Syntheses of new Mo(II) and W(II) mono(hydrosulfido) complexes and their conversion into di- and tetranuclear sulfido-bridged heterobimetallic complexes

Treatment of [Cp′MH(CO)₃] (M = Mo, W; Cp′ = η⁵-C₅H₅ (Cp), η⁵-C₅Me₅ (Cp*)) with 1/8 equiv of S₈ in THF, followed by the reaction with dppe under UV irradiation, gave new mono(hydrosulfido) complexes [Cp′M(SH)(CO)(dppe)] (Cp′ = Cp: M = Mo (5), W (6); Cp′ = Cp*: M = Mo (7), W (8); dppe = Ph₂PCH₂CH₂PPh₂). When 5 and 6 dissolved in THF were allowed to react with [RhCl(PPh₃)₃] in the presence of base, heterodinuclear complexes with bridging S and dppe ligands [CpM(CO)(μ-S)(μ-dppe)Rh(PPh₃)] (M = Mo (9), W(10)) were obtained. Semi-bridging feature of the CO ligands were also demonstrated. Upon standing in CH₂Cl₂ solutions, 9 and 10 were converted further to the dimerization products [(CpM)₂{Rh(dppe)}₂(μ₂-CO)₂(μ₃-S)₂] (M = Mo (13), W). Detailed structures of mononuclear 7 and 8, dinuclear 9 and tetranuclear 13 have been determined by the X-ray diffraction.     

Nucleophilic substitution reactions at the Si-Cl bonds of the dichloro(methyl)silyl ligand in five- and six-coordinate complexes of ruthenium(II) and osmium(II)

Treatment of either RuHCl(CO)(PPh₃)₃ or MPhCl(CO)(PPh₃)₂ with HSiMeCl₂ produces the five-coordinate dichloro(methyl)silyl complexes, M(SiMeCl₂)Cl(CO)(PPh₃)₂ (1a, M = Ru; 1b, M = Os). 1a and 1b react readily with hydroxide ions and with ethanol to give M(SiMe[OH]₂)Cl(CO)(PPh₃)₂ (2a, M = Ru; 2b, M = Os) and M(SiMe[OEt]₂)Cl(CO)(PPh₃)₂ (3a, M = Ru; 3b, M = Os), respectively. 3b adds CO to form the six-coordinate complex, Os(SiMe[OEt]₂)Cl(CO)₂(PPh₃)₂ (4b) and crystal structure determinations of 3b and 4b reveal very different Os-Si distances in the five-coordinate complex (2.3196(11) Å) and in the six-coordinate complex (2.4901(8) Å). Reaction between 1a and 1b and 8-aminoquinoline results in displacement of a triphenylphosphine ligand and formation of the six-coordinate chelate complexes M(SiMeCl₂)Cl(CO)(PPh₃)(κ²(N,N)-NC₉H₆NH₂-8) (5a, M = Ru; 5b, M = Os), respectively. Crystal structure determination of 5a reveals that the amino function of the chelating 8-aminoquinoline ligand is located adjacent to the reactive Si-Cl bonds of the dichloro(methyl)silyl ligand but no reaction between these functions is observed. However, 5a and 5b react readily with ethanol to give ultimately M(SiMe[OEt]₂)Cl(CO)(PPh₃)(κ²(N,N-NC₉H₆NH₂-8) (6a, M = Ru; 6b, M = Os). In the case of ruthenium only, the intermediate ethanolysis product Ru(SiMeCl[OEt])Cl(CO)(PPh₃)(κ²(N,N-NC₉H₆NH₂-8) (6c) was also isolated. The crystal structure of 6c was determined. Reaction between 1b and excess 2-aminopyridine results in condensation between the Si-Cl bonds and the N-H bonds with formation of a novel tridentate “NSiN” ligand in the complex Os(κ³(Si,N,N)-SiMe[NH(2-C₅H₄N)]₂)Cl(CO)(PPh₃) (7b). Crystal structure determination of 7b shows that the “NSiN” ligand coordinates to osmium with a “facial” arrangement and with chloride trans to the silyl ligand.     

Nickel (II) complexes bearing 2-ethylcarboxylate-6-iminopyridyl ligands: synthesis, structures and their catalytic behavior for ethylene oligomerization and polymerization

A series of nickel (II) complexes (L)NiCl₂ (7-9) and (L)NiBr₂ (10-12) were prepared by the reactions of the corresponding 2-carboxylate-6-iminopyridine ligands 1-6 with NiCl₂ · 6H₂O or (DME)NiBr₂ (DME = 1,2-dimethoxyethane), respectively. All the complexes were characterized by IR spectroscopy and elemental analysis. Solid-state structures of 7, 8, 10, 11 and 12 were determined by X-ray diffraction. In the cases of 7, 8 and 10, the ligands chelate with the nickel centers in tridentate fashion in which the carbonyl oxygen atoms coordinate with the metal centers, while the carbonyl oxygen atoms are free from coordinating with the nickel centers in 11 and 12. Upon activation with methylaluminoxane (MAO), these complexes are active for ethylene oligomerization (up to 7.97 × 10⁵ g mol⁻¹ (Ni) h⁻¹ for 11 with 2 equivalents of PPh₃ as auxiliary ligand) and/or polymerization (1.37 × 10⁴ g mol⁻¹ (Ni) h⁻¹ for 9). The ethylene oligomerization activities of 7-12 were significantly improved in the presence of PPh₃ as auxiliary ligands. The effects of the coordination environment and reaction conditions on the ethylene catalytic behaviors have been discussed.     

Synthesis, structures, and catalytic properties for ethylene polymerization of bridged [η,η-C5H4CHPhArO]TiCl2 complexes

A number of bridged half-sandwich titanium complexes [η⁵:η¹-2-C₅H₄CHPh-4-R¹-6-R²C₆H₂O]TiCl₂ [R¹ = H (5), Me (6), ^tBu (7, 8); R² = H (6, 7), ^tBu (5, 8)] were synthesized from the reaction of their corresponding trimethylsilyl substituted ligand precursors 2-Me₃SiC₅H₄CHPh-4-R¹-6-R²C₆H₂OSiMe₃ [R¹ = H (1), Me (2), ^tBu (3, 4); R² = H (2, 3), ^tBu (1, 4)] with TiCl₄ in hexane. All new complexes were characterized by ¹H and ¹³C NMR spectroscopy. Molecular structures of complexes 5 and 8 were determined by single crystal X-ray diffraction analysis. Upon activation with AlⁱBu₃/Ph₃CB (C₆F₅)₄, complexes 5-8 exhibit reasonable catalytic activity for ethylene polymerization and copolymerization with 1-hexene, producing polyethylene and poly(ethylene-co-1-hexene) with moderate molecular weights.     

Syntheses and characterization of [(η-C6Me6)Ru(μ-N3)(X)]2 (X = N3 and Cl) complexes and their reactions towards mono- and bidentate ligands

The reaction of the complex [{(η⁶-C₆Me₆)Ru(μ-Cl)Cl}₂] 1 with sodium azide ligand gave two new dimers of the composition [{(η⁶-C₆Me₆)Ru(μ-N₃)(N₃)}₂] 2 and [{(η⁶-C₆Me₆)Ru(μ-N₃)Cl}₂] 3, depending upon the reaction conditions. Complex 3 with excess of sodium azide in ethanol yielded complex 2. These complexes undergo substitution reactions with monodentate ligands to yield monomeric complexes of the type [(η⁶-C₆Me₆)Ru(X)(N₃)(L)] {X = N₃, Cl, L = PPh₃ (4a, 9a); PMe₂Ph (4b, 9b); AsPh₃ (4c, 9c); X = N₃, L = pyrazole (Hpz) (5a); 3-methylpyrazole (3-Hmpz) (5b) and 3,5-dimethyl-pyrazole (3,5-Hdmpz) (5c)}. Complexes 2 and 3 also react with bidentate ligands to give bridging complexes of the type [{(η⁶-C₆Me₆)Ru(N₃)(X)]₂(μ-L)} {X = N₃, Cl, L = 1,2-bis(diphenylphosphino)methane (dppm) (6, 10); 1,2-bis(diphenylphosphino)ethane (dppe) (7, 11); 1,2-bis(diphenylphosphino)propane (dppp) (8, 12); X = Cl, L = 4,4-bipyridine (4,4′-bipy) (13)}. These complexes were characterized by FT-IR and FT-NMR spectroscopy as well as by analytical data.The molecular structures of the representative complexes [{(η⁶-C₆Me₆)Ru(μ-N₃)(N₃)}₂] 2, [{(η⁶-C₆Me₆)Ru(μ-N₃)Cl}₂] 3,[(η⁶-C₆Me₆)Ru(N₃)₂(PPh₃)] 4a and [{(η⁶-C₆Me₆)Ru(N₃)₂}₂ (μ-dppm)] 6 were established by single crystal X-ray diffraction studies.     

Nickel(II) complexes bearing phosphinooxazoline ligands: Synthesis, structures and their ethylene oligomerization behaviors

A series of Ni(II) complexes 4a-f ligated by the unsymmetrical phosphino-oxazolines (PHOX) were synthesized and characterized by elemental analysis and IR spectroscopy, and the structures of complexes 4c-4e were confirmed by the X-ray crystallographic analysis. All derivatives showed distorted tetrahedron geometry by the nickel center and coordinative atoms. Upon activation with methylaluminoxane (MAO) or Et₂AlCl, these complexes exhibited considerable to high activity of ethylene oligomerization. The ligands environments and reaction conditions significantly affect their catalytic activities, while the highest oligomerization activity (up to 1.18 × 10⁶ g · mol⁻¹(Ni) · h⁻¹) was observed for 4d at 20 atm of ethylene. Incorporation of 2-4 equivalents of PPh₃ as auxiliary ligands in the 4a-f/MAO catalytic systems led to higher activity and longer catalytic lifetime.     

Synthesis, characterization and ethylene oligomerization studies of nickel complexes bearing 2-imino-1,10-phenanthrolines

A series of nickel (II) complexes ligated by 2-imino-1,10-phenanthrolines were synthesized and characterized by elemental and spectroscopic analysis as well as by single-crystal X-ray crystallography. X-ray crystallographic analysis reveals complexes 3, 5, 7 and 11 as the five-coordinated distorted trigonal-bipyramidal geometry. Upon activation with Et₂AlCl, these complexes exhibited considerably high activity for ethylene oligomerization (up to 3.76 × 10⁷ g mol⁻¹(Ni) h⁻¹ for 12 with 10 equiv. of PPh₃). The ligand environment and reaction conditions significantly affect the catalytic activity of their nickel complexes.     

Insertion of nitrene and chalcogenolate groups into the Ir-C σ bond in a cyclometalated iridium(III) complex

Treatment of [Cp∗Ir(ppy)Cl] (Cp∗ = η⁵-C₅Me₅, ppyH = 2-(2-pyridyl)phenyl) with Ag(OTf) (OTf⁻ = triflate) in MeOH and MeCN gave the solvento complexes [Cp∗Ir(ppy)(solv)][OTf] (solv = MeOH (1) and MeCN (2)). Complex 1 is capable of catalyzing oxidation and azirdination of styrene with PhIO and PhINTs (Ts = tosyl), respectively. Treatment of 2 with a stoichiometric amount of PhINTs resulted in the insertion of the NTs group into the Ir-C(ppy) bond and formation of [Cp∗Ir(η²-ppy-NTs)(MeCN)][OTf] (3). Treatment of 1 with R₂E₂ afforded [Cp∗Ir(ppy)(η¹-R₂E₂)][OTf] (E = S (4), Se (5), Te (6)). Reactions of 4 and 5 with Ag(OTf) resulted in cleavage of the E-E bond and insertion of an ER group into the Ir-C(ppy) bond. The crystal structures of complexes 2-6 and [Cp∗Ir(η²-ppy-S-p-tol)(H₂O)][OTf]₂ have been determined.     

Dimerization of terminal alkynes catalyzed by chloro(η-pentadienyl) bis(triphenylphosphine)ruthenium(II) and kinetics of phosphine substitution

Exchange of PMe₂Ph for PPh₃ in (η⁵-pentadienyl)ruthenium{bis(triphenylphosphine)}chloride, (η⁵-C₅H₇)Ru(PPh₃)₂Cl (1) under first order conditions proceeds rapidly in THF at room temperature. A pseudo-first order rate constant of 17 ± 2 × 10⁻⁴ s⁻¹ is obtained for the reaction at 21 °C. The rate constant is essentially independent of the phosphine concentration. The activation parameters, ΔH^† = 16.1 ± 0.4 kcal mol⁻¹ and ΔS^† = −16 ± 1 cal K⁻¹ mol⁻¹ differ from those reported for phosphine exchange in CpRu(PPh₃)₂Cl (2) and (η⁵-indenyl)Ru(PPh₃)₂Cl (3). The reaction of 1 with PMe₂Ph is about 70 times faster than the reaction of 2 at 30 °C and some 40 times faster than the reaction of 3 at 20 °C. (η⁵-C₅H₇)Ru(PPh₃)₂Cl(1) is more active than the ruthenium(II) complexes 2, 3, and TpRu(PPh₃)₂Cl (4) in the catalytic dimerization of terminal alkynes with nearly quantitative conversion of PhCCH and FcCCH at ambient temperature in 24 h. The enhanced substitution rate is accompanied by >50% conversion of phenylacetylene to oligomeric products. Reaction of 1 with NaPF₆ in acetonitrile yields the cationic ruthenium(II) complex [(η⁵-C₅H₇)Ru(PPh₃)₂(CH₃CN)][PF₆] (7). The latter complex is much less active in reactions with phenylacetylene than 1 but avoids the formation of oligomeric products.     

Study of half-sandwich platinum group metal complexes bearing dpt-NH2 ligand

A quite general approach for the preparation of η⁵-and η⁶-cyclichydrocarbon platinum group metal complexes is reported. The dinuclear arene ruthenium complexes [(η⁶-arene)Ru(μ-Cl)Cl]₂ (arene = C₆H₆, C₁₀H₁₄ and C₆Me₆) and η⁵-pentamethylcyclopentadienyl rhodium and iridium complexes [(η⁶-C₅Me₅)M(μ-Cl)Cl]₂ (M = Rh, Ir) react with 2 equiv. of 4-amino-3,5-di-pyridyltriazole (dpt-NH₂) in presence of NH₄PF₆ to afford the corresponding mononuclear complexes of the type [(η⁶-arene)Ru(dpt-NH₂)Cl]PF₆ {arene = C₁₀H₁₄ (1), C₆H₆ (2) and C₆Me₆ (3)} and [(η⁶-C₅Me₅)M(dpt-NH₂)Cl]PF₆ {M = Rh (4), Ir (5)}. However, the mononuclear η⁵-cyclopentadienyl analogues such as [(η⁵-C₅H₅)Ru(PPh₃)₂Cl], [(η⁵-C₅H₅)Os(PPh₃)₂Br], [(η⁵-C₅Me₅)Ru(PPh₃)₂Cl] and [(η⁵-C₉H₇)Ru(PPh₃)₂Cl] complexes react in presence of 1 equiv. of dpt-NH₂ and 1 equiv. of NH₄PF₆ in methanol yielded mononuclear complexes [(η⁵-C₅H₅)Ru(PPh₃)(dpt-NH₂)]PF₆ (6), [(η⁵-C₅H₅)Os(PPh₃)(dpt-NH₂)]PF₆ (7), [(η⁵-C₅Me₅)Ru(PPh₃)(dpt-NH₂)]PF₆ (8) and [(η⁵-C₉H₇)Ru(PPh₃)(dpt-NH₂)]PF₆ (9), respectively. These compounds have been totally characterized by IR, NMR and mass spectrometry. The molecular structures of 4 and 6 have been established by single crystal X-ray diffraction and some of the representative complexes have also been studied by UV–Vis spectroscopy.     

Synthesis and structural characterisation of five copper(I) and silver(I) complexes with 2-aminopyridine (2-APy), [Cu(μ-Cl)(2-Apy)(PPh3)]2, [Ag(μ-X)(2-Apy)(PPh3)]2 (X = Cl,Br), [Ag(μ-ONO2)(2-Apy)(EPh3)]2 (E = P,As)

Five new copper(I)/silver(I) complexes containing 2-aminopyridine, [Cu(μ-Cl)(2-Apy)(PPh₃)]₂(1), [Ag(μ-Cl)(2-Apy)(PPh₃)]₂(2), [Ag(μ-Br)(2-Apy)PPh₃)]₂(3), [Ag(μ-ONO₂)(2-Apy)(PPh₃)]₂(4), [Ag(μ-ONO₂)(2-Apy)(AsPh₃)]₂(5) have been synthesised for the first time. Complexes 1–5 are obtained by the reactions of MX (MX = CuCl for 1; M = Ag for 2–5; X = Cl, Br for 2–3; X = NO₃ for 4–5) with the monodentate ligands EPh₃ (E = P for 1–4; E = As for 5) and 2-Apy in the molar ratio of 1:1:2 in the mixed solvent of CH₂Cl₂ and MeOH. Complexes 1–5 are characterised by IR and X-ray diffraction. In 1–5, chloride, bromide and nitrate ions bridge two metal atoms to form dinuclear complexes containing the parallelogram cores M₂X₂ (M = Cu, Ag).     

Syntheses and characterization of η-cyclopentadienyl and η-indenyl ruthenium(II) complexes of arylazoimidazoles: The molecular structure of the complex [(η-C5H5)Ru(PPh3)(C6H5-NN-C3H3N2)]

The complex [(η⁵-C₅H₅)Ru(PPh₃)₂Cl] (1) reacts with several arylazoimidazole (RaaiR′) ligands, viz., 2-(phenylazo)imidazole (Phai-H), 1-methyl-2-(phenylazo)imidazole (Phai-Me), 1-ethyl-2-(phenylazo)imidazole (Phai-Et), 2-(tolylazo)imidazole (Tai-H), 1-methyl-2-(tolylazo)imidazole (Tai-Me) and 1-ethyl-2-(tolylazo)imidazole (Tai-Et), gave complexes of the type [(η⁵-C₅H₅)Ru(PPh₃)(RaaiR′)]⁺ {where R, R′ = H (2), R = H, R′ = CH₃ (3), R = H, R′ = C₂H₅ (4), R = CH₃, R′ = H (5), R, R′ = CH₃ (6), R = CH₃, R′ = C₂H₅ (7)}. The complex [(η⁵-C₉H₇)Ru(PPh₃)₂(CH₃CN)]⁺ (8) undergoes reactions with a series of N,N-donor azo ligands in methanol yielding complexes of the type [(η⁵-C₉H₇) Ru(PPh₃)(RaaiR′)]⁺ {where R, R′ = H (9), R = H, R′ = CH₃ (10), R = CH₃, R′ = H (11), R = CH₃, R′ = C₂H₅ (12)}, respectively. These complexes were characterized by FT IR and FT NMR spectroscopy as well as by analytical data. The molecular structure of the complex [(η⁵-C₅H₅)Ru(PPh₃)(C₆H₅-NN-C₃H₃N₂)]⁺ (2) was established by single crystal X-ray diffraction study.     

Syntheses and characterization of cyano-bridged homo and hetero bimetallic complexes containing η and η-cyclic hydrocarbons

The reactions of [(ind)Ru(PPh₃)₂CN] (ind = η⁵-C₉H₇) (1) and [CpRu(PPh₃)₂CN] (Cp = η⁵-C₅H₅) (2) with [(η⁶-p-cymene)Ru(bipy)Cl]Cl (bipy = 2,2′-bipyridine) (3) in the presence of AgNO₃/NH₄BF₄ in methanol, respectively, yielded dicationic cyano-bridged complexes of the type [(ind)(PPh₃)₂Ru(μ-CN)Ru(bipy)(η⁶-p-cymene)](BF₄)₂ (4) and [Cp(PPh₃)₂Ru(μ-CN)Ru(bipy)(η⁶-p-cymene)](BF₄)₂ (5). The reaction of [CpRu(PPh₃)₂CN] (2), [CpOs(PPh₃)₂CN] (6) and [CpRu(dppe)CN] (7) with the corresponding halide complexes and [(η⁶-p-cymene)RuCl₂]₂ formed the monocationic cyano-bridge complexes [Cp(PPh₃)₂Ru(μ-CN)Os(PPh₃)₂Cp](BF₄) (8), [Cp(PPh₃)₂Os(μ- CN)Ru(PPh₃)₂Cp](BF₄) (9) and [Cp(dppe)Ru(μ-CN)Os(PPh₃)₂Cp](BF₄) (10) along with the neutral complexes [Cp(PPh₃)₂Ru(μ-CN)Ru (η⁶-p-cymene)Cl₂] (11), [Cp(PPh₃)₂Os(μ-CN)Ru(η⁶-p-cymene)Cl₂] (12), and [Cp(dppe) Ru(μ-CN)Ru(η⁶-p-cymene)Cl₂] (13). These complexes were characterized by FT IR, ¹H NMR, ³¹P{¹H} NMR spectroscopy and the molecular structures of complexes 4, 8 and 11 were solved by X-ray diffraction studies.     

Palladium (II) complexes with mono-oxide 1,1′-bis(diphenylphosphino)metallocene ligands [Fe(η-C5Me4PPh2)(η-C5Me4P{O}Ph2)] and [Os(η-C5H4PPh2)(η-C5H4P{O}Ph2)]

The monoxides [Fe(η⁵-C₅Me₄PPh₂)(η⁵-C₅Me₄P{O}Ph₂)] (1) and [Os(η⁵-C₅H₄PPh₂)(η⁵-C₅H₄P{O}Ph₂)] (2) have been prepared by treatment of the corresponding diphosphines with CCl₄ and methanol.These ligands react with [Pd(PhCN)₂Cl₂] to give dichloride complexes of different structure.The dimeric complex [{Os(η⁵-C₅H₄PPh₂)(η⁵-C₅H₄P{O}Ph₂)}PdCl(μ-Cl)]₂ (4) contains the monodentate P-coordinated osmocene ligand with the free P{O}Ph₂ group, while the octamethylferrocene ligand gives the chelate k²-P,O complex [{Fe(η⁵-C₅Me₄PPh₂)(η⁵-C₅Me₄P{O}Ph₂)}PdCl₂] (3).The structures of 3 and 4 have been determined crystallographically.Treatment of 3 and 4 with silver salts in CH₂Cl₂ or acetonitrile leads to the corresponding dicationic complexes[{M(η⁵-C₅R₄PPh₂)(η⁵-C₅R₄P{O}Ph₂)}Pd(MeCN)_x]²⁺ (5, M = Fe, R = Me; 6, M = Os, R = H). Complex 5 decomposes upon isolation, in contrast 6 is rather stable, probably due to Os-Pd bonding. The dichlorides 3 and 4 catalyze catalytic amination of p-bromotoluene with N-(4-tolyl)morpholine with lower activity than (dppf)PdCl₂, however they perform comparable to (dppf)PdCl₂ activity in coupling of p-bromotoluene with p-methoxyphenyl boronic acid.     

Heterocyclic thioamides of copper(I): Synthesis and crystal structures of copper complexes with 1,3-imidazoline-2-thiones in the presence of triphenyl phosphine

Reaction of copper(I) chloride with 1,3-imidazoline-2-thione (imzSH) in the presence of Ph₃P in 1:2:2 or 1:1:2 (M:L:PPh₃) molar ratios yielded a compound of unusual composition, [Cu₂(imzSH)(PPh₃)₄Cl₂] · CH₃OH (1), whose X-ray crystallography has shown that its crystals consist of four coordinated [CuCl(1κS-imzSH)(PPh₃)₂] (1a), and three coordinated [Cu(PPh₃)₂Cl] (1b) independent molecules in the same unit cell. In contrast, crystals of complexes of copper(I) bromide/iodide are formed by single molecules of [CuBr(1κS-imzSH)(PPh₃)₂] · H₂O (2) and [CuI(1κS-imzSH)(PPh₃)₂] (3), respectively, similar to molecule 1a. The related ligand, 1,3-benzimidazoline-2-thione (bzimSH) formed a complex [CuBr(1κS-bzimSH)(PPh₃)₂] · CH₃COCH₃ (4), similar to 2. The formation of 1a and 1b has been also revealed by NMR spectroscopy. The NMR spectra of 2–4 also showed weak signals indicating formation of compounds similar to 1b. It reveals that the lability of the Cu–S bond varies in the order: Cl ? Br ∼ I. Weak interactions {e.g. C–H?π electrons of ring, –NH?halogens/oxygen, C–H?halogens/oxygen, π?π (between rings)} have played an important role in building 2D chains of complexes 1–4.     

SPh functionalized bridging-vinyliminium diiron and diruthenium complexes

The SPh functionalized vinyliminium complexes [Fe₂{μ-η¹:η³-C_γ(R′)C_β(SPh)C_αN(Me)(R)}(μ-CO)(CO)(Cp)₂][SO₃CF₃] [R = Xyl, R′ = Me, 2a; R = Me, R′ = Me, 2b; R = 4-C₆H₄OMe, R′ = Me, 2c; R = Xyl, R′ = CH₂OH, 2d; R = Me, R′ = CH₂OH, 2e; Xyl = 2,6-Me₂C₆H₃] are generated in high yields by treatment of the corresponding vinyliminium complexes [Fe₂{μ-η¹:η³-C_γ(R′)C_β(H)C_αN(Me)(R)}(μ-CO)(CO)(Cp)₂][SO₃CF₃] (1a-e) with NaH in the presence of PhSSPh. Likewise, the diruthenium complex [Ru₂{μ-η¹:η³-C_γ(Me)C_β(SPh)C_αN(Me)(Xyl)}(μ-CO)(CO)(Cp)₂][SO₃CF₃] (2f) was obtained from the corresponding vinyliminium complex [Ru₂{μ-η¹:η³-C_γ(Me)C_β(H)C_αN(Me)(Xyl)}(μ-CO)(CO)(Cp)₂] (1f). The synthesis of 2c is accompanied by the formation, in comparable amounts, of the aminocarbyne complex [Fe₂{μ-CN(Me)(4-C₆H₄OMe)}(SPh)(μ-CO)(CO)(Cp)₂] (3).The molecular structures of 2d, 2e and 3 have been determined by X-ray diffraction studies.     

Syntheses and characterization of η-hexamethylbenzeneruthenium(II)-β-diketone complexes: their reactions with mono- and bidentate neutral ligands

The complex [(η⁶-C₆Me₆)Ru(μ-Cl)Cl]₂1 react with sodium salts of β-diketonato ligands in methanol to afford the oxygen bonded neutral complexes of the type [(η⁶-C₆Me₆)Ru(κ²-O,O′-R¹COCHCOR²)Cl] {R¹, R² = CH₃ (2), CH₃, C₆H₅ (3), C₆H₅ (4), OCH₃ (5), OC₂H₅ (6)}. Complex 4 with AgBF₄ yields the γ-carbon bonded ruthenium dimeric complex 7. Complex 4 also reacts with tertiary phosphines and bridging ligands to yield complexes of the type [(η⁶-C₆Me₆)Ru(κ²-O,O′-C₆H₅COCHCOC₆H₅)(L)]⁺ (L = PPh₃ (8), PMe₂Ph (9)) and [{η⁶-C₆Me₆)Ru(κ²-O,O′-C₆H₅COCHCOC₆H₅)}₂(μ-L)] L = 4,4′-bipyridine (4,4′-bipy) (11), 1,4-dicyanobenzene (DCB) (12) and pyrazine (Pz) (13). Complexes 2-4 react with sodium azide to yield neutral complexes [(η⁶-C₆Me₆)Ru(κ²-O,O′-R¹COCHCOR²)N₃] {R¹, R² = CH₃ (10a), CH₃, C₆H₅ (10b), C₆H₅ (10c). All these complexes were characterized by FT-IR and FT-NMR spectroscopy as well as analytical data. The molecular structures of complexes [(η⁶-C₆Me₆)Ru(κ²-O,O′CH₃COCH-COC₆H₅)Cl] (3) and [(η⁶-C₆Me₆)Ru(κ²-O,O′-C₆H₅COCHCOC₆H₅] (4) were established by single crystal X-ray diffraction studies. The complex 3 crystallizes in the triclinic space group, [a = 7.9517(4), b = 9.0582(4) and c = 14.2373(8) Å, α = 88.442(3)°, β = 76.6.8(3)° and γ = 81.715(3)°. V = 987.17(9) ų, Z = 2]. Complex 4 crystallizes in the monoclinic space group, P2₁/c [a = 7.5894(8), b = 20.708(2) and c = 29.208(3) Å,β = 92.059(3)° V = 4587.5(9) ų, Z = 8].     

Electronically variable imino-phenanthrolinyl-cobalt complexes; synthesis, structures and ethylene oligomerisation studies

The 2-imino-1,10-phenanthroline ligands, 1,10-C₁₂H₇N₂-2-CRN(2,6-i-Pr₂-4-R¹-C₆H₂) [R = R¹ = H (L1); R = H, R¹ = Br (L2); R = H, R¹ = CN (L3); R = H, R¹ = i-Pr (L4); R = Me, R¹ = H (L5); R = Me, R¹ = i-Pr (L6)], have been prepared in high yield from the condensation reaction of 1,10-C₁₂H₇N₂-2-CRO (R = H, Me) with one equivalent of the corresponding 4-substituted 2,6-diisopropylaniline. The molecular structures of L2, L5 and L6 reveal the imino nitrogen atoms to adopt a transoid configuration with respect to the phenanthrolinyl nitrogen atoms. Treatment of Lx with one equivalent of CoCl₂ in n-BuOH at 90 °C gives the high spin complexes, (Lx)CoCl₂ [Lx = L1 (1a), L2 (1b), L3 (1c), L4 (1d), L5 (1e), L6 (1f)], in which the metal centres exhibit distorted square pyramidal geometries. Activation of 1a-1f with excess methylaluminoxane (MAO) gives catalysts that are modestly active for the oligomerisation of ethylene affording mainly linear α-olefins along with some degree of internal olefins. While the donor capability of the 4-position of the N-aryl group does not appear to affect the activity of the catalyst, it does have an influence on the ratio of α-olefins to internal olefins. Single crystal X-ray diffraction studies have been performed on L2, L5, L6, 1a, 1c and 1f.     

Chemistry of vinylidene complexes. XVIII. Synthesis and molecular structure of the novel trinuclear μ3-vinylidene complex CpReFePt(μ3-CCHPh)(CO)6(PPh3)

The interaction between Cp(CO)₂RePt(μ-CCHPh)(PPh₃)₂ (1) and Fe₂(CO)₉ afforded the new heterometallic μ₃-vinylidene cluster CpReFePt(μ₃-CCHPh)(CO)₆(PPh₃) (2). An X-ray diffraction study shows the complex 2 possesses a trimetallic Re-Fe-Pt chain core. The bond lengths are Re-Fe 2.8221(8), Fe-Pt 2.5813(8) Å; the Re?Pt distance is 3.3523(7) Å; the bond angle Re-Fe-Pt is 76.55(3)°. The μ₃-CCHPh ligand is η¹-bound to the Re and Pt atoms and η²-coordinated to the Fe atom. The CC bond length is 1.412(4) Å. The Pt atom is coordinated by the PPh₃ and CO groups. Complex 2 is characterized by the IR and ¹H, ¹³C and ³¹P NMR spectra.     

C-C bond formation through olefin-thiocarbyne coupling in diiron complexes

The bridging diiron thiocarbyne complex [Fe₂{μ-CS(Me)}(μ-CO)(CO)₂(Cp)₂][SO₃CF₃] (1) reacts with activated olefins (methyl acrylate, acrylonitrile, styrene, diethyl maleate), in the presence of Me₃NO and NaH, to give the corresponding μ-allylidene complexes [Fe₂{μ-η¹:η³-C_α(SMe)C_β(R′)C_γ(H)(R″)} (μ-CO)(CO)(Cp)₂] (R″ = CO₂Me, R′ = H, 3a; R″ = CN, R′ = H, 3b; R″ = C₆H₅, R′ = H, 3c; R″ = R′ = CO₂Et, 3d). The coupling reaction of olefin with thiocarbyne is regio- and stereospecific, leading to the formation of only one isomer. C-C bond formation occurs between the less substituted alkene carbon and the thiocarbyne. Moreover, olefinic hydrogens of the bridging ligands are mutually trans.The reactions of 3a-b with MeSO₃CF₃ result, selectively, in the formation of the cationic μ-sulphonium allylidene complexes [Fe₂{μ-η¹:η³-C_α(SMe₂)C_β (H)C_γ(H)(R)}(μ-CO)(CO)(Cp)₂][SO₃CF₃] (R = CO₂Me, 4a; R = CN, 4b). Compound 4a undergoes displacement of the SMe₂ group by nucleophiles such as NaBH₄, NBu₄CN and NaOMe, affording the complexes [Fe₂{μ-η¹:η³-C_α(R)C_β (H)C_γ(H)(CO₂Me)}(μ-CO)(CO)(Cp)₂] (R = H, 5a; R = CN, 5b; R = OMe, 5c), respectively. The molecular structures of 3a and 5a have been determined by X-ray diffraction studies.