M.C. Barral

Reaction of diruthenium(II,III) acetate with triphenylphosphine

Abstract The reaction of [Ru2(μ-O2CCH3)4(thf)2]BF4 with triphenylphosphine in thf or toluene is described. In this reaction, a yellow compound of formula Ru(O2CCH3)2 (PPh3)·CH3C6H5 (1), and a violet, diamagnetic oxo-bridged compound, formulated as Ru2(μ-O)(μ-O2CCH3)2(O2CCH3)2(PPh3)2 (2) are obtained. The compounds have been characterized by elemental analysis, magnetic susceptibility measurements and spectroscopic techniques. The structure of 2 has been determined by X-ray crystallography. Two pseudo-octahedral ruthenium(III) atoms are bridged by an oxo and two acetate ligands. The hexacoordination of each ruthenium atom is completed with a bidentate acetate and a triphenylphosphine ligand. Some spectroscopic evidence for the formation of a tetranuclear intermediate compound is also presented.

Synthesis and structure of a new complex of ruthenium containing the tetra(μ-tertbutylbenzoate)diruthenium(II,III) unit

Abstract The compound Ru2Cl(μ-O2CC6H4-p-CMe3)4 has been prepared by the reaction of Ru2Cl(μ-O2CCH3)4 with p-tertbutylbenzoic acid in a water/methanol mixture (1 : 1). The reactions of Ru2Cl(μ-O2CC6H4-p-CMe3)4 with AgBF4, in anhydrous or wet thf, lead to [Ru2(μ-O2CC6H4-p-CMe3)4(thf)2]BF4 and [Ru2(μ-O2CC6H4-p-CMe3)4(thf)2]OH, respectively. The compounds are characterized by elemental analysis, magnetic measurements and spectroscopic techniques. The structure of [Ru2(μ-O2CC6H4-p-CMe3)4(thf)2]OH has been determined by X-ray crystallography. The compound has four bridging p-tertbutylbenzoate ligands with an RuRu distance of 2.260(1) A; the coordination of each ruthenium atom is completed with a thf ligand which is occupying the axial position in the Ru25+ unit.

New di-η5-cyclopentadienyldialkynyl derivatives of titanium(IV)

A series of new stable dialkynyltitanium(IV) derivatives of the type (η5-R′C5H4)2Ti(CCR)2 (R = phenyl, cyclohexyl, n-hexyl, 2,2-diphenylethyl and 2-cyano-2,2-diphenylethyl; R′ = hydrogen, methyl) has been prepared by treatment of (η5-R′C5H4)2TiCl2 with NaCCR in ether. The compounds were characterized by elemental microanalysis and by infrared, electronic and 1H NMR spectroscopy.

Synthesis and characterization of new carboxylate dimers of ruthenium

A series of Ru2Cl(μ-O2CR)4 [R = C2H5 (I), cyclo-C6H11 (II), C6H5 (III), o-ClC6H4 (IV), o-HOC6H4 (V)] complexes has been synthesized by reaction of Ru2Cl(μ-O2CCH3)4 with the appropriate carboxylic acid. The reaction of these insoluble compounds with AgBF4 in thf gives [Ru2(μ-O2CR)4(thf)2]BF4 (VI)-(X) which are soluble in polar organic solvents. The substitution in these complexes of the thf axial ligands in toluene by OPPh3 or pyridine leads to new adducts of the type [Ru2(μ-O2CR)4L2]BF4 [L = OPPh3 (XI)-(XV), L = py (XVI)-(XIX)] which are not easily accessible by other methods. The compounds have been characterized by elemental analysis, electrical conductance, magnetic susceptibility measurements and spectral data.

Influence of carboxylic acids on the reactions with chlorotetraacetatodiruthenium(II,III): X-ray crystal structure of [Ru2(μ-O2CC4H3S)4(OPPh3)2]BF4·2H2O

Abstract The reaction of Ru 2 Cl(μ-O 2 CCH 3 ) 4 with indole-2-carboxylic, N -methyl-pyrrole-2-carboxylic, furane-2-carboxylic, thiophene-2-carboxylic and benzofurane-2-carboxylic acids, which contain nitrogen, oxygen or sulphur atoms in the α position with respect to the carboxylate group, leads to compounds of the type Ru 2 Cl(μ-O 2 CR) 4 . In these compounds O,O-coordination of the carboxylate ligands has been found. The analogous reaction with quinoline-2-carboxylic acid (Hquin) gives a disproportionation process with formation of Ru(quin) 3 and Ru 2 (quin) 4 ; in this case, N,O-coordination of the ligand has been observed. The indole-2-carboxylato derivative has a non-polymeric structure, whereas with the other ligands polymeric structures with chlorine atoms bridging Ru 2 5+ units are formed. Treatment of Ru 2 Cl(μ-O 2 CR) 4 in thf or acetone with AgBF 4 gave [Ru 2 (μ-O 2 CR) 4 L 2 ]BF 4 (L = thf, acetone; R = N -methyl-2-pyrrolyl, 2-furyl, 2-thienyl) or [Ru 2 (μ-O 2 CR) 4 ]BF 4 (R = 2-benzofuryl). The axial positions of these compounds can be occupied by OPPh 3 to give the corresponding [Ru 2 (μ-O 2 CR) 4 (OPPh 3 ) 2 ]BF 4 The compounds have been characterized by analytical, spectroscopic and magnetic data. The structure of [Ru 2 (μ-O 2 CC 4 H 3 S) 4 (OPPh 3 ) 2 BF 4 ·2H 2 O has been determined by X-ray crystallography. The dinuclear cation has two ruthenium atoms linked by four bridging thiophene-2-carboxylate ligands and two OPPh 3 ligands coordinated to axial positions, with an Ru—Ru distance of 2.2747(11) A.

New σ-alkynylides of Cu(I) and Ag(I)

Abstract Polymeric compounds of the type (MCCR) x (MCu, Ag; R = cyclohexyl, n -hexyl) and M 2 ( p -(CC)C 6 H 4 )] x (MCu, Ag) have been prepared. The preparation media and solvent (liquid ammonia, methanol and methanol/ or methanol-ether/aqueous ammonia) exert an influence over the nature of the alkynyl compound, leading either to the formation of adducts or to the formation of metal alkynylides with identical empirical formulae, but differing in colour, which seems be related to the different extent of molecular association.

Synthesis and properties of bis(η5-cyclopentadienyl)bis(alkynyl)zirconium(IV) complexes

Abstract The preparation of the air- and moisture-stable complexes (η5-R′C5H4)Zr(CCR)2, (R = phenyl, cyclohexyl, n-hexyl, 2,2-diphenylethyl and 2-cyano-2,2-diphenylethyl; R′ = hydrogen, methyl) is described. Their physical and chemical properties point to the presence of the (R′C5H4)2Zr group and ZrC σ-bonds. The compounds were characterized by elemental microanalysis and by infrared, 1H NMR, and electronic spectroscopy.

σ-Acetylides of Ni(II), Pd(II), and Pt(II)

Abstract Several stable alkynyl complexes K2[(M(CCR)4] [M = Ni(II), Pd(II), Pt(II); R = -CH2C(Ph)2(CN), -CH2C(CH3)2(CN)] have been obtained. The IR spectra of these complexes have been studied and on attempt to assign ν(MC) stretching frequencies has been made. Study of the thermal decomposition by thermal analysis (DTA) and other methods has allowed the relative thermal stabilities of these compounds to be established. In some cases thermal decomposition pathways were also investigated.

Synthesis and properties of diruthenium (II,III)compounds with trans-2-methyl-2-pentenoate ligand. Crystal structure of Ru2Cl(μ-O2CC(Me)CHEt)4

Abstract The reaction of Ru2Cl(μ-O2CMe)4 with trans-2-methyl-2-pentenoic acid affords the polymeric compound Ru2Cl(μ-O2CC (Me)CHEt)4 (1). This compound has polymeric structure in solid state, but is non-polymeric in solution. The reaction of 1 with OPPh3 in CH2Cl2 solution gives Ru2Cl(μ-O2CC(Me)CHEt)4(OPPh3) (2) supporting the non-polymeric structure of 1 in solution. The reaction of 1 with AgSCN leads to Ru2(μ-O2CC(Me)CHEt)4(SCN) (3) which also has a polymeric structure in solid state. The Ru–Cl bond in 1 was broken with AgBF4 in THF solution, giving [Ru2(μ-O2CC(Me)CHEt)4]BF4(4). All compounds have been characterised by analysis elemental, spectroscopic data and mass and magnetic measurements. The X-ray analysis of 1 shows [Ru2(μ-O2CC(Me)CHEt)4]+ units linked by chloride ions giving linear chains. The Ru–Ru and Ru–Cl distances are 2.281(1) and 2.5705(9) A respectively.

Liquid secondary ion mass spectrometric study of diruthenium(II,III) complexes

Liquid secondary ion mass spectra of diruthenium(II,III) compounds of the type Ru2Cl(μ-O2CCMe3)4(H2O) (1), Ru2Cl(μ-O2CCHMe2)4(thf) (2), Ru2X(μ-O2CR)4 (X Cl, R CMe3 (3), CHMe2 (4), CHEt2 (5), CHMePh (6), Me (9), C6H4-p-CMe3 (10); X SCN, RCMe3 (7), CHEt2 (8)), Ru2X(μ-O2CR)4(OPPh3) (XCl, RCHMe2 (11), CMe3 (12); XSCN, RCMe3 (13)) and Ru2Cl(μ-NHOCR)4 (RCMe3 (14), C6H4-p-CMe3 (15)) have been studied. The positive ion of Ru2X(μ-O2CR)4 (XCl, SCN) compounds typically contains intact M+ or [M + H]+ cations. For the complexes Ru2X(μ-O2CR)4(OPPh3) (XCl, SCN) no molecular peaks were found, but the detected fragment clearly confirms the proposed stoichiometries. MS/MS experiments have been carried out to establish general fragmentation pathways of these complexes. Also, clustering processes — as a result of ion molecule reactions which give [Ru2(μ-O2CR)4XRu2(μ-O2CR)4]+ (XCl, SCN) — have been found. These results show that the liquid secondary ion mass spectrometry (LSIMS) technique is useful to establish the structure and molecular formula of diruthenium(II,III) compounds, even when the molecular peaks are not observed. This technique also informs us on the polymeric/non-polymeric nature of this type of complex.