G. Zassinovich

Antineoplastic activity and toxicity of an organometallic complex of ruthenium(II) in comparison with cis-PDD in mice bearing solid malignant neoplasms

The antineoplastic activity of an organometallic complex of ruthenium(II), [cis-RuCl2(DMSO)4]o, has been examined in comparison with that of cis-PDD, using three metastasizing tumors of the mouse: Lewis lung carcinoma, B16 melanoma and MCa mammary carcinoma. [cis-RuCl2(DMSO)4]o significantly reduces primary tumor growth in all the tumors tested, and its activity is similarly pronounced at three different dosages in mice bearing Lewis lung carcinoma. On the contrary, the survival time of animals having i.v. or i.m. tumor implants are only moderately increased, and also in the case of combined treatments with surgery. The antineoplastic activity of cis-PDD appears to be less pronounced than that of [cis-RuCl2(DMSO)4]o, and is limited to mice bearing B16 melanoma, which, among the three tumors used, appears to be naturally more responsive to cis-PDD and [cis-RuCl2(DMSO)4]o. The use of [cis-RuCl2(DMSO)4]o appears advantageous over that of cis-PDD since, unlike cis-PDD, its antineoplastic effects have been obtained at dosages with reduced host toxicity, indicated by the absence of significant hematological toxicity and toxicity for normal proliferating tissues.

Optically active phenanthrolines in asymmetric catalysis. III. Highly efficient enantioselective transfer hydrogenation of acetophenone by chiral rhodium/3-alkyl phenanthroline catalysts.

Abstract The in situ catalysts prepared from [Rh(Diol)Cl]2 (Diol = 1,5-Hexadiene or 1,5-Cyclooctadiene) and 3-alkylphenanthrolines display an extremely high catalytic activity in the transfer hydrogenation of acetophenone. Turn over rates up to 10,000 cycles-per-hour (c/h) have been recorded in 2-propanol solution at 83°C in the presence of KOH as a promoter. Asymmetric inductions up to 655 e.e. are obtained with the ligand 3c bearing a chiral trimethylpropyl substituent. This is an extraordinarily high value in view of the long distance existing between the chiral carbon atom and the reactive site of the catalyst. Experimental evidences suggest that in the asymmetric process the most active and stereoselective catalytic species might be a rhodium hydride complex containing two phenanthroline ligands in a chiral C2 array.

Complexes of rhodium(I) and iridium(I) with 2,2′-bipyridine and similar ligands as hydrogenation catalysts

Abstract Complexes of the type [Rh(Chel)ED]PF6 (Chel = 2,2-bipyridine; 1,10-phenanthroline; methyl substituted phenanthrolines; ED = 1,5-hexadiene; X- = PF6-; B(Ph)4) have been synthesized. They are good catalysts for hydrogenation of ketones in an alkaline medium even at atmospheric pressure and room temperature. In the presence of an excess of Chel (Chel : Rh = 2), they also catalyse the selective reduction of C=O groups in the presence of C=C bonds.

Antitumor effects of rhodium(I), iridium(I) and ruthenium(II) complexes in comparison with cis-dichlorodiammino platinum(II) in mice bearing Lewis lung carcinoma

The effects of square planar rhodium, [RhacacCOD]o and iridium, [IracacCOD]o complexes and of octahedral ruthenium, [cis-RuCl2 (DMSO)4]o complex have been examined in comparison with cis-dichlorodiammino platinum(II) (cis-PDD). The toxicity in BDF1 mice varies widely and decreasing LD50-values, ranging from 0.94 mg/kg to 1000 mg/kg, have been obtained for cis-PDD, [RhacacCOD]o, [IracacCOD]o and [cis-RuCl2(DMSO)4]o, respectively. All the tested complexes similarly inhibit the growth of subcutaneous Lewis lung carcinoma and the development of spontaneous as well as of artificial metastases, with the exception of [IracacCOD]o which is inactive on metastases. The antitumor activity of [RhacacCOD]o and [cis-RuCl2(DMSO)4]o appears interesting, since it is of the same magnitude as that of cis-PDD, considering also that they were found to be only marginally nephrotoxic.

Enantioselective hydrogen transfer reactions from propan-2-ol to ketones catalyzed by pentacoordinate iridium(I) complexes with chiral Schiff bases

Abstract Some diastereoisomeric pentacoordinate complexes of the type [Ir(COD)-(NNR ★ )I] (COD = cis , cis -1,5-cyclooctadiene; NNR ★ = 2-pyridinal-1-phenylethylimine (PPEI) (I), 2-acetylpyridine-1-phenylethylimine (APPEI) (II)) have been synthesized. The complexes are active and selective catalysts for asymmetric hydrogen transfer from propan-2-ol to prochiral ketones. Optical yields of up to 84% have been obtained in the reduction of t-butyl phenyl ketone. The structure and absolute configuration of complexes I and II were determined by X-ray diffraction.

Complexes of rhodium(I) with 2,2′-bipyridine and 1,10-phenanthroline : Synthesis and reactions of cationic carbonyl derivatives

The synthesis and reactions of RhI carbonyl complexes of the type [RhChel(CO)2]+ and RhChelCOX (Chel = Bipy, Phen; X = Cl, Br, I) are described. Coordinative, oxidative-addition, and substitution reactions are compared with those of the corresponding IrI derivatives.

Diolefinic complexes of rhodium(I) and iridium(I) with nitrogen-containing ligands

Abstract The synthesis and the substitution and oxidation reactions of the series of Rh1 and Ir1 complexes M(LL)(B)Cl, [M(LL)(B)2]X and [M(LL)(Chel)]X (LL = cis, cis-cycloocta-1,5-diene, cycloocta-1,3,5,7-tetraene, bicyclo[2.2.1]-hepta-2,5-diene; Chel = 8-aminoquinoline, phenylendiamine, dipyridylketone, substituted phenanthrolines; X = Cl−, PF6−, ClO4−) are described. The use of these complexes as anti-tumour agents is considered.

Transfer of hydrogen from alcohols to ketones catalyzed by iridium complexes with 2,2′-bipyridine, 1,10-phenanthroline, and their derivatives

Abstract Complexes of the type Ir(I)chelCODCl (chel = bipy; 4,4′-Me 2 bipy; phen; 4,7-Me 2 phen; 3,4,7,8-Me 4 phen; 4,7-Ph 2 Phen; COD = 1,5-cyclooctadiene) catalyze the hydrogen transfer from alcohols to ketones. The dependence of the rate and the stereoselectivity on the complex, the concentrations of the water and KOH is studied in detail, and a reaction mechanism is proposed. The most active of the above complexes is the 3,4,7,8-Me 4 phen derivative, which gaves turnovers of up to 1150 cycles/min and is still efficient at 4 X 10 −6 M concentration. Furthermore it favours the formation of the trans alcohol in the reduction of the t-butylcyclohexanone with high stereoselectivity.

Selective hydrogenation of unsaturated ketones by rhodium(I) complexes containing 2,2′-bipyridine ligand

Abstract The selective homogeneous reduction of CO groups in the presence of CC bonds with [Rh(Bipy)S 2 ] + or [Rh(Bipy) 2 ] + as catalyst was studied. Stereochemical features of the hydrogenation of substituted cyclohexanones with the two complexes are also reported.

Complexes of iridium(I) with 2,2′-bipyridine and 1,10-phenanthroline: Synthesis and reactions of cationic complexes with diolefins

Abstract The synthesis and reactions of IrI complexes of the type [IrChel(L—L)]+ (Chel = Bipy or Phen; L—L = cyclooctadiene or 2,5-norbornadiene) are described. Coordinative- and oxidative-addition, and substitution reactions are compared with those of the corresponding RhI derivatives.