Franco Morandini

Cationic complexes of rhodium(I) as catalysts in the homogeneous O2-oxidation of terminal alkenes to methyl ketones

Abstract [Rh(LL) 2 ] + , [Rh(LL)(diene)] + and [Rh(LL)S 2 ] + complexes are effective as catalysts for the oxidation by dioxygen of terminal olefins to methyl ketones. The complexes act as monooxygenases, the second oxygen atom being transferred to the alcohol solvent.

HYDROGENATION OF ALKENES AND KETONES CATALYZED BY RHODIUM(I) COMPLEXES CONTAINING THIOPHOSPHINE LIGANDS

Abstract Rhodium(I) complexes containing hybrid ‘hemilabile’ ligands of general formula [Rh(NBD)(PSR)]+ and [Rh(PSR)2]+ (RMe, Et, Ph) were checked as hydrogenation catalysts of terminal olefins to alkanes and of ketones to the corresponding alcohols. The profiles of the hydrogen uptake were determined for the above complexes.

Synthesis and NMR studies of palladium(II) and platinum(II) complexes with hybrid bidentate ligands Ph2P(CH2)2SR

Abstract The reactions of a series of hybrid, potentially bidentate ligands Ph 2 P(CH 2 ) 2 SR (P-SR; R = Me, Et, Ph) with palladium(II) and platinum(II) salts are described, together with the syntheses and characterization of a variety of cationic and neutral square- planar complexes of the types [MCl 2 ( P - S R)], cis - or trans -[MX 2 ( P -SR) 2 ] (X = Cl, CN), [MCl( P - S R)( P - SR)] + and [M( P - S R) 2 ] 2+ , in which the P-SR molecules can act either as chelating ( P - S R) or monodentate, P-bound ligands ( P -SR). In solution, the various species are interconverted among each other by equilibria which show a marked dependence on solvent polarity, presence of excess ligand, temperature, nature of X and R groups.

Activation of molecular oxygen, selective oxidation of terminal olefins and alcohols catalyzed by cationic complexes of rhodium(I)

Abstract Rhodium(I) complexes containing hybrid “hemilabile” ligands of general formula [Rh(Ph2PCH2CH2SR)2]+ (R  Ph, Et, Me) are found to catalyze air oxidation of terminal olefins to the corresponding methyl ketones, of primary alcohols to acetals and of secondary alcohols to ketones.

Synthesis and NMR characterization of cationic rhodium(I) complexes containing phosphorus—sulfur bidentate ligands

Abstract The reaction of [Rh(diene)(acac)] (diene=cyclooctadiene or norbornadiene; acac=acetylacetonate) with bidentate ligands of the type Ph2P(CH2)nSR (n=1, 2 or 3; R=Me, Et, Ph, not all combinations) or cis-Ph2PCHCHPPh2 leads to [Rh(diene)(LL)]+ or [Rh(LL)2]+, depending on the stoichiometry of the reaction. The complexes were fully characterized by 1H and 31P NMR spectroscopy.

Cationic rhodium (I) and iridium (I) complexes with phosphorus-sulfur bidentate ligands. Formation of dioxygen adducts

Synthese des complexes [M(PSR) 2 ]Y avec PSR=(C 6 H 5 ) 2 P(CH 2 ) 2 SR. Spectre RMN de 31 P

Homogeneous hydrogenation of alk-1-enes and alkynes catalyzed by the 1-[Ir(CO)(PhCN)(PPh3)]-7-C6H5-1,7-(σ-C2B10H10) complex

The complex [Ir(σ-carb)(CO)(PhCN)(PPh3)], where carb = -7-C6H5-1,2C2B10H10, was found to be an effective catalyst for homogeneous hydrogenation of terminal olefins and acetylenes at room temperature and atmospheric or subatmospheric hydrogen pressure. Internal olefins are not hydrogenated, but simple alk-1-enes are readily converted into the corresponding alkanes. Isomerization of the double bond catalyzed by the metal complex occurs at very small extent. Catalytic hydrogenation of olefins having carboxylate substituents on the unsaturated carbon atoms is prevented by the formation of thermally stable chelate hydridoalkyl complexes of the type I(H)(σ-CHRCHR′C(O)OR″) (σ-carb)(CO)(PPh3)]. Acetylenes are hydrogenated to alkenes. The alk-1-enes formed in the hydrogenation of the alkynes HCCR in turn undergo the more slow reactions either of hydrogenation to alkanes or isomerization to internal olefins which cannot be further hydrogenated. Hydrogenation of alkynes of the type RCCR′ is stereospecifically cis, yielding cis- olefins. Catalyzed cis → trans isomerization reaction of these internal olefins occurs only to a negligeable extent.

Nickel catalyzed asymmetric cross-coupling reaction between C6H5X and s-BuMgX. The influence of the nature of the halogens of the two reagents

Abstract The asymmetric cross-coupling reaction between phenyl halides and sec-butyl-magnesium halides has been carried out in the presence of [(+)( R -1,2-bis(diphenylphosphino)propane]nickel(II) chloride. The optical purity and the absolute configuration of the 2-phenylbutane were dependent on which halogen was present in the organic and the organometallic moieties.

Oxidative-addition and reductive-elimination reactions of carboraneiridium complexes

The addition reactions of diatomic molecules, X-Y (X-Y = HCl, HBr, HI, Cl2 and Br2) to square-planar d8 carborane-iridium(I) complexes of general formula trans-[Ir(σ-carb)(CO)L2], where L = PPh3, PMePh2 and carb = -2-R-1,2- and -7-R-1, 7-B10C2H10 (R = H, CH3, C6H5) have been investigated in both the solid state and in solution of a variety of solvents. The stereochemistry of the obtained octahedral adducts was determined by i.r. and 1H nmr spectroscopy. The stereochemical course of the addition reactions appears to be dependent on the reaction medium and on the type of the carborane anionic ligands. Evidence suggesting that these oxidative-addition reactions proceed through solvent-containing intermediates when they are carried out in coordinating solvents is reported. The HX adducts of general formula [Ir(H)(X)(σ-carb)(CO)L2], (X = Cl, Br, I), reductively eliminate the carborane molecule, H-carb. Factors governing these elimination reactions are also described.

A three-membered ring formed through internal metallation in a diphenylmethylphosphine—platinum(II) complex

Abstract Prolonged treatment of cis-(MePh2P)2PtCl2 with a large excess of 1-Li-2-C6H5-1,2-B10C2H10 in ether gives the internally metallated complex cis-1-[(MePh2P) Pt(PC H2Ph2)]-2-C6H5-1,2-(σ-B10C2H10) in which a methyl group of one coordinated phosphine is involved in the ring formation.