A new synthetic method for the preparation of cyclo-olefin ruthenium complexes

Abstract

Hydrated ruthenium trichloride reacts with cyclohexa-1,3-diene and cyclo-octa-1,5-diene, in the presence of metallic zinc, to give the ruthenium(0) compounds 1–6-η-benzene (1–4-η-cyclohexa-1,3-diene)ruthenium, (1), and (1–2 : 5–6-η-cyclo-octa-1,5-dinee)(1–6-η-cyclo-octa-1,3,5-triene)ruthenium, (2), respectively. The analogous reaction with cyclo-octa-1,3-diene, cyclohepta-1,3-diene, and cyclopentadiene leads to the isolation of the corresponding dienyl complexes bis(1–5-η-cyclo-octadienyl)ruthenium, (3), bis(1–5-η-cycloheptadienyl)ruthenium, (4), and ruthenocene, (5). Complex (3) is best prepared by heating (2) in hydrocarbon solvents at ca. 100 °C.