Josep Ros

Insertion reactions of acetylenes with hydridocarbonyl-chlorotris(triphenylphosphine)ruthenium(II). X-ray structure of carbonylchloro(cis-1,2-diphenylethenyl)bis(triphenylphosphine)ruthenium(II)

Abstract Reactions between Ru(CO)ClH(PPh 3 ) 3 and phenylacetylene, pent-1-yne and diphenylacetylene in CH 2 Cl 2 give the red crystalline alkenyl species Ru(CO)Cl-(RCHR′)(PPh 3 ) 2 (R = H, R′ = C 3 H 7 , Ph; R = R′ = Ph), which can be regarded as resulting from elimination of one phosphine molecule and insertion of the alkyne into the RuH bond. The reaction with phenylacetylene in MeOH/CH 2 Cl 2 ( 1 1 ) gives the yellow crystalline complex Ru(CO)Cl(PhCCH 2 )-(PPh 3 ) 3 , seemingly resulting from a simple insertion of the alkyne into the RuH bond. The complexes have been characterized by elemental analysis and 1 H NMR and IR spectroscopy. The molecular structure of Ru(CO)Cl(PhCCHPh)(PPh 3 ) 2 , determined by X-ray diffraction, can be described as a distorted trigonal bipyramidal species, in which the phosphine molecules occupy the axial positions and the alkenyl ligand has the phenyl groups in a cis configuration. Similar molecular structures are probable for the other red complexes. The yellow complex derived from phenylacetylene seems to be a six-coordinate species, in which two phosphine molecules are respectively cis - and trans -coordinated with respect to the alkenyl ligand.

Ruthenium(II) complexes containing both arene and functionalized phosphines. Synthesis and catalytic activity for the hydrogenation of styrene and phenylacetylene

Abstract The [RuCl2(η6-arene)]2 complex reacts with PPh2R (R=H, Py, CH2Py, CCPh, CCtBu and CCp-Tol) ligands in CH2Cl2 to give neutral P-coordinated ruthenium(II) complexes [RuCl2(p-cymene)PPh2R]. The structure of [RuCl2(p-cymene)PPh2H] and [RuCl2(p-cymene)PPh2Py] complexes has been established by X-ray diffraction. The neutral P-coordinated complexes [RuCl2(p-cymene)PPh2Py] and [RuCl2(p-cymene)PPh2CH2Py] react with NaBF4 in CH2Cl2–MeOH mixture to give [RuCl(η6-p-cymene)PPh2Py]BF4 and [RuCl(η6-p-cymene)PPh2CH2Py]BF4 complexes, in which PPh2Py and PPh2CH2Py act as bidentate ligands. The structure of [RuCl(η6-p-cymene)PPh2Py]BF4 was determined by X-ray diffraction. The reaction of [RuCl2(η6-arene)]2 with PPh2CCPPh2 led to the [RuCl2(p-cymene)]2PPh2CCPPh2 complex, in which the diphosphine ligand bridges two [RuCl2(p-cymene)] units. [RuCl2(p-cymene)PPh2Py] and [RuCl(η6-p-cymene)PPh2Py]BF4 are suitable catalyst precursors for the hydrogenation of styrene and phenylacetylene.

Organometallic rhodium (I) complexes with 1-alkylaminopyrazole ligands

Abstract New bidentate NN ′ and tridentate NN ′ N 1-alkylaminopyrazoles were synthesized and characterized by elemental analyses and spectroscopic methods. The reaction of [RhCl(cod) 2 ] (cod=cycloocta-1,5-diene) with one equivalent of L 1-alkylaminopyrazoles afforded Rh 2 Cl 2 (L)(cod) 2 complexes (L= NN ′ and NN ′ N ). These rhodium (I) compounds were studied by IR, 1 H- and 13 C-NMR and liquid mass (with electrospray and APCI interfaces) spectrometries. The 1 H-NMR spectra and molar conductances of these complexes suggested the presence of 1:1 electrolyte species, [Rh(L)cod] + [RhCl 2 (cod)] − , in solution. A combined electrospray and APCI liquid mass spectroscopy study confirmed the presence of both [Rh(L)cod] + and [RhCl 2 (cod)] − species in solution but the existence of a neutral molecular form of complexes in solution could not be demonstrated.

Bismuth nanoparticles for phenolic compounds biosensing application

The rapid determination of trace phenolic compounds is of great importance for evaluating the total toxicity of contaminated water samples. Nowadays, electrochemical tyrosinase (Tyr) based biosensors constitute a promising technology for the in situ monitoring of phenolic compounds because of their advantages such as high selectivity, low production cost, promising response speed, potential for miniaturization, simple instrumentation and easy automatization. A mediator-free amperometric biosensor for phenolic compounds detection based on the combination of bismuth nanoparticles (BiNPs) and Tyr for phenol detections will be hereby reported. This is achieved through the integration of BiNPs/Tyr onto the working electrode of a screen printed electrode (SPE) by using glutaraldehyde as a cross-linking agent. BiNPs/Tyr biosensor is evaluated by amperometric measurements at -200 mV DC and a linear range of up to 71 μM and 100 μM and a correlation coefficient of 0.995 and 0.996 for phenol and catechol, respectively. The very low DC working potential ensures the avoidance of interferences making this biosensor an advantageous device for real sample applications. In addition, the response mechanism including the effect of BiNPs based on electrochemical studies and optical characterizations will be also discussed. The obtained results may open the way to many other BiNPs applications in the biosensing field.

Reaction of platinum(II) derivatives with 1-hydroxyalkyl-3,5-dimethylpyrazole ligands. Cleavage of the N(pz)C(sp3) bond. X-ray crystal structure of cis-[PtCl2(HL2)2] (HL2=1-(2-hydroxyethyl)-3,5-dimethylpyrazole) and trans-[PtCl2(dmpz)2] (dmpz=3,5-dimethylpyrazole)

The reactions of 1-hydroxymethyl-3,5-dimethylpyrazole (HL 1 ) and 1-(2-hydroxyethyl)-3,5-dimethylpyrazole (HL 2 ) with several platinum starting materials ([PtCl 2 (CH 3 CN) 2 ], cis - and trans -[PtCl 2 (PhCN) 2 ], PtCl 2 and K 2 PtCl 4 ) under different conditions have been examined and compared with those obtained from the reactions with Pd(II). cis and trans Pt(II) adducts are obtained in a different ratio depending on the metallic starting complex. The reaction of HL 1 with any of the Pt(II) complexes differs from that with Pd(II) and also from the equivalent reaction of HL 2 with Pt(II). This reaction implies the rupture of the ligand: the cleavage of the N(pz)C(sp 3 ) bond leads to [PtCl 2 (dmpz) 2 ] (dmpz=3,5-dimethylpyrazole). For comparison, the direct reaction of dmpz with Pt(II) has also been studied. The crystal structure of cis -[PtCl 2 (HL 2 ) 2 ] and trans -[PtCl 2 (dmpz) 2 ] are here reported.

Cobalt(II) complexes with pyrazole-derived ligands: crystal structure of {bis[3-phenyl-5-(2-pyridyl) pyrazole]aquachlorocobalt(II)}chloride monohydrate

Abstract The synthesis of the new pyrazole-derived ligands 3-phenyl-5-(2-pyridyl) pyrazole (HL0) and 3-phenyl-5-(6-methyl-(2-pyridyl))pyrazole (HL1) and their Co(II) complexes is reported. Elemental analyses, conductivity measurements and IR and UV–Vis spectroscopies defined all complexes. 1H and 13C NMR spectroscopies were also used in the characterization of ligands. The crystal and molecular structures of [Co(HL0)2Cl(H2O)]Cl·H2O, consisting of discrete ions and water molecules linked by hydrogen bonds, are also reported. The hexacoordinated metal atom is bonded to two pyridinic nitrogens, two pyrazolic nitrogens (one of each nitrogen belonging to two different ligands), one chlorine atom and one water molecule, forming a distorted octahedral environment. The ligands are not exactly planar and the arrangement of ligands is cis, with a dihedral angle between the two mean planes of ligands of 89.21(6)°. The degree of distortion from regular octahedral geometry is compared to that of closely related structures.

Synthesis of New PdII Complexes Containing Thioether−Pyrazole Hemilabile Ligands − Structural Analysis by 1H and 13C NMR Spectroscopy and Crystal Structures of [PdCl2(bddo)] and [Pd(bddo)](BF4)2 [bddo = 1,8-Bis(3,5-dimethyl-1-pyrazolyl)-3,6-dithiaoctane]

Treatment of the ligands 1,6-bis(3,5-dimethyl-1-pyrazolyl)-2,5-dithiahexane (bddh), 1,7-bis(3,5-dimethyl-1-pyrazolyl)-2,6-dithiaheptane (bddhp), 1,8-bis(3,5-dimethyl-1-pyrazolyl)-3,6-dithiaoctane (bddo) and 1,9-bis(3,5-dimethyl-1-pyrazolyl)-3,7-dithianonane (bddn) with [PdCl2(CH3CN)2] produces [PdCl2(L)] or [Pd2Cl4(L)] complexes, depending on the stoichiometry. Treatment of the complexes [PdCl2(bddo)] and [PdCl2(bddn)] with AgBF4 gives [Pd(bddo)](BF4)2 and [Pd(bddn)](BF4)2. These PdII complexes have been characterised by elemental analyses, conductivity measurements, IR and 1H and 13C NMR spectroscopy where possible. The X-ray structures of the complexes [PdCl2(bddo)] and [Pd(bddo)](BF4)2 have been determined. In [PdCl2(bddo)] the thioether−pyrazole ligand is coordinated through the azine nitrogen atoms to the metal atom, which completes its coordination with two chloride ions in a trans disposition. In [Pd(bddo)](BF4)2 the metal atom is tetracoordinated by the two thioether sulfur atoms and the two azine nitrogen atoms of the pyrazole rings. Complexes [PdCl2(bddo)] and [PdCl2(bddn)] were obtained again when the complexes [Pd(bddo)](BF4)2 and [Pd(bddn)](BF4)2 were heated under reflux in a solution of Et4NCl in CH2Cl2/MeOH (1:1). (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

Pyrazolic palladium compounds containing alcohol functionality: hindered rotation around PdN bond

Abstract Reactions of the ligands 1-hydroxymethyl-3,5-dimethylpyrazole (HL1), 1-(2-hydroxyethyl)-3,5-dimethylpyrazole (HL2) and 1-(3-hydroxypropyl)-3,5-dimethylpyrazole (HL3) with [PdCl2(CH3CN)2] lead to trans-[PdCl2(HL)2] complexes. The ligands are co-ordinated to the Pd(II) by a N atom of the pyrazolic ring in a trans disposition. Two chlorides complete the environment of the metallic atom. These Pd(II) complexes were characterised by elemental analyses, conductivity measurements and IR, 1H and 13C NMR spectroscopies and X-ray diffraction. The NMR study of the complexes is consistent with a very slow rotation of ligands around the PdN bond, so that two conformational isomers can be observed in solution. The crystal structures of [PdCl2(HL)2] (HL=HL1, HL2) complexes are described. These complexes react with AgNO3 to give [Pd(NO3)(HL)2]NO3 compounds.

Synthesis of a New Potentially Hemilabile Ligand: 1-[2-(Diphenylphosphanyl)ethyl]-3,5-dimethylpyrazole, and Comparison of Its Bonding Properties with the Related 1-[2-(Ethylamino)ethyl]-3,5-dimethylpyrazole Ligand toward RhI

The new ligand 1-[2-(diphenylphosphanyl)ethyl]-3,5-dimethylpyrazole (2) has been prepared by the reaction of 1-(chloroethyl)-3,5-dimethylpyrazole and PPh2Li. The bidentate N,N ligand 1-[2-(ethylamino)ethyl]-3,5-dimethylpyrazole (1) and 2 react with [Rh(COD)(THF)2][BF4] to give [Rh(COD)(1)][BF4] (3) and [Rh(COD)(2)][BF4] (4), respectively. Substitution of 1,5-cyclooctadiene with carbon monoxide in the latter complexes generates [Rh(CO)2(1)][BF4] (5) and

Bis[(3,5-dimethyl-1-pyrazolyl)methyl]ethylamine − A Versatile Ligand for Complexation in RhI Cationic Complexes

The bis[(3,5-dimethyl-1-pyrazolyl)methyl]ethylamine ligand (1) reacts with [Rh(COD)(THF)2][BF4] leading to [Rh(COD)(1)][BF4] ([2][BF4]) in which 1 is κ3 bonded in the solid state. Because of the steric bulk of 1,5-cyclooctadiene, it prefers the κ2 mode of bonding in solution. Substitution of 1,5-cyclooctadiene by carbon monoxide generates [3][BF4] in which 1 is κ3 bonded in solution and solid state. Variable temperature NMR spectroscopic studies give evidence of a κ3 κ2 equilibrium in solution. [3][BF4] is easily decarbonylated to [Rh(CO)(1)][BF4] [4][BF4] in which 1 is κ3 bonded; however on bubbling carbon monoxide through, [3][BF4] is regenerated. The single-crystal X-ray structures of [2][BF4], [3][BPh4], and [4][BPh4] are reported.