Umesh Agarwala

Mixed complexes of ruthenium(III) and ruthenium(II) with triphenylphosphine or triphenylarsine and other ligands

Abstract The reactions of [RuCl3(AsPh3)3] with ligands containing nitrogen (ammonia, hydrazines, amine and thiocyanate) and oxygen (carboxylates) and the reactions of β-diketones (acetylacetone, dibenzoylmethane and benzoylacetone) with [RuCl2(PPh3)2]n and [RuCl2(AsPh3)2]2 have been studied. Apart from this, a new Ru(III) complex, [RuBr3(AsPh3)3] has also been synthesized. The compounds obtained have been characterised by analyses, conductivity and magnetic measurements, molecular weight and spectral studies (IR and visible). An equilibrium between hexacoordinated and pentacoordinated species is suggested on the basis of electronic spectral studies.

Vibrational spectra of xanthate complexes

Abstract Vibrational spectra of xanthates have been studied and potential constants are determined by Wilsons GF matrix method using Urey-Bradely force field. The empirical assignments made by earlier workers are compared with those of the normal coordinate analysis. Regions of four bands characteristic of COCS 2 group have been identified.

Complexing behaviour of 1,3,4-thiadiazole-2-thiol-5-amino—I: Complexes of Fe(II), Co(II), Ru(III), Ru(II), Rh(III), Pd(IV), Ir(III) and Pt(IV)

Abstract Complexes of Fe(II), Co(II), Ru(III), Ru(II), Rh(III), Pd(IV), Ir(III) and Pt(IV) with 1,3,4-thiadiazole-2-thiol-5-amino, have been prepared and characterised on the basis of chemical analyses, infrared and visible spectral and magnetic susceptibility data; crystal field parameters are calculated and probable structures assigned. The ligand acts as bidentate in all the complexes.

Triphenyl arsine and phosphine complexes of ruthenium(II) and their reactions with pyridine

Abstract A new complex of ruthenium(II) with triphenylarsine [Ru(AsPh3)2Cl2]2 has been prepared. Magnetic, spectral (visible, i.r.), X-ray powder diffraction, and various chemical and physical studies have been made on [Ru(AsPh3)2Cl2]2 and Ru(PPh3)2Cl2 and structures have been assigned. [Ru(AsPh3)2 Cl2]2 and Ru(PPh3)2Cl2 have been reacted with pyridine and Ru(PPh3)(Py)3Cl2, Ru(PPh3)2(Py)2Cl2 and Ru(Py)4Cl2 have been obtained. Structures have been assigned on the basis of magnetic, spectral (visible, i.r.) and other physical studies.

Cyclopentadienyl ruthenium complexes. Part I. Reactivity of some η5-cyclopentadienylbistriphenylphosphineruthenium(II) complexes with N-donor heterocyclic ligands

Abstract Reactions of η 5 -cyclopentadienylruthenium complexes of the type [Ru(η 5 -C 5 H 5 )(PPh 3 ) 2 X] (where X = Cl, Br, I, H, CN, NCS or SnCl 3 ) with N-donor ligands such as pyridine picolines, 2,2′-bipyridine and 1,10-phenanthroline have been described for the first time. The reactions afforded cationic and neutral complexes which were characterised by elemental microanalyses, TLC, magnetic measurements, electronic, IR and 1 H NMR spectral data. The α-picoline did not give stable, isolable complexes and [Ru(η 5 -C 5 H 5 )(PPh 3 ) 2 H] failed to undergo ligand displacement reactions.

Reactions of Ru(PPh3)2Cl2 and [Ru(AsPh3)2Cl2]2 with various donor molecules

Abstract Ru(PPh3)2Cl2 and [Ru(AsPh3)2Cl2]2 have been reacted with aniline, o-chloroniline, o-toluidine, quinoline, 2-methylpyridine, 2-aminopyridine, N,N′-bipyridyl, diethylamine, triethylamine, carbon disulfide and acetonitrile. New complexes, obtained in these reactions have been characterized and structures have been assigned on the basis of magnetic, spectral (visible, i.r.) and other physical studies.

Mixed complexes of Ru(III) with bromotropolonato ion

Abstract Some new mixed ligand complexes of Ru(III) with bromotropolone, halide and triphenylphosphine or triphenylarsine as ligands have been synthesized and characterized. Their magnetic susceptibilities, EPR and and electronic spectra are reported. The results are discussed in terms of ligand field theory for low spin d 5 systems and the stereochemistry of the complexes.

Syntheses and characterization of [Ru(η5-C5H5) (AsPh3)(L)X] and [Ru(η5-C5H5)(AsPh3)(L)(MeCN)]+mY− (L = PPh3 or AsPh3; X = F, Cl, Br, I, CN, H or SnCl3; Y = HgCl3, Zn2Cl6 or BPh4; m = 1 or 2)

Abstract The syntheses of the complexes [(η5-C5H5)Ru(AsPh3)(L)X] (L = PPh3 or AsPh3; X = Cl, F, Br, I, H, CN or SnCl3) and [(η5-C5H5)Ru(AsPh3)(L)(MeCN)]+Y− (Y = HgCl3, BPh4 or Zn2Cl6) are described. They were characterized by elemental analyses, IR, UV and visible, PMR spectroscopy, X-ray powder diffraction, and mass spectral studies.

Complexing behaviour of 2-thioorotic acid complexes of Ni(II), Pd(II), Pt(II) and Rh(I)

Abstract Complexes of 2-thioorotic acid have been prepared with Ni(II), Pd(II), Pt(II) and Rh(I). The complexes were characterised by chemical analyses, IR and visible spectra and magnetic susceptibility data. Ligand field parameters have been calculated. Tentative structures have been proposed for these complexes.

Transition metal complexes of 1-substituted tetrazoline-5-thiones

Abstract Transition metal (Ru2+, Ru3+, Rh2+, Pt2+, Pt4+) complexes of a number of 1-substituted tetrazoline-5-thiones have been prepared. It has been proposed from conductivity and i.r. studies that the Pt2+ and Rh2+ (anhydrous) complexes are square planar and the rest of the transition metals form octahedral complexes. However, (RhL2)2 complexes have been found to be diamagnetic indicating the formation of dimeric Rh(II) complexes which with pyridine and water form adducts, (RhL2)2.2Py and (RhL2)2.2H2O, respectively, having octahedral structures. It has also been shown that there are two Pt4+ complexes, red and yellow. The red complex exists in equilibrium with the yellow complex in chloroform, dioxane, acetone.