New Water-Soluble Diamine Complexes as Catalysts for the Hydrogenation of Ketones Under Hydrogen Pressure

Abstract

New water‐soluble rhodium and iridium complexes of 2,2′‐bipyridines, functionalized with PO3Na2 groups, show very good catalytic activities in the reduction of various substituted acetophenones under hydrogen pressure in basic aqueous media. No significant loss of catalyst activity is observed after one use.

Catalytic Reduction of Acetone by [(bpy)Rh]+: A Theoretical Mechanistic Investigation and Insight into Cooperativity Effects in This System

“…Recently, Töllner et al reported on the solution and monolayer hydrogenation of acetone to 2-propanol by the complex (4,4‘-dialkyl-2,2‘-bipyridine)rhodium(hexadiene) hexafluorophosphate (alkyl = methyl or heptadecyl). The solution reactivity of similar complexes was earlier reported by Mestroni et al, and more recently by, for example, Pénicaud et al In an acetone solution (alkyl = methyl), the complex shows a low activity of 500 turnover numbers (TON) after 48 h and little selectivity between acetone and butanone. When, however, a monolayer, specifically a Langmuir−Blodgett film, is prepared from the complex (alkyl = heptadecyl), the reactivity changes dramatically, and in an aqueous acetone solution over 50 000 TON are obtained in 48 h. Moreover, the catalyst becomes selective to acetone and does not reduce butanone at all.…”

Water-soluble carbene complexes as catalysts for the hydrogenation of acetophenone under hydrogen pressure

“…Based on the commonly accepted mechanism together with observations made in the literature by Bujoli et al [59] and Zhang et al [61] (see Scheme 6), the main role of the added base appears to be deprotonation of the intermediate A, while water can protonate the alkoxide ligand. A is obtained from the insertion of a ketone into one of the M-H bonds.…”

“…The suspension was stirred at room temperature for another 24 2.4. General procedure for hydrogenation [59] In a Schlenk tube 0.06 mmol of ligand (1, 2) and 0.96 ml of 1 M aqueous sodium hydroxide solution was added to 10 ml of water under argon and the mixture was degassed. After complete dissolution of the ligand, 0.03 mmol of metal precursor (Rh (III) acetate, [RuCl 2 (p-cymene)] 2 ) was added.…”

Platonic Relationships in Metal Phosphonate Chemistry: Ionic Metal Phosphonates

“…This procedure is an adaptation of a reduction protocol employed for the synthesis of 4-(diethoxyphosphoryl)aniline [26].…”