Decomposition of organometallic precursor tricarbonyl(trimethylenemethane)ruthenium Ru(C4H6)(CO)3+/0 in the gas phase investigated by thermal desorption spectrometry†
Abstract
Thermal decomposition of an organometallic precursor Ru(C4H6)(CO)3+/0 was observed using gas-phase thermal desorption spectrometry. It was found that the CO ligands were readily released, forming Ru(C4H6)+ at 600 K. Then, Ru(C4H4)+ and Ru(C2H2)+ were produced as a result of sequential H2 and C2H2 release above 800 K. The activation energies of the ligand losses were estimated from the temperature dependences, and were consistent with the available internal energies obtained by DFT calculations. Based on experimental and computational results, Ru(C4H4)+ was identified as a ruthenium complex with unsubstituted cyclobutadiene, [η4-(C4H4)Ru]+. For the thermal decomposition of neutral Ru(C4H6)(CO)3, the appearance of photoionized Ru(C4H6)(CO) is evidence of CO loss from Ru(C4H6)(CO)2 at 740 K. The decomposition further proceeds above 800 K, forming Ru(C4H6).