6533b7d9fe1ef96bd126bfe2

RESEARCH PRODUCT

The fluxional behaviour of η6(bicyclo[6.2.0]deca-2,4,6-triene) hexacarbonyl diruthenium (Ru-Ru) by 1H and 13C NMR techniques

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Abstract The variable temperature 1 H NMR spectra of [Ru 2 (CO) 6 η 6 -C 10 H 12 )] (C 10 H 12 = bicyclo [6.2.0]-deca-2,4,6-triene) shows that this molecule undergoes the fluxional behaviour previously reported for [M 2 (CO) 6 (η 6 -polyolefin)] complexes (M = Fe, Ru) which have in the solid an asymmetric skew-type structure. The use of 13 C NMR techniques, employed for the first time for a diruthenium complex of the above type, allows a comparison of the mechanism of the fluxional process with that of the diiron analog. Although the observed line shape changes of the carbonyl resonances in the two complexes are somewhat different the process are basically the same. In the case of the diruthenium complex, however, the simple twitching process, the local scrambling of the carbonyl groups on the allyl bound ruthenium atom, and the local scrambling on the other ruthenium atom, are all well separated and allow a direct proof of the correctness of the predicted changes. The activation energies of the three processes have a higher value than those of the diiron analog and this appears to be a general trend.