Synthesis, characterisation and electrochemical analysis of a bis(ferrocenyl) vinyl allyl ether-substituted triosmium cluster
Abstract
From the reaction of [Os3(CO)10(MeCN)2] with ethynylferrocene was isolated the known cluster [Os3(CO)10{(C5H5)FeC5H4CCH}]1; in addition the bis(ferrocenyl)-substituted triosmium cluster [Os3(CO)9{[(C5H5)FeC5H4CCH]2CO}]2 was obtained in reasonable yield. Both 1H and 13C-{1H} NMR studies of 2 indicate that the ferrocenyl groups are inequivalent. A single-crystal X-ray analysis of 2 showed that on co-ordination to the triosmium cluster the two ethynylferrocene groups have been linked via a metal carbonyl to give a composite ligand that may be described as a 2,6-bis(ferrocenyl) vinyl allyl ether. An electrochemical analysis of the compounds (C5H5)FeC5H4CCH, 1 and 2 reveals reversible one-electron oxidations attributable to the ferrocenyl moiety, with the two well separated redox processes found in 2 indicating inequivalent ferrocenyl sites. In addition, irreversible two-electron cluster-based oxidation processes were observed for 1 and 2.