Bimetallic complexes with ruthenium and tantalocene moieties: Synthesis and use in a catalytic cyclopropanation reaction

Abstract

The reaction of the tantalocene dichloride monophosphines ( 1– 2) with the binuclear complex [( p-cymene)RuCl 2] 2 gives the heterobimetallic compounds ( p-cymene)[(η 5-C 5H 5)(μ-η 5:η 1-C 5H 4(CH 2) 2PR 2)TaCl 2]RuCl 2 ( 3– 4). The air oxidation of these bimetallic species 3– 4, leads to the cationic hydroxo tantalum ruthenium derivatives 5– 6. The last ones are easily deprotonated by a base to afford the oxo analogues 7– 8. A preliminary assessment in catalytic cyclopropanation of styrene with tantalum ruthenium bimetallic complexes 3– 8 as precatalysts revealed a cooperative effect with a subtle role of the early metal fragment.