Decomposition studies of triruthenium dodecacarbonyl and triosmium dodecacarbonyl

The thermal behaviour of Ru3(CO)12 and Os3(CO)12 have been investigated by thermogravimetry, in argon, nitrogen and air dynamic atmosphere and by DTA and DSC in argon. Meaningful differences were observed between the two complexes: while Ru3(CO)12 in argon and nitrogen atmosphere decomposes to metallic ruthenium and carbon monoxide, Os3(CO)12 sublimates completely before decomposition and a condensation of the vapour was observed on the cold wall of the quartz furnace tube of the TG apparatus. Both the complexes ignite in air dynamic atmosphere but only Ru3(CO)12 shows a residue at the end of the experiment. The melting heats and entropies, the decomposition heats were evaluated and found to be for Ru3(CO)12: 10.40 kcal mol−1, 24.03 cal deg−1 mol−1, 89.45 kcal mol−1 and for Os3(CO)12: 10.70 kcal mol−1, 21.37 cal deg−1 mol−1, 70.5 kcal mol−1