Aj. Arce et al., Facile changes in bonding modes of azulene in di- and triruthenium clusters upon interaction with CO, ORGANOMETAL, 20(2), 2001, pp. 359-362
Carbonylation of the known cluster [Ru-3 (CO)(6)(mu -CO)(mu (3)-eta (5):eta
(3):eta (3)-C10H8)] (1) gives the metastable trinuclear derivative [Ru-3(C
O)(8)(mu (3)-eta (5):eta (2):eta (1)-C10H8)] (2). On further carboxylation
of 1 the stable product [Ru-2(CO)(5)(mu (2)-eta (5):eta (3)-C10H8] (3) is o
btained. X-ray diffraction studies and full spectroscopic assignment of 3 s
how that the azulene ligand is bonded through a pi -Cp to one metal and via
a pi -allyl moiety to the other. Compound 3 reacts reversibly with CO to y
ield, [Ru-2(CO)(6)(mu (2)-eta (5):eta (1)-C10H8] (4), which maintains the p
i -Cp bond while the heptadienyl ring contributes to the bonding only throu
gh one sigma -C-Ru interaction.