR spectroscopic characterization of some complexes of acetyldiphenylphosphine,diphenyl(2-thienyl)phosphine,bis(2-thienyl)phenylphosphine and cyanodiphenylphosphine

The syntheses and multinuclear NMR and IR spectroscopic characterizations of some mononuclear Mo, Pd and Pt complexes of acetyldiphenylphosphine, diphenyl(2-thienyl)phosphine, bis(2-thienyl)phenylphosphine and cyanodiphenylphosphine are presented. The NMR and IR spectra of the Mo carbonyl complexes indicate that the electron-donor ability of the P substituents increases in the order CN < C(O)Me < 2-thienyl < Ph. The reactions of free and coordinated acetyldiphenylphosphine with amines and borohydrides are reported. These reactions do not lead to the desired imino and hydroxymethyl complexes but rather result in PC bond cleavage. Attempts to form dinuclear complexes with bridging 2-thienylphosphine ligands from mononuclear complexes with P-coordinated ligands have not been successful. The products of the reactions result from ligand exchange between the mononuclear precursors and contain only P-coordinated ligands .The structure suggested for a previously reported homodinuclear complex containing a bridging cyanophenylphosphine ligand, [(CO)₅Mo(Ph₂PCN)]₂, has been confirmed by multinuclear NMR and IR spectroscopic studies. An attempt to form a heterodinuclear MoPt complex with bridging cyanophosphine ligands has not been successful. The products of this reaction result from ligand exchange between the mononuclear precursors.     

MonodentateN coordination of 1aza4oxo1,3butadienes [R1NC(R2)C(R3)O] to platinum(II). X-ray structure of trans-[PtCl2(PEt3){σ-N-(t-BuNCHC(Me)O)}]

Reaction of dimeric trans-[PtCl₂(PR₃)]₂ with 1-aza-4-oxo-1,3-butadienes [R¹NC(R²)C(R³)O, R³ = Me, Ph, OMe, NEt₂] in a 1:2 molar ratio results in almost quantitative formation of mononuclear complexes trans·[PtCl₂(PR₃){σ-N-(R¹NC(R²)C(R³)O)}]. The ligands are bonded in the monodentate σ-N bonding mode to the platinum(II) centre. This has been established by an X-ray structure determination of trans-[PtCl₂(PEt₃){σ-N-(t-BuNCHC(Me)O)}]. Crystals of the latter compound are orthorhombic with space group Pc2₁n; cell constants are a = 14.712(3), b = 15.053(2), c = 9.025(5) Å, Z= 4 and R_w = 0.056 for 3281 reflections. The 1aza4oxol,3butadiene (α-iminoketone for R³ is alkyl or aryl) has the E-configuration about the imine bond (CN 1.34(4) Å), with a C(5)C(6) distance of 1.44(5) Å and a NC(5)/ C(6)O torsion angle of 89(4)°. As a result of this ligand conformation, the acetyl hydrogen atoms are positioned (on average) into the neighbourhood of the Pt-atom above the Pt-coordination plane. Infrared and NMR (¹H, ¹³C, ³¹p) data show that these structural features are also predominant in solution.     

Synthesis and spectroscopic properties of some new seven-coordinate thioacetamide complexes of molybdenum(II) and tungsten(II)

The compounds [MI₂(CO)₃(NCMe)₂] (M = Mo or W) react with one equivalent of SC(NH₂)Me in CH₂Cl₂ at room temperature to initially give the acetonitrile substituted products [MI₂(CO)₃(NCMe)- {SC(NH₂)Me}] which was isolated for M = W. However, the molybdenum complex rapidly dimerizes with loss of acetonitrile to give the iodide-bridged compound [Mo(σ-I)I(CO)₃ {SC(NH₂)Me}]₂. The tungsten complex does not appear to dimerize, even after stirring at room temperature for 72 h in CH₂Cl₂. Two equivalents of thioacetamide react with [MI₂- (CO)₃(NCMe)₂] in CH₂Cl₂ at room temperature to give the new bisthioacetamide compounds [MI₂- (CO)₃{SC(NH₂)Me}₂] via displacement of the labile acetonitrile ligands. The low temperature (−70 °C) ¹³C NMR spectrum of [WI₂(CO)₃{SC(NH₂)Me}₂] indicates that the geometry of the complex is capped octahedral with a carbonyl ligand in the unique capping position.     

Some new derivatives of organozirconium(IV) and organotitanium(IV) with thiophenecarboxylic acids

The complexes of the type Cp₂M(3-TC)Cl, Cp₂M(3-TC)₂, Cp₂M(3-TA)Cl, Cp₂M(3-TA)₂, Cp₂M(2-TB)Cl, Cp₂M(2-TB)₂ [where Cp = cyclopentadienyl, M = Zr or Ti] were synthesized by the reactions of dichlorobis(cyclopentadienyl)zirconium(IV) and dichlorobis(cyclopentadienyl)titanium(IV) with 3-thiophenecarboxylic acid (3-TCH), 3-thiopheneacetic acid (3-TAH) and 2-thiophenebutyric acid (2-TBH) respectively in different stoichiometric ratios. The new complexes were characterized by their elemental analysis, ¹H NMR, IR, and electronic spectral data.     

Gold acyls and imidoyls prepared from anionic Fischer-type carbene complexes

Reaction of [(CO)₅WC(O)Ph]Li or [(CO)₅WC(O)Ph]NBu₄ with Ph₃PAuCl affords acyl complexes of gold. In the latter conversion, both the crystalline products [(CO)₅WCl]NBu₄ (2) and Ph₃PAuC(O)Ph (3) have been isolated and fully characterised. Similarly, imidoyl gold compounds (4-8) result from deprotonated aminocarbene complexes, [(CO)₅MC(NR²)R¹]Li (M = Cr, W; R¹ = Ph, Me; R² = H, Me) and Ph₃PAuCl. Crystal and molecular structure determinations of dinuclear [Ph₃PAuC(NH)Ph] · Cr(CO)₅ (6) show N-coordination of the chromium carbonyl unit that selectively affords a Z-isomer.     

The reactions of organosulfur transfer reagents with Fe2(CO)9 and the synthesis of the Fe2(CO)6 derivative of α-lipoic acid

Treatment of Fe₂(CO)₉ with sulfur-transfer reagents of the types ImideSSImide and RSSImide where H-imide = phthalimide, succinimide, benzimidazole, morpholine and piperazine, and R  CH₂Ph and CMe₃ leads to cleavage of both the sulfursulfur bond and the sulfurnitrogen bond to give Fe₃(CO)₉S₂ in varying yields, some Fe₂(CO)₆S₂ plus low yields of the appropriate dimers of the type Fe₂(CO)₆(SR)(SR′), where R = R′ = phthal imido, CH₂Ph, CMe₃ and R = CH₂Ph, CMe₃, R′ = phthalimido. The naturally occurring cyclic disulfide D,L-α-lipoic acid, its methyl ester and amide react with Fe₂(CO)₉ to give Fe₂(CO)₆ derivatives wherein the sulfursufur bond has been broken.     

Synthesis and characterization of some aminoarsonium chlorides

R₃As reacts with NR′R″Cl to give good yields of a new homologous series of aminoarsonium chlorides, [R₃AsNR′R″]Cl, in which R = Me, Et, n-Pr, and Ph; R′ and/or R″ = H, Me. IR, NMR, mass, and X-ray spectral data suggest that the arsenic is tetra- coordinate. Electfical conductivity and temperature and concentration dependent NMR studies suggest that hydrogen-bonding interactions are important in solution. Quaternization of the arsenic produces a downfield ¹H NMR chemical shift for the protons in the alkyl chains and a change from non-equivalence to equivalence of the C-1 protons. The NMR data are compared with those for the analogous phosphorus compounds. The electron impact, chemical ionization, and negative ion mass spectral data and fragment ion identities are given for the compounds. Ions corresponding to a variety of AsCl containing species, in addition to those associated .with fragmentation of the R₃As moieties, are observed in the EI mass spectra. AsN, AsNAs, and AsNAsN containing fragments are observed in the Cl mass spectra and AsCl bonding species in the NI mass spectra. A preliminary X-ray diffraction study of [n-Pr₃AsNH₂]Cl indicates near tetrahedral geometry about the arsenic atom.     

Interactions of dichloro-bis(η5-cyclopentadienyl)titanium(IV) with nucleosides

The interactions of dichloro-bis(η⁵-cyclopentadienyl)titanium(IV) (titanocene dichloride, Cp₂TiCl₂) with nucleosides have been studied in methanolic solutions. Complexes of the general formula [Cp₂Ti(Nucl)MeOH]Cl₂ were isolated. The nucleoside complexes with one N(1)H ionizable imino proton (i.e. inosine and guanosine) undergo ionization in alkaline solution and complexes of the formula [Cp₂Ti(NuclH⁺)] Cl were isolated. All complexes have been characterized by elemental analyses and various spectroscopic techniques. In the first series of complexes, [Cp₂Ti(Nucl)MeOH]Cl₂, the nucleosides act as monodentate ligands with an intramolecular hydrogen bond between the coordinated methanol and the C6O group, while in the second, [Cp₂Ti(NuclH⁺)] Cl, they coordinate through both their N7 and O6 atoms.     

Haloalkyl complexes of the transition metals. Part 5. The synthesis and reactions of some new pentamethylcyclopentadienyl halomethyl and methoxymethyl complexes of molybdenum(II) and tungsten(II) and the X-ray crystal structure of the cationic ylide complex [η-C5Me5W(CO)3CH2PPh3]I

Synthetic routes are described for the new halo- methyl complexes of the type [η-C₅Me₅M(CO)₃- CH₂X]. The complexes where M = Mo, X = Cl or OMe and M = W, X = Cl, I, OMe have been fully characterized. Reaction of [η-C₅Me₅Mo(CO)₃CH₂Cl] with PPh₃ in methanol under reflux or acetonitrile at room temperature gives [η-C₅Me₅Mo(CO)₂(PPh₃)- Cl], whereas reaction of [η-C₅Me₅W(CO)₃CH₂I] with PPh₃ under similar conditions gives the cationic phosphorus ylide complex [η-C₅Me₅W(CO)₃CH₂- PPh₃]I. The structure of this ylide complex has been determined by X-ray crystallography. The complex crystallizes with half a molecule of CH₂Cl₂ in the monoclinic space group P2₁/n with a = 16.616- (8), b = 11.738(6), c = 18.126(9) Å, β = 101.74(2)° and Z = 4. The structure was solved and refined to R = 0.076. It confirms the formulation of the compound and the presence of the ylide ligand, WC_ylide 2.34(2) Å, PC_ylide 1.82(2) Å and the WC_ylideP angle of 119(1)°.     

The crystal and molecular structures of dioxo mo(VI) complexes of tripodal,tetradentate N,S-donor ligands

The crystal and molecular structures of the complexes MoO₂((SCH₂CH₂)₂NCH₂CH₂SCH₃), I and MoO₂((SCH₂CH₂)₂NCH₂CH₂N(CH₃)₂), II, have been determined from X-ray intensity data collected by counter methods. Compound I crystallizes in two forms, Ia and Ib. In form Ia the space group is P2₁/n with cell parameters a = 7.235(2), b = 7.717(2), c = 24.527(6) Å, β = 119.86(2)°, V = 1188(1) ų, Z = 4. In form Ib the space group is P2₁/c with cell parameters a = 14.945(5), b = 11.925(5), c = 14.878(4) Å, β = 114.51(2)°, V = 2413(3) ų, Z = 8. The molecules of I in Ia and Ib are very similar having an octahedral structure with cis oxo groups, trans thiolates (cis to both oxo groups) and N and thioether sulfur atoms trans to oxo groups. Average ditances are MoO = 1.70, MoS (thiolate) = 2.40, MoN = 2.40 and MoS (thioether) = 2.79 Å. Molecule II crystallizes in space group P2₁2₁2₁ with a = 7.188(1), b = 22.708(8), c = 7.746(2) Å, V = 1246(1) ų and Z = 4. The coordination about Mo is octahedral with cis oxo groups, trans thiolates and N atoms trans to oxo. Distances in the first coordination sphere are MoO = 1.705(2), 1.699(2), MoS = 2.420(1), 2.409(1) and MoN = 2.372(2), 2.510(2) Å. The conformational features of the complexes are discussed. Complex I displays MoO and MoS distances which are very similar to those found by EXAFS in sulfite oxidase. This similarity is discussed.     

Structural comparison of octahedral MoO22+ complexes of bidentate and linear tetradentate N,S-donor ligands

The structures of MoO₂[NH₂C(CH₃)₂CH₂S]₂ and MoO₂[SC(CH₃)₂CH₂NHCH₂CH₂NHCH₂C(CH₃)₂S] have been determined using X-ray diffraction intensity data collected by counter techniques. MoO₂[NH₂C(CH₃)₂CH₂S]₂ crystallizes in space group Pbca with a = 11.234(3), b = 11.822(3) and c = 20.179(5) Å, V = 2680(2) ų and Z = 8. Its structure is derived from octahedral coordination with cis oxo groups [MoO = 1.705(3) and 1.705(3)], trans thiolate donors cis to the oxo groups [MoS = 2.416(1) and 2.402(1) and N donors trans to oxo [MoN = 2.325(3) and 2.385(4) Å]. MoO₂[SC(CH₃)₂CH₂NHCH₂CH₂NHCH₂C(CH₃)₂S] crystallizes in the space group P2₁/c with a = 10.798(5), b = 6.911(2), c = 20.333(9) Å, β = 95.20°, V = 1511(2) Å₃ and Z = 4. Its structure is very similar to that of MoO₂[NH₂C(CH₃)₂CH₂S]₂ with MoO = 1.714(2) and 1.710(2), MoS = 2.415(1) and 2.404(1) and MoN = 2.316(3) and 2.362(3). The small differences in the geometries of the two compounds are attributed to the constraints of the extra chelate ring in the complex with the tetradentate ligand. The structures in this paper stand in contrast to those reported for complexes of similar ligands wherein steric hindrance produces complexes with a skew trapezoidal bipyramidal structure.     

Self assembly of a Fe(L) complex with octacyano metallates [M(CN)8] (L = pentadentate macrocyclic ligand, M = Mo, W): Crystal structure and magnetic properties

The self assembly of [Fe^III(L)]Cl₂ClO₄ (L = pentadentate macrocyclic ligand) with octacyano metallates [M^IV(CN)₈]⁴⁻ (M = Mo, W) leads to bimetallic cyano-bridged 2-D coordination polymers of formula [{Fe(L)}₃{M(CN)₈}₂]Cl·xH₂O with M = Mo (2), or W (3). The structure of the tungsten analogue has been established by single crystal X-ray diffraction. The magnetic properties for both Mo and W derivative are reported.     

Reaction behavior of molybdocene dichloride towards ribonucleosides and ribonucleoside monophosphates: Rare example of sugar coordination

The coordination behavior of Cp₂Mo²⁺ towards the ribonucleosides and ribonucleoside monophosphates uridine, adenosine, cytidine, guanosine, 5′-UMP, 5′-AMP, 5′-CMP and 5′-GMP has been studied in solution in the range 4 ? pD ? 9 using NMR spectroscopy. The ribonucleosides were found to bind Cp₂Mo²⁺ exclusively through the ribose moiety giving rise to the chelate complexes [Cp₂Mo(urd-O2′,O3′)], [Cp₂Mo(ade-O2′,O3′)], [Cp₂Mo(cyd-O2′,O3′)], and [Cp₂Mo(gua-O2′,O3′)]. The ribonucleotides form three types of complex with Cp₂Mo²⁺ in neutral solution, namely N,PO-macrochelates, PO,O3′-coordinated species as well as O2′,O3′-chelates, while at pD 9 only sugar coordination is observed.     

Synthesis and some reactivity of amidinato(pyridine) complexes of molybdenum and tungsten formulated as [M(η-allyl)(amidinato)(CO)2(NC5H5)]

Bis(pyridine) complexes of molybdenum and tungsten, [M(η³-allyl)Cl(CO)₂(NC₅H₅)₂] (M=Mo; 3-Mo, M=W; 3-W), reacted with an equimolar amount of lithiated amidinate, Li[(PhN)₂CR] (R=H; 4a-Li, R = CH₃; 4b-Li), to yield corresponding amidinato(pyridine) complexes, [M(η³-allyl){(PhN)₂CR}(CO)₂(NC₅H₅)] (M=Mo, R=H; 5a-Mo, M=Mo, R=CH₃; 5b-Mo, M=W, R=H; 5a-W), as a yellow solid. The dissociation of pyridine ligand from the central metal in complexes 5a was observed in a polar solvent such as acetonitrile. In these cases, although the formation of amidinato(acetonitrile) complexes, [M(η³-allyl){(PhN)₂CH}(CO)₂(NCMe)] (M=Mo; 6a-Mo, M=W; 6a-W), was suggested spectroscopically, isolation of complexes 6a was not successful but the re-formation of pyridine complexes 5a was observed. In the reactions of complexes 5a with PEt₃ and with P(OMe)₃, the substitution reactions easily took place to give [M(η³-allyl){(PhN)₂CH}(CO)₂(PEt₃)] (M=Mo; 7a-Mo, M=W; 7a-W) and [M(η³-allyl){(PhN)₂CH}(CO)₂{P(OMe)₃}] (M=Mo; 8a-Mo, M=W; 8a-W), respectively. These complexes were characterized spectroscopically as well as, in some cases, by X-ray analyses.     

Reactivity of platina-β-diketones towards chelating nitrogen and sulfur donors: formation of acyl(hydrido)platinum(IV) and acyl(chloro)platinum(II) complexes

The platina-β-diketone [Pt₂{(COMe)₂H}₂(μ-Cl)₂] (1) was found to react with chelating N,N-ligands 2(R^′NCR)C₅H₄N (R/R^′=Ph/OH, H/Ph, Me/Ph) to form acyl(hydrido)platinum(IV) complexes [Pt(COMe)₂Cl(H){2-(R^′NCR)C₅H₄N}] (R/R^′=Ph/OH 2a; H/Ph 2b; Me/Ph (2c)). Reactions of complex 1 with chelating S,S- and N,S-donors (RS-CH₂-CH₂-SR, 2-(RSCH₂)C₅H₄N, R=Et, Ph, t-Bu) afforded acyl(chloro)platinum(II) complexes [Pt(COMe)Cl(RSCH₂CH₂SR)] (R=Et, 3a; Ph, 3b; t-Bu, 3c) and [Pt(COMe)Cl{2-(RSCH₂)C₅H₄N}] (R=Et, 4a; Ph, 4b; t-Bu, 4c), respectively. All complexes were fully characterized by microanalysis, IR and NMR (¹H, ¹³C) spectroscopy. Furthermore, molecular structures of complexes 3b and 4b were determined by single-crystal X-ray diffraction analyses revealing close to square-planar configuration. In complex 4b the acetyl ligand is trans to pyridine N atom (configuration index SP-4-2). The reactions are discussed in terms of consecutive oxidative addition and reductive elimination reactions.     

Effect of 7-fluoro prostacyclin,a stable prostacyclin analogue,on cAMP accumulation and prostaglandin binding in mastocytoma P-815 cells

The effect of 7-fluoro proscyclilin (PGI₂-F), a chemically stable analogue of prostacyclin, on cAMP accumulation in and [³H]PGE binding to mastocytoma P-815 cells was compared with those of the Na salt and methyl ester of prostacyclin (PGI₂Na or PGI₂Me), which are rapidly inactivated in aqueous solution or metabolized in the tissue.PGIF was as effective as PGI₂Me, and slightly less effective than PGI₂Na in stimulating cAMP accumulation in mastocytoma cells and rabbit platelets. PGI₂F was also more stable than PGI₂Me or PGI₂Na, and retained its original cAMP elevating activity even after incubation with or without cells for 4 h at 37°C. Cells which had been exposed to PGI₂F and then washed free of unbound reagent continued to produced cAMP for more than 3 h. PGI₂F was also as effective as PGE₁ or PGE₂ in displacing [³H]PGE₂ bound to the cells. Non-competitive inhibition by PGI₂F or PGI₂Me of [³H]PGE₂ binding to the cells, with apparent K_is of 1.29 μM and 1.13 μM, respectively, indicates the presence of different receptors for PGE₂ and for PGI₂F or PGI₂Me in mastocytoma P-815 cells.     

Synthesis and spectroscopic properties of CpRuCl(R-DAB(4e)) and CpRuCo(CO)3(R-DAB(6e)). Part XVII. X-ray structure determination of CpRuCo(CO)3(t-Bu-DAB(6e))

CpRuCl(PPh₃)₂ reacted with excess R-DAB in refluxing toluene to give CpRuCl(R-DAB(4e)) (1a: R = i-Pr; 1b: R = t-Bu; 1c: R = neo-Pent; 1d: R =p-Tol). ¹H NMR and ¹³C NMR spectroscopic data indicated that in these complexes the R-DAB ligand is bonded in a chelating 4e coordination mode.Reaction of 1a and 1b with one equivalent of [Co(CO)₄]⁻ afforded CpRuCo(CO)₃(R-DAB(6e)) (2a: R = i-Pr; 2b: R = t-Bu). The structure of 2b was determined by a single crystal X-ray structure determination. Crystals of 2b are monoclinic, space group P2₁/n, with four molecules in a unit cell of dimensions: a = 16.812(4), b = 12.233(3), c = 9.938(3) Å and β = 105.47(3)°. The structure was solved via the heavy atom method and refined to R = 0.060 and R_w = 0.065 for the 3706 observed reflections. The molecule contains a RuCo bond of 2.660(3) Å and a cyclopentadienyl group that is η⁵-coordinated to ruthenium [RuC(cyclopentadienyl) = 2.208(3) Å (mean)]. Two carbonyls are terminally coordinated to cobalt (CoC(1) = 1.746(7) and CoC(2) = 1.715(6) Å) while the third is slightly asymmetrically bridging the RuCo bond (RuC(3) = 2.025(6) and CoC(3) = 1.912(6) Å). The RuC(3)O(3) and CoC(3)O(3) angles are 138.4(5)° and 136.5(5)°, respectively. The t-Bu-DAB ligand is in the bridging 6e coordination mode: σ-N coordinated to Ru (RuN(2) = 2.125(4) Å), μ₂-N′ bridging the RuCo bond and η²-CN coordinated to Co (RuN(1) = 2.113(5), CoN(1) = 1.941(4) and CoC(4) = 2.084(5) Å). The η²-CN′ bonded imine group has a bond length of 1.394(7) Å indicating substantial π-backbonding from Co into the anti-bonding orbital of this CN bond.¹H NMR spectroscopy indicated that 2a and 2b are fluxional on the NMR time scale. The fluxionality of 6e bonded R-DAB ligands is rarely observed and may be explained by the reversible interchange of the σ-N and η²-CN′ coordinated imine parts of the R-DAB ligand.     

Comparative reactivity study of cyclopentadienyl and fulvalene molybdenum complexes

The reactions of cis-1,1′-[η⁵:η⁵-(C₅H₃CO₂Me)₂]Mo₂(CO)₆ (1), in the presence of 1 equiv. of Me₃NO, and [(η⁵-C₅H₄CO₂Me)Mo(CO)₃]₂ (2) with dppe produce CO labilization and formation of the dinuclear zwitterions trans-1,1′-[η⁵:η⁵-(C₅H₃CO₂Me)₂]Mo₂(CO)₅(dppe) (3) and disproportionation species [(η⁵-C₅H₄CO₂Me)Mo(CO)₂(dppe)]⁺ [(η⁵-C₅H₄CO₂Me)Mo(CO)₃]⁻ (4), respectively. Using the same method, the reactions of trans-1,1′-[η⁵:η⁵-(C₅H₃CO₂Me)₂]Mo₂(CO)₆I₂ and (η⁵-C₅H₄CO₂Me)Mo(CO)₃I with PPh₃ in the presence of 1 and 2 equiv. of Me₃NO yield trans-1,1′-[η⁵:η⁵-(C₅H₃CO₂Me)₂]Mo₂(CO)₄(PPh₃)₂I₂ (5) and (η⁵-C₅H₄CO₂Me)Mo(CO)₂(PPh₃)I (6). The reactions of the several anionic carbonyl species {trans-1,1′-[η⁵:η⁵-(C₅H₃CO₂Me)₂]Mo₂(CO)₆}²⁻, [(η⁵:η⁵-C₁₀H₈)W₂(CO)₆]²⁻ and [(η⁵-C₅H₄CO₂Me)Mo(CO)₃]⁻ with S₂Ph₂ give rise to the thiolate–fulvalene complexes cis-1,1′-[η⁵:η⁵-(C₅H₃CO₂Me)₂]Mo₂(CO)₄(μ-SPh)₂ (7) and (η⁵:η⁵-C₁₀H₈)W₂(CO)₆(SPh)₂ (8) and the thiolate-bridged dimer [(η⁵-C₅H₄CO₂Me)Mo(CO)(μ-SPh)]₂ (9). Treatment of 6 with 1 equiv. of HCCCCH and with (η⁵-C₅H₅)Mo(CO)(dppe)(CCCCH), in the presence of CuI at room temperature, afford the cyclopentadiene complexes (η⁵-C₅H₄CO₂Me)Mo(CO)₂(PPh₃)(CCCCH) (10) and (η⁵-C₅H₄CO₂Me)(PPh₃)(CO)₂Mo(CCCC)Mo(CO)(dppe)(η⁵-C₅H₅) (11), respectively. The reaction of (η⁵-C₅H₅)Mo(CO)(dppe)(CCCCH) with Co₂(CO)₈ yields [Co₂{μ-HC₂CC[Mo(CO)(dppe)(η⁵-C₅H₅)]}(CO)₆] (12). All the new compounds have been characterized by analytical and spectroscopic methods.     

Synthesis and crystal structure of (pipzH2)2Mo2Cl8·4H2O (pipz = piperazine)

The title compound (pipzH₂)₂Mo₂Cl₈·4H₂O (pipz = piperazine),was isolated from the solution of (morphH)₂Mo₂Cl₆(H₂O)₂ in HCl 1:1 by addition of (pipzH₂)Cl₂. This reaction indicates the reversibility of the substitution of chloride ions in Mo₂Cl₈^4? by water molecules. (pipzH₂)₂Mo₂Cl₈·4H₂O crystallizes in the Pbca space group, with a = 15.154(2), b = 13.170(2), c = 12.208(2) Å and Z = 4. The structure was solved by the Patterson method and refined to the unweighted and weighted residuals of 0.050 and 0.048. The crystal structure is built form Mo₂Cl₈^4?, (pipzH₂)²⁺ and H₂O. The MoMo distance of 2.129(3) Å is the shortest one found in all structurally-characterised Mo₂X₈^4? (X = Cl, Br) anions. Four independent MoCl distances are 2.456(3), 2.445(3), 2.463(4) and 2.455(4) Å. The (pipzH₂²⁺ exists in a usual chair conformation. There is a network of hydrogen bonds of the type NH?Cl, NH?O, OH?Cl and OH?O between the ions and water molecules.