Reactivity of co-ordinated ligands. Part XVI. The reaction of bicyclo[3.2.1]octa-2,6-diene with dodecacarbonyltriruthenium

Abstract

The complexes C₈H₁₀Ru(CO)₃(1) and C₁₆H₂₀Ru(CO)₃(2) have been prepared from the reaction of bicyclo[3.2.1]octa-2,6-diene (C₈H₁₀) with dodecacarbonyltriruthenium in benzene under reflux. Complex (1) was characterised as (2—4,6-η-bicyclo[3.2.1]octadiene)tricarbonylruthenium on the basis of ¹H n.m.r. spectroscopic data. This complex undergoes hydride-ion abstraction with Ph₃CBF₄ to yield the monocationic complex [(2—4,6,7-η-C₈H₉)Ru(CO)₃]BF₄. Treatment of this complex with NaBH₄ yields the initial complex (1). Two possible mechanisms for the formation of complex (1) have been considered; ¹H n.m.r. data on the complex derived from 2—4,6-η-C₈H₉D suggest that the mechanism involves co-ordination of the diene followed by H migration via the metal rather than a bond-breaking mechanism.