Preparation of Ru(η3-2-alkenylallyl)(CO)Cl(PPh3)2 complexes via carbometallation of allenes with alkenyl ruthenium complexes

Alkenyl ruthenium complex, Ru(CHCHR)(Cl)(CO)(PPh₃)₂ 1, reacted with allenes 2 to give η³-allyl ruthenium complexes, Ru(η³-2-alkenylallyl)(Cl)(CO)(PPh₃)₂ 3, in good yields. The reaction depends on the structure of the alkenyl group. When R was phenyl or methoxycarbonyl group, the carbometallated complex 3 was yielded as a sole product. However, when R was butyl or trimethylsilyl group, besides the carbometallation product as main product, was obtained a small amount of 2-unsubstituted η³-allyl ruthenium complex which was formed via β-elimination of the alkenyl complex followed by the reaction with allene. Structure of 3 was determined by the X-ray crystal structure analysis.     

Diastereotopic relationship between planar and central chiralities in the formation of Ru(η3-allyl)(CO)(PPh3)(L–L′) complexes

Hydride ruthenium complexes, RuHCl(CO)(PPh₃)₂(L–L^′) 3 (L–L^′=bidentate ligand having nitrogen and oxygen) react with allenes to give Ru(η³-allyl)(CO)(PPh₃)(L–L^′) complexes 5 in good yields via hydrometalation reaction. The complexes 5 have planar chirality at the η³-allyl ligand and central chirality at the Ru metal, and consist of one pair of enantiomers. Ligand substitution reaction of Ru(η³-allyl)Cl(CO)(PPh₃)₂ complexes 6 with bidentate ligands (L–L^′) also afford the complexes 5 which have the same stereochemistry as those formed by the hydrometalation reaction. The planar chirality is controlled by the central chirality at the Ru metal in both the formations of the complexes 5. The structure of 5a (L–L^′=N–N bidentate ligand) was determined by the X-ray crystal structure analysis.     

The preparation,structure and unusual substitution reactions of the cationic 2-butyne complex [WI(CO)(NCMe){P(OiPr)3}2(η2-MeC2Me)][BPh4]

Reaction of equimolar amounts of [WI₂(CO){P(OⁱPr)₃}₂(η²-MeC₂Me)] and Na[BPh₄] in acetonitrile at room temperature gave the crystallographically characterised complex [WI(CO)(NCMe){P(OⁱPr)₃}₂(η²-MeC₂Me)][BPh₄] (1). Complex 1 undergoes a series of substitution reactions, including the reaction of 1 with 1,10-phenanthroline at room temperature, to afford the unexpected structurally characterised product, [WI(CO){P(OⁱPr)₃}(1,10-phen)(η²-MeC₂Me)][BPh₄] (2) via displacement of one phosphite and the acetonitrile ligand.     

Reactivity of [WCl(SnCl3)(CO)3(NCMe)2] towards tBuCCH.: X-ray crystal structure of [WCl(CO)(tBuCCH)(NCMe)(PPh3)2]2[SnCl6]

In the reaction of [WCl(SnCl₃)(CO)₃(NCMe)₂] with tert-butylacetylene the very labile bis(alkyne) complex [WCl(SnCl₃)(CO)(^tBuCCH)₂(NCMe)] has been observed as the major product by means of IR and NMR spectroscopy. The latter compound in reaction with two equivalents of PPh₃ in CH₂Cl₂ solution gives very poorly soluble purple crystals of the tungsten(II) cationic complex. The crystal structure of this compound consists of the discrete [SnCl₆]²⁻ anion, two independent [WCl(CO)(^tBuCCH)(NCMe)(PPh₃)₂]⁺ cations and four MeCN (solvent) molecules. This is the first crystallographically characterized cationic chlorocarbonyl complex of tungsten(II) containing a terminal alkyne as ligand.     

Synthesis and structure of the pentanuclear mixed-metal cluster [Co4MoCp(μ3-SBut)(μ3-S)(μ3-CO)(μ-CO)2(CO)6]

The pentanuclear mixed-metal cluster [Co₄MoCp(μ₃-SBu^t)(μ₃-S)(μ₃-CO)(μ-CO)₂(CO)₆] (1) has been synthesised by reaction of [CoMoCp(CO)₇] with Bu^tSSBu^t. X-ray structural analysis identified an asymmetric unit with three cobalt atoms and one molybdenum forming an irregular tetrahedron while one cobalt–molybdenum edge is bridged by a cobalt atom. Crystal data: space group P2(1)/n, a=10.162(2), b=13.722(3), c=17.69(5) Å, β=91.44(2)°, Z=4.     

An unusual intramolecular metallalactone formation from coordinated alkoxide and CO: molecular structure of Au3Ru3{μ3-η1:η1:η1,η2-CCHCPh2OC(O)}(CO)8(PPh3)3

Sequential treatment of Ru₃(μ-H){μ₃-C₂CPh₂(OH)}(CO)₉ with K[BHBu^s₃] and AuCl(PPh₃) afforded Au₃Ru₃{μ₃-η¹:η¹:η¹,η²-CCHCPh₂OC(O)}(CO)₈(PPh₃)₃, formed by intramolecular attack of alkoxide on an adjacent CO ligand, and characterised by a single-crystal X-ray study.     

Synthesis,characterization and crystal structure of (cis-P,P′-diphenyl-1,4-diphospha-cyclohexane)molybdenum(0)tetracarbonyl

The preparation of the novel (cis-P,P′-diphenyl-1,4-diphospha-cyclohexane)molybdenum(0)tetracarbonyl complex is described. The spectral data and X-ray structure of the title complex are reported. The results of the crystallographic work show a distorted octahedral complex around the metal center, the first of its kind reported for the P,P′-diphenyl-1,4-diphospha-cyclohexane ligand.     

Migratory insertion reaction in alkenyl ruthenium(II) complexes containing a trifluoroacetate ligand. X-ray structure of the Ru(η2- O2CCF3)(η1-OCCHCHtBu)(CO)(PPh3)2 complex

Reaction of compound Ru(O₂CCF₃)(CHCH^tBu)(CO)(PPh₃)₂ with CO gives the η¹-alkeneacyl complex Ru(O₂CCF₃)(OCCHCH^tBu)(CO)(PPh₃)₂, which is in equilibrium with the dicarbonyl Ru(O₂CCF₃)(CHCH^tBu)(CO)₂(PPh₃)₂ derivative in CH₂Cl₂ solution. The η¹-acyl form involves an η¹-coordination of the O₂CCF₃ ligand, whereas the dicarbonyl form contains the carboxylate ligand η²-coordinated to the metal. The same mixture of carbonylated compounds can be obtained from the reaction of Ru(CHCH^tBu)Cl(CO)₂(PPh₃)₂ with Na[O₂CCF₃] in a CH₂Cl₂/MeOH solution. These reactions reveal the significance of ancillary bidentate ligands for the η-nature of the acyl–metal bond. The molecular structure of the complex Ru(O₂CCF₃)(OCCHCH^tBu)(CO)(PPh₃)₂ was established by X-ray diffraction study of a monocrystal obtained from a CH₂Cl₂/MeOH solution of the mixture of carbonylated compounds.     

Synthesis and structural characterization of [(μ-H)Ru3(CO)8{μ-S(CH2)3SH}(μ-dppe)] and [Ru3(CO)5{μ2-S(CH2)3S}2(η2-dppe)] (dppe=Ph2PCH2CH2PPh2)

The reaction of 1,3-propanedithiol with [Ru₃(CO)₁₀(μ-dppe)] (2) at 66°C afforded the thiolate complexes [(μ-H)Ru₃(CO)₈{μ-S(CH₂)₃SH}(μ-dppe)] (6) and [Ru₃(CO)₅{μ₂-S(CH₂)₃S}₂(η²-dppe)] (7) in 25 and 23% yields respectively. Compound 6 is formed by simple oxidative addition of one of the S–H bonds of 1,3-propanedithiol while the structurally unique 7 consists of an open triruthenium cluster with four terminal and one asymmetrically bridged carbonyl groups, two doubly bridged propanedithiolate ligands and a chelating dppe ligand.     

Unexpected fragmentation of the Fe3(CO)9(μ3-Se)(μ3-AsCH3) cluster core in the reaction with CpCo(CO)2: synthesis and structure of Fe3(CO)6(μ3-Se)(μ-AsCH3{CpFe(CO)2})2(μ-CO)

The [Fe₃(CO)₆(μ₃-Se)(μ-AsCH₃{CpFe(CO)₂})₂(μ-CO)] (Cp=η⁵-C₅H₅) cluster has been obtained by the reaction of [Fe₃(CO)₉(μ₃-Se)(μ₃-AsCH₃)] with [CpCo(CO)₂]. Its crystal and molecular structures have been determined by X-ray analysis.     

Synthesis and X-ray characterization of the new pentanickel cluster cation [Ni5(μ5-S)(μ3-S)2(μ2-S)(μ-CH3COO)(PPh3)5]+

By reacting Ni(CH₃COO)₂·6H₂O with H₂S in the presence of PPh₃, the new Ni/S cluster of formula [Ni₅(μ₅-S)(μ₃-S)₂(μ₂-S)(μ-CH₃COO)(PPh₃)₅]PF₆·C₇H₈·0.5CH₂Cl₂ has been isolated and characterized by X-ray diffraction analysis. Crystal data: space group P2₁/c, a=15.774(4), b=21.235(7), c=29.288(7) Å, β=95.66(4)°. The inner core consists of a square pyramid of five nickel atoms, linked together by a bridging acetate and four variously bridging sulfur ligands. The ³¹P{¹H} NMR spectra in dichloromethane solution are consistent with the above geometry.     

Solvent/C60 exchange on Ir(CO)(PPH3)2(Cl)(η2-C60) and solvent/solvent’ exchange on Ir(CO)(PPH3)2(Cl)(solvent)

Dissociation of C₆₀ from Ir(CO)(PPh₃)₂(Cl)(η²-C₆₀) in a binary mixture of solvents (solvent₁ and solvent₂) produced non-equilibrium mixtures of Ir(CO)(PPh₃)₂(Cl)(solvent₁) and Ir(CO)(PPh₃)₂(Cl)(solvent₂). Once the solvated species were produced, they underwent a relative fast solvent exchange between them to produce an equilibrium mixture.     

Molecular structure of [In2(μ,η1-OR)(μ,η2-OR)(η2-OR)3(η1-OR)] R = C2H4NMe2, a pincer ligand

Functional indium [In(OR)₃]_m alkoxides (R = C₂H₄OMe, C₂H₄NMe₂) have been obtained by alcoholysis of In[N(SiMe₃)₂]₃ and characterised by elemental analysis, FT-IR and NMR spectroscopy. The 2-dimethylaminoethoxide was characterised by X-ray diffraction. It corresponds to the association of two InO₆ octahedra giving the unsymmetrical dimer [In₂(μ,η¹-OR)(μ,η²-OR)(η²-OR)₃(η¹-OR)] (2). 2 was used as a pincer ligand toward Cu(acac)₂.     

Sulfur-assisted chloride and triphenylphosphine dissociation of palladium(II) complex [Pd(PPh3)2(η1-SCNMe2)(Cl)]. X-ray structures of [Pd(PPh3)2(η1-SCNMe2)(Cl)], [Pd(PPh3)(Cl)]2(μ,η2-SCNMe2)2, and [Pd(PPh3)2(η2-SCNMe2)][PF6]

Treatment of Pd(PPh₃)₄ with Me₂NC(S)Cl in dichloromethane at −20 °C produces the complex [Pd(PPh₃)₂(η¹-SCNMe₂)(Cl)], 2. Variable temperature ¹H and ³¹P{H} NMR experiments of complex 2 shows the dissociation of either the chloride or the triphenylphosphine ligand to form complex [Pd(PPh₃)₂(η²-SCNMe₂)][Cl], 3 or the dipalladium complex [Pd(PPh₃)Cl]₂(μ,η²-SCNMe₂)₂, 4. The reaction of complex 2 with NaPF₆ affords complex [Pd(PPh₃)₂(η²-SCNMe₂)][PF₆], 5. Complexes 2, 4, and 5 are characterized by X-ray diffraction analyses.     

Ca(BH4)2 as a simple tool for the preparation of thorium and uranium metallocene borohydride complexes: First synthesis and crystal structure of (C5Me5)2Th(η3-H3BH)2

Calcium borohydride allows for the high-yielding synthesis of (C₅Me₅)₂An(η³-H₃BH)₂ (An = Th, U) by reaction with (C₅Me₅)₂AnCl₂ (An = Th, U). While a preparative synthesis of (C₅Me₅)₂U(η³-H₃BH)₂ has been previously reported in the literature using K(C₅Me₅) and U(BH₄)₄, the use of Ca(BH₄)₂ is higher yielding and mild. Full characterization of the novel compound (C₅Me₅)₂Th(η³-H₃BH)₂ is presented.     

Synthesis and structure of {η3-MeSi(CH2SPh)3}Cr(CO)3: how long can a Cr(0)–S(thioether) bond length be?

The new tridentate thioether ligand MeSi(CH₂SPh)₃ has been prepared in good yield and its first transition metal derivative, the octahedral chromium tricarbonyl complex {η³-MeSi(CH₂SPh)₃}Cr(CO)₃, has been synthesized and fully characterized. In agreement with the reduced basicity of arylthioethers and the expected lability of their metal complexes, the new complex exhibits the longest Cr(0)–S(thioether) bond distances observed to date.