The protonation of ruthenium- and rhodium-bridged carboxylates and their use as homogeneous hydrogenation catalysts for unsaturated substances

Abstract

The protonation of rhodium(l1) acetate by non-complexing non-oxidising acids such as fluoroboric acid gives the green rhodium(l1) cation Rh24+. The interaction with triphenylphosphine and carbon monoxide lead to the complexes R h (P Ph,) 3B F, and R h (CO) (P Ph,) 3B F, .The new ruthenium(l1) acetate Ru,(OCOMe), and its adducts with triphenylphosphine and pyridine have been characterised.The methanolic fluoroboric acid solutions of Rhrl and RuIr acetates and of Ru,(OAc),CI, in the presence of triphenylphosphine, are active catalysts for the homogeneous hydrogenation of alkenes, alkynes, and other unsaturated substances.

Propriedades e aplicações de clusters trinucleares de carboxilatos de rutênio

“…A primeira evidência de que os clusters apresentam atividade catalítica veio dos estudos de Wilkinson e colaboradores 73 , os quais verificaram que uma solução metanólica do cluster contendo trifenilfosfina e ácido fluorobórico, na presença de H 2 , era capaz de hidrogenar alcenos, alcinos e outras substân-cias insaturadas. Estudos posteriores 74 2+ .…”

Intramolekulare Cycloadditionen mit Isobenzofuranen, IX. Synthese eines Pyrano[3,2-c]carbazols / Intramolecular Cycloadditions with Isobenzofurans, IX. Synthesis of a Pyrano[3,2-c]carbazol

“…intram olekular abgefangen. Als Ausgangs m aterial diente der bekannte [15], aus N-M ethyl-N-phenylhydrazin und Zitronensäuredimethyl-ester über das Hydrazon 1 (tautomere Formen: 2, 3; zur Struktur s. Teil D.) nach Fischer [5] zugäng liche Dimethylester 4 a. W urde der daraus herge stellte Diazoester 4 b mit D irhodium tetraacetat (CH2)n co2r2 C, a,b a: X=H; b: X=N [16] in 1,2-Dichlorethan in Gegenwart von N-Phenylmaleinimid zersetzt, ließ sich nur 4 c in einer Ausbeute von 10% isolieren; mit Kupferhexafluoracetylacetonat (Cu(acacF6)2) [17] in Toluol und dem gleichen Abfangreagens wird 62% des Pyrroloindols 6 erhalten. Die Abfangreaktion mit Acetylendicarbonsäuredimethylester nimmt einen un erwarteten Verlauf.…”

Tetrakis(μ-benzoato-κ2O:O′)bis[(piperidine-κN)rhodium]

“…A procedure analogous to that for the pyridine adduct has been applied (Legzdins et al, 1970). A stirred solution of rhodium trichloride trihydrate (1 g, 0.0038 mol) in methanol (125 ml) was treated with solid benzoic acid (12 g, 0.098 mol), solid sodium benzoate (5 g, 0.0035 mol) and with piperidine (8.515 g, 0.1 mol).…”