Sl. Ingham et al., ISOMER DIFFERENTIATION BY TRI-OSMIUM CLUSTER COMPLEXATION OF SUBSTITUTED 1,3-CYCLOHEXADIENES, Journal of organometallic chemistry, 531(1-2), 1997, pp. 237-242
A series of methyl- and dimethyl-substituted 1,3-cyclohexadienes have
been prepared from their aromatic analogues via Birch reduction and su
bsequent isomerisation with Fe(CO)(3) fragments. These ligands were re
acted with [Os-3(CO)(10)(CH3CN)(2)] to form tri-osmium decacarbonyl cl
uster compounds containing the eta(4)-coordinated substituted 1,3-cycl
ohexadienes. The various isomers of the substituted dienes show a dram
atic difference in their reactivity towards the tri-osmium cluster and
it is likely that this is due to the steric interactions between the
methyl substituents and the cluster framework, with this effect being
more marked for the di-substituted ligands.