A modular design of metal catalysts for the transfer hydrogenation of aromatic ketones

The ability of transition metal catalysts to add or remove hydrogen from organic substrates by transfer hydrogenation is a valuable synthetic tool. Towards a series of novel metal complexes with a P―NH ligand, [Ph₂PNHCH₂―C₄H₃O] derived from furfurylamine were synthesized. Reaction of [Ph₂PNHCH₂―C₄H₃O] 1 with [Ru(η⁶‐p‐cymene)(μ‐Cl)Cl]₂, [Ru(η⁶‐benzene)(μ‐Cl)Cl]₂, [Rh(μ‐Cl)(cod)]₂ and [Ir(η⁵‐C₅Me₅)(μ‐Cl)Cl]₂ gave a range of new monodentate complexes [Ru(Ph₂PNHCH₂―C₄H₃O)(η⁶‐p‐cymene)Cl₂] 2 , [Ru(Ph₂PNHCH₂―C₄H₃O)(η⁶‐benzene)Cl₂] 3 , [Rh(Ph₂PNHCH₂‐C₄H₃O)(cod)Cl] 4 , and [Ir(Ph₂PNHCH₂‐C₄H₃0)(η⁵‐C₅Me₅)Cl₂] 5 , respectively. All new complexes were fully characterized by analytical and spectroscopic methods. ³¹P‐{¹H} NMR, distortionless enhancement by polarization transfer (DEPT) or ¹H‐¹³C heteronuclear correlation (HETCOR) experiments were used to confirm the spectral assignments. Following activation by KOH, compounds 1 , 2 , 3 , 4 catalyzed the transfer hydrogenation of acetophenone derivatives to 1‐phenylethanol derivatives in the presence of iso‐PrOH as the hydrogen source. Notably [Ru(Ph₂PNHCH₂‐C₄H₃O)(η⁶‐benzene)Cl₂] 3 acts as an excellent catalyst, giving the corresponding alcohols in 98–99% yield in 20 min at 82°C (time of flight ≤ 297 h^?1) for the transfer hydrogenation reaction in comparison to analogous rhodium or iridium complexes. Copyright © 2012 John Wiley & Sons, Ltd.     

Organometallic ruthenium, rhodium and iridium complexes containing a P-bound thiophene-2-(N-diphenylphosphino)methylamine ligand: Synthesis, molecular structure and catalytic activity

Reaction of Ph₂PNHCH₂-C₄H₃S with [Ru(η⁶-p-cymene)(μ-Cl)Cl]₂, [Ru(η⁶-benzene)(μ-Cl)Cl]₂, [Rh(μ-Cl)(cod)]₂ and [Ir(η⁵-C₅Me₅)(μ-Cl)Cl]₂ yields complexes [Ru(Ph₂PNHCH₂-C₄H₃S)(η⁶-p-cymene)Cl₂], 1, [Ru(Ph₂PNHCH₂-C₄H₃S)(η⁶-benzene)Cl₂], 2, [Rh(Ph₂PNHCH₂-C₄H₃S)(cod)Cl], 3 and [Ir(Ph₂PNHCH₂-C₄H₃S)(η⁵-C₅Me₅)Cl₂], 4, respectively. All complexes were isolated from the reaction solution and fully characterized by analytical and spectroscopic methods. The structure of [Ru(Ph₂PNHCH₂-C₄H₃S)(η⁶-benzene)Cl₂], 2 was also determined by single crystal X-ray diffraction. 1-4 are suitable precursors forming highly active catalyst in the transfer hydrogenation of a variety of simple ketones. Notably, the catalysts obtained by using the ruthenium complexes [Ru(Ph₂PNHCH₂-C₄H₃S)(η⁶-p-cymene)Cl₂], 1 and [Ru(Ph₂PNHCH₂-C₄H₃S)(η⁶-benzene)Cl₂], 2 are much more active in the transfer hydrogenation converting the carbonyls to the corresponding alcohols in 98-99% yields (TOF ≤ 200 h⁻¹) in comparison to analogous rhodium and iridium complexes.     

Study of novel η-cyclopentadienyl and η-arene platinum group metal complexes containing a N4-type ligand and their structural characterization

The mononuclear η⁵-cyclopentadienyl complexes [(η⁵-C₅H₅)Ru(PPh₃)₂Cl], [(η⁵-C₅H₅)Os(PPh₃)₂Br] and pentamethylcyclopentadienyl complex [(η⁵-C₅Me₅)Ru(PPh₃)₂Cl] react in the presence of 1 eq. of the tetradentate N,N′-chelating ligand 3,5-bis(2-pyridyl)pyrazole (bpp-H) and 1 eq. of NH₄PF₆ in methanol to afford the mononuclear complexes [(η⁵-C₅H₅)Ru(PPh₃)(bpp-H)]PF₆ ([1]PF₆), [(η⁵-C₅H₅)Os(PPh₃)(bpp-H)]PF₆ ([2]PF₆) and [(η⁵-C₅Me₅)Ru(PPh₃)(bpp-H)]PF₆ ([3]PF₆), respectively. The dinuclear η⁵-pentamethylcyclopentadienyl complexes [(η⁵-C₅Me₅)Rh(μ-Cl)Cl]₂ and [(η⁵-C₅Me₅)Ir(μ-Cl)Cl]₂ as well as the dinuclear η⁶-arene ruthenium complexes [(η⁶-C₆H₆)Ru(μ-Cl)Cl]₂ and [(η⁶-p-ⁱPrC₆H₄Me)Ru(μ-Cl)Cl]₂ react with 2 eq. of bpp-H in the presence of NH₄PF₆ or NH₄BF₄ to afford the corresponding mononuclear complexes [(η⁵-C₅Me₅)Rh(bpp-H)Cl]PF₆ ([4]PF₆), [(η⁵-C₅Me₅)Ir(bpp-H)Cl]PF₆ ([5]PF₆), [(η⁶-C₆H₆)Ru(bpp-H)Cl]BF₄ ([6]BF₄) and [(η⁶-p-ⁱPrC₆H₄Me)Ru(bpp-H)Cl]BF₄ ([7]BF₄). However, in the presence of 1 eq. of bpp-H and NH₄BF₄ the reaction with the same η⁶-arene ruthenium complexes affords the dinuclear salts [(η⁶-C₆H₆)₂Ru₂(bpp)Cl₂]BF₄ ([8]BF₄) and [(η⁶-p-ⁱPrC₆H₄Me)₂Ru₂(bpp)Cl₂]BF₄ ([9]BF₄), respectively. These compounds have been characterized by IR, NMR and mass spectrometry, as well as by elemental analysis. The molecular structures of [1]PF₆, [5]PF₆ and [8]BF₄ have been established by single crystal X-ray diffraction studies and some representative complexes have been studied by UV–vis spectroscopy.     

Cyclopentadienyl titanium complexes with aryldiazenido- or phosphiniminato-ligands

[Ti(η⁵-C₅H₅)Cl₃] reacts with Me₃SiNNPh to give [Ti(η⁵-C₅H₅)Cl₂(N₂Ph)], and this gives [Ti(η⁵-C₅H₅)₂Cl(N₂Ph)] on treatment with sodium cyclopentadienide in THF at ?80°C. [Ti(η⁵-C₅H₄R)Cl₃] (R  H, Me) reacts analogously with Me₃SiNPR₃ (PR₃  PPh₃, PPh₂Me) to give [Ti(η⁵-C₅H₄R)Cl₂(NPR₃)]. Under similar conditions TiCl₄ gives [TiCl₄(Me₃SiNPR₃)].     

Cyclopentadienyl- and pentamethylcyclopentadienyl-rhodium(III) complexes containing isocyanide ligands

The complexes [(η⁵-C₅H₅)RhCl₂]₂ and [(η⁵-C₅Me₅)RhCl₂]₂ react with stoichiometric amounts of isocyanide ligands L to give (η⁵-C₅H₅)RhLCl₂ and (η⁵-C₅Me₅)RhLCl₂ (L = CNC₆H₁₁, CNC₆H₄CH₃-p); an excess of ligand L reacts further with (η⁵-C₅Me₅)RhLCl₂ to give the cationic complex [(η⁵-C₅Me₅)RhL₂Cl]⁺ which was isolated as tetraphenylborate salt. The cationic complexes [(η⁵-C₅Me₅)RhL(PPh₃)Cl]⁺ and [(η⁵-C₅Me₅)Rh(Ph₂PC₂H₄PPh₂)Cl]⁺ were obtained in the reaction of (η⁵-C₅Me₅)RhLCl₂ with PPh₃ and Ph₂PC₂H₄PPh₂ respectively. Unidentified solids which do not contain the cyclopentadienyl moiety were obtained in the analogous reactions of (η⁵-C₅H₅)RhLCl₂ with an excess of isocyanide or of tertiary phosphine.The complexes (η⁵-C₅H₅)Rh(CNC₆H₁₁)Cl₂ and (η⁵-C₅Me₅)Rh(CNC₆H₁₁)Cl₂ react with SCN^? or SeCN^? giving the corresponding dithiocyanate or diselenocyanate derivatives in which the pseudohalogen groups are S- or Se-bonded to the metal atom. The analogous reactions with C₆Cl₅MgCl gave the chiral complexes (η⁵-C₅H₅)Rh(CNC₆H₁₁)(C₆Cl₅)Cl and (η⁵-C₅Me₅)Rh(CNC₆H₁₁)(C₆Cl₅)Cl.The potentially chelating anion Ph₂PSS^? reacts with (η⁵-C₅H₅)Rh(CNC₆H_n11)Cl₂ and (η⁵-C₅Me₅)Rh(CNC₆H₁₁)Cl₂ to give (η⁵-C₅H₅)Rh(CNC₆H¹¹)(SSPPh₃)Cl and (η⁵-C₅Me₅)Rh(CNC₆H¹¹)(SSPPh₂)Cl in which the dithio ligand acts as monodentate; these compounds react with MeI or EtI to give the dihalide derivatives and the esters Ph₂PSSMe and PSSEt. The complex [(η⁵-C₅Me₅)Rh(CNC₆H₁₁)(SSPPh₂)]Cl was obtained by refluxing a benzene solution of the corresponding neutral complex; the cyclopentadienyl derivative failed to give the analogous chelate complex.The complexes (η⁵-C₅H₅)RhLCl₂, (η⁵-C₅Me₅)RhLCl₂ and [(η⁵-C₅Me₅)RhL₂Cl]⁺ (L = CNC₆H₁₁) were found to be unreactive towards amines.     

Metallkomplexe mit biologisch wichtigen Liganden. XCV. η5- Pentamethylcyclopentadienyl-Rhodium-, -Iridium-, (η6-Benzol)-Ruthenium- und Phosphan-Palladium-Komplexe von Prolinmethylester und Prolinamid

Metal Complexes of Biologically Important Ligands. XCV. η⁵-Pentamethylcyclopentadienyl Rhodium, Iridium, η⁶- Benzene Ruthenium, and Phosphine Palladium Complexes of Proline Methylester and Proline Amide Proline methylester (L¹) and proline amide (L²) give with the chloro bridged complexes [(η⁵ -C₅Me₅)MCl₂]₂ (M ? Rh, Ir), [(η⁶ -benzene)RuCl₂]₂ and [Et₃PPdCl₂]₂ N and N,O coordinated compounds: (η⁵ -C₅Me₅)M(Cl₂)L¹ ( 1, 2 M ? Rh, Ir), [(η⁵-C₅Me₅) Rh(Cl)(L²)]⁺Cl^? ( 5 ), [(η⁶- C₆Me₆) Ru(Cl)(L²)]⁺Cl^? ( 6 ), [(η⁶-p-cymene)Ru(Cl)(L²)]⁺Cl^? ( 7 ), [(eta;⁵-C₅Me₅)M(Cl)(L²-H⁺)] ( 9, 10 M ? Rh, Ir), (Et₃P)Pd(Cl)₂L¹ ( 3 ), and [(Et₃P)Pd(Cl)(L²)]⁺Cl^? ( 8 ). The NMR spectra indicate that for 5 and 6 only one diastereoisomer is formed. The complexes 1, 2, 3 and 5 were characterized by X-ray diffraction.     

Palladium(II)-, Platin(II)-, Ruthenium(II)-, Rhodium(III)- und Iridium(III)-Komplexe von Desoxyfructosazin

Metal Complexes of Biologically Important Ligands. CIII. [1] Palladium(II), Platinum(II), Ruthenium(II), Rhodium(III), and Iridium(III) Complexes of Desoxyfructosazine The reactions of the pyrazine derivative desoxyfructosazin(pz) with K₂PtCl₄ and with the chlorobridged [M(PR₃)Cl₂]₂ (M = Pd, Pt), [(η⁵-C₅Me₅)MCl₂]₂ and [(η⁶-p-Cymol)RuCl₂]₂ give the watersoluble complexes cis-Cl₂Pt(pz)₂, (R₃P)(Cl)M(pz)M(Cl)(PR₃) (M = Pd, Pt), (η⁵-C₅Me₅)(Cl)₂M(pz)M(Cl)₂(η⁵-C₅Me₅) (M = Rh, Ir), (η⁶-p-Cymol)(Cl₂)Ru(pz)Ru(Cl)₂(η⁶-p-Cymol).     

SYNTHESES AND REACTIONS OF THE COMPLEXES (η5-C5Me5)Re(CO)2(C6CL5–nHn)Cl (n = 2,3): COMPOUNDS DERIVED FROM INITIAL C—CI ACTIVATION

Abstract

The UV irradiation of (η⁵-C₅Me₅)Re(CO)₃ in the presence of 1,2,4,5-C₆Cl₄H₂ and 1,3,5-C₆Cl₃H₃ (λ = 350 nm, hexane solution) effected intramolecular C—Cl activation, generating the complexes trans-(η⁵-C₅Me₅)Re(CO)₂(2,4,5-C₆Cl_5-nH_n)Cl, ((1), n = 2; (2), n = 3), respectively. Complex (1) dissolved in polar organic solvents produces, an equilibrium mixture with its cis isomer. The reaction of (1) with AgBF₄, in acetonitrile, led to formation of the cationic complex [cis-(η⁵-C₅Me₅)Re(CO)₂(2,4,5-C₆Cl₃H₂)(MeCN)]⁺. The tetramethylfulvene complex (η⁶-C₅Me₄CH₂)Re(CO)₂(2,4,5-C₆Cl₃H₂) (3) was obtained by reacting the cationic complex with the fluorinating agent Et₃N′3HF.     

Mono and dinuclear complexes of half-sandwich platinum group metals (Ru, Rh and Ir) bearing a flexible pyridyl-thiazole multidentate donor ligand

The mononuclear cationic complexes [(η⁶-C₆H₆)RuCl(L)]⁺ (1), [(η⁶-p-ⁱPrC₆H₄Me)RuCl(L)]⁺ (2), [(η⁵-C₅H₅)Ru(PPh₃)(L)]⁺ (3), [(η⁵-C₅Me₅)Ru(PPh₃)(L)]⁺ (4), [(η⁵-C₅Me₅)RhCl(L)]⁺ (5), [(η⁵-C₅Me₅)IrCl(L)]⁺ (6) as well as the dinuclear dicationic complexes [{(η⁶-C₆H₆)RuCl}₂(L)]²⁺ (7), [{(η⁶-p-ⁱPrC₆H₄Me)RuCl}₂(L)]²⁺ (8), [{(η⁵-C₅H₅)Ru(PPh₃)}2(L)]²⁺ (9), [{(η⁵-C₅Me₅)Ru(PPh₃)}₂(L)]²⁺ (10), [{(η⁵-C₅Me₅)RhCl}₂(L)]²⁺ (11) and [{(η⁵-C₅Me₅)IrCl}₂(L)]²⁺ (12) have been synthesized from 4,4′-bis(2-pyridyl-4-thiazole) (L) and the corresponding complexes [(η⁶-C₆H₆)Ru(μ-Cl)Cl]₂, [(η⁶-p-ⁱPrC₆H₄Me)Ru(μ-Cl)Cl]₂, [(η⁵-C₅H₅)Ru(PPh₃)₂Cl)], [(η⁵-C₅Me₅)Ru(PPh₃)₂Cl], [(η⁵-C₅Me₅)Rh(μ-Cl)Cl]₂ and [(η⁵-C₅Me₅)Ir(μ-Cl)Cl]₂, respectively. All complexes were isolated as hexafluorophosphate salts and characterized by IR, NMR, mass spectrometry and UV-vis spectroscopy. The X-ray crystal structure analyses of [3]PF₆, [5]PF₆, [8](PF₆)₂ and [12](PF₆)₂ reveal a typical piano-stool geometry around the metal centers with a five-membered metallo-cycle in which 4,4′-bis(2-pyridyl-4-thiazole) acts as a N,N′-chelating ligand.     

Applications of transition metal complexes containing aminophosphine ligand to transfer hydrogenation of ketones

Hydrogen transfer reduction processes are attracting increasing interest from synthetic chemists in view of their operational simplicity. Reaction of [Ph₂PNHCH₂‐C₄H₃S] with [Ru(η⁶‐benzene)(µ‐Cl)Cl]₂, [Rh(µ‐Cl)(cod)]₂ and [Ir(η⁵‐C₅Me₅)(µ‐Cl)Cl]₂ gave a range of new monodendate complexes [Ru(Ph₂PNHCH₂‐C₄H₃S)(η⁶‐benzene)Cl₂], 1, [Rh(Ph₂PNHCH₂‐C₄H₃S)(cod)Cl], 2, and [Ir(Ph₂PNHCH₂‐C₄H₃S)(η⁵‐C₅Me₅)Cl₂], 3, respectively. All new complexes were fully characterized by analytical and spectroscopic methods. ¹H? ³¹P NMR, ¹H? ¹³C HETCOR or ¹H? ¹H COSY correlation experiments were used to confirm the spectral assignments. 1–3 are suitable catalyst precursors for the transfer hydrogenation of acetophenone derivatives. Notably [Ru(Ph₂PNHCH₂‐C₄H₃S)(η⁶‐benzene)Cl₂], 1, acts as an excellent catalyst, giving the corresponding alcohols in 98–99% yields in 30 min at 82 °C (TOF ≤200 h^?1) for the transfer hydrogenation reaction in comparison to analogous rhodium or iridium complexes. This transfer hydrogenation is characterized by low reversibility under these conditions. Copyright © 2011 John Wiley & Sons, Ltd.     

A heteronuclear compound of ruthenium and silver containing bridging tris(pyridyl)methanoate ligands

The reaction of [{Ru(η⁶-C₆H₆)Cl(μ-Cl)}₂] with Py₃COH in ethanol results in the formation of the cation [Ru(η⁶-C₆H₆)(N,N′,O,-(C₅H₄N)₃CO)]⁺ which is isolated as its hexafluorphosphate salt 1. The cation acts as a ligand towards other transition metal ions. With Ag⁺ the hetero-trinuclear complex [{Ru(η⁶-C₆H₆)((C₅H₄N)₃CO)}₂Ag][PF₆]₃ 2 is formed, while reaction with [Pd(PhCN)₂Cl₂] gives the bimetallic [Ru(η⁶-C₆H₆)((C₅H₄N)₃CO)PdCl₂][PF₆] 3. Both compounds were fully characterised by spectroscopic methods and the trinuclear complex was additionally characterised by X-ray diffraction.     

The synthesis of new paracyclophane complexes of ruthenium(II): Crystal structure of [Ru(η6-C16H16)Cl(C5H5N)2][PF6]

The dimer [Ru(η⁶-C₁₆H₁₆)Cl₂]₂ reacts with ligands L (L  PMe₂Ph, PPh₃, C₅H₅N) to give both neutral monomeric [Ru(η⁶-C₁₆H₁₆)Cl₂L] and cationic monomeric [Ru(η⁶-C₁₆H₁₆)ClL₂]⁺ products. One example, [Ru(η⁶-C₁₆H₁₆)Cl(C₅H₅N)₂]-[PF₆], has been characterised by X-ray crystallography. Reaction with the bidentate ligand 2,2′-bipyridyl gives the mononuclear cation [Ru(η⁶-C₁₆H₁₆)Cl(bipy)]⁺, isolated as its [BPh₄]⁻ salt, whereas reaction with OMe⁻ or OEt⁻ gives dinuclear products [Ru(η⁶-C₁₆H₁₆)₂(OR)₃]⁺.     

Zur Strukturchemie der Alkyl- und Arylhalogenoarsenate(III), [Me2As2Cl5]–, [RAsCl3]–, [R2As2Br6]2– (R = Me,Et, Ph) und [Ph2AsX2]– (X = Cl,Br)

Structural Chemistry of the Alkyl- and Arylhaloarsenates(III) [Me₂As₂Cl₅]^–, [RAsCl₃]^–, [R₂As₂Br₆]^2– (R = Me, Et, Ph) and [Ph₂AsX₂]^– (X = Cl, Br) The alkyl- and arylhaloarsenates(III) [Ph₄P][Me₂As₂Cl₅] ( 1 ), [Ph₄P][RAsCl₃] (R = Me, Et, Ph, 2 – 4 ), [Me₃PhN][PhAsCl₃] ( 5 ), [Ph₄P]₂[R₂As₂Br₆] (R = Me, Et, Ph, 6 – 8 ), [n-Pr₄N][Ph₂AsCl₂] ( 9 ) and [n-Bu₄N][Ph₂AsBr₂] ( 10 ) have been prepared and their structures established by X-ray diffraction. In contrast to the chloroarsenates(III) 2 – 5 , which all contain isolated ψ-trigonal bipyramidal anions [RAsCl₃]^–, the analogous bromoarsenates(III) 6 – 8 exhibit dimeric structures. Whereas the trans sited As–Cl distances in 2 and 3 are very similar a pronounced degree of asymmetry is apparent for the Cl–As–Cl three-centre bonds in 4 and 5 [2.396(1) and 2.602(1) Å in 5]. In 6 and 7 C_i symmetry related RAsBr₂ units are connected through long As…Br bonds [2.926(1) and 3.116(2) Å in 6 ]. The bromophenylarsenate(III) anion of 8 which contains two effectively undistorted ψ-trigonal bipyramids [PhAsBr₃]^– associated by weak As…Br interactions [3.117(2) Å]. In view of its very long bridging As…Cl distances the [Me₂As₂Cl₅]^– anion in 1 can, as 6 an 7 , be regarded as two MeAsCl₂ molecules weakly linked through a chloride ion.     

Syntheses,spectroscopic and structural studies of indenyl ruthenium complexes incorporating amine and nitrile ligands: molecular structures of [(η5-C9H7) Ru(η2-dppe)(CH3CN)]PF6 and [(η5-C9H7)Ru(η2-dppe)(NH3)]PF6

The reaction of [(η⁵-C₉H₇)Ru(η²-dppe)Cl] (1) with monodentate nitriles, (L) in the presence of NH₄PF₆ afforded the complexes [(η⁵-C₉H₇)Ru(η²-dppe)(L)]PF₆, with L?=?CH₃CN (2a), CH₃CH=CHCN (2b), NCC₆H₄CN (2c), C₆H₅CH₂CN (2d), respectively. However, reaction of 1 with NH₄PF₆ in methanol yielded an amine complex of the type [(η⁵-C₉H₇) Ru(η²-dppe)(NH₃)]PF₆ (3a). The complexes were fully characterized by spectroscopy and analytical data. The molecular structures of the complexes [(η⁵-C₉H₇)Ru(η²-dppe) (CH₃CN)]PF₆ (2a) and [(η⁵-C₉H₇)Ru(η²-dppe)(NH₃)]PF₆ (3a) have been determined by single crystal X-ray analyses.     

Iridium (III) and rhodium (III) triazoles by 1,3-dipolar cycloadditons to a coordinated azide in iridium (III) and rhodium (III) compounds

The reaction of [(η⁵-C₅Me₅)M(μCl)Cl]₂ with the ligand (L^∩L) in the presence of sodium methoxide yielded compounds of general formula [(η⁵-C₅Me₅)M(L^∩L)Cl] (1–10) (where M = Ir or Rh and L^∩L = N^∩O or O^∩O chelate ligands). Azido complexes of formulation [(η⁵-C₅Me₅)M(L^∩L)N₃] (11–20) have been prepared by the reaction of [(η⁵-C₅Me₅)M(μN₃)(X)]₂ (X = Cl or N₃) with the corresponding ligands or by the direct reaction of [(η⁵-C₅Me₅)M(L^∩L)Cl] with NaN₃. These azido complexes [(η⁵-C₅Me₅)M(L^∩L)N₃] undergo 1,3-dipolar cycloaddition reaction with substituted alkynes in CH₂Cl₂ and for the first time in ethanol at room temperature to yield iridium (III) and rhodium (III) triazoles (21–28). The compounds were characterized on the basis of spectroscopic data, and the molecular structures of 2 and 26 have been established by single crystal X-ray diffraction.     

Synthesis and reactivity of homo-bimetallic Rh and Ir complexes containing a N,O-donor Schiff base

Binuclear complexes [{(η⁵-C₅Me₅)RhCl}₂(μ-bsh)] (1) and [{(η⁵-C₅Me₅)IrCl}₂(μ-bsh)] (2) containing N,N′-bis(salicylidine)hydrazine (H₂bsh) are reported. The complexes 1 and 2 reacted with EPh₃ (E = P, As) to afford cationic complexes [(η⁵-C₅Me₅)Rh(PPh₃)(κ²-Hbsh)]PF₆ (3), [(η⁵-C₅Me₅)Rh(AsPh₃)(κ²-Hbsh)]PF₆ (4), [(η⁵-C₅Me₅)Ir(PPh₃)(κ²-Hbsh)]PF₆ (5), and [(η⁵-C₅Me₅)Ir(AsPh₃)(κ²-Hbsh)]PF₆ (6) which were isolated as their hexafluorophosphate salts. Representative complexes 3 and 5 have been used as a metallo-ligand in the synthesis of binuclear complexes [(η⁵-C₅Me₅)RhCl(μ-bsh)Ru(η⁶-C₁₀H₁₄)Cl]PF₆ (7) and [(η⁵-C₅Me₅)IrCl(μ-bsh)Ru(η⁶-C₁₀H₁₄)Cl]PF₆ (8). The complexes under study have been fully characterized by analytical and spectral (FAB/ESI-MS, IR, NMR, electronic and emission) studies. Molecular structures of 1, 2, 3 and 5 have been determined crystallographically. Structural studies on 1 and 2 revealed the presence of extensive inter- and intra-molecular C-H···O and C-H···π weak bonding interactions. The complexes 1, 2, 3 and 5 moderately emit upon excitation at their respective MLCT bands.     

Half-sandwich ruthenium(II) complexes containing a tricyclic β-iminophosphine ligand: Catalytic activity in Diels–Alder reactions

The diastereoselective κ²-P,N-coordination of a chiral tricyclic β-iminophosphine ligand to the half-sandwich ruthenium(II) fragments [RuCl(η⁶-arene)]⁺ (arene = C₆H₆, p-cymene, 1,3,5-C₆H₃Me₃, C₆Me₆), [Ru(η⁶-p-cymene)(NCMe)]²⁺ and [Ru(η⁵-C₅H₅)(NCMe)]⁺ is described. The structures of the resulting mono- and dicationic cymene derivatives have been confirmed by X-ray crystallography. Studies on the catalytic activity of these Ru(II) compounds in Diels–Alder cycloaddition processes are also reported.     

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.     

Novel cyclohexyl‐based aminophosphine ligands and use of their Ru(II) complexes in transfer hydrogenation of ketones

Two new aminophosphines – furfuryl‐(N‐dicyclohexylphosphino)amine, [Cy₂PNHCH₂–C₄H₃O] ( 1 ) and thiophene‐(N‐dicyclohexylphosphino)amine, [Cy₂PNHCH₂–C₄H₃S] ( 2 ) – were prepared by the reaction of chlorodicyclohexylphosphine with furfurylamine and thiophene‐2‐methylamine. Reaction of the aminophosphines with [Ru(η⁶‐p‐cymene)(μ‐Cl)Cl]₂ or [Ru(η⁶‐benzene)(μ‐Cl)Cl]₂ gave corresponding complexes [Ru(Cy₂PNHCH₂–C₄H₃O)(η⁶‐p‐cymene)Cl₂] ( 1a ), [Ru(Cy₂PNHCH₂–C₄H₃O)(η⁶‐benzene)Cl₂] ( 1b ), [Ru(Cy₂PNHCH₂–C₄H₃S)(η⁶‐p‐cymene)Cl₂] ( 2a ) and [Ru(Cy₂PNHCH₂–C₄H₃S)(η⁶‐benzene)Cl₂] ( 2b ), respectively, which are suitable catalyst precursors for the transfer hydrogenation of ketones. In particular, [Ru(Cy₂PNHCH₂–C₄H₃S)(η⁶‐benzene)Cl₂] acts as a good catalyst, giving the corresponding alcohols in 98–99% yield in 30 min at 82 °C (up to time of flight ≤ 588 h^?1). Copyright © 2014 John Wiley & Sons, Ltd.     

Ethyltetramethylcyclopentadienyl complexes of cobalt,rhodium, iridium and ruthenium

Summary The syntheses of the ethyltetramethylcyclopentadienyl complexes Ru(⁵-C₅Me₄Et)(CO)₂Cl, CO( ⁵-C₅Me₄Et)(CO)₂, and [M( ⁵-C₅Me₄Et)Cl₂]₂ (M = Rh or Ir) are described; the ruthenium complex reacts with triphenylarsine to give Ru( ⁵-C₅Me₄Et)(AsPh₃)(CO)Cl.¹H and¹³C n.m.r. spectra, i.r. spectra and the physical properties of the compounds are discussed and contrasted with the known C₅H₅ and C₅Me₅ analogues.