Sanshiro Komiya

C–O and C–S bond activation of allyl esters, ethers, and sulfides by low valent ruthenium complexes

Abstract Allyl carboxylates or ethers react with Ru(cod)(cot) (1) [cod: 1,5-cyclooctadiene, cot: 1,3,5-cyclooctatriene] in the presence of monodentate tertiary phosphines such as PMe3, PEt3, PMe2Ph or PMePh2 to give a series of neutral (η3-allyl)ruthenium(II) complexes Ru(η3-C3H5)(OCOCF3)(PR3)3 [PR3=PEt3 (2a), PMe3 (2b), PMe2Ph (2c), PMePh2 (2d)], Ru(η3-C3H5)(OCOR′)(PMe3)3 [R′=Me (2e), Ph (2f)], Ru(η3-syn-C3H4R)(OCOCF3)(PMe3)3 [R=Me (2g), Ph (2h)] and Ru(OAr)(η3-C3H5)(PMe3)3 [Ar=Ph (3a), C6H4-o-Me (3b), C6H4-o-Et (3c), C6H4-o-OMe (3d)], whereas similar reactions of these allyl ethers, sulfides and carboxylates in the presence of the bidentate depe ligand [depe=1,2-bis(diethylphosphino)ethane] afford the cationic (η3-allyl)ruthenium(II) complexes, [Ru(η3-C3H5)(depe)2]+[RY]− [RY=PhS (4a), MeS (4b), PhO (4c), CF3COO (4d), CH3COO (4e)]. Protonolysis of all (η3-allyl)ruthenium(II) and (η3-crotyl)ruthenium(II) complexes with HCl liberate propylene and trans-2-butene, respectively. Complex 2a reacts with benzaldehyde to give 1-phenyl-3-butene-1-ol. Reaction of 2b with CO forces the bonding mode of allyl moiety in 2a from η3 to η1.

SYNTHESIS OF ORGANO(SILOXO)PLATINUM AND -PALLADIUM COMPLEXES AND PREPARATION OF SUPPORTED NANOCLUSTERS BY FACILE LIGAND REDUCTION

Abstract A series of organosiloxo complexes of platinum and palladium, MR(OSiPh3)(L2) (M=Pt, Pd; R=Me, Et, Ph; L2=cod, dppe), has been prepared and characterized. The square planar geometries of PtPh(OSiPh3)(cod) and PtEt(OSiPh3)(cod) are confirmed by X-ray structure analysis. In the reactions with hydrogen at 0°C and 1 atm, the siloxo complexes of Pt and Pd are reduced readily to give agglomerates of nanoclusters with complete hydrogenation of the ligands. The reduction activities of the siloxo and alkoxo complexes are higher than those of the corresponding alkyl complex PtMe2(cod). This high activity in reduction is applied to the preparation of supported Pt or Pd nanoclusters on silica, and the siloxo complexes adsorbed on silica are reacted with hydrogen at mild conditions. The resulting Pt/SiO2 gives a smaller mean diameter than that prepared from H2PtCl6/SiO2.

Synthesis and structure of thiolato bridged Pt–Ti heterobimetallic complexes with methyl group

Abstract Sulfur bridged Pt–Ti heterobimetallic complexes, Cp2Ti(μ-SR)2PtMe2, (R=Me (1a), Ph (1b)) have been prepared by the reaction of Cp2Ti(SR)2 with PtMe2(nbd). X-ray structure analysis of 1a reveals the syn conformation of the compound, while a facile equilibration between syn and anti conformers is observed in toluene solution by variable temperature 1H-NMR.

Synthesis, structure and reactions of a carbon dioxide complex of iron(0) containing 1,2-bis(diethylphosphino)ethane ligands

Reaction of [Fe(N2)(depe)2] with carbon dioxide gives trigonal bipyramidal [Fe(η2-CO2)(depe)2], where the coordinated CO2 lies on equatorial plane by an η2-fashion and converts into dimethyl ether and [FeX(CO)(depe)2]X (X = I, OTf) on interaction with methyl halide or triflate.