M. Carmen Barral

MMX polymer chains on surfaces

Fibres of [Ru(2)Br(micro-O(2)CEt)4]n polymer have been isolated on different surfaces under specific conditions, and morphologically characterised by AFM and STM, showing an unexpected helical internal structure.

Non-polymeric diruthenium(II,III) carboxylates. Crystal structures of [Ru2Cl(µ-O2CCMe3)4(H2O)] and [Ru2Cl(µ-O2CCHMe2)4(thf)](thf = tetrahydrofuran)

The reaction of [Ru2Cl(µ-O2CMe)4] with trimethylacetic acid and isobutyric acid in methanol–water gave [Ru2Cl(µ-O2CCMe3)4(H2O)]1 and [Ru2Cl(µ-O2CCHMe2)4(H2O)]2 respectively. Recrystallization of these compounds from tetrahydrofuran (thf) led to [Ru2Cl(µ-O2CCMe3)4(thf)]3 and [Ru2Cl(µ-O2CCHMe2)4(thf)]4, which lose thf giving [Ru2Cl(µ-O2CCMe3)4]5 and [Ru2Cl(µ-O2CCHMe2)4]6. The complexes were characterized by elemental analysis, IR spectroscopy, conductivity and magnetic measurements; the crystal structures of 1 and 4 were determined by X-ray diffraction methods. Complex 1 has two ruthenium atoms bridged by four trimethylacetato ligands, one axial position being occupied by a chlorine atom and the other by a water molecule. Complex 4 has a similar structure with one chlorine atom and one thf molecule occupying the axial positions. Thus, in both cases the crystal structure determination shows the non-polymeric nature, the first examples for compounds of this type with alkanecarboxylate ligands.

N-bonded TCNQ in stacked dimeric systems. Synthesis and crystal structure of [Ru(PPh3)2(TCNQ)]2(TCNQ = 7,7,8,8-tetracyanoquinodimethane)

The reaction of [Ru(CO)2(PPh3)2(thf)2](BF4)2(thf = tetrahydrofuran) with PPh3 in CH2Cl2 and LiTCNQ in methanol leads to the formation of [Ru(PPh3)2(TCNQ)]; the crystal structure of this compound shows a tetrahedral environment of the ruthenium atom with the TCNQ molecule coordinated via N.

Synthesis and reactivity of non-polymerictetracarboxylatochloro-diruthenium(II,III)complexes. Crystal structure of[Ru2Cl(µ-O2CCHMe2)4(OPPh3)]

New non-polymeric diruthenium(II,III) carboxylates of the type [Ru 2 Cl(µ-O 2 CR) 4 ] (R = CHEt 2 1, CHMeEt 2 or CHMePh 3) were obtained by reaction of HO 2 CR with [Ru 2 Cl(µ-O 2 CMe) 4 ] in methanol–water. The mixed-ligand complex [Ru 2 Cl(µ-O 2 CMe) 2 (µ-O 2 CCMe 3 ) 2 ] 4 has also been prepared. The reactivity of these complexes and of the previously described [Ru 2 Cl(µ-O 2 CR) 4 ] (R = CMe 3 5 or CHMe 2 6) has been studied and compared with those found for polymeric [Ru 2 Cl(µ-O 2 CR) 4 ] (R = alkyl or aryl). The interaction of AgSCN with [Ru 2 Cl(µ-O 2 CR) 4 ] or [Ru 2 Cl(µ-O 2 CMe) 2 (µ-O 2 CCMe 3 ) 2 ] leads to [Ru 2 (µ-O 2 CR) 4 (SCN)] (R = CHEt 2 7, CHMePh 8 or CMe 3 9) and [Ru 2 (µ-O 2 CMe) 2 (µ-O 2 CCMe 3 ) 2 (SCN)] 10 respectively. The first derivatives of the type [Ru 2 X(µ-O 2 CR) 4 (OPPh 3 )] (X = Cl; R = CHEt 2 11, CHMeEt 12, CHMePh 13, CMe 3 14 or CHMe 2 15; X = SCN; R = CHEt 2 17, CHMePh 18 or CMe 3 19) and [Ru 2 Cl(µ-O 2 CMe) 2 (µ-O 2 CCMe 3 ) 2 (OPPh 3 )] 16 containing two different axial ligands have been obtained. Cationic compounds of the type [Ru 2 (µ-O 2 CR) 4 (thf) 2 ]BF 4 (R = CMe 3 20 or CHMe 2 21; thf = tetrahydrofuran), [Ru 2 (µ-O 2 CCHMe 2 ) 4 (OPPh 3 ) 2 ]BF 4 22 or [Ru 2 (µ-O 2 CCHMe 2 ) 4 (OPPh 3 )(thf)]BF 4 23 were also prepared. The crystal structure of 15 has been determined by X-ray crystallography. It has two ruthenium atoms linked by four bridging isobutyrate ligands with the axial positions being occupied by one chlorine atom and one OPPh 3 molecule.

Reaction of tetraacetatochlorodiruthenium(II,III) with pyridine-2-carboxylic acid. X-Ray crystal structures of tris(pyridine-2-carboxylato-?N,O)ruthenium(III) monohydrate and trans-bis(pyridine-2-carboxylato-?N,O)bis(triphenylphosphine)ruthenium(II)?methanol(1/2)

The reaction of [Ru2Cl(µ-O2CMe)4] with pyridine-2-carboxylic acid (Hpyca) in methanol-water (1:1) affords a ruthenium(III) complex, [Ru(pyca)3]·H2O 1, and a diruthenium(II) compound, [Ru2(pyca)4]2. The reaction of both complexes with PPh3 leads to the new compound [Ru(pyca)2(PPh3)2]·2MeOH 3. The crystal structures of 1 and 3 have been determined. Crystals of both are monoclinic: 1, space group C2/c, a= 30.415(7), b= 8.506(1), c= 13.943(3)A, β= 94.55(2)°, Z= 8; 3, space group P21/n, a= 9.578(1), b= 20.540(3), c= 11.501(2)A, β= 98.57(1)°, Z= 2. Compound 1 consists of Ru(pyca)3 units linked by water molecules; the ruthenium environment is pseudo-octahedral with the ligands giving a mer arrangement. Compound 3 shows a trans disposition for the phosphine ligands with the pyridine-2-carboxylate ligands in the equatorial plane. In these complexes the pyridine-2-carboxylate ligands are co-ordinated in a bidentate mode through a carboxylate O atom and the pyridine nitrogen.