Hydrido complexes of iridium with a tertiary arsine

α-​and β-​IrHX2(Ph2AsMe)​3 (X = Cl, Br, I) were prepd. and characterized. The α-​compds. were prepd. by treating the IrX3 in the arsine in alc. with Zn and the corresponding HX; while the β-​compds. were prepd. by refluxing IrX3 and the arsine in alc. in the presence of KOH. The compds. were characterized by m.p. and ir spectra

Reactions of rhodium and iridium salts with multidentate N-heterocycles

Complexes of rhodium and iridium of the types MX3L, MX(CO)2L and MX3(CO)L (X = halide) containing multidentate N-heterocycles (L), 2,6-bis(benzimidazolyl)pyridine (bBzlH2py) and 2,6-bis(N-methyl-benzimidazolyl)pyridine (bBzlMe2py) have been prepared and characterized by IR, electronic and 1H and 13C NMR spectral data. RhX(CO)2L, on treatment with alcoholic solvents or DMF undergoes reversible decarbonylation to produce RhXL·2H2O. Passage of NO or O2 through the carbonyl suspended in hot 2-methoxyethanol releases CO2. Copyright © 1997 Elsevier Science Ltd

Hydrogenation of nitroarenes using polybenzimidazole-supported rhodium catalyst

Polybenzimidazole (PBI)-supported rhodium PBI-Rh(I) catalyst was prepared and characterised by chemical analysis, IR, TGA and X-ray photoelectron spectroscopy. Sodium borohydride was used to produce active species of the catalyst. The anchored catalyst PBI-Rh(I) was found to be effective for the reduction of nitrophenols, nitrobenzoic acids and nitroanilines in methanol at room temperature and at 1 atm hydrogen. The influence of temperature, concentrations of the catalyst and substrate and nature of the solvent on the reaction rates was investigated. The recycling efficiency of the catalyst was found to be good. A probable mechanism for the catalytic reaction has been suggested. © 2004 Elsevier B.V. All rights reserved

Cyclometallation of bis-benzimidazole derivatives with rhodium(III) halides

Treatment of rhodium(III) halides with the N-heterocycles (LH), 1,3-bis(benzimidazolyl)benzene (bBzlH2bzH; Ia) and its N-methyl derivative (bBzlMe2bzH; Ib) in methanol gave halobridged binuclear cyclometallated products of the composition RhX2L2 (X=Cl, Br or I). The chloro complex undergoes halobridge cleavage reactions to yield several new mononuclear complexes of the types RhCl2(bBzlH2bz)(AsPh3), RhCl(bBzlH2bz)(OClO3)(Lâ²/N-N) (Lâ²=AsPh3; N-N=2,2â²-bipyridine or 1,10-phenanthroline) and the heterocycle bridged binuclear complexes of the composition RhCl2(bBzlH2bz)2(μ-N-N) (N-N=pyrazine or 4,4â²-bipyridine). Passage of CO through RhCl2(bBzlH2bz)2 in DMF yielded mononuclear carbonyl complex RhCl2(CO)(bBzlH2bz)·2H2O. Treatment of carbonylated solution of rhodium trichloride with Ia produced non-cyclometallated mononuclear complex of the type Rh(CO)2(bBzlH2bzH)Cl. The complexes are characterised by 1H, 13C NMR, IR, Far-IR, electronic and FAB-mass spectral studies. © Elsevier Science Ltd

Complexes of osmium with tertiary arsines and carbonmonoxide

Osmium halides (Cl and Br) react with monotertiary arsines Ph2RAs (R=Me, Et, Pr and Bu) in alcoholic medium to give paramagnetic octahedral complexes of the type OsX3L3 (X=Cl, Br; L=Ph2RAs) which further react with carbonmonoxide to give dihalo dicarbonyl complexes of osmium(II) of the type OsX2 (CO)2 L2. Similarly, osmium halides react with tertiary arsines in the presence of formaldehyde to give monocarbonyl complexes of osmium(II) of the type OsX2 (CO)L3. Structures have been assigned to all these compounds on the basis of IR and NMR studies. © 1980 Indian Academy of Sciences

Carbonyl and hydridocarbonyl complexes of rhodium

New carbonyl complexes of Rh of the type RhX(CO)​L2 [X = Br and L is P(p-​CH3C6H4)​3 or AsPh3; and X = Cl, Br or I and L is AsMePh2 or AsEtPh2] were prepd. The Rh(I) bromocarbonyl compds. add on HBr to form compds. of the type RhHBr2(CO)​L2. These hydridocarbonyls though stable in the solid state dissoc. in soln. to give the reactants. The Rh(I) chlorocarbonyls, on the other hand, show very little tendency to add on HCl. The Rh(I) carbonyl compds. easily add on the corresponding halogens to give Rh(III) compds. of the type RhX3(CO)​L2. Possible structures for the hydridocarbonyls and the trihalocarbonyls were discussed

NMR and infrared spectral studies of some hydrides of iridium

The PMR and ir spectra (in C6H6 and CHCl3) of the 2 series (α and β) of hydrides of iridium of the type IrHX2L3 (where X = Cl or Br and L = AsMePh2 or AsEtPh2) were investigated. The hydridic H of an α-​compd. shows a higher chem. shift (30.7-​31.6 τ) in the NMR spectrum when compared to that of the corresponding β-​compd. (25.2-​25.9 τ)​. The νM-​H values of the α-​compds. are higher by 10-​14 cm-​1 in the polar solvent CHCl3 as compared to their values in the non-​polar solvent C6H6. The νM-​H of the β-​compds., on the other hand, do not show any solvent sensitivity. Assignments of configurations for the α and β isomers are given

Complex hydrides of rhodium and iridium with ethyldiphenylarsine

Hydrido complexes of the general formula MHX2(AsEtPh2)​3 and the corresponding trihalo complexes of the type MX3(AsEtPh2)​3, where M = Rh or Ir and X = Cl, Br or I, have been prepd. The hydrido compds. have been obtained in 2 isomeric forms (α and β)​. For the prepn. of the hydrides, hypophosphorous acid, and Zn and halogen acid mixt. have been used as reducing agents. The properties of these hydrides and the trihalo compds. have also been recorded